A Growing Freshwater Lens in the Arctic Ocean With Sustained Climate Warming Disrupts Marine Ecosystem Function
One of the most robust changes in the hydrological cycle predicted by Earth System Models (ESMs) during the remainder of 21st century is an increase in the difference between precipitation and evapotranspiration (P-E) in arctic and boreal regions. We explore the long-term consequences of this change...
Published in: | Journal of Geophysical Research: Biogeosciences |
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Online Access: | http://www.osti.gov/servlets/purl/1852284 https://www.osti.gov/biblio/1852284 https://doi.org/10.1029/2020jg005693 |
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ftosti:oai:osti.gov:1852284 2023-07-30T04:00:48+02:00 A Growing Freshwater Lens in the Arctic Ocean With Sustained Climate Warming Disrupts Marine Ecosystem Function Fu, Weiwei Moore, J. Keith Primeau, François W. Lindsay, Keith Randerson, James T. 2022-08-31 application/pdf http://www.osti.gov/servlets/purl/1852284 https://www.osti.gov/biblio/1852284 https://doi.org/10.1029/2020jg005693 unknown http://www.osti.gov/servlets/purl/1852284 https://www.osti.gov/biblio/1852284 https://doi.org/10.1029/2020jg005693 doi:10.1029/2020jg005693 54 ENVIRONMENTAL SCIENCES 2022 ftosti https://doi.org/10.1029/2020jg005693 2023-07-11T10:10:50Z One of the most robust changes in the hydrological cycle predicted by Earth System Models (ESMs) during the remainder of 21st century is an increase in the difference between precipitation and evapotranspiration (P-E) in arctic and boreal regions. We explore the long-term consequences of this change for marine ecosystems in the Arctic Ocean using the Community Earth System Model forced with a business as usual scenario of future greenhouse gas concentrations. We find that by the year 2300 increases in freshwater delivery considerably reduce Arctic Ocean surface salinity, creating a freshwater lens that has far-reaching impacts on marine biogeochemistry. The expanding freshwater lens limits vertical nutrient supply into the euphotic zone by enhancing vertical stratification and accelerating surface lateral mixing with surface waters in the North Atlantic, which become increasingly nutrient depleted from weakening of the Atlantic Meridional Overturning Circulation (AMOC). The resulting increase in nutrient stress reduces marine export production in the Arctic Ocean by 53% in 2300 relative to the 1990s and triggers a shift in community composition with small phytoplankton replacing diatoms. At the same time, the seasonal timing of export production undergoes a 2-month forward shift, with the peak advancing from July to May. This suggests that the threat to food webs and higher trophic levels may intensify after the year 2100 as gains in productivity from sea ice loss saturate and freshwater impacts on nutrient stress continue to strengthen. Our analysis highlights the critical importance of changing terrestrial hydrology and land-ocean coupling as drivers of long-term biogeochemical change in the Arctic Ocean and the necessity of multi-century climate change projections. Other/Unknown Material Arctic Arctic Ocean Climate change North Atlantic Phytoplankton Sea ice SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Arctic Arctic Ocean Journal of Geophysical Research: Biogeosciences 125 12 |
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Open Polar |
collection |
SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
op_collection_id |
ftosti |
language |
unknown |
topic |
54 ENVIRONMENTAL SCIENCES |
spellingShingle |
54 ENVIRONMENTAL SCIENCES Fu, Weiwei Moore, J. Keith Primeau, François W. Lindsay, Keith Randerson, James T. A Growing Freshwater Lens in the Arctic Ocean With Sustained Climate Warming Disrupts Marine Ecosystem Function |
topic_facet |
54 ENVIRONMENTAL SCIENCES |
description |
One of the most robust changes in the hydrological cycle predicted by Earth System Models (ESMs) during the remainder of 21st century is an increase in the difference between precipitation and evapotranspiration (P-E) in arctic and boreal regions. We explore the long-term consequences of this change for marine ecosystems in the Arctic Ocean using the Community Earth System Model forced with a business as usual scenario of future greenhouse gas concentrations. We find that by the year 2300 increases in freshwater delivery considerably reduce Arctic Ocean surface salinity, creating a freshwater lens that has far-reaching impacts on marine biogeochemistry. The expanding freshwater lens limits vertical nutrient supply into the euphotic zone by enhancing vertical stratification and accelerating surface lateral mixing with surface waters in the North Atlantic, which become increasingly nutrient depleted from weakening of the Atlantic Meridional Overturning Circulation (AMOC). The resulting increase in nutrient stress reduces marine export production in the Arctic Ocean by 53% in 2300 relative to the 1990s and triggers a shift in community composition with small phytoplankton replacing diatoms. At the same time, the seasonal timing of export production undergoes a 2-month forward shift, with the peak advancing from July to May. This suggests that the threat to food webs and higher trophic levels may intensify after the year 2100 as gains in productivity from sea ice loss saturate and freshwater impacts on nutrient stress continue to strengthen. Our analysis highlights the critical importance of changing terrestrial hydrology and land-ocean coupling as drivers of long-term biogeochemical change in the Arctic Ocean and the necessity of multi-century climate change projections. |
author |
Fu, Weiwei Moore, J. Keith Primeau, François W. Lindsay, Keith Randerson, James T. |
author_facet |
Fu, Weiwei Moore, J. Keith Primeau, François W. Lindsay, Keith Randerson, James T. |
author_sort |
Fu, Weiwei |
title |
A Growing Freshwater Lens in the Arctic Ocean With Sustained Climate Warming Disrupts Marine Ecosystem Function |
title_short |
A Growing Freshwater Lens in the Arctic Ocean With Sustained Climate Warming Disrupts Marine Ecosystem Function |
title_full |
A Growing Freshwater Lens in the Arctic Ocean With Sustained Climate Warming Disrupts Marine Ecosystem Function |
title_fullStr |
A Growing Freshwater Lens in the Arctic Ocean With Sustained Climate Warming Disrupts Marine Ecosystem Function |
title_full_unstemmed |
A Growing Freshwater Lens in the Arctic Ocean With Sustained Climate Warming Disrupts Marine Ecosystem Function |
title_sort |
growing freshwater lens in the arctic ocean with sustained climate warming disrupts marine ecosystem function |
publishDate |
2022 |
url |
http://www.osti.gov/servlets/purl/1852284 https://www.osti.gov/biblio/1852284 https://doi.org/10.1029/2020jg005693 |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Climate change North Atlantic Phytoplankton Sea ice |
genre_facet |
Arctic Arctic Ocean Climate change North Atlantic Phytoplankton Sea ice |
op_relation |
http://www.osti.gov/servlets/purl/1852284 https://www.osti.gov/biblio/1852284 https://doi.org/10.1029/2020jg005693 doi:10.1029/2020jg005693 |
op_doi |
https://doi.org/10.1029/2020jg005693 |
container_title |
Journal of Geophysical Research: Biogeosciences |
container_volume |
125 |
container_issue |
12 |
_version_ |
1772811474430853120 |