Tag Archives: lakes

World’s lakes are losing oxygen rapidly as the planet warms

Oxygen levels in many of the world’s freshwater lakes are declining rapidly — even faster than in the oceans — and this is suffocating wildlife and threatening drinking water supplies, a new study reports. Oxygen levels fell by 19% in deep waters and 5% at the surface of lakes since 1980 — three to nine times faster than in the oceans. 

Image credit: Flickr / Barniz

Previous studies have extensively reported on the declining oxygen levels in the ocean because of climate change. But lakes have been largely ignored, despite their importance for both wildlife and human communities. They comprise 3% of the planet’s land surface but are home to the bulk of the world’s biodiversity, making any alteration because of climate change concerning. 

“All complex life depends on oxygen. It’s the support system for aquatic food webs. And when you start losing oxygen, you have the potential to lose species,” Kevin Rose, co-author, said in a statement. “Lakes are losing oxygen 2.75-9.3 times faster than the oceans, a decline that will have impacts throughout the ecosystem.”

The researchers looked at the effect of declining oxygen levels on lakes, analyzing more than 45,000 dissolved oxygen samples and temperature trends across 393 temperate lakes in North America and Europe. They looked at temperatures at the surface and deep-water levels as well as the concentration of dissolved oxygen. The team identified rising temperatures as the main cause behind lake’s oxygen loss, as warmer water can’t hold as much oxygen as cooler ones.

Physics further amplifies the problem. When water gets hotter, it is lighter and floats towards the surface of the lake. This hotter, oxygen-poorer water stays at the surface of the lake, while more of the oxygen supply falls towards the bottom.

The good, the bad, and the cyanobacteria

Researchers also observed an effect which, at first glance, is a way to counterbalanace this effect. When lakes get hotter (and especially if they are also polluted with nutrient-rich runoff), cyanobacteria blooms become more likely. These bacteria produce a lot of oxygen through photosynthesis, but this is not a healthy process for the lake.

“The fact that we’re seeing increasing dissolved oxygen in those types of lakes is potentially an indicator of widespread increases in algal blooms, some of which produce toxins and are harmful. Absent taxonomic data, however, we can’t say that definitively, but nothing else we’re aware of can explain this pattern,” Rose said in a statement.

The concentration of oxygen in aquatic systems influences biodiversity, nutrient biogeochemistry, greenhouse gas emissions, the quality of drinking water, and, ultimately, human health. Many aquatic species require well-oxygenated habitats and cool water to survive warm summers. Loss of oxygen degrades water quality by promoting the release of accumulated nutrients from sediments into water.

“Lakes are indicators or ‘sentinels’ of environmental change and potential threats to the environment because they respond to signals from the surrounding landscape and atmosphere,” lead author Stephen Jane said in a statement. “We found that these disproportionally more biodiverse systems are changing rapidly.”

The study was published in the journal Nature. 

Global warming is making lakes everywhere hotter, and this is putting wildlife at risk

Lakes hold over 80% of the Earth’s surface freshwater and support wildlife communities across the planet. But many are already experiencing the effects of climate change, according to a new study. Researchers used satellite data to show the vulnerability of lakes and the consequences for freshwater species.

Credit Pixabay

The distribution and abundance of freshwater species is influenced by rising mean temperatures in lakewater, a consequence of climate change. A new paper estimates that the rate at which lake surface water temperature will change in the future, and compared this to the ability of species to move to cooler areas.

Known as climate change velocity, this figure is used by scientists to help understand the impacts of climate change.

In line with previous studies, the researchers found that most of the lakes, 99%, became by 0.13°C warmer per decade on average between 1979 to 2018. But, even more importantly, they discovered that climate change velocity will likely accelerate during the current century, with consequences on freshwater species.

Climate change velocity was 3.5 km per decade from 1861-2005, with a standard deviation of 2.3 km, the study showed. While this figure is similar to, or lower than, the rates at which some mobile species can migrate, the rate is expected to accelerate from now to the end of the century.

Under a low greenhouse gas emissions scenario, the researchers found climate velocity would increase to 8.7 km per decade, with a standard deviation of 5.5 km. Meanwhile, under a high-level emissions scenario, velocity would be as high as 57 km per decade, with a standard deviation of 17 km.

Iestyn Woolway, co-author of the study, said: “Lake temperatures are set to rise faster than the ability of some species to disperse to cooler areas. The consequences will be more serious for species that disperse less readily, such as freshwater mollusks, but even more motile species, such as some fish, which could migrate more rapidly are likely to be restricted by physical barriers.”

While lake climate change velocity is half that of marine environments, the fragmented and often isolated distribution of lakes across the landscape limits dispersal and puts pressure on freshwater species as well as the goods and services they provide, the researchers argued.

The study was published in the journal Nature Climate Change.

Great Lakes sediments show high levels of microplastic contamination

New research from the University of Western Ontario reports that the sediment lining the bottom of the Great Lakes is chock-full of microplastics.

Image credits Bruno Glätsch.

Plastics are one of the most widespread contaminants on Earth — and every bit of it was made by humans. A particular subset of them, that of plastic particles under five millimeters in size (known as microplastics), are particularly problematic.

Microplastics are tiny enough to evade most natural and man-made filtration systems, they’re easily mistaken for food and swallowed by wildlife (but aren’t digestible), and they can also be produced by the degradation of plastic masses dumped into the ocean.

And there’s a lot of it

As microplastics build up in the world’s waterways, they are also getting lodged in sediment layers. A new paper looked at the Great Lakes as a case study for microplastic pollution and its place in geologic processes.

The team, comprised of sedimentary petrologist Patricia Corcoran and her students at the University of Western Ontario, looked at the main sources of microplastics in sediment samples recovered from the Great Lakes. They also analyzed the distribution of these contaminants, looked for areas with particularly high levels of microplastics, and estimated which animals are placed at risk by exposure to these particles. Towards this goal, they retrieved sediment samples (both offshore and nearshore) from Lakes Huron, Ontario, Erie, St. Clair, and their tributaries.

Lab analyses revealed that microplastic concentrations in these samples reached as high as 4.270 microplastic particles per kilogram of (dry) sediment in the lakes, and up to 2.444 microplastic particles per kilogram of (dry) river sediment.

The team reports that microplastic content shows a strong link to the levels of organic debris in a given sample: the more organic material, the more microplastics were found. They add that benthic (lake bottom) microplastics were more abundant near areas with large human populations (these areas are further associated with plastic use and plastic production facilities).

One particularly important finding was that, although a large number of man-made particles were found in the samples, only around one-third were actual plastic.

“When we chemically analyzed fibers only 33% were plastic — the others, materials like dyed cotton or cellulose,” Corcoran says. “So we can’t assume that every fiber we see under the microscope is plastic.”

The team also looked at pellets (bigger microplastic particles, around the size of an individual lentil) in samples taken from 66 beaches across all five Great Lakes. They report finding 12.974 pellets over 660 square meters (7.104 sq ft) of investigated beach area. Two of the beaches that contained most pellets were close to population or industrial centers, but, apart from them, the team didn’t find any significant association between pellet number and areas of human activity. The pellets, they explain, were mostly concentrated around tributaries.

“In other words,” she says, “rivers and creeks are the main pathways used by pellets to reach the lakes.”

Corcoran has previously studied anthropogenic stones in Hawaii, a very in your face example of how plastics are imprinting themselves into the Earth’s geological record. She and her team at the time named these rocks “plastiglomerates” to showcase just how much plastic they contained — and she says the present study finds the early stages of a similar process underway in the Great Lakes.

The paper “Anthropogenic Grains: Microplastics in Benthic Compartments of the Great Lakes Watershed” will be presented by Sara Belontz of the University of Western Ontario at the GSA Annual Meeting in Phoenix, Arizona (Tuesday, 24 Sept. 2:30 p.m., in the North Building of the Phoenix Convention Center, Room 224A).

Just Stunning and Tranquil - Bafa Lake

3 Natural Turkish Lakes

Turkey is a beautiful country, whether visiting for a beach holiday under the sun, or a partying holiday in the cities, but for some, Turkey’s natural lakes make the perfect relaxing holiday. Camping, Trekking or visiting the local villages and experiencing their culture and cuisines are just a few of the attractions found at some of the most beautiful and ecologically sound lakes in the world.

Bafa Lake

Just Stunning and Tranquil - Bafa Lake

Just Stunning and Tranquil – Bafa Lake

Bafa Lake is situated southeast of the Buyuk Menderes Delta, 25 km from Soke from where you can access it. Once part of the Aegean Sea, the lake became a lake as result of geomorphologic development of Buyuk Menderes Delta. Its main sources are from Buyuk Menderes, plus the underground rivers flowing from the mountains. Plant life is rife, consisting of tamarisks, pine trees, and olive groves. Lake Bafa protects the ecosystem, and therefore provides a winter habitat for lots of species of birds, which would otherwise be in danger of extinction – approximately 300,000 birds take residence here. Pelicans, cormorants and sea eagles are just a few species. There are also over 700 kinds of plankton in the lake and a huge variety of plants, which feed many species of fish.

Bolu – Abant Lake

Bolu - Abant Lake

Bolu – Abant Lake – Amazing Clear and Peaceful Place

Abant Lake is 33km away from Bolu, in the west of the Black Sea area, halfway between Ankara and Istanbul. Abant lake can be reached by the E-5, the Ankara motorway, finally turning off at Omerler Madensuy. Bolu is connected by bus to other parts of the country. The lake is home to a wide variety of plants – 1150 hectares were designated by the status of Natural Park in 1988. Main species include Scotch pine, beech, larch, oak, poplar, ash, horn- beam, willow, juniper, forest rose, tamarisk, hazelnut, holly, dog-rose, bracken, blackberry, strawberry, mint, raspberry, ivy, nettle, mare’s tail, and a variety of pasture grasses and trees. Animal species include pig, deer, roe deer, bear, fox, jackal, and rabbit. You’ll also find birds of prey and singing birds – a real natural haven.

Lake Van

Lake - Van - Just Beautiful

Lake – Van – Just Beautiful

Lake Van is the biggest lake in Turkey and the largest soda water lake in the world. Lake Van lies on the high grounds of the Eastern Anatolian district near the border with Iran. Formed by a crater created by a volcanic explosion of Mt. Nemrud, its elevation from the sea level is over 1600 metres. The water is not very suitable for drinking or irrigation because of its high salinity content – sodium chloride and sodizm carbonate. There is a scenic lookout close to the unpaved road on the eastern slope of Mt. Nemrut, accessible by car/MTB/hike – perfect to make a day of endurance exercise.

Turkey has some truly stunning lakes and mountains you can get great Turkey breaks from Direct Line Holidays and get amongst this amazing environment. Such relaxing places and wonderful scenery if would be foolish to no explore this country.

 

6 geographical facts you’re not going to believe

Our world is a strange and awesome place — but some things are just hard to believe! Here are some mind-blowing geography facts.

Canada has more lakes than the rest of the world combined

Photo: LASZLO ILYES.

Canada is the second largest country on the face of the Earth, and it has a lot to brag about. Out of all the natural lakes in the world, more than 50% are situated in Canada.

Photo by Christianabend.

The number of lakes larger than three square kilometers is estimated at close to 31,752 by the Atlas of Canada, of which 561 lakes have a surface area larger than 100 km2, including four of the Great Lakes. All in all, a whopping 9% of Canada’s surface is covered in fresh water.

After Warsaw, Chicago has the largest Polish population in the world

Warsaw. Photo by Adrian Grycuk.

Warsaw is Poland’s capital, having under 3 million inhabitants, out of which 95% are have Polish origins. However, besides Warsaw, there isn’t a single city with a larger Polish population than Chicago, even though Poland number 40 million inhabitants.

Polish market

Polish market in Chicago

Chicago is the third largest city in the US, with 7.5 million people living in the metropolitan area. Due to the huge Polish population, the architecture and culture of the city greatly resemble that of Poland, and you can find Polish theaters, markets, even a newspaper.

Girls Wearing Traditional Polish Outfits. Photo by włodi

Girls Wearing Traditional Polish Outfits. Photo by włodi

It’s pretty difficult to say just how much of Chicago’s population is Polish, with estimates ranging from 150,000 inhabitants to 10 times more – there’s no exact number.

Chicago. Photo by Allen McGregor.

The largest city in the world is Hulunbuir, at 263,953 km2

Where would you expect to see the world’s largest city? China, India, Russia? Just so you can make an idea, this city in inner Mongolia (China) is about as half as big as France, and it’s just a city !

The grasslands of Hulunbuir. Photo by llee_wu

However, the urban agglomeration is just a small fraction of the city, with the area population density being otherwise really small. All accross the megacity you can see large landscapes of grassland, and industrialization is only existant in the center. For all its surface, the city has “only” 2.5 million inhabitants.

The driest place on Earth is near Ross Island, Antactica; it hasn’t rained there for millions of years

Photo by NASA.

Yes, Antarctica is the driest place on the Earth, with the Atacama desert being 2nd, and Sahara the third.

The deepest hole dug by man is over 12 km deep

The Kola Superdeep Borehole has a depth of 12,261 meters — that’ s one and a half Everest long, or deeper than the Mariana trench.

The core is under this rusty, metallic cap. Photo by Rakot13

The core is under this rusty, metallic cap. Photo by Rakot13

The borehole also led to some interesting discoveries, including a massive amount of hydrogen, so massive that the mud was actually “boiling” with it.

In New York, there are more Italians than in Rome, more Irish than in Dublin and more Jews than in Tel Aviv

The big apple stands out anytime, no matter who you are or what you’re interested in. But still, I was really shocked to see this. I mean, with Rome having more than 3.5 million people, Dublin at 1 million and Tel Aviv at more than 3, that’s almost 8 million people !

Times Square, New York. Photo by Terabass.

Not to mention the other nationalities (which are quite abundent), one can only wonder how many Americans are living in New York.

Now c’mon people, hit me with your best geographical fact !

Picture sources: 1 2 3 4 5 6 7 8 9 10

[no_toc]

Underwater… lakes !

underwater-lake-1

The lake floor, composed mostly of mussels

Boy I’ve gotta tell you, my jaw really dropped when I heard this one. There are actual lakes, on the bottom of oceans, especially in the Gulf of Mexico region; they’ve got their own shores and all. The brine water of these lakes actually hosts unique wildlife, creating an absolutely amazing environment. The fact that these are brine water means that they have an extremely high salinity, way more than the rest of the ocean, which means of course they are heavier, which is why they stick to the bottom.

2523112090103830173s600x600q85

Think about the very bottom of the ocean, below the waves, below the light. What’s the first thing that comes to mind ? For me, it’s a cold dark environment filled with weird squids and fish with sharp teeth. I’m guessing your first picture is (and probably should be) something else, but it most definitely wouldn’t be an underwater lake ! I didn’t even know such a thing existed until recently. I’m telling you, you really REALLY should look at these videos


These lakes are located in brine pools, which formed during the Jurassic period. During that period, the shallow lakes from the Gulf of Mexico dried out, as a result of tectonic movements in a salt-rich area and perhaps the overall heat in the Jurassic period (it was so hot there were no polar caps). Later on, the 8 km saline layer was covered with sediments and preserved, becoming an underwater lake.

Of course such extreme amounts of salt make it almost impossible to live there, but as (almost) always, some extremophiles will adapt to the extreme conditions. Such is the case with some bacteria, shrimp or mollusks that managed to find a way to survive off of the methane, which is quite abundant in the area. The bacteria get the necessary energy from it through a process called chemosynthesis and then pass it on through symbiosis, which means they rely only on chemical energy instead of solar energy, like the other ecosystems on Earth.