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IMAGE: Seasonal blooms of tiny algae play an important role in marine carbon cycling. Now a new detail of the surrounding mysteries has been uncovered. view more
Credit: Max Planck Institute for Marine Microbiology / G. Reintjes
The annually occurring algal spring blooms play an important role for our climate, as they remove large amounts of carbon dioxide from the atmosphere. However, they are an ephemeral phenomenon. Most of the carbon is released into the water once the algae die. There, bacteria are already waiting to finish them off and consume the algal remains.
Previous studies have shown that in these blooms, different algae can come out on top each year. However, within the bacteria subsequently degrading the algae, the same specialised groups prevail year after year. Apparently not the algae themselves but rather their components - above all chains of sugar molecules, the so-called polysaccharides - determine which bacteria will thrive. However, th
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IMAGE: This Airyscan super-resolution image shows that fucose-containing sulphated polysaccharide, or FCSP, (in green) occurred around the cells of the chain-forming diatom Chaetoceros socialis and their spines. Sample collected during the. view more
Credit: Max Planck Institute for Marine Microbiology/S. Vidal-Melgosa
A major pathway for carbon sequestration in the ocean is the growth, aggregation and sinking of phytoplankton - unicellular microalgae like diatoms. Just like plants on land, phytoplankton sequester carbon from atmospheric carbon dioxide. When algae cells aggregate, they sink and take the sequestered carbon with them to the ocean floor. This so called biological carbon pump accounts for about 70 per cent of the annual global carbon export to the deep ocean. Estimated 25 to 40 per cent of carbon dioxide from fossil fuel burning emitted by humans may have been transported by this process from the atmosphere to depths below 1000 meter, where carbon
Tracking Arctic climate change from a Greenhouse to an Icehouse world eurekalert.org - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from eurekalert.org Daily Mail and Mail on Sunday newspapers.
Scientists’ discovery that fresh water, not salt water, once filled ice-covered sections of the Arctic could dramatically reshape our understanding of both ancient sea levels and climate change.
Tens of thousands of years ago, vast, ancient reserves of freshwater in the Arctic Ocean mixed with saline water in the Atlantic Ocean in a sudden exchange marked by a period of low sea levels and frigid temperatures. (Courtesy of Alfred Wegener Institute / Martin Künsting)
(CN) An analysis of sediment in the Arctic Ocean and Nordic seas found that during at least two glacial periods over the last 150,000 years the bodies of water were covered by a thick layer of ice and filled mostly with fresh water, not salt water, according to a study released Wednesday.
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IMAGE: In glacial periods with low sea levels, exchange with the Pacific was halted and exchange with the North Atlantic was extremely reduced, while the Arctic basin was still receiving freshwater. view more
Credit: Graphics: Alfred Wegener Institute/Martin Künsting
The Arctic Ocean was covered by up to 900 m thick shelf ice and was filled entirely with freshwater at least twice in the last 150,000 years. This surprising finding, reported in the latest issue of the journal
Nature, is the result of long-term research by scientists from the Alfred Wegener Institute and the MARUM. With a detailed analysis of the composition of marine deposits, the scientists could demonstrate that the Arctic Ocean as well as the Nordic Seas did not contain sea-salt in at least two glacial periods. Instead, these oceans were filled with large amounts of freshwater under a thick ice shield. This water could then be released into the North Atlantic in very short periods of time.