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The oceans’ sensitive skin—Ocean acidification affects climate-relevant functions at the sea-surface
http://www.geomar.de/en/news/article/die-empfindliche-haut-des-ozeans/[font face=Serif]11.11.2014
[font size=5]The oceans’ sensitive skin[/font]
[font size=4]Ocean acidification affects climate-relevant functions at the sea-surface microlayer[/font]
[font size=3]November 11, 2014/Kiel. Ocean acidification might alter climate-relevant functions of the oceans’ uppermost layer, according to a study by a group of marine scientists published in the “Journal of Geophysical Research: Oceans”. In an experiment led by GEOMAR Helmholtz Centre for Ocean Research Kiel, the researchers observed a close coupling between biological processes in the seawater and the chemistry of the sea surface microlayer. Also, they noted a growing number of specialised bacterial and algal cells in this microenvironment. These changes might influence interactions between the ocean and the atmosphere such as the air-sea gas exchange and the emission of sea-spray aerosols that can scatter solar radiation or contribute to the formation of clouds.
Like a skin, the sea-surface microlayer separates the ocean from the atmosphere. The exchange of gases and the emission of sea-spray aerosols – two functions that are crucial for climate – take place in this boundary film. A mesocosm experiment by scientists from GEOMAR Helmholtz Centre for Ocean Research Kiel, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research Bremerhaven (AWI) and the Institute for Baltic Sea Research Warnemünde (IOW) reveals for the first time how ocean change might affect the special physical, chemical and biological characteristics of the ocean’s uppermost boundary. The results are published in the “Journal of Geophysical Research: Oceans”. First author is Dr. Luisa Galgani who conducted the study as part of her PhD at GEOMAR and AWI.
“Experiments have shown how ocean acidification, a change in the ocean chemistry due to the uptake of man-made carbon dioxide, influences the growth and efficiency of marine bacteria as well as the sinking of carbon-rich particles”, Dr. Luisa Galgani resumes. “We know that organic material and microorganisms accumulating in the sea-surface microlayer are similar to those found in the water column below. So we expected that ocean acidification-driven changes in ocean biogeochemistry in the water column can also be reflected in the microlayer. It is important to understand changes in this microenvironment, because it might have consequences for air-sea interactions that are relevant for our climate.”
…
Analyses of the samples verified that organic compounds in the sea-surface microlayer reflected the temporal development of phytoplankton growth in the water column. Also, at higher CO2 levels, the concentrations of bacterioneuston, marine bacteria inhabiting the surface, increased. More acidic conditions promoted changes in the dynamics of organic matter. Especially proteinaceous marine gels became smaller but more abundant probably because they served as a nutritional substrate in the sea-surface microlayer, where higher abundances of microorganisms were more efficient in degrading the organic material accumulated during a phytoplankton bloom.
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http://onlinelibrary.wiley.com/doi/10.1002/2014JC010188/abstract[font size=5]The oceans’ sensitive skin[/font]
[font size=4]Ocean acidification affects climate-relevant functions at the sea-surface microlayer[/font]
[font size=3]November 11, 2014/Kiel. Ocean acidification might alter climate-relevant functions of the oceans’ uppermost layer, according to a study by a group of marine scientists published in the “Journal of Geophysical Research: Oceans”. In an experiment led by GEOMAR Helmholtz Centre for Ocean Research Kiel, the researchers observed a close coupling between biological processes in the seawater and the chemistry of the sea surface microlayer. Also, they noted a growing number of specialised bacterial and algal cells in this microenvironment. These changes might influence interactions between the ocean and the atmosphere such as the air-sea gas exchange and the emission of sea-spray aerosols that can scatter solar radiation or contribute to the formation of clouds.
Like a skin, the sea-surface microlayer separates the ocean from the atmosphere. The exchange of gases and the emission of sea-spray aerosols – two functions that are crucial for climate – take place in this boundary film. A mesocosm experiment by scientists from GEOMAR Helmholtz Centre for Ocean Research Kiel, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research Bremerhaven (AWI) and the Institute for Baltic Sea Research Warnemünde (IOW) reveals for the first time how ocean change might affect the special physical, chemical and biological characteristics of the ocean’s uppermost boundary. The results are published in the “Journal of Geophysical Research: Oceans”. First author is Dr. Luisa Galgani who conducted the study as part of her PhD at GEOMAR and AWI.
“Experiments have shown how ocean acidification, a change in the ocean chemistry due to the uptake of man-made carbon dioxide, influences the growth and efficiency of marine bacteria as well as the sinking of carbon-rich particles”, Dr. Luisa Galgani resumes. “We know that organic material and microorganisms accumulating in the sea-surface microlayer are similar to those found in the water column below. So we expected that ocean acidification-driven changes in ocean biogeochemistry in the water column can also be reflected in the microlayer. It is important to understand changes in this microenvironment, because it might have consequences for air-sea interactions that are relevant for our climate.”
…
Analyses of the samples verified that organic compounds in the sea-surface microlayer reflected the temporal development of phytoplankton growth in the water column. Also, at higher CO2 levels, the concentrations of bacterioneuston, marine bacteria inhabiting the surface, increased. More acidic conditions promoted changes in the dynamics of organic matter. Especially proteinaceous marine gels became smaller but more abundant probably because they served as a nutritional substrate in the sea-surface microlayer, where higher abundances of microorganisms were more efficient in degrading the organic material accumulated during a phytoplankton bloom.
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