FN Archimer Export Format PT J TI Late spring bloom development of pelagic diatoms in Baffin Bay BT AF LAFOND, Augustin LEBLANC, Karine QUEGUINER, Bernard MORICEAU, Brivaela LEYNAERT, Aude CORNET, Veronique LEGRAS, Justine RAS, Josephine PARENTEAU, Marie GARCIA, Nicole BABIN, Marcel TREMBLAY, Jean-Eric AS 1:1;2:1;3:1;4:2;5:2;6:1;7:1;8:5;9:3,4;10:1;11:3,4;12:3,4; FF 1:;2:;3:;4:;5:;6:;7:;8:;9:;10:;11:;12:; C1 Aix Marseille Univ, Univ Toulon, CNRS, IRD,MIO,UM 110, F-13288 Marseille, France. Inst Univ Europeen Mer, Lab Sci Environm Marin, Technopole Brest Iroise, Plouzane, France. Laval Univ, CNRS, Takuvik Joint Int Lab, Quebec City, PQ, Canada. Univ Laval, Dept Biol & Quebec Ocean, Quebec City, PQ, Canada. Sorbonne Univ, Univ Paris 06, Lab Oceanog Villefranche, CNRS,IMEV,UPMC, Villefranche Sur Mer, France. C2 UNIV AIX MARSEILLE, FRANCE UBO, FRANCE UNIV LAVAL, CANADA UNIV LAVAL, CANADA UNIV PARIS 06, FRANCE UM LEMAR IN WOS Cotutelle UMR DOAJ copubli-france copubli-univ-france copubli-int-hors-europe IF 4.212 TC 23 UR https://archimer.ifremer.fr/doc/00615/72752/72021.pdf https://archimer.ifremer.fr/doc/00615/72752/72022.pdf LA English DT Article DE ;Diatoms;Spring bloom;Sea ice;Community composition;Baffin Bay;Arctic AB The Arctic Ocean is particularly affected by climate change, with changes in sea ice cover expected to impact phytoplankton primary production. During the Green Edge expedition, the development of the late spring-early summer diatom bloom was studied in relation with the sea ice retreat by multiple transects across the marginal ice zone. Biogenic silica concentrations and uptake rates were measured. In addition, diatom assemblage structures and their associated carbon biomass were determined, along with taxon-specific contributions to total biogenic silica production using the fluorescent dye PDMPO. Results indicate that a diatom bloom developed in open waters close to the ice edge, following the alleviation of light limitation, and extended 20-30 km underneath the ice pack. This actively growing diatom bloom (up to 0.19 mu mol Si L-1 d(-1)) was associated with high biogenic silica concentrations (up to 2.15 mu mol L-1), and was dominated by colonial fast-growing centric (Chaetoceros spp. and Thalassiosira spp.) and ribbon-forming pennate species (Fragilariopsis spp./Fossula arctica). The bloom remained concentrated over the shallow Greenland shelf and slope, in Atlantic-influenced waters, and weakened as it moved westwards toward ice-free Pacific-influenced waters. The development resulted in a near depletion of all nutrients eastwards of the bay, which probably induced the formation of resting spores of Melosira arctica. In contrast, under the ice pack, nutrients had not yet been consumed. Biogenic silica and uptake rates were still low (respectively <0.5 mu mol L-1 and <0.05 mu mol L-1 d(-1)), although elevated specific Si uptake rates (up to 0.23 d(-1)) probably reflected early stages of the bloom. These diatoms were dominated by pennate species (Pseudo-nitzschia spp., Ceratoneis closterium, and Fragilariopsis spp./Fossula arctica). This study can contribute to predictions of the future response of Arctic diatoms in the context of climate change. PY 2019 PD NOV SO Elementa-science Of The Anthropocene SN 2325-1026 PU Univ California Press VL 7 IS 44 UT 000496003700001 DI 10.1525/elementa.382 ID 72752 ER EF