Impact of freshwater runoff from the southwest Greenland Ice Sheet on fjord productivity since the late 19th century
Research output: Contribution to journal › Journal article › Research › peer-review
Standard
Impact of freshwater runoff from the southwest Greenland Ice Sheet on fjord productivity since the late 19th century. / Oksman, Mimmi; Kvorning, Anna Bang; Larsen, Signe Hillerup; Kjeldsen, Kristian Kjellerup; Mankoff, Kenneth David; Colgan, William; Andersen, Thorbjørn Joest; Nørgaard-Pedersen, Niels; Seidenkrantz, Marit-Solveig; Mikkelsen, Naja; Ribeiro, Sofia.
In: The Cryosphere, Vol. 16, No. 6, 2022, p. 2471-2491.Research output: Contribution to journal › Journal article › Research › peer-review
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - JOUR
T1 - Impact of freshwater runoff from the southwest Greenland Ice Sheet on fjord productivity since the late 19th century
AU - Oksman, Mimmi
AU - Kvorning, Anna Bang
AU - Larsen, Signe Hillerup
AU - Kjeldsen, Kristian Kjellerup
AU - Mankoff, Kenneth David
AU - Colgan, William
AU - Andersen, Thorbjørn Joest
AU - Nørgaard-Pedersen, Niels
AU - Seidenkrantz, Marit-Solveig
AU - Mikkelsen, Naja
AU - Ribeiro, Sofia
PY - 2022
Y1 - 2022
N2 - Climate warming and the resulting acceleration of freshwater discharge from the Greenland Ice Sheet are impacting Arctic marine coastal ecosystems, with implications for their biological productivity. To accurately project the future of coastal ecosystems and place recent trends into perspective, palaeo-records are essential. Here, we show runoff estimates from the late 19th century to the present day for a large sub-Arctic fjord system (Nuup Kangerlua, southwest Greenland) influenced by both marine- and land-terminating glaciers. We followed a multiproxy approach to reconstruct spatial and temporal trends in primary production from four sediment core records, including diatom fluxes and assemblage composition changes and biogeochemical and sedimentological proxies (total organic carbon, nitrogen, C=N ratio, biogenic silica, delta C-13, delta N-15, and grain-size distribution). We show that an abrupt increase in freshwater runoff in the mid-1990s was reflected by a 3-fold increase in biogenic silica fluxes in the glacier-proximal area of the fjord. In addition to increased productivity, freshwater runoff modulates the diatom assemblages and drives the dynamics and magnitude of the diatom spring bloom. Our records indicate that marine productivity is higher today than it has been at any point since the late 19th century and suggest that increased mass loss of the Greenland Ice Sheet may continue pro- moting high productivity levels at sites proximal to marineterminating glaciers. We highlight the importance of palaeorecords in offering a unique temporal perspective on iceocean-ecosystem responses to climate forcing beyond existing remote sensing or monitoring time series.
AB - Climate warming and the resulting acceleration of freshwater discharge from the Greenland Ice Sheet are impacting Arctic marine coastal ecosystems, with implications for their biological productivity. To accurately project the future of coastal ecosystems and place recent trends into perspective, palaeo-records are essential. Here, we show runoff estimates from the late 19th century to the present day for a large sub-Arctic fjord system (Nuup Kangerlua, southwest Greenland) influenced by both marine- and land-terminating glaciers. We followed a multiproxy approach to reconstruct spatial and temporal trends in primary production from four sediment core records, including diatom fluxes and assemblage composition changes and biogeochemical and sedimentological proxies (total organic carbon, nitrogen, C=N ratio, biogenic silica, delta C-13, delta N-15, and grain-size distribution). We show that an abrupt increase in freshwater runoff in the mid-1990s was reflected by a 3-fold increase in biogenic silica fluxes in the glacier-proximal area of the fjord. In addition to increased productivity, freshwater runoff modulates the diatom assemblages and drives the dynamics and magnitude of the diatom spring bloom. Our records indicate that marine productivity is higher today than it has been at any point since the late 19th century and suggest that increased mass loss of the Greenland Ice Sheet may continue pro- moting high productivity levels at sites proximal to marineterminating glaciers. We highlight the importance of palaeorecords in offering a unique temporal perspective on iceocean-ecosystem responses to climate forcing beyond existing remote sensing or monitoring time series.
KW - TIDEWATER OUTLET GLACIERS
KW - SPRING BLOOM DYNAMICS
KW - MASS-BALANCE
KW - SEA-ICE
KW - NE GREENLAND
KW - CO2 UPTAKE
KW - SEDIMENTS
KW - MARINE
KW - CLIMATE
KW - PHYTOPLANKTON
U2 - 10.5194/tc-16-2471-2022
DO - 10.5194/tc-16-2471-2022
M3 - Journal article
VL - 16
SP - 2471
EP - 2491
JO - The Cryosphere
JF - The Cryosphere
SN - 1994-0416
IS - 6
ER -
ID: 312626448