Tag Archives: Mediterranean

The Mediterranean Sea is filled with plastics that come from elsewhere

Almost every country in the Mediterranean Sea has at least one Marine Protected Area (MPA) where over half of its macroplastics originated from another country, according to a new study. The findings highlight that plastic pollution is an international problem and we need international collaboration in order to tackle it, the researchers argue.

Image credit: Joan / Flickr.

Slowly but surely, plastic pollution has become one of the major environmental issues of our times, comparable to the climate crisis and overfishing. While much recent research focused on microplastics, this new effort looked at how macroplastics (plastic bits bigger than five millimeters) affect the marine ecosystem, as organisms ingest or become entangled in plastic litter — often with dramatic consequences. 

Plastic pieces (especially small ones) can travel very long distances and end far from their original sources. They come in unseen for multiple, often distant sources, threatening wildlife and their habitats in marine areas. Previous studies in the Arctic, the Pacific and the Atlantic have shown MPAs are very affected by plastic pollution. 

In the new study, a group of researchers focused on the Mediterranean Sea, one of the most polluted regions globally which also happens to be an important biodiversity hotspot. It’s shared by numerous countries in Europe, Africa, and Asia, which brings big differences in terms of governance, politics, and cultures — which makes it difficult to implement common regulations of marine ecosystems. 

About 229,000 tons of plastic leak every year into the Mediterranean Sea, according to a report by IUCN from 2020, equivalent to 500 shipping containers. Roughly speaking, it’s like dumping a container and a half of plastic straight into the sea. Egypt, Italy, and Turkey were identified as the countries with the highest plastic leakage rates into the Mediterranean, mainly because of mismanaged waste and large coastal cities.

“Our study shows that specific sites, important for the conservation of biodiversity, concentrate high amounts of plastics,” Dr Yannis Hatzonikolkis, lead author of the study, said in a statement. “Although marine protected areas are protected by restrictions from other threats as tourism, plastic acts like an ‘invisible’ enemy.” 

Plastics and the Mediterranean

The researchers carried out a three-year simulation (from 2016 to 2018) of the distribution of plastic particles in the Mediterranean Sea. They used a particle drift model that considers the main dispersion processes such as winds and currents, incorporating three land-based sources of plastic particles – wastewater discharge, rivers, and cities. 

Image credit: The researchers.

The findings showed that coastal zones were the hardest hit, both by macroplastics and microplastics (plastic pieces smaller than five millimeters). As MPAs tend to be closer to coastal zones, they accumulated more plastic waste than sites in offshore waters. Most plastics were traced back to land-based sources, which means the issue has to be tackled at source.

The average concentration of macroplastics in inshore waters was larger than five kilograms per squared kilometer, while offshore waters had over 1.5 kilograms. Meanwhile, average microplastics concentration in inshore waters was higher than 1.5 million particles per squared kilometer, and 0.5 million particles in offshore waters. 

“The most effective way to reduce plastic pollution in protected areas is by reducing marine litter at the sources. A management plan including litter reduction at its sources can occasionally be successfully implemented locally,” the researchers wrote, suggesting the use of a floating barrier installation and a pre-filtering device. 

The study was published in the journal Frontiers. 

Climate change is turning the Eastern Mediterranean into a completely new ecosystem

As global warming intensifies, the Mediterranean are feeling the heat. Some mollusk populations in the eastern areas of the sea are buckling the waters they call home have become too hot to survive in, new research shows.

Image via Pixabay.

The waters around the coast of Israel are some of the hottest in the whole Mediterranean. But they’re rapidly becoming even hotter, as average temperatures have risen here by 3° Celsius over the last four decades. Today, water temperatures here regularly exceed 30°C (86°F) which, alongside invasive species coming through the Suez Canal from the Red Sea, are putting local mollusk populations under a lot of pressure.

Wipe-out

“My expectation was to find a Mediterranean ecosystem with these ‘newcomers’,” said Paolo Albano from the University of Vienna’s Department of Paleontology, lead author of the paper, for the AFP.

“However, after the first dive, I immediately realised that the problem was another one: the lack of the native Mediterranean species, even the most common ones that you would find everywhere in the Mediterranean.”

Albano initially set out to study the differences between native and non-native populations along the Israeli shelf in the eastern Mediterranean but was stuck by the dearth of local species in the area.

The team gathered over 100 samples from the seafloor, using these to gauge the characteristics of local mollusc populations, such as which species were present, their numbers, and so forth. These were then compared to historical data on the same topic. Only around 12% of the shallow-sediment molluscs noted in the historical records were still present today, the paper reports. In rocky reef environments, that figure dropped as low as 5%.

Furthermore, the researchers estimate that 60% of the remaining local mollusc populations are below their reproductive size, meaning they’re shrinking over time.

Albano says that there are many factors contributing to this collapse, most notably pollution and the pressures from invasive species. But warming waters are playing the main part in driving local mollusk populations into the ground.

“Tolerance to temperature is what really matters here and most of the native Mediterranean species are in the easternmost Mediterranean Sea at the limits of their tolerance to temperature,” said Albano.

Populations of invasive species, however, are thriving in the area. In effect, these changes are setting the stage for a “novel ecosystem“, the team explains, as species moving in from the Red Sea stand poised to effectively replace local ones. Albano says the Eastern Mediterranean is “paradigmatic of what is happening in marine ecosystems due to global warming: species respond to warming by shifting their ranges and in some areas, this means local eradication of species.”

The paper “Native biodiversity collapse in the eastern Mediterranean” has been published in the journal Proceedings of the Royal Society B.

The Mediterranean Sea is packed with plastic waste and it could get worse soon

The Mediterranean Sea is one of the most heavily-affected environments in the world in terms of plastic pollution, with about 230,000 tons dumped there every year, according to a new report. The researchers warned that the figure could double by 2040 unless ambitious steps are taken as soon as possible.

Credit Flickr Cheasepeake

The International Union for the Conservation of Nature (IUCN) published the report “The Mediterranean: Mare plasticum” which reviews the role of plastic pollution in the Mediterranean. It considered 33 countries, either coastal or part of a hydrological basin flowing into the Mediterranean Sea.

“The region represents a perfect model to advance our understanding of plastic. It’s a semi-enclosed sea, making the definition of plastic mass balance and the comparison between modeling approaches and field sampling approaches easier,” said Mina Epps, director of the IUCN Global Marine program, in a statement.

The total plastic accumulated in the Mediterranean is estimated at around 1,178,000 tons, the researchers found. Most of it seems to be deposited on the seafloor either in the form of microplastics in the sediments or as macroplastics and mesoplastics scattered on the seafloor.

The top three countries by the amount of plastic released into the sea are Egypt, Italy, and Turkey. But on a per capita basis, Montenegro, Albania, Bosnia and Herzegovina, and North Macedonia have the highest levels of plastic waste leakage. Plastic hotspots tend to form near the mouth of major rivers and close to large cities.

“The report refines the estimates of the quantity of plastic currently floating into the Mediterranean, based on a compilation of data from field studies and using the footprint methodology to estimate the yearly input of plastic into the Mediterranean Sea,” said Epps in a statement.

Under a business as usual scenario, the current 229,000 tons of plastic leaking every year into the Mediterranean Sea would grow to 500,000 by 2040, the researchers estimate. That’s why they argued for ambitious interventions beyond current commitments to reduce the flow of plastic into the sea.

There are concrete ways to achieve such a reduction, according to the report. Over 50,000 tons could be slashed each year if waste management was improved in the top 100 contributing cities alone. They also recommended a ban on plastic bags in the Mediterranean basin region.

“Governments, private sector, research institutions, and other industries and consumers need to work collaboratively to redesign processes and supply chains, invest in innovation and adopt sustainable consumption patterns and improved waste management practices to close the plastic tap,” said Antonio Troya, head of the IUCN Centre for Mediterranean Cooperation.

Cetaria.

Roman fish salting workshops reveal two whale species lost from the Mediterranean

The Roman Empire used to dine on whale fished from the Mediterranean Sea — the two species have, since then, virtually disappeared from the area and the wider North Atlantic, however.

Grey whale.

Adult grey whale.
Image credits José Eugenio Gómez Rodríguez.

Bones discovered in the ruins of a Roman fish salting compound near the strait of Gibraltar suggest that the Empire’s subjects may have hunted whales for food. The implications are interesting not only from a historical and archaeological point of view — the Romans are not traditionally regarded as accomplished sailors — but also from an ecological standpoint.

Bread, games, and salted whale

Back in Rome’s heyday, the Gibraltar region served as a central fish-processing hub. Ruins from hundreds of factories outfitted with large salting tanks (indicative of an industrial-scale endeavor) still litter the area. Based on the scale of the industry, it’s likely that the products manufactured here used to reach far and wide onto plates across the Roman Empire.

The recent discovery of whale bones amid these workshops in the Gibraltar region stands to change our understanding of the Roman fishing industry and the history of two whale species — which have now virtually disappeared from the North Atlantic area.

One team, led by researchers from the Archaeology Department at the University of York, drew on DNA analysis and collagen fingerprinting to identify the bones — their results showing the remains belonged to the North Atlantic right whale (Eubalaena glacialis) and the Atlantic gray whale (Eschrichtius robustus).

The findings surprised them, to say the least. On the one hand, the Mediterranean, despite housing several species of whales and other cetaceans today, was always considered outside of the historical range of both the gray and right whale. On the other hand, the Romans simply didn’t have the means to fish such large prey — none that we’re aware of, anyway.

Cetaria.

Some fish-salting tanks in the ancient Roman city of Baelo Claudia (near today’s Tarifa in Spain). The largest circular tank is 3 meters / 10 feet wide, with some 18 meters3 / 193 cubic feet capacity. They were used to salt large fish such as tuna, but perhaps whales as well.

Right whales are listed as Endangered under the IUCN’s Red List, and are further protected by the Endangered Species Act in the US. The species is considered to be one of the hardest-pressed species of whales in the world. Populations in the western North Atlantic can only boast a few hundred individuals, while those in the eastern North Atlantic may already be functionally extinct, with under 50 members.

Gray whales technically fare much better and are listed under ‘least concern’ overall, as there are enough individuals to ensure a stable population and the last three years have seen an increase in their numbers. The western subpopulation is listed separately — based on genetic evidence showing they’re an isolated, distinct group — as ‘Critically Endangered.’ However, it must be noted that the gray whale has been completely wiped out in the North Atlantic, and the family’s range is now limited to the North Pacific exclusively.

Both species got so ragged after centuries of whaling. For context, the first records of right whale hunting come from Basque (northern Spain) whalers plying their trade in the Bay of Biscay in the 11th century. Gray whales have been hunted by indigenous populations since antiquity, although it’s likely that right whales suffered a similar fate.

Previously widespread

The findings, however, suggest that both species once inhabited much wider ranges than we ever suspected. The findings were only made possible by their use of “new molecular methods” to analyze the whale bones, the team says.

“Whales are often neglected in Archaeological studies,” says Dr. Camilla Speller, paper co-author, “because their bones are frequently too fragmented to be identifiable by their shape.”

“Our study shows that these two species were once part of the Mediterranean marine ecosystem and probably used the sheltered basin as a calving ground.”

Since both species are migratory, their presence east of Gibraltar (the strait that connects the Mediterranean sea to the Atlantic) suggests they came here to give birth in safer waters.

Southern Right Whale.

Southern Right Whale (Eubalaena australis).
Image credits Gregory “Slobirdr” Smith / Flickr.

The findings also raise the possibility that the Romans developed a form of whaling alongside traditional fishing practices. However, the evidence is far from conclusive. There is evidence that they fished for large species such as tuna, but based on what we know of their sailing and boat-building capabilities, it seems rather unlikely they would be able to hunt something as large as a whale.

“[…] perhaps the bones are evidence of opportunistic scavenging from beached whales along the coast line,” adds Dr. Speller.

“Romans did not have the necessary technology to capture the types of large whales currently found in the Mediterranean, which are high-seas species. But right and gray whales and their calves would have come very close to shore, making them tempting targets for local fishermen,” says study lead author Dr. Ana Rodrigues.

The opportunistic approach is more likely, especially since we know Basque whalers centuries later would successfully hunt for their prey using small rowing boats and hand harpoons.

The findings also help clarify historic sources such as texts penned by Roman naturalist Pliny the Elder, which describes killer whales attacking newborn calves and their mothers in the Cadiz bay. Today, such descriptions simply don’t make any sense, “but it fits perfectly with the ecology if right and gray whales used to be present,” according to co-author Anne Charpentier, a lecturer at the University of Montpellier.

The authors hope that — armed with their findings that coastal whales once formed an important part of the Mediterranean ecosystem — historians and archeologists can make better sense of other primary sources.

The paper “Forgotten Mediterranean calving grounds of gray and North Atlantic right whales: evidence from Roman archaeological records” has been published in the journal Proceedings of the Royal Society of London B.

Drought.

Europe will see a doubling of drought areas if climate change isn’t addressed

Europe will have to contend with more and more frequent droughts over larger areas than ever before if we don’t take steps to limit climate change.

Drought.

Image credits Grégory Roose.

According to the work of an international team of researchers, drought areas in Europe will double in size under a three-degree Celsius global warming scenario — from 13% of total area (calculated for the reference period 1971-2000) to 26%. If warming can be limited to 1.5°C, the target of the Paris Climate Protection Agreement, this expansion can be restricted to 19% of the total area, the researchers add.

With the exception of the Scandinavian region, droughts will also last longer — three to four times longer than in the past. Overall, some 400 million people could be affected by droughts throughout Europe.

Europe, dry

One of the areas that the team says will see the worst consequences is also one of the prettiest today — the Mediterranean region. Droughts here could expand from 28% of the area (calculated over the reference period) to 49% in some of the more extreme scenarios. Droughts would also last for significantly longer in Southern Europe than they do today.

“In the event of a three-degree warming, we assume there will be 5.6 drought months per year,” says Dr. Luis Samaniego, one of the two main authors of the study and a hydrologist at the Helmholtz Centre for Environmental Research (UFZ).

“Up to now, the number has been 2.1 months. For some parts of the Iberian Peninsula, we project that the drought could even last more than seven months.”

A three-degree Celsius temperature increase would also reduce water content in the soil by about 35 millimeters up to a depth of two meters. This roughly translates to a loss of 35,000 cubic meters of water per square kilometer (some 300,000 cubic feet of water per square mile) of land. It’s a huge quantity of water, a deficit that’s comparable to that experienced by large areas throughout Europe during the drought of 2003. It was one of the hottest summers ever recorded on the continent and led to crop failures or shortfalls in many areas. Alongside the economic impact, the heat wave associated with the drought claimed some 70,000 lives.

The researchers warn that if we don’t take steps to address climate change, scenarios like the 2003 drought won’t be just commonplace — they will be a fond memory. Under a three-degrees-warming (Celsius) scenario, droughts of comparable intensity and extent would occur twice as often in the coming years, essentially becoming the ‘default weather’ in many parts of Europe. In the future, droughts will far exceed even this new normal state in severity and duration, with major impacts on society and economy.

Under a 1.5-degree-warming (Celsius) scenario, the team estimates that the Mediterranean could be looking at roughly 3.2 months of drought annually and a decline in water content by about eight millimeters.

Spatial distribution of changes.

Spatial distribution of changes in drought area, duration and frequency.
Image credits L. Samaniego et al., 2018, Nature.

If, on the other hand, global warming increases by only 1.5 degrees Celsius, only 3.2 months of drought could be expected annually in the Mediterranean region and there would be a decline in the water content in the soil of about eight millimeters.

Other regions in Europe will fare better than the Mediterranean across all scenarios. In the Atlantic, Continental and Alpine regions, drought areas will enlarge by under 10% of the total area, the team writes.

In the Baltic states and Scandinavia, the team estimates that changes induced by global warming to precipitation patterns will actually cause drought-affected areas to shrink by three percent. In central Europe (i.e. around Germany), warming would have relatively mild consequences, although Thober warns that “here too, summers would be drier in the future than has been the case so far.”

The paper “Anthropogenic warming exacerbates European soil moisture droughts” has been published in the journal Nature Climate Change.

Fifteen ton Monolith found under the Mediterranean Sea, estimates put its carving at 9350 years ago

Zvi Ben-Avraham of Tel Aviv University and Emanuele Lodolo of the National Institute of Oceanography and Experimental Geophysics in Trieste, have discovered a monolith in deep water, resting on a spot that was once an island off the coast of Sicily. Their study has been published in the Journal of Archeological Science.

3-D perspective view of the high-resolution bathymetric map where the monolith has been discovered. No vertical exaggeration. Numbers indicate the locations of the corresponding rock samples.
Image source Journal of Archeological Science, supplied.

The 12-metre high, limestone monolithic structure is believed to have been carved by stone-age men some nine millennia ago. This enormous stone totem was cut using primitive tools from a rocky outcrop found a few hundred meters away from its current position in an age when the Mediterranean Sea was still a dry basin.

“It was cut and extracted as a single stone from the outer rectilinear ridge situated about 300 to the south, and then transported and possibly erected,” the study reads. ”From the size of the monolith, we may presume that it weighs about 15 tons.”

The bloc now rests, split in two, on the bed of the Mediterranean Sea in the Sicilian Channel -between Tunisia and Sicily- under 40 meters of water.

The two pieces of the monolith. Image source Journal of Archeological Science, supplied.

The two pieces of the monolith.
Image source Journal of Archeological Science, supplied.

The area was submerged about 9350 years ago (give or take 200 years) when the last Ice Age retreated. Before that time the area was believed to be something of an archipelago, with a string of islands linking Europe to North Africa via a shallow sea.

The most striking feature the carvers cut into the stone are three deep holes. Two of these are on the sides of the stone, the third passes through the stone at one end.

“There are no reasonable known natural processes that may produce these elements,” the team wrote in the Journal of Archaeological Science.

The three holes cut into the monolith. Image source ndad

The three holes cut into the monolith.
Image source Journal of Archeological Science, supplied.

Archeologists believe that the monolith had a practical, rater than religious use to the community. The island it was created on, Pantelleria Vecchia Bank, housed a thriving people that traded by sea and fished, before it was swallowed up by the Mediterranean.

“Most likely the structure was functional to the settlement. These people were used to fishing and trading with the neighboring islands. It could have been some sort of a lighthouse or an anchoring system, for example,” Lodolo said.

Manufacturing, moving and erecting a monolith of such size required careful cutting work, extraction techniques and transportation. Such skills had not been previously associated with such an ancient people, the study says.

“The discovery of the submerged site in the Sicilian Channel may significantly expand our knowledge of the earliest civilisations in the Mediterranean basin and our views on technological innovation and development achieved by the Mesolithic inhabitants.”