Arctic Tipping Points

Scientists from IMEDEA, Spain, and ATP have been dedicated to understand the relation between primary production and respiration in the Arctic Ocean. There is a surprising dearth of information in these matters and by far the greatest quantity of information from the Arctic Ocean has been derived by IMEDEA. In principle there should be a balance between production and respiration over lengthy periods of time in the ocean. However, in certain regions and times the ratio between production and respiration deviates. It has also been discussed that the ocean consumes more carbon than it produces. This surprising findings resulted in vivid debates from the missing carbon derives. To prepare a well-balanced annual budget it is essential to investigate various seasons and ATP contributes to this. So far few production/respiration data have been obtained from the spring bloom period and ATP will try to fill this knowledge gap.

The Arctic Ocean is the region on Earth supporting the steepest warming rate and is also particularly vulnerable due to the vanishing ice cover. Intense warming in the Arctic has strong implications for biological activity and the functioning of an Arctic Ocean deprived of ice cover in summer. IMEDEA and the University of Lund, Sweden evaluated the impact of increasing temperature on respiration rates of surface marine planktonic communities, a property constraining the future role of the Arctic Ocean in the CO2 balance of the atmosphere. Plankton respiration rates due to warming will soon exceed increases in photosynthetic rates. Bacterial production increases by two-fold and respiration by 8-fold (on average) with a + 6° C warming. The future Arctic Ocean may consume most of the autotrophic production through the microbial food web, implying that the harvestable production caused by more light and higher temperatures (less ice) will not increase. Arctic Ocean primary production models must be improved to include realistic temperature-depended respiration and metabolism algorithms. An future Arctic Ocean void of summer ice will probably be less productive as currently projected and increase atmospheric CO2 concentrations, thus adding to the general increase of CO2 concentrations caused by human activities.