Late spring bloom development of pelagic diatoms in Baffin Bay
|Author(s)||Lafond Augustin1, Leblanc Karine1, Queguiner Bernard1, Moriceau Brivaela2, Leynaert Aude2, Cornet Veronique1, Legras Justine1, Ras Josephine5, Parenteau Marie3, 4, Garcia Nicole1, Babin Marcel3, 4, Tremblay Jean-Eric3, 4|
|Affiliation(s)||1 : Aix Marseille Univ, Univ Toulon, CNRS, IRD,MIO,UM 110, F-13288 Marseille, France.
2 : Inst Univ Europeen Mer, Lab Sci Environm Marin, Technopole Brest Iroise, Plouzane, France.
3 : Laval Univ, CNRS, Takuvik Joint Int Lab, Quebec City, PQ, Canada.
4 : Univ Laval, Dept Biol & Quebec Ocean, Quebec City, PQ, Canada.
5 : Sorbonne Univ, Univ Paris 06, Lab Oceanog Villefranche, CNRS,IMEV,UPMC, Villefranche Sur Mer, France.
|Source||Elementa-science Of The Anthropocene (2325-1026) (Univ California Press), 2019-11 , Vol. 7 , N. 44 , P. 24p.|
|WOS© Times Cited||19|
|Keyword(s)||Diatoms, Spring bloom, Sea ice, Community composition, Baffin Bay, Arctic|
|Abstract||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.|