by Rutgers University, Dec 2, 2021 in WUWT
New Brunswick, N.J. (Dec. 1, 2021) – Using artificial intelligence techniques, an international team that included Rutgers-New Brunswick researchers have traced the evolution of coccolithophores, an ocean-dwelling phytoplankton group, over 2.8 million years.
Their findings, published this week in the journal Nature, reveal new evidence that evolutionary cycles in a marine phytoplankton group are related to changes in tropical seasonality, shedding light on the link between biological evolution and climate change.
Coccolithophores are abundant single-celled organisms that surround themselves with microscopic plates made of calcium carbonate, called coccoliths. Due to their photosynthetic activity, mineral production and widespread abundance throughout the world’s oceans, coccolithophores play an important role in the carbon cycle.
Scientists have long thought that climate changes’ effects on plants, animals and other organisms occur in cycles, which are reversed when each cycle is completed, thus erasing any small evolutionary changes during each cycle. In contrast, evolutionary changes, as known from the fossil record, are non-cyclic trends that occur over millions of years.
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by Stanford’s School of Earth, Energy & Environmental Sciences, June 5, 2019 in WUWT
More “settled science” of the carbon cycle~ctm
Stanford study shows how hydrothermal vents fuel massive phytoplankton blooms — and possible hotspots for carbon storage
Researchers at Stanford University say they have found an aquatic highway that lets nutrients from Earth’s belly sweep up to surface waters off the coast of Antarctica and stimulate explosive growth of microscopic ocean algae.
Their study, published June 5 in the journal Nature Communications, suggests that hydrothermal vents – openings in the seafloor that gush scorching hot streams of mineral-rich fluid – may affect life near the ocean’s surface and the global carbon cycle more than previously thought.
Mathieu Ardyna, a postdoctoral scholar and the study’s lead author, said the research provides the first observed evidence of iron from the Southern Ocean’s depths turning normally anemic surface waters into hotspots for phytoplankton – the tiny algae that sustain the marine food web, pull heat-trapping carbon dioxide out of the air and produce a huge amount of the oxygen we breathe. “Our study shows that iron from hydrothermal vents can well up, travel across hundreds of miles of open ocean and allow phytoplankton to thrive in some very unexpected places,” he said.
Kevin Arrigo, a professor of Earth system science and senior author of the paper, called the findings “important because they show how intimately linked the deep ocean and surface ocean can be.”
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by Charles the moderator, February 5, 2019 in WUWT
Climate-driven changes in phytoplankton communities will intensify the blue and green regions of the world’s oceans
From the Massachusetts Institute of Technology
Climate change is causing significant changes to phytoplankton in the world’s oceans, and a new MIT study finds that over the coming decades these changes will affect the ocean’s color, intensifying its blue regions and its green ones. Satellites should detect these changes in hue, providing early warning of wide-scale changes to marine ecosystems.
Writing in Nature Communications, researchers report that they have developed a global model that simulates the growth and interaction of different species of phytoplankton, or algae, and how the mix of species in various locations will change as temperatures rise around the world. The researchers also simulated the way phytoplankton absorb and reflect light, and how the ocean’s color changes as global warming affects the makeup of phytoplankton communities.
The researchers ran the model through the end of the 21st century and found that, by the year 2100, more than 50 percent of the world’s oceans will shift in color, due to climate change.
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by Bigelow Laboratory for Ocean Sciences, January 8, 2019 in ScicneDaily
Microscopic marine plants flourish beneath the ice that covers the Greenland Sea, according to a new study. These phytoplankton create the energy that fuels ocean ecosystems, and the study found that half of this energy is produced under the sea ice in late winter and early spring, and the other half at the edge of the ice in spring.
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by Helmholtz Centre for Ocean Research Kiel (GEOMAR), Auhsut 14, 2018 in ScienceDaily
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The unusual timing of highly-productive summer plankton blooms off Greenland indicates a connection between increasing amounts of meltwater and nutrients in these coastal waters. Researchers now show that this connection exists, but is much more complex than widely supposed. Whether increasing meltwater has a positive or negative effect on summertime phytoplankton depends on the depth at which a glacier sits in the ocean.
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“So, the study shows that further melting of Greenland’s glaciers only leads to stronger summer plankton blooms under very specific conditions, an effect that will ultimately end with very extensive further melting,” Hopwood summarizes the results of the study.
by University of Bristol, August 10, 2018 in ScienceDaily
Silica is needed by a group of marine algae (the microscopic plants of the oceans) called diatoms, who use it to build their glassy cell walls (known as frustules).
These plankton take up globally significant amounts of carbon — they remove carbon dioxide from the atmosphere via photosynthesis, and act as a natural carbon sink when they die and fall to the bottom of the ocean — and form the base of the marine food chain.
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The researchers are also planning to use more complex and realistic computer models to delve deeper into the potential changes in the global silica cycle since the last glacial maximum. These might include more accurate representations of ocean currents, recycling of silica in the water column, and potential changes to the marine algal community.
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- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, May 22, 2018 in ScienceDaily
When marine algae die, they usually float in slow motion to the ocean’s depths. However, during an expedition with the research icebreaker Polarstern to the Arctic in the spring of 2015, scientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) discovered a phenomenon that significantly accelerate this transport: tiny gypsum crystals, which form during the freezing of salt in the porous spaces of Arctic sea ice, weigh down the phytoplankton like heavy ballast, pulling them to the bottom within a matter of hours. The effect is like an express elevator for the carbon they contain. “This mechanism was previously completely unknown,” says marine bio-geologist Dr Jutta Wollenburg … (…)
by Forschungsverbund Berlin e.V. (FVB), September 21, in ScienceDaily
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With the help of satellite observations from 188 lakes worldwide, scientists have shown that the warming of large lakes amplifies their color. Lakes which are green due to their high phytoplankton content tend to become greener in warm years as phytoplankton content increases. Clear, blue lakes with little phytoplankton, on the other hand, tend to become even bluer in warm years caused by declines in phytoplankton. Thus, contrary to previous assumptions, the warming of lakes tends to amplify their richness or poverty of phytoplankton.
See also here
La géologie, une science plus que passionnante … et diverse
