Kim JM, Lee K, Shin K, Yang EJ, Engel A, Karl DM, Kim HC
inorganic carbon, biogenic carbon, acidification, warming, CO2 enrichment, mesocosm, 3 m3, Korea
Photosynthesis by phytoplankton in sunlit surfacewaters transforms inorganic carbon and nutrients intoorganic matter, a portion of which is subsequentlytransported vertically through the water column by theprocess known as the biological carbon pump (BCP). TheBCP sustains the steep vertical gradient in total dissolvedcarbon, thereby contributing to net carbon sequestration.Any changes in the vertical transportation of the organicmatter as a result of future climate variations will directlyaffect surface ocean carbon dioxide (CO2) concentrations,and subsequently influence oceanic uptake of atmosphericCO2 and climate. Here we present results of experimentsdesigned to investigate the potential effects of oceanacidification and warming on the BCP. These perturbationexperiments were carried out in enclosures (3,000 Lvolume) in a controlled mesocosm facility that mimickedfuture pCO2 (?900 ppmv) and temperature (3°C higherthan ambient) conditions. The elevated CO2 andtemperature treatments disproportionately enhanced theratio of dissolved organic carbon (DOC) production toparticulate organic carbon (POC) production, whereas thetotal organic carbon (TOC) production remained relativelyconstant under all conditions tested. A greater partitioningof organic carbon into the DOC pool indicated a shift in theorganic carbon flow from the particulate to dissolvedforms, which may affect the major pathways involved inorganic carbon export and sequestration under future oceanconditions. Citation: Kim, J.?M., K. Lee, K. Shin, E. J. Yang,A. Engel, D. M. Karl, and H.?C. Kim (2011), Shifts in biogenic carbonflow from particulate to dissolved forms under high carbondioxide and warm ocean conditions