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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
1Université d'Aix-Marseille; CNRS; LOPB-UMR 6535, Laboratoire d'Océanographie Physique et Biogéochimique; OSU/Centre d'Océanologie de Marseille, UMR 6535, Campus de Luminy Case 901, 163 Avenue de Luminy, 13288 Marseille Cedex 09, France
2Woods Hole Group, Inc., 100 Carlson Way, Suite 9, Dover, Delaware, 19901, USA
3Laboratory of Marine Ecology and Environmental Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
4Department of Environmental Earth System Science, Stanford University, Stanford, CA 94305, USA
5Hollings Marine Laboratory, College of Charleston, Charleston, SC 29412, USA
6NASA/SSAI/BWTech 1450 S Rolling Road Halethorpe, MD 21227, USA
7Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
8Romberg Tiburon Center for Environmental Studies San Francisco State University 3152 Paradise Drive Tiburon, CA 94920, USA
9Max-Planck-Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany
10Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, CA 90089, USA
11University of Nebraska, the Department of Biological Sciences, in Lincoln, NE 68583, USA
12Marine Science Institute, University California Santa Barbara, CA 93106, USA
13Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
14Center for Satellite Applications and Research, National Oceanographic and Atmospheric Administration, College Park, MD 20740, USA
Abstract. The late stage of the North East Atlantic (NEA) spring bloom was investigated during June 2005 along a transect section from 45 to 66° N between 15 and 20° 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 resolved.
Final Revised Paper (PDF, 4009 KB) Discussion Paper (BGD)
Citation: Leblanc, K., 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., and Hutchins, D. A.: 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, Biogeosciences, 6, 2155-2179, 2009. Bibtex EndNote Reference Manager
