Distribution of calcifying and silicifying phytoplankton in relation to environmental and biogeochemical parameters during the late stages of the 2005 North East Atlantic Spring Bloom

• Main Authors: Leblanc, Karine, Hare, C. E., Feng, Y., Berg, G. M., Ditullio, G. R., Neeley, A., Benner, I., Sprengel, C., Beck, A., Sanudo-Wilhelmy, S. A., Passow, U., Klinck, K., Rowe, J. M., Wilhelm, S. W., Brown, C. W., Hutchins, D. A.
• Other Authors: Laboratoire d'océanographie et de biogéochimie (LOB), Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Woods Hole Oceanographic Institution (WHOI), CAS Key Laboratory of Marine Ecology and Environmental Science (KLMEES), CAS Institute of Oceanology (IOCAS), Chinese Academy of Sciences Beijing (CAS)-Chinese Academy of Sciences Beijing (CAS), Department of Earth System Science Stanford (ESS), Stanford EARTH, Stanford University-Stanford University, Hollings Marine Laboratory, College of Charleston, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine (AWI), Helmholtz-Gemeinschaft = Helmholtz Association, Max Planck Institute for Marine Microbiology, Max-Planck-Gesellschaft, Department of Biological Sciences Los Angeles, University of Southern California (USC), University of Nebraska–Lincoln, University of Nebraska System, Deparment of Microbiology UTK, The University of Tennessee Knoxville, NOAA Center for Satellite Applications and Research (STAR), NOAA National Environmental Satellite, Data, and Information Service (NESDIS), National Oceanic and Atmospheric Administration (NOAA)-National Oceanic and Atmospheric Administration (NOAA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2009
• Subjects: OCEANIC WATERS; TRANSPARENT EXOPOLYMER PARTICLES; MARINE-PHYTOPLANKTON; EMILIANIA-HUXLEYI; INCREASED PCO(2); NORTHEASTERN ATLANTIC; COCCOLITHOPHORE BLOOM; SPATIAL VARIABILITY; PARTICULATE MATTER; UPWELLING REGIME; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; North East Atlantic
• Online Access: https://hal.science/hal-00703804; https://hal.science/hal-00703804/document; https://hal.science/hal-00703804/file/Leblanc_2009.pdf

The late stage of the North East Atlantic (NEA) spring bloom was investigated during June 2005 along a transect section from 45 to 66 degrees N between 15 and 20 degrees W in order to characterize the contribution of siliceous and calcareous phytoplankton groups and describe their distribution in relation to environmental factors. We measured several biogeochemical parameters such as nutrients, surface trace metals, algal pigments, biogenic silica (BSi), particulate inorganic carbon (PIC) or calcium carbonate, particulate organic carbon, nitrogen and phosphorus (POC, PON and POP, respectively), as well as transparent exopolymer particles (TEP). Results were compared with other studies undertaken in this area since the JGOFS NABE program. Characteristics of the spring bloom generally agreed well with the accepted scenario for the development of the autotrophic community. The NEA seasonal diatom bloom was in the late stages when we sampled the area and diatoms were constrained to the northern part of our transect, over the Icelandic Basin (IB) and Icelandic Shelf (IS). Coccolithophores dominated the phytoplankton community, with a large distribution over the Rockall-Hatton Plateau (RHP) and IB. The Porcupine Abyssal Plain (PAP) region at the southern end of our transect was the region with the lowest biomass, as demonstrated by very low Chla concentrations and a community dominated by picophytoplankton. Early depletion of dissolved silicic acid (DSi) and increased stratification of the surface layer most likely triggered the end of the diatom bloom, leading to coccolithophore dominance. The chronic Si deficiency observed in the NEA could be linked to moderate Fe limitation, which increases the efficiency of the Si pump. TEP closely mirrored the distribution of both biogenic silica at depth and prymnesiophytes in the surface layer suggesting the sedimentation of the diatom bloom in the form of aggregates, but the relative contribution of diatoms and coccolithophores to carbon export in this area still needs to be ...