UNESCO scuba divers have discovered a new coral reef in the depths of Tahiti’s coastline.
Most of the news regarding coral reefs we’ve heard recently revolves around bleachings — deadly events that take place when waters get too hot for corals to survive. Amid this backdrop, we get a rare piece of good news: divers from the United Nations Educational, Scientific and Cultural Organization (UNESCO) report discovering a new, massive reef off the coast of Tahiti, the largest island in French Polynesia, South Pacific.
The reef is composed of rose-shaped corals, untouched by humans so far, and in surprisingly good health given the global plight of coral reefs.
The reef, which remains unnamed so far, measures around 1.9 miles (3 kilometers) in length and between 98 to 213 feet (30 to 65 meters) across. It formed at a depth of between 100 and 180 feet (31 to 55 meters), unusually deep for a coral reef in the tropics; they are usually found in shallow water, less than 82 feet (25 meters) from the surface.
Researchers believe that this depth helped insulate the reef from the brunt of climate-change-induced effects.
An encrusting plate coral species, Pachyseris speciosa, is the main dweller of the reef. It forms rose-like groupings that can reach up to 6.5 feet (2 meters) wide. The reef was discovered by seafloor explorers of the Ocean 1 project in November 2021.
“It was magical to witness giant, beautiful rose corals which stretch for as far as the eye can see,” Alexis Rosenfeld, an underwater photographer and founder of the Ocean project, which is jointly run by UNESCO, said in a statement. “It was like a work of art.”
The new reef lies close to the upper limit of the mesophotic zone. Corals in this zone receive less sunlight than those in shallower reefs and, to make up for this lack of light, corals like P. speciosa grow wide and flat to maximize their surface area and enable them to capture more light.
Reefs at this depth have historically been very hard to study, as unprotected divers cannot operate here for long due to a variety of reasons. At the same time, this zone is too shallow for the use of remotely operated vehicles (ROVs), according to NOAA. Novel developments, however, such as the use of air-helium mixes to prevent hallucinations and decompression sickness, mean that divers were able to explore these regions for longer periods of time. Better underwater camera equipment also allows them to capture more data faster than ever before, the statement adds, making the mesophotic zone fully explorable for the first time in history.
With the help of such advancements, the team carried out around 200 total diving hours on the reef, allowing them to map it out in great detail and even observe the spawning of corals.
This discovery is particularly exciting as coral reefs are one of the most at-risk ecosystems on the planet. Climate change, chemical and plastic pollution, sediment run-off, overfishing, explosive fishing (using dynamite), and tourism are all affecting them. In total, 237 species of coral are listed as threatened with extinction on the International Union for the Conservation of Nature (IUCN) Red List to date.
Climate change is the main driver of extinction among coral reefs, as it raises sea-surface temperatures and increases the acidity levels of the oceans. This combination of factors causes coral bleaching, a process through which heat-stressed corals expel their symbiotic, photosynthetic algae, the same organisms that supply them with energy. This process, often repeated at short intervals due to warmer climates, is very usually fatal for coral colonies. Roughly 75% of the world’s reefs experienced some degree of bleaching between 2014 and 2017.
The newly-found reef seems unaffected by climate change so far.
“The discovery of this reef in such a pristine condition is good news and can inspire future conservation,” Laetitia Hedouin, a coral expert at the French National Center for Scientific Research, who was involved with the project, said in the statement. “We think that deeper reefs may be better protected from global warming”.
The findings could suggest that mesophotic reefs may have a vital role to play as backups for shallow-water reefs, which are struggling to survive due to bleaching events. They can also provide new homes for species that rely on those reefs, such as fish and crustaceans, when shallow-water reefs are destroyed.
Baleen whales eat a lot more food than previously assumed: three times as much, to be exact, according to new research. The findings are not meant to shame these animals into going on a diet. Rather, they shed light on the key ecological role whales play in the ocean.
The sheer size and appetite of whales make them important players in the ocean. In particular, they serve as key drivers of nutrient recycling in the ocean. They consume vast amounts of food, releasing important nutrients back into the water following digestion. A new paper refines our understanding of just how much food whales as a group can consume, and take a look at the ecological implications of the decline in whale numbers since the onset of the 20th century.
“While it may just seem like a fun trivia fact, knowing how much whales eat is an important aspect of ecosystem function and management,” Matthew Scott Savoca, a Postdoctoral Research Fellow at Stanford University and corresponding author of the paper, told ZME Science. “If we want to protect whales and make sure they are thriving in modern oceans, then knowing how much food they need to survive and reproduce is critical.”
“There are implicit benefits of having whales on the planet — isn’t it cool to think that we live at a time when we’re alongside the largest animal in the history of life on Earth? Beyond that, whales have direct value as carbon sinks (e.g., sequestering carbon in their bodies and exporting it to the deep sea when they die and sink – which we did not discuss in this study). In addition, whale watching is a multi-billion dollar per year global business that is expanding as whales are recovering.”
Previous estimates of just how much whales eat were built upon data obtained from metabolic models or direct analysis of the stomach contents of whale carcasses. Such data can give us a ballpark figure but, according to the new paper, they are quite inaccurate.
Savoca and his colleagues directly measured the feeding rates of 321 baleen whales across seven species in the Atlantic, Pacific, and Southern oceans. They tracked foraging behavior and estimated prey consumption by tracking the whales using GPS tags. Location data was then combined with sonar measurements of prey density, of the quantity of prey consumed per feeding, and current estimates of how much each species typically eats per feeding event.
Overall, the results suggest that we’ve underestimated how much food baleen whales ingest by a factor of three. On average, these animals consume between 5% and 30% of their body weight per day, depending on species, across all the investigated regions. In total, blue, fin, and humpback whales in the California Current Ecosystem consume over two million tonnes of krill every year per species.
The study also puts into perspective just how massive an impact whaling and other stressors have placed on whales and, by extension, on the ecosystems they inhabit. Prior to the 20th century, the team estimates, whales in the Southern Ocean were consuming around 430 million tonnes of Antarctic krill per year. This figure is twice the total estimated biomass of Antarctic krill today.
Whales, the paper explains, serve an important ecological role as nutrient recyclers, tying into that last tidbit of information. Prior to the 20th century, before whales were hunted in meaningful numbers, these animals consumed a massive amount of biomass, releasing much of the nutrients in their food back into the ocean as waste. This, in turn, allowed for much greater productivity in the ocean (as they made large quantities of nutrients freely-available for krill and other phytoplankton to consume).
“In brief, if whales eat more than we thought, then they also recycle more nutrients (i.e., poop) than we thought. If that is the case then limiting nutrients may have been used more effectively and efficiently in a system that had many more whales,” Savoca said for ZME Science. “It’s not that these whales add more iron (or other nutrients) to the system, they just [move] it from within the bodies of their prey, to in the seawater itself where it could, in theory, fertilize phytoplankton — the base of all open ocean food webs.”
To put things into perspective, the authors estimate that today, baleen whales in the Southern Ocean recycle around 1,200 tons of iron per year; prior to the 20th century, this figure was likely around 12,000 tons of iron per year. In essence, whaling has led to a 90% decrease in the amount of essential nutrients whales can recycle in their ecosystems.
I asked Savoca whether there is any overlap between the decline in baleen whale populations and the detrimental effects of industrial fishing on today’s ocean ecosystems. Should we expect trouble ahead as we’re removing key nutrient recyclers from one side of the equation, and taking more fish out of the sea on the other?
“You are hitting on a major issue,” he admitted. “We have noticed that oceans have become less productive after removing millions of large whales in the 19th and 20th centuries. The same is true of ongoing industrial fishing. The collapse of predatory fish communities have the same detrimental impacts on marine communities as the wholesale decimation of the whales did.”
“I am not against fishing, but we have to do so as sustainably as possible if we want to maintain essential ocean productivity into the future.”
Whales and their extended family — cetaceans — have been experiencing immense pressures ever since the onset of industrial-scale whaling in the early 20th century. Commercial whaling only slowed down in the 1970s, which is a very, very short time ago from an ecological perspective. This has allowed whales and other cetaceans some much-needed respite, but they are still struggling. Over half of all known cetacean species today are inching towards extinction, 13 of which are listed as “Near Threatened”, “Vulnerable”, “Endangered”, or “Critically Endangered” on the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species. Besides the lingering effects of whaling, this family is still struggling under the combined effects of (chemical and noise) pollution, loss of habitat, loss of prey, climate change, and direct collisions with ships.
Research such as this study and many others before it can raise an alarm that not all is well with the whales. But actually doing something about it hinges on us and governments the world over taking the initiative to protect them. Understanding just how important whales are for the health of our oceans and, through that, for our own well-being and prosperity definitely goes a long way towards spurring us into action.
But Savoca’s conclusion to our email discussion left an impression on me. There is great beauty in natural ecosystems that we’re destroying, oftentimes unaware. Beyond the practical implications of conserving whale species, we have a chance to conserve these for our children and all future generations.
“I remember one day in Monterey Bay when we were surrounded by blue whales (likely over a dozen), each about twice the size of the boat we were on. I will also never forget the sound and scale of the ice in Antarctica,” Savoca wrote for ZME Science.
“My life’s work is devoted to making sure people and animals have these (and ideally ever better) ecosystems of awe and plenty well into the future.”
The paper “Baleen whale prey consumption based on high-resolution foraging measurements” has been published in the journal Nature.
The world’s oceans have a plastic problem. However, a bold new approach from researchers at several institutions says that the same plastic could also be the solution.
The team, with members from Worcester Polytechnic Institute, Woods Hole Oceanographic Institution, and Harvard University, believes that the plastic clogging up our oceans can be used as fuel for ships that work to clean the oceans of plastic. In a new study, they describe the process through which plastic can be converted to ship fuel in order to support such a scheme.
If applied, this approach would allow ships to operate continuously to clean the oceans.
Putting it to good use
“Plastic waste accumulating in the world’s oceans forms massive ‘plastic islands’ in the oceanic gyres. Removing [it] offers an opportunity to restore our oceans to a more pristine state,” the authors explain. “To clean the gyres, ships must collect and store the plastic before transporting it to port, often thousands of kilometers away. Instead, ocean plastic waste can be converted into fuel shipboard, for example, using hydrothermal liquefaction”.
Millions of tons of plastic find their way into the ocean year after year. The smaller fragments disperse, while larger pieces of plastic clump together forming plastic ‘islands’. These tend to end up in ocean gyres, large systems of ocean currents generated by winds and the rotation of the planet that ‘spin’ in place.
Plastic waste poses a very real threat to marine life. As such, efforts to clean up the seas have been repeatedly attempted over time. Ships are sent out to garbage patches where they collect as much plastic as they can hold and bring it back to port for processing. Although this approach works, it’s by no means ideal. Going back and forth between these patches and port areas takes time, fuel, and slows down the efforts overall.
The authors of this study propose using the plastic itself as fuel for the ships and machines used to process the waste. This could have a powerful dual benefit. It would dramatically improve the efficiency of clean-up efforts by slashing downtime, while also being a greener option overall, as it would reduce emissions associated with fuel use (and ships can be very polluting).
Plastic waste can be converted to a type of oil via a process known as hydrothermal liquefaction (HTL), the authors explain. During HTL, plastic is heated to around 300–550 degrees Celsius (572-1022 Fahrenheit) at high pressure — 250 to 300 times the standard atmospheric pressure.
According to their estimates, one ship equipped with an HTL converter could produce enough oil to be self-sustainable (i.e. to keep both the ship and the converter operational). They envision a system where permanent collection booms would be stationed at multiple sites around a large garbage patch and maintain a steady supply of plastic for the ships to convert.
Such an approach is not without its problems. The HTL process itself, as well as the burning of the oil it produces, would obviously release carbon dioxide. That being said, the authors explain that it would still be a lower quantity than what a ship burning conventional fuel would emit during a clean-up mission. There would still be practical constraints on how long a mission could carry on for; the HTL process would produce a relatively small quantity of solid waste that would eventually need to be returned to port, and there’s only so much time a crew’s supplies and sanity can last for on the open seas. However, it would reduce the need for round trips down to once every few months or so, which would also be fueled by the oil produced by the converters.
I personally like the idea of such an approach. It makes practical sense, and I’m sold on the idea of turning a problem into an opportunity or solution. So far the idea is still in its theoretical stage, but it definitely has promise. Fingers crossed that we’ll see it implemented in the not-so-distant future.
The paper “Thermodynamic feasibility of shipboard conversion of marine plastics to blue diesel for self-powered ocean cleanup” has been published in the journal PNAS.
Being a fish was never easy, but a new paper reports that it’s been getting harder over the last 15 years or so. According to the findings, oxygen levels are dropping in the depths of the oceans, forcing fish to move ever closer to the surface.
New research from the University of California – Santa Barbara and the University of South Carolina is warning us that fish are slowly drowning. Changes in ecology, as well as the effects of climate change on seasonal patterns, water temperature, and its gradient over different depths, have been causing deeper layers of the ocean to lose their dissolved oxygen content. This, in turn, is forcing fish to either move closer to the surface, or asphyxiate.
It may seem like a trivial matter, but this shift is causing wide-scale changes in marine ecosystems and could have a very real impact on the health of the ocean as a whole. It also raises important questions for fishery management and conservation efforts, with the authors underscoring the importance of accounting for this shift with policy to avoid further damaging marine ecosystems.
Swimming out of breath
“This study finds that oxygen is declining at all the depths we surveyed: from 50 meters to 350 meters,” said lead author Erin Meyer-Gutbrod, assistant professor at the University of South Carolina, “and so fish seem to be moving up to shallower regions to get to an area where the oxygen is relatively higher.”
The findings are based on 15 years’ worth of recordings, surveys, and measurements. These included measurements of dissolved oxygen in samples of water taken at varying depths, of temperature, salinity, and surveys of the average depth at which certain fish species tend to congregate. A total of 60 different species of fish were encountered often enough during these 15 years to be statistically relevant and included in the study.
Data was collected on a yearly basis, every fall, from 1995 through to 2009. The team focused on three reef features between the Anacapa and Santa Cruz islands in Southern California. These were the Anacapa Passage area, with an average depth of 50m, a seamount known as the “Footprint”, at around 150m, and the “Piggy Bank”, with an average depth of around 300m. During the surveys, the team identified all fish species that came within two meters of the submarine or were visible and within two meters of the seafloor. They also estimated the length of each individual fish.
During this time, they saw depth changes in 23 species. Four of these shifted towards deeper waters, while the other 19 moved towards the surface in response to low oxygen conditions (as shown by analysis of water samples).
The team explains that surface waters tend to be better oxygenated (have higher levels of dissolved oxygen) due to surface motions such as waves continuously mixing gases into the top layer of bodies of water. Over time, as waters mix, this oxygen also finds its way lower along the column of water. However, the team explains that warming climates make for warmer surface waters, which increases the buoyancy of these layers compared to those deeper down, reducing their ability to mix. This process is known as ocean stratification.
In addition to this, warmer water has a lower ability to dissolve and hold oxygen compared to colder water, so there’s less of this gas being mixed into the ocean to begin with.
In the end, this means less oxygen makes it to the bottom layers of water. Although salinity and temperature gradients along the column of water also influence the extent of vertical mixing, the team reports that both remained relatively constant over the study period. In other words, the trend towards lower oxygen levels seen at the study site is primarily driven by climate-associated changes in surface water temperatures. That being said, the other factors can’t be discounted completely either.
“A third of [the 60 fish species’] distributions moved shallower over time,” Meyer-Gutbrod said. “I personally think that’s a remarkable result over such a short time period.”
The team acknowledges that their study only included a relatively small area, but it did include a wide range of depths, which was the ultimate objective of the research. This narrower area actually helps reduce confounding factors, they explain, since it allowed for most conditions (apart from depth) to be constant across all the survey areas.
“Other scientists have used lab experiments to show that fish don’t like low oxygen water,” Meyer-Gutbrod said, “but what nobody’s ever done is just return to the same location year after year to see if there’s actually a change in the distribution of fish stemming from a change in oxygen over time.”
In closing, the authors explain that this trend can have quite severe negative impacts on marine ecosystems, and indirectly, on all life on Earth. Fish are simply forced to move away from their optimal depths, which will eventually result in them being pushed out entirely out of several ecosystems. According to co-author Milton Love, a researcher at UC Santa Barbara’s Marine Science Institute, we could even see a point in which species are forced into depth ranges that they simply cannot survive in.
They also cite previous research showing that many fish species also cannot tolerate high water temperatures, and are migrating towards lower depths. In the end, these factors can leave many species in an impossible situation — where they cannot breathe if too low, and can’t bear the heat if too close to the surface.
In the end, even if we start working to redress climate change right now, meaningful progress will take quite a lot of time. Until then, policymakers need to recognize and react to the pressures faced by fish species and issue regulation that protects them as best as possible, or risk wide-ranging ecological collapse in the world’s oceans.
“If you throw your net in the water and you get a ton of fish — more than you’re used to getting — you may think, ‘Oh, it’s a good year for the fish. Maybe the population is recovering,'” Meyer-Gutbrod said. “But instead, it could be that all the fish are just squished into a tighter area. So you could have fishery regulations changing to increase fish allowances because of this increase in landings.”
The paper “Moving on up: Vertical distribution shifts in rocky reef fish species during climate‐driven decline in dissolved oxygen from 1995 to 2009” has been published in the journal Global Change Biology.
Floating robots could become indispensable in helping us monitor the health of ocean ecosystems and the flow of carbon between the atmosphere and oceans, according to a new study.
Although the microscopic marine plants and animals which make up plankton are the bedrock of ocean ecosystems. While they’re essential for the well-being of everything that swims, they’re also very important for our comfort and well-being, too. Plankton is one of the largest single sources of oxygen on the planet, and it consumes a lot of CO2 to do it. This process is known as marine primary productivity.
Knowing how they’re faring, then, would be a great help. Floating robots can help us out in that regard, according to a new paper.
Floats my boats
“Based on imperfect computer models, we’ve predicted primary production by marine phytoplankton will decrease in a warmer ocean, but we didn’t have a way to make global-scale measurements to verify models. Now we do,” said Monterey Bay Aquarium Research Institute (MBARI) Senior Scientist Ken Johnson, first author of the paper.
Together with former MBARI postdoctoral fellow Mariana Bif, Johnson shows how a fleet of marine robots could completely change our understanding of primary productivity on a global scale. Data from these crafts would allow researchers to more accurately model the flow of carbon between the atmosphere and the ocean, thus improving our understanding of the global carbon cycle.
Furthermore, the duo explains, shifts in phytoplankton productivity can have significant effects on all life on Earth by changing how much carbon oceans absorb, and by altering oceanic food webs. The latter can easily impact human food security, as the oceans are a prime source of food for communities all over the world. In the context of our changing climate, it’s especially important to know with accuracy how much carbon plankton can scrub out of the atmosphere, and what factors influence this quantity.
Part of what makes the ocean such a good carbon sink is that dead organic matter sinks to the bottom. Plankton grows by consuming atmospheric oxygen, and is in turn consumed by other organisms, such as fish. As these eventually die, they sink to the bottom of the sea, where they’re decomposed by bacteria, releasing carbon in the process. However, because this happens at great depths, the carbon is effectively prevented from returning to the atmosphere for very long periods of time. Generally, it seeps into deep-water sediments and stays there for millions of years or more.
That being said, this process is very sensitive to environmental factors such as changes in climate. While we understand that this happens, we’ve not been able to actually monitor how primary productivity is responding to climate change on a global scale, as most of it happens in the depths of the oceans.
“We might expect global primary productivity to change with a warming climate,” explained Johnson. “It might go up in some places, down in others, but we don’t have a good grip on how those will balance.”
“Satellites can be used to make global maps of primary productivity, but the values are based on models and aren’t direct measurements,”
Autonomous robots could help us get the data we need, the study argues. For starters, it’s much easier to build robots that can withstand the humongous pressures of the deep ocean than it is to build equivalent manned submarines. Secondly, robots are mass-producible for relatively little cost. Human crews are expensive and slow to train — they’re also quite limited in availability. Finally, robots can operate for much longer periods of time than human crews, and nobody needs to risk their life in the process.
The authors point to the deployment of Biogeochemical-Argo (BGC-Argo) floats across the globe as a great example of how robots can help monitor primary productivity. These automated floats can measure temperature, salinity, oxygen, pH, chlorophyll, and nutrient content in marine environments, at depths of up to 2,000 meters (6,600 ft). A float can perform its monitoring tasks autonomously, shifting between different depths and supplying live data to researchers onshore. These robots have been deployed in increasing numbers over the past decade, providing reliable — but as of yet, still sparse — measurements of oxygen production across the globe.
Although the data they’ve been feeding us didn’t tell us anything new, it is the first time we’ve been able to quantitatively measure primary productivity directly.
“Oxygen goes up in the day due to photosynthesis, down at night due to respiration—if you can get the daily cycle of oxygen, you have a measurement of primary productivity,” explained Johnson.
In order to confirm that these robots were actually performing their job reliably, the team compared primary productivity estimates computed from the BGC-Argo floats to ship-based sampling data in two regions: the Hawaii Ocean Time-series (HOT) Station and the Bermuda Atlantic Time-series Station (BATS). The data from these two sources matched over several years, proving the reliability of the system.
“We can’t yet say if there is change in ocean primary productivity because our time series is too short,” cautioned Bif. “But it establishes a current baseline from which we might detect future change. We hope that our estimates will be incorporated into models, including those used for satellites, to improve their performance.”
Seeing as we have drones flying about the atmosphere taking pictures of everything and anything, it only makes sense that we’d eventually have some doing the same underwater. I am personally very thrilled to see robots taking on the deepest depths. The ocean is a fascinating place, but I’m also terrified of drowning, so I’ll probably never work up the courage to actually explore it. Hopefully, our automated friends will do the work for us and help us understand what is still a very much unexplored frontier of Earth.
The paper “Constraint on net primary productivity of the global ocean by Argo oxygen measurements” has been published in the journal Nature.
Researchers at the University of Rhode Island’s (URI) Graduate School of Oceanography report that a whole ecosystem of microbes below the sea dines not on sunlight, but on chemicals produced by the natural irradiation of water molecules.
Whole bacterial communities living beneath the sea floor rely on a very curious food source: hydrogen released by irradiated water. This process takes place due to water molecules being exposed to natural radiation, and feeds microbes living just a few meters below the bottom of the open ocean. Far from being a niche feeding strategy, however, the team notes that this radiation-fueled feeding supports one of our planet’s largest ecosystems by volume.
Cooking with radiation
“This work provides an important new perspective on the availability of resources that subsurface microbial communities can use to sustain themselves. This is fundamental to understand life on Earth and to constrain the habitability of other planetary bodies, such as Mars,” said Justine Sauvage, the study’s lead author and a postdoctoral fellow at the University of Gothenburg who conducted the research as a doctoral student at URI.
The process through which ionizing radiation (as opposed to say, visible light) splits the water molecule is known as radiolysis. It’s quite natural and takes place wherever there is water and enough radiation. The authors explain that the seafloor is a particular hotbed of radiolysis, most likely due to minerals in marine sediment acting as catalysts for the process.
Much like radiation in the form of sunlight helps feed plants, and through them most other life on Earth, ionizing radiation also helps feed a lot of mouths. Radiolysis produces elemental hydrogen and oxygen-compounds (oxidants), which serve as food for microbial communities living in the sediment. A few feet below the bottom of the ocean, the team adds, it becomes the primary source of food and energy for these bacteria according to Steven D’Hondt, URI professor of oceanography and a co-author of the study.
“The marine sediment actually amplifies the production of these usable chemicals,” he said. “If you have the same amount of irradiation in pure water and in wet sediment, you get a lot more hydrogen from wet sediment. The sediment makes the production of hydrogen much more effective.”
Exactly why this process seems to be more intense in wet sediment, we don’t yet know. It’s likely the case that some minerals in these deposits can act as semiconductors, “making the process more efficient,” according to D’Hondt.
The discovery was made after a series of experiments carried out at the Rhode Island Nuclear Science Center. The team worked with samples of wet sediment collected from various points in the Pacific and Atlantic Oceans by the Integrated Ocean Drilling Program and other U.S. research vessels. Sauvage put some in vials and then blasted these with radiation. In the end, she compared how much hydrogen was produced in vials with wet sediment to controls (irradiated vials of seawater and distilled water). The presence of sediment increased hydrogen production by as much as 30-fold, the paper explains.
“This study is a unique combination of sophisticated laboratory experiments integrated into a global biological context,” said co-author Arthur Spivack, URI professor of oceanography.
The implications of these findings are applicable both to Earth and other planets. For starters, it gives us a better understanding of where life can thrive and how — even without sunlight and in the presence of radiation. This not only helps us better understand the depths of the oceans, but also gives clues as to where alien life could be found hiding. For example, many of the minerals found on Earth are also present on Mars, so there’s a very high chance that radiolysis could occur on the red planet in areas where liquid water is present. If it takes place at the same rates it does on Earth’s seafloor, it “could potentially sustain life at the same levels that it’s sustained in marine sediment.”
With the Perseverance rover having just landed on Mars on a mission to retrieve samples of rocks and to keep an eye out for potentially-habitable environments, we may not have to wait long before we can check.
At the same time, the authors explain that their findings also have value for the nuclear industry, most notably in the storage of nuclear waste and the management of nuclear accidents.
“If you store nuclear waste in sediment or rock, it may generate hydrogen and oxidants faster than in pure water. That natural catalysis may make those storage systems more corrosive than is generally realized,” D’Hondt says.
Going forward, the team plans to examine how the process takes place in other environments, both on Earth and beyond, with oceanic crust, continental crust, and subsurface Mars being of particular interest to them. In addition to this, they also want to delve deeper into how the subsurface communities that rely on radiolysis for food live, interact, and evolve.
The paper “The contribution of water radiolysis to marine sedimentary life” has been published in the journal Nature Communications.
A new paper reports on the first documented instance of a non-social animal showing self-control in the marshmallow test. They also join humans, chimps, parrots, and crows as the only known species capable of delaying gratification.
The Stanford marshmallow test is an experiment that checks for an individual’s ability to delay gratification. It’s usually performed with young children and involves, surprisingly, a marshmallow (or another type of sweet temptation). The child is told to not eat the treat before the researcher has’ to leave for a short period. If the child can resist the sugary bait by the time the scientist is back, it’s safe to assume that they have ample capacity for self-control and delay gratification.
Both of those traits are relatively reliable indicators of success later in life, as we need self-control to resist distractions and the ability to delay gratification so we can put the work in first. But it also seems to be an indicator of intelligence, since you need some cognitive capacity to understand that giving up some food now is worth a greater reward later on. And now, a new species has passed the test.
The cuttlefish and the marshmallow
“We used an adapted version of the Stanford marshmallow test, where children were given a choice of taking an immediate reward (1 marshmallow) or waiting to earn a delayed but better reward (2 marshmallows),” says lead author Alexandra Schnell of University of Cambridge, UK.
“Cuttlefish in the present study were all able to wait for the better reward and tolerated delays for up to 50-130 seconds, which is comparable to what we see in large-brained vertebrates such as chimpanzees, crows, and parrots.”
The cuttlefish in this study showed that they can wait for a better meal even if it means giving up one that’s right in front of them. This is the first time this link between self-control and intelligence has been underscored in a species other than humans and chimpanzees. The study was carried out at the Marine Biological Laboratory (MBL) at Woods Hole Oceanographic Institution.
Cuttlefish were trained to associate a particular visual cue with a reward, in the form of food. These cues were markings placed on chambers with different foods inside. One marking, for example, meant that the door would open the moment food was placed inside. Another, that there would be a delay before the door would open. One cue was meant to give them more trouble: it meant that even if food was placed in the chamber, and the door opened, there would be an extra wall of plastic preventing them from reaching the reward.
At first, the cuttlefish would attack the rewards immediately. Over time, however, they started learning the rules of each symbol — they would stop approaching the walled-off chambers entirely, for example.
After this, the experiment was restarted but with an extra condition. The researchers would place the animal’s favorite reward in the delay chamber, and a second-best option in the immediately-opening chamber. The control measure put the favorite reward in the “immediate” chamber, but it was also walled-off and marked as such.
“We wanted to see if they were able to exert self-control in a flexible manner depending on the context,” said Dr Schnell.”They could see their preferred food in the unobtainable chamber, but they could never get to it – so they needed to make a decision whether to attempt to, or just take the immediate option.”
They typically waited for the preferred prey if given the option, the team notes, being able to maintain delays of up to 130 seconds in some cases.
As to why cuttlefish have developed this ability is still relatively unclear. For us humans, a very social species, the ability to delay gratification is probably tied to our need to prevent conflict and strengthen bonds inside the group. Waiting for your partner or children to eat first, before you do as well is a good example of how such behavior can benefit us socially and the species as a whole. It could also be tied to our history as tool-makers and hunters (we had to wait for the tools to be ready and the animals to show up before we ate). Birds likely developed it for similar reasons.
Cuttlefish, however, do not share these traits. They’re smart but not very social, and they don’t build tools (as far as we know). The authors believe that their ability to delay gratification is tied to their ability — and need — to use camouflage. Motion is very easy to spot, so an impatient cuttlefish risks getting chewed on, no matter how good their camouflage is.
“Cuttlefish spend most of their time camouflaging, sitting and waiting, punctuated by brief periods of foraging,” Schnell says. “They break camouflage when they forage, so they are exposed to every predator in the ocean that wants to eat them.”
“We speculate that delayed gratification may have evolved as a byproduct of this, so the cuttlefish can optimize foraging by waiting to choose better quality food.”
The findings are exciting in themselves, but they’re especially exciting since the cuttlefish is the first animal that we know can delay gratification outside of the primate and bird families. The authors explain this is a great example of convergent evolution, where completely unrelated lineages develop the same trait or behavior.
The paper “Cuttlefish exert self-control in a delay of gratification task” has been published in the journal Proceedings of the Royal Society B.
Noise pollution is a growing issue on land — but the seas are not safe either, apparently.
Marine shipping and construction, along with activity from sonar and seismic sensors are making the ocean a very loud place. While that may sound like just any other day in the big city, these high levels of noise pollution are causing a lot of damage to the health of marine ecosystems. A new paper reports on an “overwhelming body of evidence” that man-made noise is to blame.
Loud and deeply
“We’ve degraded habitats and depleted marine species,” said Prof Carlos Duarte from King Abdullah University, Saudi Arabia, lead author of the study. “So we’ve silenced the soundtrack of the healthy ocean and replaced it with the sound that we create.”
Sound plays a very important part in the lives of marine animals, the team explains, being involved in everything from feeding and navigation to communication and social interactions. A lot of what we know of marine animals such as whales comes from sound recordings.
But this state of affairs could change forever. According to the team, the youngest generations of marine animals are missing out on the “production, transmission, and reception” of key behaviors due to “an increasing cacophony in the marine environment” caused by man-made sound.
Freshly-spawned fish larvae use environmental sound and “follow it”, Duarte explains. But these sounds that helped them navigate and understand their environment are now being drowned out. Beyond noise from vessels, sonars, and acoustic deterrent devices, energy and construction infrastructure are also contributing to the issue.
“[T]here is clear evidence that noise compromises hearing ability and induces physiological and behavioral changes in marine animals,” the authors explain, adding however that currently “there is lower confidence that anthropogenic noise increases the mortality of marine animals and the settlement of their larvae” directly.
While the problems caused by marine sound pollution are pronounced and wide-reaching, the quarantine also showcased how quickly and easily they can be averted. According to the authors, levels of man-made sound in the ocean fell by around 20% last year.
Among some of the effects of this drop, the team notes that large marine mammals have been observed in waterways or coastlines that they’ve abandoned for generations. Such effects show that tackling the issue of marine noise is the “low-hanging fruit” of ocean health.
“If we look at climate change and plastic pollution, it’s a long and painful path to recovery,” Prof Duarte said. “But the moment we turn the volume down, the response of marine life is instantaneous and amazing.”
The paper “The soundscape of the Anthropocene ocean” has been published in the journal Science.
Hurricanes are getting a boost from climate change and taking longer after making landfall to slow down and disperse. These changes are likely to mean that hurricanes in the future will affect communities farther inland.
A new study showcases how climate change is making hurricanes more dangerous and farther-reaching. Hurricanes that form above warmer waters in higher atmospheric temperatures can carry more moisture, the team explains, which allows them to keep raging stronger and for longer after reaching dry land. The problem is only going to get worse if climate change continues unabated and mean temperatures keep increasing.
“The implications are very important, especially when considering policies that are put in place to cope with global warming,” said Professor Pinaki Chakraborty, senior author of the study and head of the Fluid Mechanics Unit at the Okinawa Institute of Science and Technology Graduate University (OIST).
“We know that coastal areas need to ready themselves for more intense hurricanes, but inland communities, who may not have the know-how or infrastructure to cope with such intense winds or heavy rainfall, also need to be prepared.”
The link between climate change and more powerful hurricanes is already well documented, with previous research showing that they’re becoming more intense over the open ocean. This is the first study to look at how climate change makes these storms — also known as typhoons — behave after they reach dry land.
The team looked at hurricanes in the North Atlantic that made landfall throughout the last five decades. On the first day after reaching dry land, the storms weaken roughly twice as slowly today as they did 50 years ago, the team explains.
They further explored the mechanisms behind this behavior in a series of computer simulations of four hurricanes in different sea surface temperature contexts. Once these simulated hurricanes reached Category 4 strength, the team simulated their making landfall by turning off any upwelling moisture.
“When we plotted the data, we could clearly see that the amount of time it took for a hurricane to weaken was increasing with the years. But it wasn’t a straight line — it was undulating — and we found that these ups and downs matched the same ups and downs seen in sea surface temperature,” said Lin Li, first author and PhD student in the OIST Fluid Mechanics Unit.
Li adds that hurricanes are “heat engines, just like engines in cars”, where the fuel is moisture taken up from the surface of the ocean. The heat energy it carries intensifies and sustains the storm by powering winds. Once a hurricane reaches dry land, its fuel supply is cut, meaning it will eventually decay.
Although each hurricane in the simulation made landfall at the same intensity, those that formed over warmer oceans took more time to dampen down, the team explains. All in all, they write that “warmer oceans significantly impact the rate that hurricanes decay, even when their connection with the ocean’s surface is severed”.
Additional simulations showed that the moisture stored in each hurricane explained this inertia. They start weakening as this stored moisture starts depleting. Simulated hurricanes that weren’t allowed to store moisture showed no changes in their rate of decay relative to the surface temperatures of the water they formed over.
“This shows that stored moisture is the key factor that gives each hurricane in the simulation its own unique identity,” said Li. “Hurricanes that develop over warmer oceans can take up and store more moisture, which sustains them for longer and prevents them from weakening as quickly.”
More stored moisture also makes hurricanes “wetter”, meaning they release more rainfall over the areas they reach.
The authors explain that our current models don’t take into account hurricanes’ stored humidity, making them incomplete — which is why we haven’t yet understood the relationship between sea surface temperatures and the behavior of hurricanes over dry land.
The team is now working on studying hurricanes from other areas of the world to see whether climate change is impacting hurricane decay rates across the globe.
“Overall, the implications of this work are stark. If we don’t curb global warming, landfalling hurricanes will continue to weaken more slowly,” Prof. Chakraborty concludes. “Their destruction will no longer be confined to coastal areas, causing higher levels of economic damage and costing more lives.”
The paper “Slower decay of landfalling hurricanes in a warming world” has been published in the journal Nature.
The oceans are warming up alongside the rest of the planet, reaching record temperatures not seen in thousands of years. Two recent studies found global warming is causing temperature changes in the surface of the ocean, as well as the freezing layers at its bottom.
A team of researchers from universities in the US and Canada found that the Atlantic Ocean has reached its hottest temperature in 2,900 years. They looked at the “multidecadal sea surface temperature variability” (AMV), which are naturally-occurring warm and cool phases that can last up to 40 years at a time.
The study looked at temperature data as well as ice and sediment cores, drilled from ice sheets and the sea bed. This allowed scientists to sift through layers of microbes and chemical clues to reconstruct the past. The samples were taken from South Sawtooth Lake, an 80-meter-deep lake in the Canadian Arctic.
The researchers looked at titanium in the sediment cores to discover the story of the past 2,900 years in Atlantic Ocean temperatures, revealing variability from decade to decade. They found warm conditions from 100BC to AD420, followed by the period with the longest and most persistent drop in temperatures in the Little Ice Age.
“Temperatures have steadily increased since the 15th-century minimum; the rate and magnitude of warming over the last few centuries are unprecedented in the entire record, leading to the last decade which was the warmest” in the past 2,900 years, the scientists wrote.
They also compared other evidence from across the North Atlantic, which backed their findings at the Sawtooth Lake. They observed that other sediment cores collected on Iceland’s coast gave clues about what was happening over a shorter time period, roughly the past two centuries.
They found that Turborotalita quinqueloba, minuscule, shelled, single-celled organisms which like cold waters, have “been declining at an accelerating pace during the past century and reached unprecedented low values in the last decade”. This led them to conclude that the recent Atlantic warming is “unparalleled” in at least 2,900 years.
Another study found that the freezing waters at the bottom of the ocean are also warming up, with temperatures rising quicker than previously thought. Between 2009 and 2019, water temperatures at four different depths in the Atlantic Ocean warmed by 0.002-0.04ºC. This might seem minuscule, but it’s actually quite significant.
“If you think about how large the deep ocean is, it’s an enormous amount of heat,” Christopher Meinen, an oceanographer at the US National Oceanic and Atmospheric Administration (NOAA) and lead author of the study, told The Guardian. He said the findings are consistent with human-caused climate change.
The data was obtained from a set of instruments scientists had been using for years to study ocean currents. The scientists concluded that deep ocean temperatures need to be taken at least yearly to understand long-term trends. They hope the study will prompt others to examine their own temperature data from existing instruments. A better system for observing the ocean could help scientists forecast seasonal weather, Meinen said.
Oceans are frequently polluted by oil from spills, routine shipping, run-offs, and illegal dumping. But what if we could prevent that oil from getting to the oceans in the first place? A group of residents from the town of Brignoles in Southeast France has come up with an innovative recycling scheme using human hair.
The citizens from Brignoles have accumulated 40 tons of hair in a warehouse, sent from salons far and wide. They plan to stuff nylon stockings with it in order to make floating tubes, which they will place near harbors to clean up ocean oil pollution. They have already performed a successful trial in the nearby port of Cavalaire-sur-Mer and have big expansion plans.
Thierry Gras, a hairdresser in Saint-Zacharie near Brignoles and founder of the project Coiffeurs Justes (Fair Hairdressers), explained that hair is lipophilic, meaning it absorbs fats and hydrocarbons. He is now waiting for the project to be approved by anti-pollution and labor officials in order to start large-scale production of the tubes before the end of the year.
The tubes, each around the length of a forearm, can absorb eight times their weight in oil and will be sold at $10.50 apiece. Their manufacturing process starts at the Brignoles warehouse, where hairdressers from all over France, Germany, Belgium, and Luxembourg send their waste hair. It is then sent to a closeny location, where the tubes are manufactured.
“Every day, thousands of hairdressers cut, color, trim and brush your hair. But what happens after? What becomes of these cut hair? What could be its use? How could we add value to this organic matter?,” the website of Fair Hairdressers reads. “You, us, individuals, professionals, citizens, elected officials, communities, we can all act at our level to ensure that this matter is promoted.”
Gras, one of the leaders of the project, told AFP he became interested in fighting pollution when he was a child and heard about the stranding of the Amoco Cadiz tanker off France’s Brittany coast in 1978. Human hair was used back then to mop up the more than 200,000 tons of spilled oil, the first time such an idea was implemented.
He eventually became a hairdresser and was surprised to find out there wasn’t a recycling facility for hair waste, a material that can also be used as fertilizer, isolation material, concrete reinforcement, or in water filtration. Reacting to the news, he came up with the idea of creating hair-filled oil absorbers and founded the Fair Hairdressers association for this purpose in 2015.
The tubes, Gras said, could be used in case of a serious spill, such as the recent one in Mauritius, but the goal is actually to remove micro-pollution on a continuous basis in ports. A dozen tubes are already in use in Cavalaire, soaking up the oil leaked from the engines of the more than 1,000 boats docked in the port.
Just like the atmosphere, oceans are warming because of climate change. They have absorbed about 90% of the excess heat trapped by greenhouse gases. Now, researchers have found a new way to calculate the ocean’s rate of warming by studying undersea earthquakes.
Tracking the warming of the oceans has so far been challenging. Ship-based observations only capture snapshots in time of a small portion of the seas, whereas satellite observations can’t penetrate deeply below the surface. The most detailed picture of ocean heat was captured by a group of autonomous floats known as Argo that has been looking at the seas since the early 2000s — but this isn’t feasible at a global scale.
Now, a group of researchers at the California Institute of Technology and the Chinese Academy of Sciences have found a new way to measure ocean warming. In their study, they compared the speed of sound waves produced by undersea earthquakes. Sound travels faster in the water when it’s warmer so differences in speed can show changing temperatures.
“I am very impressed with the methods the study’s authors are using and the fact that they could pull this all off,” Frederik Simons, a Princeton University geophysicist, who was not involved in the research, told Scientific American. “They’re opening up a whole new area of study.”
The idea of measuring ocean heat with sound actually isn’t new. Back in 1979, oceanographers Carl Wunsch and the late Walter Munk proposed using sea-based acoustic emitters and land-based receivers to measure the speed of sound waves, calculating temperatures based on the results. But the idea never caught on.
Inspired by those earlier efforts, lead author Wenbo Wu realized that the seafloor actually produces its own regular sound waves in the form of earthquakes. These aren’t the seismic waves from the earthquakes but instead low-frequency acoustic waves that move through the water. This realization led Wu to explore their use to measure ocean warming.
To test the idea, the team focused on Indonesia’s island of Nias, where the Indo-Australian Plate is bumping under the Sunda Plate. They collected acoustic data from over 4,000 earthquakes of magnitude 3 or above from 2004 to 2016 and found 2,047 pairs of quakes that each shared the same point of origin.
They compared earthquakes that ruptured at the same spot over the years, which showed the ocean near Nias is warming by about 0.008-degree Fahrenheit per decade. This is more than the 0.0047-degree Fahrenheit of warming that had been previously suggested by Argo’s data.
The numbers are more accurate, the researchers believe, because the other information sources were limited. While less than one-degree Fahrenheit might not seem a lot, these temperature changes are happening over massive volumes of water in the eastern Indian Ocean. Nevertheless, it will take more work to confirm the results for other regions.
“It is important to emphasize that this is a result that applies to this particular region and this particular decade,” said Dr. Wu to BBC News. We need to apply our method in many more regions and over different time frames to evaluate whether there is any systematic under- or over-estimation of the deep-ocean trend globally. It is much too early to draw any conclusions in this direction.”
Climate change could starve out the oceans, finds a new study from the University of Adelaide.
Man-made climate change is a threat to all life on the planet whether it flies, walks, swims, or crawls. That being said, individual types of ecosystems will feel the heat at different times, and in different ways.
Sadly for us, marine ecosystems will be among the first. The oceans have always had a special connection to life — this is where it spawned. Even today, ocean ecosystems are the linchpin of life, supplying food, oxygen, and recycling essential nutrients for us landlubbers.
Marine ecosystems, the new paper reports, are in for a rough time. Increased average temperatures and higher CO2 atmospheric content threaten to push the food webs maintaining marine ecosystems beyond their breaking point.
“Healthy food webs are critical for ecosystems so that the world’s oceans can continue to provide an important source of food for humans,” says lead author Professor Ivan Nagelkerken, from the University of Adelaide’s Environment Institute.
“Greenhouse gas emissions are affecting the health and persistence of many marine species because of increasing seawater temperatures and CO2 levels. Our research shows that ocean warming reshuffles species communities; the abundance of weedy plant species increases but the abundance of other species, especially invertebrates, collapses.”
The researchers modeled a coastal ecosystem consisting of three habitats that are predominant in the Gulf St. Vincent, Adelaide, where the South Australian Research and Development Institute (SARDI) maintains a site. They then observed how higher temperatures and ocean acidification would impact these areas.
All in all, the ‘trophic pyramid’, which is a schematic of who eats who in an ecosystem, would grow at the base and the top, but contract in its middle layers. This “unusual profile” most likely describes a “transitory state” before a collapse, Nagelkerken explains. After this collapse, marine food webs will be “shortened, bottom-heavy”, meaning they will house much fewer species, and most of them will be plants or plant-eaters. In marine food webs, fish are generally the top predators (and, as such, the highest on the pyramid).
Trophic pyramids show how energy and nutrients flow in an ecosystem; to be sustainable, they need to be triangular in shape, with many species at the bottom (thereby concentrating energy on this level). As each species feeds on the level below, this energy is moved up the pyramid. If the lower levels aren’t abundant enough, everything above them falls apart (goes extinct, or close to).
“Where food web architecture lacks adjustability, ecosystems lack the capacity to adapt to global change and ecosystem degradation is likely,” says collaborator and co-author Professor Sean Connell from the University of Adelaide’s Environment Institute.
“Marine food webs that are not able to adapt to global change show all the signs of being transformed into a food web dominated by weedy algae. Even though there were more plants at the bottom of the food web, this increased energy does not flow upwards towards the top of the food web.”
While things don’t look encouraging now, the team says that future emissions of carbon dioxide are only going to make the problem worse.
Unless some species quickly adapt to the new conditions, ocean ecosystems are likely to become much less abundant in the future. The species we most rely on economically and for food are exactly the ones that are at risk of collapse.
“An ecological tipping point may be passed beyond which the top of the food web can no longer be supported, with an ensuing collapse into shorter, bottom-heavy trophic pyramids,” says Professor Nagelkerken.
“This will weaken the health and sustainability of ocean ecosystems unless species are capable of genetic adaptation to climate stressors in the near future.”
The paper “Trophic pyramids reorganize when food web architecture fails to adjust to ocean change” has been published in the journal Science.
Despite recent private efforts, the global problem of plastic pollution won’t be solved by clean-up devices that collect waste from the ocean surface, according to a new study. The authors call for collection at rivers or a combination of river barriers and clean up devices as an alternative solution.
Plastic waste has become a global and widespread problem. Marine plastic debris is now found in coastal areas all around the globe. Its accumulation in the environment is increasingly hazardous and global policy actions have been invoked to reduce the effects of plastic pollution.
A group of international researchers compared estimates of current and future plastic waste with the ability of floating clean-up devices to collect it. They found the impact of such devices was “very modest” and that river barriers could be more effective, reducing pollution “significantly” when used alongside surface clean-up technology.
“The important message of this paper is that we can’t keep polluting the oceans and hoping that technology will tidy up the mess,” said Dr. Jesse F. Abrams, co-author in a press release. “Even if we could collect all the plastic in the ocean, which we can’t, it’s really difficult to recycle, especially if plastic fragments have floated for a long time.”
The study focused on floating plastic as it’s much easier to remove than sunken waste (depending on size and location). The authors estimated that the amount of plastic that reaches the ocean will peak in 2029, while surface plastic will reach 860,000 metric tons by 2052, more than double the current estimate.
Private initiatives are proposing to collect plastic from oceans and rivers, such as the Ocean Cleanup, which aims to clean the garbage patch in the Pacific using 600 million floating barriers to collect plastic. The study looked at the impact of using 200 of such devices, working non-stop for 130 years until 2150.
Using such devices would reduce global floating plastic debris by 44,900 metric tons. This is just over 5% of the estimated global total by the end of that period, leaving a “very modest” impact “compared to the amount of plastic that constantly enters the ocean,” said Dr. Sönke Hohn, co-author, in a press release.
The best strategy to mitigate marine plastic pollution would be to use river barriers instead, the researchers argued, as most plastic enters the oceans via rivers. This could prevent most of the pollution expected for the next decades. Nevertheless, the barriers couldn’t be installed on a large scale as large rivers are important for global shipping.
The researchers also suggested other paths to tackle the plastic problem across the world, including implementing extended producer responsibility strategies, creating taxes, fees, and/or bans on single-use plastic, promoting a circular economy and increasing recycling rates, among others.
“Plastic is an extremely versatile material with a wide range of consumer and industrial applications, but we need to look for more sustainable alternatives and rethink the way we produce, consume and dispose of plastic,” said Professor Agostino Merico, of Leibniz Centre for Tropical Marine Research and Jacobs University, co-author of the study.
Every time you bathe in the sea, you have geology to thank for the extra buoyancy that salty water provides. Large-scale geological processes bring salt into the oceans and then recycle it deep into the planet. The short answer to ‘why is the ocean salty’ sounds something like this:
Salts eroded from rocks and soil are carried by rivers into the oceans, where salt accumulates. Another source of salts comes from hydrothermal vents, deep down on the surface of the ocean floor. We say “salts” — because the oceans carry several types of salts, not just what we call table salt.
But the longer answer (that follows below) is so much more interesting.
In the beginning there was saltiness
As it is so often the case in geology, our story begins with rocks and dirt, and we have to go back in time — a lot. Billions of years ago, during a period called the Archean, our planet was a very different environment than it is today. The atmosphere was different, the landscape was different, but as far as ocean saltiness goes, there may have been more similarities than differences.
Geologists look at ancient rocks that preserved ancient water (and therefore, its ancient salinity); one such study found that Earth’s Archean oceans may have been ~1.2 times saltier than they are today.
At first glance, this sounds pretty weird. Since salt in the seas and oceans is brought in by river runoff and erosion, the salts hadn’t yet had time to accumulate in Earth’s earliest days. So what’s going on?
It is believed that while the very first primeval oceans were less salty than they are today, our oceans have had a significant salinity for billions of years. Although rivers hadn’t had sufficient time to dissolve salts and carry them to oceans, this salinity was driven by the oceanic melting of briny rocks called evaporites, and potentially volcanic activity. It is in this water that the first life forms on Earth emerged and started evolving.
“The ions that were put there long ago have managed to stick around,” says Galen McKinley, a UW-Madison professor of atmospheric and oceanic sciences. “There is geologic evidence that the saltiness of the water has been the way that it is for at least a billion years.”
The ancient salinity of oceans is still an area of active research with many unknowns. But while we don’t fully understand what’s going on with the ancient oceans, we have a much better understanding of what drives salinity today.
So how do the oceans get salty today?
Oceans today have an average of 3.5% salinity. In other words, 3.5% of the ocean’s weight is made of dissolved salts. Most, but not all of that is sodium chloride (what we call ‘salt‘ in day to day life). Around 10% of the salt ions come from different minerals.
At first glance, 3.5% may not seem that much, but we forget that around 70% of our planet is covered in oceans. If we took all the salt in the ocean and spread it evenly over the land surface, it would form a layer over 500 feet (166 meters) thick — a whopping 40-story building’s height of salt covering the entire planet’s landmass. That’s how much 3.5% means in this particular case.
All these salts come from rocks. Rocks are laden with ionic elements such as sodium, chlorine, and potassium. Much of this material was spewed as magma by massive volcanic eruptions and can form salts under the right conditions.
Because it is slightly acidic, rainwater can slowly dissolve, erode rocks. As it does so, it gathers ions that make up salts and transfers them to streams and rivers. We consider rivers to be “freshwater”, but that’s not technically true: all rivers have some salt dissolved in them, but because they flow, they don’t really accumulate it. Rivers are agents for carrying salts, but they don’t store salts themselves.
Rivers constantly gather more salts, but they constantly push it downstream. Influx from precipitation also ensures that the salt concentration doesn’t increase over time.
Meanwhile, the oceans have no outlet, and while they also have currents and are still dynamic, they have nowhere to send the salts to, so they just accumulate more and more salt. Which leads us to an interesting question.
So, are the oceans getting saltier?
No, not really. Although it’s hard to say whether oceans will get saltier in geologic time (ie millions of years), ocean salinity remains generally constant, despite the constant influx of salt.
“Ions aren’t being removed or supplied in an appreciable amount,” says McKinley. “The removal and sources that do exist are so small and the reservoir is so large that those ions just stay in the water.” For example, she says, “Each year, runoff from the land adds only 0.00005 percent of total ocean salts.”
A part of the minerals is used by animals and plants in the water and another part of salts becomes sediment on the ocean floor and is not dissolved. However, the main reason why oceans aren’t getting saltier is once more geological.
The surface of our planet is in a constant state of movement — we call this plate tectonics. Essentially, the Earth’s crust is split into rigid plates that move around at a speed of a few centimeters per year. Some are buried through the process of subduction, taking with them the minerals and salts into the mantle, where they are recycled. The movement of tectonic plates constantly recirculates material from and into the mantle.
With these processes, along with the flow of freshwater, precipitation, and a number of other processes, the salinity of the Earth’s oceans remains relatively stable — the oceans have a stable input and output of salts.
But isolated bodies of water, however, can become extra salty.
Why some lakes are freshwater, and some are *very* salty
Lakes are temporary storage areas for water, and most lakes tend to be freshwater. Rivers and streams bring water to lakes just like they do to oceans, so then why don’t lakes get salty?
Well, lakes are usually only wide depressions in a river channel — there is a water input and a water output, water flows in and it flows out. This is called an open lake, and open lakes are essentially a buffer for rivers, where water accumulates, but it still flows in and out, without salts accumulating. Many lakes are also the result of chaotic drainage patterns left over from the last Ice Age, which makes them very recent in geologic time and salts have not had the time to accumulate.
But when a lake has no water output and it has had enough time to accumulate salts, it can become very salty. This is called a closed lake, and closed lakes (and seas) can be very salty, much more so than the planetary oceans. They accumulate salts and lose water through evaporation, which increases the concentration of salts. Closed lakes are pretty much always saline.
We mentioned that world oceans are 3.5% salt on average. The Mediterranean Sea has a salinity of 3.8%. The Red Sea has some areas with salinity over 4%, and Mono Lake in California can have a salinity of 8.8%. But even that isn’t close to the saltiest lakes on Earth. Great Salt Lake in Utah has a whopping salinity of 31.7%, and the pink lake Retba in Senegal, where people have mined salt for centuries, has a salinity that reaches 40% in some points. The saltiest lake we know of is called Gaet’ale Pond — a small, hot pond with a salinity of 43% — a testament to just how saline these isolated bodies of water can get.
It’s important to note that lakes are not stable geologically, and many tend to not last in geologic time. Some of the world’s biggest lakes are drying up, both as a natural process and due to rising temperatures, drought, and agricultural irrigation.
Salt can also come from below
We’ve mentioned that rock weathering and dissolving makes oceans salty, but there is another process: hydrothermal vents.
A part of the ocean water seeps deeper into the crust, becomes hotter, dissolves some minerals, and then flows back into the ocean through these vents. The hot water brings large amounts of minerals and salts. It’s not a one-way process — some of the salts react with the rocks and are removed from seawater, but this process also contributes to salinization.
Lastly, underwater volcanic eruptions can also bring salts from the deeper parts to the surface, affecting the salt content of oceans.
The deep sea, the area of the ocean below 200 meters, could soon become the new frontier of mining activities. Companies and countries are rushing to get the green light to start extracting minerals from cobalt to manganese from the bottom of the sea. ‘Not so fast’, say conservationists.
While they can be found in abundance on land, most mineral deposits are running short as our society is fueling an increasing demand for such resources, especially for green energy technologies and consumer electronics. This has led many to draw their attention to the minerals on the deep sea.
The seafloor contains a wide array of geological resources and supports countless species, many still unknown to science. It is a highly understudied part of the world, hosting an abundance of species uniquely adapted to harsh conditions such as lack of sunlight and high pressure.
This is why conservation and environmental organizations are raising the alarm over the impacts of deep-sea mining, urging caution until the science is more thorough. Meanwhile, companies argue that the risks are low and that there’s no time to waste amid the high demand for minerals. So, what’s the case for deep-sea mining, and what’s the case against it?
What is deep seabed mining?
Deep-sea mining (or deep seabed mining) is, as the name implies, the process of retrieving mineral deposits from the deep seafloor. Generally, this ‘depth’ refers to parts of the ocean over 200 meters deep — an area that covers around 65% of the Earth’s surface.
In addition to rich biodiversity, these areas also include unique geological features such as mountain ranges, plateaus, volcanic peaks, canyons, vast abyssal plains, the world’s deepest trenches — such as the Mariana Trench, which goes down almost 11,000 meters.
“It is the largest biosphere on the planet. It exchanges biomass, nutrients and other elements with the overlying surface waters, it mixes vertically and horizontally and it comprises arguably more habitats than may be found in terrestrial environments,” said Dr. Cindy Van Dover, a deep-sea biologist at Duke University, for ZME Science.
Much has changed in how scientists regard the deep sea. When Van Dover first started work in this field in the early 1980s, the ‘deep-sea’ meant the area where light stopped coming though, about 500 meters in. While no formal definition is universally accepted, 200 m seems to be regarded as the limit now — the boundary at which photosynthesis is no longer possible, and the temperature drops sharply.
Adjectives often associated with the deep sea before the 1980s include inaccessible, remote, pristine, biological desert, adds Van Dover. These are now obsolete.
“We have access (although that access is costly), the deep-ocean is well connected to coastal and surface waters. Chemicals, wastes, plastics, and climate change are all impacting the deep sea. And we know that the diversity of life in the deep sea is rich, and in some places exuberantly abundant – far from the azoic, desert world it was believed to be in the 1800s and on into the 1900s.”
However, although we’ve learned much about this part of the planet, the vast majority of it remains unexplored and understudied, which is why the topic of industrial activities in these areas tend to touch a nerve.
Should we wait, or start mining as soon as possible?
There are some mining projects in shallow waters around the world, mainly for sand, tin, and diamonds. In the 1960s, Marine Diamond Corp. recovered nearly 1 million carats from the coast of Namibia, but not all investments have been successful — and the process is tedious.
There’s also some deep-sea mining being done in territorial waters of some countries, particularly around hydrothermal vents — fissures on the seafloor where geothermally heated water flows and tends to form rich mineral deposits. Papua New Guinea was the first country to approve a permit for the exploration of minerals in the deep seabed, and the world’s first “large-scale” mining of hydrothermal vents mineral deposits was carried out by Japan in August – September 2017.
But deep-sea mining in international waters that don’t belong to a specific country has still not taken off.
So far, thirty 15-year exploration contracts have been granted to assess the size and extent of three different types of mineral deposits in areas totaling more than 1.3 million square kilometers. But actual mining can’t start until countries agree on an international mining code, now under negotiation.
The task of developing this mining code falls International Seabed Authority (ISA), a rather obscure and autonomous United Nations organization that governs seabed mining from its headquarters in Kingston, Jamaica. Every year, delegates from all around the world fly to Kingston for one week and discuss the legislation for this trillion-dollar industry just waiting to boom, with little attention from the media and even environmental organizations.
The ISA had set 2020 as the deadline to adopt a “mining code” that would allow companies to obtain minerals from the bottom of the ocean but given the current state of affairs, meeting that deadline seems highly unlikely.
Biologists and conservationists argue that some of the difficulties to getting the code approved lies on the fact that the ISA has dual responsibilities. When it was established by the UN, the ISA was given two mandates: to protect the international seabed from serious harm, and to develop its resources, ensuring that their exploitation benefits humankind — so what do you do when those mandates clash and start pulling in different directions? If anything, the role that ISA seems to play at this time is not to prevent environmental damage from deep-sea mining, but rather to mitigate it.
Writing the regulations at this time could also encourage the industry to start mining long before there is enough information on how operators can avoid causing serious environmental harm. That’s why many are now calling for a moratorium until all the necessary information is collected.
“We need more time to drill down on the details, more time to do science and learn on the deep oceans and more time for the stakeholders to internalize all the questions,” Andrew Friedman, head of Pew’s Seabed Mining Project. “If the activity starts, we want to have a robust regulatory framework in place.”
The idea of heavy scrutiny is shared by Van Dover, though a moratorium might not be the best approach, she notes.
“While I welcome the public debate about a moratorium on deep-sea mining, I don’t know that a moratorium may be the optimal approach. To me, our goal has to be to ensure that environmental regulations, standards, and guidelines are robust before any mining begins, including being robust with regards to enforcement.”
Environmental aspects of mining applications should be scrutinized for compliance and subject to independent review by deep-sea environmental experts, she says. Mining should not be permitted where there is insufficient data to ensure no serious harm is done to the environment. However, since there are huge knowledge gaps in our understanding, that will preclude all mining activities for a while.
“It will require thoughtful, informed input to the development of regulations, standards, and guidelines by Member States of and Observers to the ISA, by deep-sea ecologists, scientists, and environmental experts, and by all other stakeholders to ensure that the environmental regulations are robust,” Van Dover adds.
Who wants to explore the deep sea?
Given the lucrative potential of deep sea mining, several countries and companies have already expressed interest.
All countries have the right and opportunity to mine the deep sea and the eventual royalties obtained from the activity will have to be divided equally among all of them. But as the rules aren’t in place yet countries are only on an exploratory phase in international waters.
A group of corporate enterprises, state-owned companies and several governments have been allocated with contracts to explore the deep sea. Each company has to be sponsored by a country, so they are both responsible for any eventual problems.
The list includes China, France, Germany, India, Japan, South Korea, Russia, and the Interoceanmetal Joint Organisation (a consortium of Bulgaria, Cuba, the Czech Republic, Poland, the Russian Federation, and Slovakia). Small island states such as the Cook Islands, Kiribati, Nauru, Singapore, and Tonga are also part of the list. Given the massive rising demand for precious metals in the world, many are closely following developments in this field.
Make no mistake, though — this isn’t some localized interest by which some countries are looking to supplement their natural resources. This is possibly the nascent moment of the largest mining operation in human history.
What minerals does the industry want?
The most common targets are nickel, copper, cobalt, manganese, zinc, silver, and gold. The exploration currently under place is focused on three types of mineral deposits: polymetallic nodules (lying on the seafloor), polymetallic sulfides (which form near hydrothermal vents), and cobalt-rich ferromanganese crusts that cover seamounts.
Once found, such minerals will be used to supplement in-demand electronic products and energy storage such as smartphones, laptops, solar panels, wind turbines, and electric vehicles. Terrestrial supplies are becoming harder and less profitable to extract while demand for minerals continues to grow. Companies argue that deep-sea mining provides a source of reliable, clean, and ethically sourced minerals.
“We are now at the age of metals. We need a lot of them to move into the fourth industrial revolution, which will be based on renewable energy,” said Dr. Gregory Stone, Chief Ocean Scientist at Deep Green. “We need to get the metals from somewhere and obtaining them from the deep sea is an elegant solution.”
Seabed formations will be scooped, dredged, or severed by gigantic machines weighing more than a blue whale. The deposits would be piped up to a ship through several kilometers of tubing and processed at sea, where waste material would be pumped back into the water.
ROV (remotely operated underwater vehicles) have also progressed greatly in recent years, becoming not only more capable and robust, but also cheaper — promising to usher in a new age of undersea exploration.
What effects could it have on the ocean?
Environmental organizations and researchers claim these activities will affect the seabed, the water column above it, and the surrounding area. The scraping of the ocean floor to extract the nodules could destroy deep-sea habitats of octopuses, sponges and other species.
Mining of the vents, which harbor massive animal communities at densities that make them one of the most productive ecosystems on Earth, is likely to stir up sediment that could smother some animals and dramatically affect the habitats of others. Other species adapted to the lack of sunlight and high pressure of deep water, could be affected by the noise and pollution, and the list of potential threats goes far and long.
“Many uncertainties remain as to the impact of this mining but widespread habitat loss will be inevitable, albeit in an environment where the faunas are often sparse,” wrote Van Dover and colleagues in a paper in 2018. “A precautionary approach will be needed with many areas set aside for protection and regional plans put in place before mining begins.”
Environmental organizations are also scrutinizing the climate implications of allowing companies to dig minerals used to make lithium-ion batteries. “Deep-sea mining could even make climate change worse by releasing carbon stored in deep-sea sediments or disrupting the processes which help deliver carbon to those sediments,” Greenpeace argued in a report.
Scientists are also concerned that not enough is known about these species or ecosystems to establish an adequate baseline from which to protect them or monitor the impact of mining. But for the industry, that shouldn’t be the case. DeepGreen said the activity should start as soon as the rules are approved.
“Everybody is in new territory, that’s why this new industry is exciting. Nobody did this type of mining before. ISA will have to get the code ready, and then we’ll do our environmental assessment against that code,” said Dr. Stone. “It will be the least invasive way of getting metals on the planet.”
We once thought the deep sea was uninhabitable but now we know that is not the case. There is an abundance of biodiversity in the deep sea, and the ecological services it provides is invaluable — not only for ocean dwellers, but for humans as well.
In between the fragile ISA mandate, the growing pressure for more mineral resources, and the environmental uncertainty, deep sea mining promises to be a contentious topic for decades to come.
Whether it will bring a revolution for mineral resources or devastate the subsurface environment, the effects will be powerful and long-lasting.
“The deep sea remains a difficult place to study and in my opinion will be impossible to “fix” if we “break” it,” Van Dover concludes.
Although Pluto orbits the sun at an average distance of 3.7 billion miles (5.9 billion kilometers), some studies claim that the icy dwarf planet may have a liquid ocean under its surface. According to a new study, the accretion of new material during Pluto’s early geological history may have generated enough heat to sustain the formation of this ocean, which would go on to continuously freeze over billions of years.
Pluto is so far away from the sun that it lies inside the Kuiper Belt, a group of rocks and ice left over from the formation of the solar system. It’s really no wonder that today the planet looks like a barren ball of ice and rock.
However, detailed images of Pluto’s surface taken during flybys by NASA’s New Horizons spacecraft have revealed intriguing geological features that can tell us many things about the dwarf planet’s past.
According to Francis Nimmo, a professor of Earth and planetary sciences at UC Santa Cruz, Pluto’s surface shows evidence of both ancient and modern extensions of its surface. This suggests that Pluto may have been ‘hot’ during its early days.
To understand why this matters, we have to make a brief tangent to talk about how water freezes. Most liquids shrink when they are cooled because molecules are moving slower, making them less able to overcome the attractive intermolecular forces that draw them closer together. When the freezing point is reached, the substance solidifies in a tightly packed crystalline matrix.
Water is an exception to this chemical behavior. Liquid water also contracts when cooled, but only until it is chilled to approximately 4 degrees Celsius. If you cool water past this threshold, it will actually expand slightly. Cool it further to its freezing point and the water will expand by about 9%.
So, water expands when it freezes and contracts when it melts — and this has important implications for Pluto’s history.
“If Pluto had a subsurface ocean shortly after it formed, that ocean would have been continuously freezing over solar system history. That would cause Pluto to be expanding and that would result in specific geologic features we can look for. In contrast, if Pluto started with a cold ice shell, that ice would have warmed and melted slowly from the heat of radioactive decay forming an ocean. That ocean would have been refreezing in more recent times as the heat from radioactive decay waned. This would lead to early compressional tectonics followed by later extension,” Carver Bierson, UCSC graduate student and co-author of the new study, told ZME Science.
If Pluto had a ‘cold start’, compression on its surface would have occurred early on, followed by more recent extensions. However, if it had a hot start, then extension would have occurred throughout Pluto’s history — and this seems to be the case, current observations suggest.
“When we look at the surface of Pluto we don’t see any clearly compressional features even on the oldest terrains. We do see many extensional features, most of which are recent. The oldest tectonic features we see look to be extensional, but are hard to interpret because they are so eroded. Taken together we think this favors Pluto’s ocean already being present very early in Pluto’s history,” Bierson added.
Pluto’s hot past
Where could all this energy have come from? Pluto is too far from the sun to be of consequential difference, which leaves us with only two main possible sources of energy.
One is the heat released through the decay of radioactive elements in the rock, the other is gravitational energy released during impact with asteroids and other cosmic bodies. Early in the solar system’s history, it was quite common for planets to be bombarded by asteroids and meteorites.
Calculations performed by the researchers suggest that if all of that gravitational energy was retained as heat, Pluto could have supported an initial liquid ocean.
In reality, however, we know that is simply not possible — some of that energy will escape into space.
“How Pluto was put together in the first place matters a lot for its thermal evolution,” Nimmo said in a press release. “If it builds up too slowly, the hot material at the surface radiates energy into space, but if it builds up fast enough the heat gets trapped inside.”
The researchers found that if Pluto formed over a period of less than 30,000 years, then it would have most certainly been hot. If it took a couple million years for accretion of proto-Pluto to take place, then a hot start would only be possible if a large impactor buried its energy deep beneath the surface.
“If Pluto’s ocean was there early on it raises another question, “What was the heat source to form that ocean?” Today Pluto sits in an extremely cold part of the solar system. Its surface temperature is about 45 Kelvin (-480 Fahrenheit). When Pluto was forming new material would have been coming in and impacting its surface. Each impact is like an explosion that will warm the nearby area. If Pluto formed slowly, the surface would cool between each impact and generally stay very cold. If however Pluto formed quickly you have impact on top of impact and the surface doesn’t have time to cool. We calculate that if Pluto formed in less than 30000 years the heat from these impacts could have been sufficient to lead to an early ocean,” Bierson said.
There are a lot of assumptions and ‘ifs’ in this study, but if the findings are confirmed, other large objects in the Kuiper belt likely started out hot, possibly harboring oceans billions of years ago.
What’s intriguing is that these oceans could persist to this day in the largest objects in the belt, such as the dwarf planets Eris and Makemake, shielded under a blanket of thick ice.
“Pluto is the first Kuiper Belt object we visited and what we found was amazing. There is no reason to think that Pluto’s neighbors (Eris, Makemake, Haumea) are any less interesting. From this work, we suggest that they also should have formed with oceans, but we don’t know if they would have completely refrozen over solar system history. Up to now, we haven’t been able to see those worlds as more than points of light in the night sky. This is hard because the Kuiper belt is very very far away. It took New Horizons 9 years from launch to Pluto and it was one of the fastest spacecraft ever launched. Still, I am optimistic that with new telescopes and maybe a future mission we can keep unlocking their secrets,” Bierson concluded.
Kathy Sullivan, the first American woman to walk in space in 1984, has now become the first woman to reach the bottom of Challenger Deep in the Mariana Trench, considered the deepest point on Earth.
She is now the only human to have done both.
The former astronaut, who made history with her spacewalk, made another groundbreaking trip by going to the bottom of the western Pacific Ocean. She reached the depth of almost 36,000 feet (about 6.8 miles) in a submersible, accompanied by Victor Nescovo – a deep-sea explorer and entrepreneur.
Sullivan and Vescovo spent about an hour and a half at their destination, located in a muddy depression in the Mariana Trench — about 200 miles southwest of Guam. They captured photos from the submarine (which was specially designed for the deep-sea) and then began the four-hour ascent.
The Challenger Deep is essentially a pitch-black place of freezing temperatures and deep-water pressure. It was first reached by Swiss oceanographer Jacques Piccard and US Navy Lt. Don Walsh in 1960. Then, in 2012, the Titanic director and underwater explorer James Cameron visited the site aboard the Deepsea Challenger.
Once Sullivan and Nescovo returned to the surface, a call was arranged between the explorers and the International Space Station (ISS), allowing them to discuss their extraordinary journey with the United States astronauts that recently arrived at the ISS thanks to SpaceX’s Crew Dragon.
“As a hybrid oceanographer and astronaut this was an extraordinary day, a once in a lifetime day, seeing the moonscape of the Challenger Deep and then comparing notes with my colleagues on the ISS about our remarkable reusable inner-space outer-spacecraft,” Sullivan said in a statement.
The submarine dive was part of the Ring of Fire expedition organized by Caladan Oceanic, a deep-sea exploration company founded by Vescovo. The company organized the Five Deeps expedition, which explored the five deepest points on Earth. The new expedition hopes to provide the first 4K video of the Challenger Deep.
Close ties with the oceans
Back in 1978, Sullivan joined NASA as part of the first group of U.S. astronauts to include women. On October 11, 1984, she became the first American woman to walk in space. “That is really great,” Dr. Sullivan said after she floated into the cargo bay of the shuttle Challenger, about 140 miles above Earth.
Later, Sullivan became the administrator of the National Oceanic and Atmospheric Administration. She always had a longstanding fascination with the ocean. Before becoming an astronaut, she participated in one of the first attempts to use a submersible to study the volcanic processes that make the ocean crust.
Tim Shank, a biologist at the Woods Hole Oceanographic Institution, told the New York Times that Sullivan is a “consummate leader” in the study of the world’s oceans. “I’m thrilled to hear that she was in it,” he said. “Anytime we can reach such extreme places on Earth to learn about them, it’s a major event.”
The adorable cephalopod has been photographed on the bottom of the Indian Ocean in the Java Trench, at around 7,000 meters of depth.
This is roughly 2 kilometres deeper than any previous reliable sighting of a cephalopod, the family that includes octopus and squids. Given that we now know how deep these animals can live — seemingly very comfortably, too — the findings “increase the potential benthic (ocean floor) habitat available to cephalopods from 75 to 99% of the global seafloor”.
The deep end
The researchers who spotted the boneless animal say it’s a species of “Dumbo” octopus, so named due to its distinctive side fins. Due to their size and shape, they’re very reminiscent of an elephant’s ears, most notably to those of Disney’s 1940s’ animated elephant Dumbo.
Still, spotting the octopus at this depth was no mean feat. Lead author Dr Alan Jamieson from the School of Natural and Environmental Sciences, Newcastle University is a pioneer of the use of “landers” for deep-sea exploration. These landers are crew-less craft, in essence large metal frames outfitted with various instruments that are dropped overboard and land on the seafloor. Once there, they observe their surroundings and record any passers-by.
And record they did. The lander picked up two octopuses, a 43-cm-long one at a depth of 5,760m and the other (35 cm) at 6,957m. Based on their physionomy, Dr. Jamieson and his co-author Michael Vecchione from the NOAA National Systematics Laboratory are confident that they belong to the Grimpoteuthis family, the group commonly known as the Dumbo octopuses.
Further down, the landers also spotted octopus fragments and eggs. The study provides the deepest-ever sightings of cephalopods. Previously, the deepest reliable sighting was a 50-year-old black-and-white photograph of one such animal taken at a depth of 5,145m.
For starters, it’s impressive that anything can live at such depths, where pressure is literally crushing.
“They’d have to do something clever inside their cells. If you imagine a cell is like a balloon — it’s going to want to collapse under pressure. So, it will need some smart biochemistry to make sure it retains that sphere,” Dr. Jamieson explained.
“All the adaptations you need to live at pressure are at the cellular level.”
Furthermore, it helps fill out our understanding of hoe octopuses live. The authors explain that the study shows that such animals can (potentially) live across 99% of the global seafloor, as the Java Trench is one of the deepest points on Earth.
The paper “First in situ observation of Cephalopoda at hadal depths (Octopoda: Opisthoteuthidae: Grimpoteuthis sp.)” has been published in the journal Marine Biology.
A new study says we should be expecting an average sea-level rise in excess of 1 meter by 2100 and 5 meters by 2300 if we don’t meet current targets for the reduction of greenhouse gas emissions.
The analysis used projections compiled by over 100 international experts to estimate changes in sea levels under low- and high-emission scenarios, the team explains, in order to help policymakers have a better understanding of “the state of the science” on this threat.
The waters are coming
“The complexity of sea-level projections, and the sheer amount of relevant scientific publications, make it difficult for policymakers to get an overview of the state of the science,” says Professor Benjamin Horton, Acting Chair of Nanyang Technological University, Singapore (NTU Singapore) Asian School of the Environment, who led the survey.
“To obtain this overview, it is useful to survey leading experts on the expected sea-level rise, which provides a broader picture of future scenarios and informs policymakers so they can prepare necessary measures.”
The most optimistic scenario analyzed in this paper considered that global warming would only increase temperatures by 2 degrees Celsius above pre-industrial levels, which would translate to a rise of 0.5 meters (roughly 2 feet) by 2100, and 0.5 to 2 meters by 2300. The high-emission scenario would involve 4.5 degrees Celsius of warming and would cause between 0.6 to 1.3 meters (2 to 4 feet) sea rise by 2100, and 1.7 to 5.6 meters by 2300.
These estimations exceed those of the International Panel on Climate Change (IPCC), who set the current targets under the Paris Agreement. Researchers from The University of Hong Kong, Maynooth University (Ireland), Durham University (UK), Rowan University (U.S.), Tufts University (U.S.), and the Potsdam Institute for Climate Impact Research (Germany) took part in this study. They were chosen as they are some of the most active publishers or scientific studies on the topic (they all had at least six published papers pertaining to sea-level rise since 2014).
The large difference in sea level rise seen in this paper “provides a great deal of hope for the future, as well as a strong motivation to act now to avoid the more severe impacts of rising sea levels,” according to Dr. Andra Garner, Assistant Professor of Environmental Science at Rowan University and co-author of the study.
Still, the findings also underscore just how important it is for policy to be set in place in order to limit emissions and sea-level rise. How bad the outcome is depends entirely on how we act, and the decisions we make right now.
However, despite the sheer wealth of expertise that went into the study, there are still uncertainties. The team points to the Greenland and Antarctic Ice Sheets as the largest unknowns, as their behavior can have dramatic effects on how sea levels evolve in the future. Both of these ice sheets are key reference points for climate change and increases in sea levels, as they hold important quantities of water — and they’re both melting at much higher rates than they would naturally.
Yet, not all is lost. Climate systems have a great deal of inertia to them (as do all systems working on such scales) but taking proactive measures to limit greenhouse gas emissions would still have a significant effect.
So while the worst-case scenario definitely does seem bleak, it’s in no way out of our hands. We can choose to make things better, to limit the impact we have on the planet and the repercussions that will have on our society in the future.
The paper “Estimating global mean sea-level rise and its uncertainties by 2100 and 2300 from an expert survey,” has been published in the journal Climate and Atmospheric Science.