Environmental drivers of under-ice phytoplankton bloom dynamics in the Arctic Ocean
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 (UI...
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ftzenodo:oai:zenodo.org:4451353 2023-05-15T14:44:30+02:00 Environmental drivers of under-ice phytoplankton bloom dynamics in the Arctic Ocean Mathieu Ardyna 2020-07-09 https://zenodo.org/record/4451353 https://doi.org/10.1525/elementa.430 eng eng info:eu-repo/grantAgreement/EC/H2020/746748/ https://zenodo.org/record/4451353 https://doi.org/10.1525/elementa.430 oai:zenodo.org:4451353 info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/legalcode Under-ice phytoplankton blooms Biogeochemical cycles Nutrients Sea Ice Climate change Arctic Ocean info:eu-repo/semantics/article publication-article 2020 ftzenodo https://doi.org/10.1525/elementa.430 2023-03-10T22:12:25Z 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 <1). The implications of such differences in UIB composition could have important ramifications for Arctic biogeochemical cycles, and ultimately impact carbon flow to higher trophic levels ... Article in Journal/Newspaper Arctic Arctic Ocean Climate change ice pack Phytoplankton Sea ice Zenodo Arctic Arctic Ocean Elementa: Science of the Anthropocene 8 |
institution |
Open Polar |
collection |
Zenodo |
op_collection_id |
ftzenodo |
language |
English |
topic |
Under-ice phytoplankton blooms Biogeochemical cycles Nutrients Sea Ice Climate change Arctic Ocean |
spellingShingle |
Under-ice phytoplankton blooms Biogeochemical cycles Nutrients Sea Ice Climate change Arctic Ocean Mathieu Ardyna Environmental drivers of under-ice phytoplankton bloom dynamics in the Arctic Ocean |
topic_facet |
Under-ice phytoplankton blooms Biogeochemical cycles Nutrients Sea Ice Climate change Arctic Ocean |
description |
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 <1). The implications of such differences in UIB composition could have important ramifications for Arctic biogeochemical cycles, and ultimately impact carbon flow to higher trophic levels ... |
format |
Article in Journal/Newspaper |
author |
Mathieu Ardyna |
author_facet |
Mathieu Ardyna |
author_sort |
Mathieu Ardyna |
title |
Environmental drivers of under-ice phytoplankton bloom dynamics in the Arctic Ocean |
title_short |
Environmental drivers of under-ice phytoplankton bloom dynamics in the Arctic Ocean |
title_full |
Environmental drivers of under-ice phytoplankton bloom dynamics in the Arctic Ocean |
title_fullStr |
Environmental drivers of under-ice phytoplankton bloom dynamics in the Arctic Ocean |
title_full_unstemmed |
Environmental drivers of under-ice phytoplankton bloom dynamics in the Arctic Ocean |
title_sort |
environmental drivers of under-ice phytoplankton bloom dynamics in the arctic ocean |
publishDate |
2020 |
url |
https://zenodo.org/record/4451353 https://doi.org/10.1525/elementa.430 |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Climate change ice pack Phytoplankton Sea ice |
genre_facet |
Arctic Arctic Ocean Climate change ice pack Phytoplankton Sea ice |
op_relation |
info:eu-repo/grantAgreement/EC/H2020/746748/ https://zenodo.org/record/4451353 https://doi.org/10.1525/elementa.430 oai:zenodo.org:4451353 |
op_rights |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/legalcode |
op_doi |
https://doi.org/10.1525/elementa.430 |
container_title |
Elementa: Science of the Anthropocene |
container_volume |
8 |
_version_ |
1766315980748750848 |