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CO 2 sensitivity of Southern Ocean phytoplankton
Author(s) -
Tortell Philippe D.,
Payne Christopher D.,
Li Yingyu,
Trimborn Scarlett,
Rost Björn,
Smith Walker O.,
Riesselman Christina,
Dunbar Robert B.,
Sedwick Pete,
DiTullio Giacomo R.
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl032583
Subject(s) - phytoplankton , biogeochemical cycle , oceanography , environmental science , carbon cycle , water column , productivity , seawater , diatom , biological pump , cycling , environmental chemistry , chemistry , ecology , nutrient , ecosystem , biology , geology , history , macroeconomics , archaeology , economics
The Southern Ocean exerts a strong impact on marine biogeochemical cycles and global air‐sea CO 2 fluxes. Over the coming century, large increases in surface ocean CO 2 levels, combined with increased upper water column temperatures and stratification, are expected to diminish Southern Ocean CO 2 uptake. These effects could be significantly modulated by concomitant CO 2 ‐dependent changes in the region's biological carbon pump. Here we show that CO 2 concentrations affect the physiology, growth and species composition of phytoplankton assemblages in the Ross Sea, Antarctica. Field results from in situ sampling and ship‐board incubation experiments demonstrate that inorganic carbon uptake, steady‐state productivity and diatom species composition are sensitive to CO 2 concentrations ranging from 100 to 800 ppm. Elevated CO 2 led to a measurable increase in phytoplankton productivity, promoting the growth of larger chain‐forming diatoms. Our results suggest that CO 2 concentrations can influence biological carbon cycling in the Southern Ocean, thereby creating potential climate feedbacks.