TY - JOUR
T1 - Environmental drivers of under-ice phytoplankton bloom dynamics in the Arctic Ocean
AU - Ardyna, Mathieu
AU - Mundy, C. J.
AU - Mills, Matthew M.
AU - Oziel, Laurent
AU - Grondin, Pierre Luc
AU - Lacour, Léo
AU - Verin, Gauthier
AU - Van Dijken, Gert
AU - Ras, Joséphine
AU - Alou-Font, Eva
AU - Babin, Marcel
AU - Gosselin, Michel
AU - Tremblay, Jean Éric
AU - Raimbault, Patrick
AU - Assmy, Philipp
AU - Nicolaus, Marcel
AU - Claustre, Hervé
AU - Arrigo, Kevin R.
N1 - Generated from Scopus record by KAUST IRTS on 2023-10-11
PY - 2020/1/1
Y1 - 2020/1/1
N2 - The decline of sea-ice thickness, area, and volume due to the transition from multi-year to first-year sea ice has improved the under-ice light environment for pelagic Arctic ecosystems. One unexpected and direct consequence of this transition, the proliferation of under-ice phytoplankton blooms (UIBs), challenges the paradigm that waters beneath the ice pack harbor little planktonic life. Little is known about the diversity and spatial distribution of UIBs in the Arctic Ocean, or the environmental drivers behind their timing, magnitude, and taxonomic composition. Here, we compiled a unique and comprehensive dataset from seven major research projects in the Arctic Ocean (11 expeditions, covering the spring sea-ice-covered period to summer ice-free conditions) to identify the environmental drivers responsible for initiating and shaping the magnitude and assemblage structure of UIBs. The temporal dynamics behind UIB formation are related to the ways that snow and sea-ice conditions impact the under-ice light field. In particular, the onset of snowmelt significantly increased under-ice light availability (>0.1-0.2 mol photons m-2 d-1), marking the concomitant termination of the sea-ice algal bloom and initiation of UIBs. At the pan-Arctic scale, bloom magnitude (expressed as maximum chlorophyll a concentration) was predicted best by winter water Si(OH)4 and PO43- concentrations, as well as Si(OH)4:NO3- and PO43-:NO3- drawdown ratios, but not NO3- concentration. Two main phytoplankton assemblages dominated UIBs (diatoms or Phaeocystis), driven primarily by the winter nitrate:silicate (NO3-:Si(OH)4) ratio and the under-ice light climate. Phaeocystis co-dominated in low Si(OH)4 (i.e., NO3:Si(OH)4 molar ratios >1) waters, while diatoms contributed the bulk of UIB biomass when Si(OH)4 was high (i.e., NO3:Si(OH)4 molar ratios
AB - The decline of sea-ice thickness, area, and volume due to the transition from multi-year to first-year sea ice has improved the under-ice light environment for pelagic Arctic ecosystems. One unexpected and direct consequence of this transition, the proliferation of under-ice phytoplankton blooms (UIBs), challenges the paradigm that waters beneath the ice pack harbor little planktonic life. Little is known about the diversity and spatial distribution of UIBs in the Arctic Ocean, or the environmental drivers behind their timing, magnitude, and taxonomic composition. Here, we compiled a unique and comprehensive dataset from seven major research projects in the Arctic Ocean (11 expeditions, covering the spring sea-ice-covered period to summer ice-free conditions) to identify the environmental drivers responsible for initiating and shaping the magnitude and assemblage structure of UIBs. The temporal dynamics behind UIB formation are related to the ways that snow and sea-ice conditions impact the under-ice light field. In particular, the onset of snowmelt significantly increased under-ice light availability (>0.1-0.2 mol photons m-2 d-1), marking the concomitant termination of the sea-ice algal bloom and initiation of UIBs. At the pan-Arctic scale, bloom magnitude (expressed as maximum chlorophyll a concentration) was predicted best by winter water Si(OH)4 and PO43- concentrations, as well as Si(OH)4:NO3- and PO43-:NO3- drawdown ratios, but not NO3- concentration. Two main phytoplankton assemblages dominated UIBs (diatoms or Phaeocystis), driven primarily by the winter nitrate:silicate (NO3-:Si(OH)4) ratio and the under-ice light climate. Phaeocystis co-dominated in low Si(OH)4 (i.e., NO3:Si(OH)4 molar ratios >1) waters, while diatoms contributed the bulk of UIB biomass when Si(OH)4 was high (i.e., NO3:Si(OH)4 molar ratios
UR - https://online.ucpress.edu/elementa/article/doi/10.1525/elementa.430/114475/Environmental-drivers-of-underice-phytoplankton
UR - http://www.scopus.com/inward/record.url?scp=85105052518&partnerID=8YFLogxK
U2 - 10.1525/elementa.430
DO - 10.1525/elementa.430
M3 - Article
SN - 2325-1026
VL - 8
JO - Elementa
JF - Elementa
ER -
