Seasonal and spatial patterns of primary production in a high-latitude fjord affected by Greenland Ice Sheet run-off
Primary production on the coast and in Greenland fjords sustains important local and sustenance fisheries. However, unprecedented melting of the Greenland Ice Sheet (GrIS) is impacting the coastal ocean, and its effects on fjord ecology remain understudied. It has been suggested that as glaciers ret...
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ftcopernicus:oai:publications.copernicus.org:bg76700 2023-05-15T16:21:26+02:00 Seasonal and spatial patterns of primary production in a high-latitude fjord affected by Greenland Ice Sheet run-off Holding, Johnna M. Markager, Stiig Juul-Pedersen, Thomas Paulsen, Maria L. Møller, Eva F. Meire, Lorenz Sejr, Mikael K. 2019-10-02 application/pdf https://doi.org/10.5194/bg-16-3777-2019 https://www.biogeosciences.net/16/3777/2019/ eng eng doi:10.5194/bg-16-3777-2019 https://www.biogeosciences.net/16/3777/2019/ eISSN: 1726-4189 Text 2019 ftcopernicus https://doi.org/10.5194/bg-16-3777-2019 2019-12-24T09:48:25Z Primary production on the coast and in Greenland fjords sustains important local and sustenance fisheries. However, unprecedented melting of the Greenland Ice Sheet (GrIS) is impacting the coastal ocean, and its effects on fjord ecology remain understudied. It has been suggested that as glaciers retreat, primary production regimes may be altered, rendering fjords less productive. Here we investigate patterns of primary productivity in a northeast Greenland fjord (Young Sound, 74 ∘ N), which receives run-off from the GrIS via land-terminating glaciers. We measured size fractioned primary production during the ice- free season along a spatial gradient of meltwater influence. We found that, apart from a brief under-ice bloom during summer, primary production remains low (between 50 and 200 mg C m −2 d −1 ) but steady throughout the ice-free season, even into the fall. Low productivity is due to freshwater run-off from land-terminating glaciers causing low light availability and strong vertical stratification limiting nutrient availability. The former is caused by turbid river inputs in the summer restricting phytoplankton biomass to the surface and away from the nitracline. In the outer fjord where turbidity plays less of a role in light limitation, phytoplankton biomass moves higher in the water column in the fall due to the short day length as the sun angle decreases. Despite this, plankton communities in this study were shown to be well adapted to low-light conditions, as evidenced by the low values of saturating irradiance for primary production (5.8–67 µ mol photons m −2 s −1 ). With its low but consistent production across the growing season, Young Sound offers an alternative picture to other more productive fjords which have highly productive spring and late summer blooms and limited fall production. However, patterns of primary productivity observed in Young Sound are not only due to the influence from land-terminating glaciers but are also consequences of the nutrient-depleted coastal boundary currents and the shallow entrance sill, features which should also be considered when generalizing about how primary production will be affected by glacier retreat in the future. Text glacier Greenland Ice Sheet Copernicus Publications: E-Journals Greenland Biogeosciences 16 19 3777 3792 |
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Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Primary production on the coast and in Greenland fjords sustains important local and sustenance fisheries. However, unprecedented melting of the Greenland Ice Sheet (GrIS) is impacting the coastal ocean, and its effects on fjord ecology remain understudied. It has been suggested that as glaciers retreat, primary production regimes may be altered, rendering fjords less productive. Here we investigate patterns of primary productivity in a northeast Greenland fjord (Young Sound, 74 ∘ N), which receives run-off from the GrIS via land-terminating glaciers. We measured size fractioned primary production during the ice- free season along a spatial gradient of meltwater influence. We found that, apart from a brief under-ice bloom during summer, primary production remains low (between 50 and 200 mg C m −2 d −1 ) but steady throughout the ice-free season, even into the fall. Low productivity is due to freshwater run-off from land-terminating glaciers causing low light availability and strong vertical stratification limiting nutrient availability. The former is caused by turbid river inputs in the summer restricting phytoplankton biomass to the surface and away from the nitracline. In the outer fjord where turbidity plays less of a role in light limitation, phytoplankton biomass moves higher in the water column in the fall due to the short day length as the sun angle decreases. Despite this, plankton communities in this study were shown to be well adapted to low-light conditions, as evidenced by the low values of saturating irradiance for primary production (5.8–67 µ mol photons m −2 s −1 ). With its low but consistent production across the growing season, Young Sound offers an alternative picture to other more productive fjords which have highly productive spring and late summer blooms and limited fall production. However, patterns of primary productivity observed in Young Sound are not only due to the influence from land-terminating glaciers but are also consequences of the nutrient-depleted coastal boundary currents and the shallow entrance sill, features which should also be considered when generalizing about how primary production will be affected by glacier retreat in the future. |
format |
Text |
author |
Holding, Johnna M. Markager, Stiig Juul-Pedersen, Thomas Paulsen, Maria L. Møller, Eva F. Meire, Lorenz Sejr, Mikael K. |
spellingShingle |
Holding, Johnna M. Markager, Stiig Juul-Pedersen, Thomas Paulsen, Maria L. Møller, Eva F. Meire, Lorenz Sejr, Mikael K. Seasonal and spatial patterns of primary production in a high-latitude fjord affected by Greenland Ice Sheet run-off |
author_facet |
Holding, Johnna M. Markager, Stiig Juul-Pedersen, Thomas Paulsen, Maria L. Møller, Eva F. Meire, Lorenz Sejr, Mikael K. |
author_sort |
Holding, Johnna M. |
title |
Seasonal and spatial patterns of primary production in a high-latitude fjord affected by Greenland Ice Sheet run-off |
title_short |
Seasonal and spatial patterns of primary production in a high-latitude fjord affected by Greenland Ice Sheet run-off |
title_full |
Seasonal and spatial patterns of primary production in a high-latitude fjord affected by Greenland Ice Sheet run-off |
title_fullStr |
Seasonal and spatial patterns of primary production in a high-latitude fjord affected by Greenland Ice Sheet run-off |
title_full_unstemmed |
Seasonal and spatial patterns of primary production in a high-latitude fjord affected by Greenland Ice Sheet run-off |
title_sort |
seasonal and spatial patterns of primary production in a high-latitude fjord affected by greenland ice sheet run-off |
publishDate |
2019 |
url |
https://doi.org/10.5194/bg-16-3777-2019 https://www.biogeosciences.net/16/3777/2019/ |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
glacier Greenland Ice Sheet |
genre_facet |
glacier Greenland Ice Sheet |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-16-3777-2019 https://www.biogeosciences.net/16/3777/2019/ |
op_doi |
https://doi.org/10.5194/bg-16-3777-2019 |
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Biogeosciences |
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16 |
container_issue |
19 |
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3777 |
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3792 |
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