Dissolved inorganic carbon dynamics and air-sea carbon dioxide fluxes during coccolithophore blooms in the northwest European continental margin (northern Bay of Biscay)

• Published in: Global Biogeochemical Cycles
• Main Authors: Suykens, Kim, Delille, Bruno, Chou, Lei, De Bodt, Caroline, Harlay, Jérôme, Borges, Alberto
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2010
• Subjects: Physical; chemical; mathematical & earth Sciences; Life sciences; Environmental sciences & ecology; Earth sciences & physical geography; Physique; chimie; mathématiques & sciences de la terre; Sciences du vivant; Sciences de l’environnement & écologie; Sciences de la terre & géographie physique; North Atlantic
• Online Access: https://orbi.uliege.be/handle/2268/73953; https://orbi.uliege.be/bitstream/2268/73953/1/suykens_et_al_2010.pdf; https://doi.org/10.1029/2009GB003730

peer reviewed We report a data set of dissolved inorganic carbon (DIC) obtained during three cruises in the northern Bay of Biscay carried out in June 2006, May 2007, and May 2008. During these cruises, blooms of the coccolithophore Emiliania huxleyi occurred, as indicated by patches of high reflectance on remote sensing images, phytoplankton pigment signatures, and microscopic examinations. Total alkalinity showed a nonconservative behavior as a function of salinity due to the cumulative effect of net community calcification (NCC) on seawater carbonate chemistry during bloom development. The cumulative effect of NCC and net community production (NCP) on DIC and the partial pressure of CO2 (pCO(2)) were evaluated. The decrease of DIC (and increase of pCO(2)) due to NCC was overwhelmingly lower than the decrease of DIC (and decrease of pCO(2)) due to NCP (NCC: NCP << 1). During the cruises, the northern Bay of Biscay acted as a sink of atmospheric CO2 (on average similar to-9.7 mmol C m(-2) d(-1) for the three cruises). The overall effect of NCC in decreasing the CO2 sink during the cruises was low (on average similar to 12% of total air-sea CO2 flux). If this is a general feature in naturally occurring phytoplankton blooms in the North Atlantic Ocean (where blooms of coccolithophores are the most intense and recurrent), and in the global ocean, then the potential feedback on increasing atmospheric CO2 of the projected decrease of pelagic calcification due to thermodynamic CO2 "production" from calcification is probably minor compared to potential feedbacks related to changes of NCP.