Retreating sea ice increases carbon storage by marine Animals.


The Article

Barnes, D.K.A., Ireland, L., Hogg, O.T., Morley, S., Enderlein, P., Sands, C.J., (2015) Why is the South Orkney Island shelf (the world’s first high seas marine protected area) a carbon immobilization hotspot? Global change biology.

Article Abstract

Abstract from the article:

“The Southern Ocean archipelago, the South Orkney Islands (SOI), became the world’s first entirely high seas marine protected area (MPA) in 2010. The SOI continental shelf (~44,000 km2), was less than half covered by grounded ice sheet during glaciations, is biologically rich and a key area of both sea surface warming and sea-ice losses. Little was known of the carbon cycle there, but recent work showed it was a very important site of carbon immobilization (net annual carbon accumulation) by benthos, one of the few demonstrable negative feedbacks to climate change. Carbon immobilization by SOI bryozoans were higher, per species, unit area and ice-free day, than anywhere-else polar. Here we investigate why carbon immobilization has been so high at SOI, and whether this is due to high density, longevity, or high annual production in six study species of bryozoans (benthic suspension feeders). We compared benthic carbon immobilization across major regions around West Antarctica with sea-ice and primary production, from remotely-sensed and directly-sampled sources.

Lowest carbon immobilization was at the northernmost study regions (South Georgia) and southernmost Amundsen Sea. However data standardised for age and density showed that only SOI was anomalous (high). High immobilization at SOI was due to very high annual production of bryozoans (rather than high densities or longevity); which were 2x, 3x and 5x higher than on the Bellingshausen, South Georgia and Amundsen shelves respectively. We found that carbon immobilization correlated to the duration (but not peak or integrated-biomass) of phytoplankton blooms, both in directly sampled, local scale data and across regions using remote sensed data. The long bloom at SOI seems to drive considerable carbon immobilization, but sea ice losses across West Antarctica mean that significant carbon sinks and negative feedbacks to climate change could also develop in the Bellingshausen and Amundsen seas.”

Read more on the topic

ScienceDaily: (September, 2015): As polar ice melts, seabed life is working against climate change.

RedOrbit (September 2015): Antarctic seabed life reduces climate change.