Some marine organisms on the seafloor thrive in corrosive seawater
Science Daily, 23 Aug 2016.
The sea floor is a habitat especially rich in species that produce calcium carbonate shells or skeletons – so-called marine calcifiers. Sea urchins, sea stars, coralline algae, crustaceans, and numerous mollusks, such as mussels, find their home here. Marine calcifiers play an important role in global biogeochemical cycles and serve important ecosystem functions. They are a food supply for other organisms and store carbon. At present, the ocean takes up a quarter of the carbon dioxide-released to the atmosphere by human industrial activities – with long-lasting consequences for the chemical composition of seawater and marine habitats. Read the full story in Science Daily.
How will seafloor marine life cope with chemical changes in sea water? Image: Scott Ling
In a new study recently published in the journal Global Biogeochemical Cycles, scientists of Kiel University (CAU) with colleagues from GEOMAR Helmholtz Centre for Ocean Research Kiel and international partners from the USA, New Zealand, and Great Britain studied marine benthic shell-forming organisms around the world in relation to the chemical conditions they currently experience -- with a surprising result: 24 percent, almost a quarter of the analyzed species, including sea urchins, sea stars, coralline algae or snails, already live in seawater unfavorable to the maintenance of their calcareous skeletons and shells (a condition referred to as CaCO3-undersaturation).
More than 100 marine benthic calcifying taxa, from the coastal zone to the deep sea, from tropical, temperate and polar regions, were included in this comprehensive study.
"The result surprised us a lot. For us, it is a sign that many marine organisms actually can live and maintain their calcareous shells under chemically unfavorable conditions which may reflect their physiological and evolutionary history," says lead author Dr. Mario Lebrato from the Institute of Geosciences at Kiel University (CAU).
Chemical parameters change when carbon dioxide dissolves in sea water. The pH decreases and the water becomes less alkaline and increasingly acidic. Ocean acidification is therefore one of the most important research areas regarding the effects of elevated CO2 on benthic marine calcifiers and the marine ecosystem in general.
Read the full story in Science Daily.
