Regional-scale phytoplankton dynamics and their association with glacier meltwater runoff in Svalbard
<p>Arctic amplification of global warming has accelerated mass loss of Arctic land ice over the past decades and led to increased freshwater discharge into glacier fjords and adjacent seas. Glacier freshwater discharge is typically associated with high sediment load which limits the euphotic d...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-01-01
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| Series: | Biogeosciences |
| Online Access: | https://bg.copernicus.org/articles/19/271/2022/bg-19-271-2022.pdf |
| _version_ | 1819284659175948288 |
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| author | T. Dunse T. Dunse K. Dong K. S. Aas L. C. Stige L. C. Stige |
| author_facet | T. Dunse T. Dunse K. Dong K. S. Aas L. C. Stige L. C. Stige |
| author_sort | T. Dunse |
| collection | DOAJ |
| description | <p>Arctic amplification of global warming has accelerated mass loss of Arctic
land ice over the past decades and led to increased freshwater discharge into
glacier fjords and adjacent seas. Glacier freshwater discharge is typically
associated with high sediment load which limits the euphotic depth but may
also aid to provide surface waters with essential nutrients, thus having
counteracting effects on marine productivity. In situ observations from a few
measured fjords across the Arctic indicate that glacier fjords dominated by
marine-terminating glaciers are typically more productive than those with only
land-terminating glaciers. Here we combine chlorophyll <i>a</i> from
satellite ocean color, an indicator of phytoplankton biomass, with glacier
meltwater runoff from climatic mass-balance modeling to establish a
statistical model of summertime phytoplankton dynamics in Svalbard (mid-June
to September). Statistical analysis reveals significant and positive
spatiotemporal associations of chlorophyll <i>a</i> with glacier runoff for
7 out of 14 primary hydrological regions but only within 10 <span class="inline-formula">km</span>
distance from the shore. These seven regions consist predominantly of the
major fjord systems of Svalbard. The adjacent land areas are characterized by
a wide range of total glacier coverage (35.5 <span class="inline-formula">%</span> to 81.2 <span class="inline-formula">%</span>)
and fraction of marine-terminating glacier area
(40.2 <span class="inline-formula">%</span> to 87.4 <span class="inline-formula">%</span>). We find that an increase in specific
glacier-runoff rate of 10 <span class="inline-formula">mm</span> water equivalent per 8 <span class="inline-formula">d</span> period
raises summertime chlorophyll <i>a</i> concentrations by
5.2 <span class="inline-formula">%</span> to 20.0 <span class="inline-formula">%</span>, depending on the region. During the annual peak discharge we estimate that glacier runoff increases chlorophyll <i>a</i> by 13.1 <span class="inline-formula">%</span> to 50.2 <span class="inline-formula">%</span> compared to situations with no runoff. This suggests that glacier runoff is an
important factor sustaining summertime phytoplankton production in Svalbard
fjords, in line with findings from several fjords in Greenland. In contrast,
for regions bordering open coasts, and beyond 10 <span class="inline-formula">km</span> distance from the
shore, we do not find significant associations of chlorophyll <i>a</i> with
runoff. In these regions, physical ocean and sea-ice variables control
chlorophyll <i>a</i>, pointing at the importance of a late sea-ice breakup
in northern Svalbard, as well as the advection of Atlantic water masses along
the West Spitsbergen Current for summertime phytoplankton dynamics. Our method
allows for the investigation and monitoring of glacier-runoff effects on primary
production throughout the summer season and is applicable on a pan-Arctic
scale, thus complementing valuable but scarce in situ measurements in both
space and time.</p> |
| first_indexed | 2024-12-24T01:50:53Z |
| format | Article |
| id | doaj.art-44602ef02d264be78535b20961a4194a |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-24T01:50:53Z |
| publishDate | 2022-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-44602ef02d264be78535b20961a4194a2022-12-21T17:21:44ZengCopernicus PublicationsBiogeosciences1726-41701726-41892022-01-011927129410.5194/bg-19-271-2022Regional-scale phytoplankton dynamics and their association with glacier meltwater runoff in SvalbardT. Dunse0T. Dunse1K. Dong2K. S. Aas3L. C. Stige4L. C. Stige5Department of Environmental Sciences, Western Norway University of Applied Sciences, Røyrgata 6, 6856 Sogndal, NorwayDepartment of Geosciences, University of Oslo, P.O. Box 1047 Blindern, 0316 Oslo, NorwayCentre of Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, 0316, Oslo, NorwayDepartment of Geosciences, University of Oslo, P.O. Box 1047 Blindern, 0316 Oslo, NorwayCentre of Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, 0316, Oslo, NorwayNorwegian Veterinary Institute, P.O. Box 64, 1431 Ås, Norway<p>Arctic amplification of global warming has accelerated mass loss of Arctic land ice over the past decades and led to increased freshwater discharge into glacier fjords and adjacent seas. Glacier freshwater discharge is typically associated with high sediment load which limits the euphotic depth but may also aid to provide surface waters with essential nutrients, thus having counteracting effects on marine productivity. In situ observations from a few measured fjords across the Arctic indicate that glacier fjords dominated by marine-terminating glaciers are typically more productive than those with only land-terminating glaciers. Here we combine chlorophyll <i>a</i> from satellite ocean color, an indicator of phytoplankton biomass, with glacier meltwater runoff from climatic mass-balance modeling to establish a statistical model of summertime phytoplankton dynamics in Svalbard (mid-June to September). Statistical analysis reveals significant and positive spatiotemporal associations of chlorophyll <i>a</i> with glacier runoff for 7 out of 14 primary hydrological regions but only within 10 <span class="inline-formula">km</span> distance from the shore. These seven regions consist predominantly of the major fjord systems of Svalbard. The adjacent land areas are characterized by a wide range of total glacier coverage (35.5 <span class="inline-formula">%</span> to 81.2 <span class="inline-formula">%</span>) and fraction of marine-terminating glacier area (40.2 <span class="inline-formula">%</span> to 87.4 <span class="inline-formula">%</span>). We find that an increase in specific glacier-runoff rate of 10 <span class="inline-formula">mm</span> water equivalent per 8 <span class="inline-formula">d</span> period raises summertime chlorophyll <i>a</i> concentrations by 5.2 <span class="inline-formula">%</span> to 20.0 <span class="inline-formula">%</span>, depending on the region. During the annual peak discharge we estimate that glacier runoff increases chlorophyll <i>a</i> by 13.1 <span class="inline-formula">%</span> to 50.2 <span class="inline-formula">%</span> compared to situations with no runoff. This suggests that glacier runoff is an important factor sustaining summertime phytoplankton production in Svalbard fjords, in line with findings from several fjords in Greenland. In contrast, for regions bordering open coasts, and beyond 10 <span class="inline-formula">km</span> distance from the shore, we do not find significant associations of chlorophyll <i>a</i> with runoff. In these regions, physical ocean and sea-ice variables control chlorophyll <i>a</i>, pointing at the importance of a late sea-ice breakup in northern Svalbard, as well as the advection of Atlantic water masses along the West Spitsbergen Current for summertime phytoplankton dynamics. Our method allows for the investigation and monitoring of glacier-runoff effects on primary production throughout the summer season and is applicable on a pan-Arctic scale, thus complementing valuable but scarce in situ measurements in both space and time.</p>https://bg.copernicus.org/articles/19/271/2022/bg-19-271-2022.pdf |
| spellingShingle | T. Dunse T. Dunse K. Dong K. S. Aas L. C. Stige L. C. Stige Regional-scale phytoplankton dynamics and their association with glacier meltwater runoff in Svalbard Biogeosciences |
| title | Regional-scale phytoplankton dynamics and their association with glacier meltwater runoff in Svalbard |
| title_full | Regional-scale phytoplankton dynamics and their association with glacier meltwater runoff in Svalbard |
| title_fullStr | Regional-scale phytoplankton dynamics and their association with glacier meltwater runoff in Svalbard |
| title_full_unstemmed | Regional-scale phytoplankton dynamics and their association with glacier meltwater runoff in Svalbard |
| title_short | Regional-scale phytoplankton dynamics and their association with glacier meltwater runoff in Svalbard |
| title_sort | regional scale phytoplankton dynamics and their association with glacier meltwater runoff in svalbard |
| url | https://bg.copernicus.org/articles/19/271/2022/bg-19-271-2022.pdf |
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