Learning from the past: Impact of the Arctic Oscillation on sea ice and marine productivity off northwest Greenland over the last 9,000 years

Climate warming is rapidly reshaping the Arctic cryosphere and ocean conditions, with consequences for sea ice and pelagic productivity patterns affecting the entire marine food web. To predict how ongoing changes will impact Arctic marine ecosystems, concerted effort from various disciplines is req...

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Bibliographic Details
Published in:Global Change Biology
Main Authors: LIMOGES, Audrey, WECKSTRÖM, Kaarina, RIBEIRO, Sofia, GEORGIADIS, Eleanor, HANSEN, Katrine Elnegaard, MARTINEZ, Philippe, SEIDENKRANTZ, Marit-Solveig, GIRAUDEAU, Jacques, CROSTA, Xavier, MASSÉ, Guillaume
Format: Article in Journal/Newspaper
Language:English
Published: 2020
Subjects:
diatoms
highly branched isoprenoid (HBI) biomarkers
marine sediment
phytoplankton
paleoceanography
Arctic Oscillation
Baffin Bay
climate change
Planète et Univers [physics]/Sciences de la Terre/Océanographie
Sciences du Vivant [q-bio]/Ecologie
Environnement/Bioclimatologie
arctic cryosphere
Arctic
Baffin
Climate change
Greenland
Phytoplankton
Sea ice
Online Access:https://oskar-bordeaux.fr/handle/20.500.12278/189138
https://hdl.handle.net/20.500.12278/189138
https://doi.org/10.1111/gcb.15334
Description
Summary:Climate warming is rapidly reshaping the Arctic cryosphere and ocean conditions, with consequences for sea ice and pelagic productivity patterns affecting the entire marine food web. To predict how ongoing changes will impact Arctic marine ecosystems, concerted effort from various disciplines is required. Here, we contribute multi-decadal reconstructions of changes in diatom production and sea-ice conditions in relation to Holocene climate and ocean conditions off Northwest Greenland. Our multiproxy study includes diatoms, sea-ice biomarkers (IP 25 and HBI III) and geochemical tracers (TOC, TOC:TN, δ 13 C, δ 15 N) from a sediment core record spanning the last ca. 9000 years. Our results suggest that the balance between the outflow of polar water from the Arctic, and input of Atlantic water from the Irminger Current into the West Greenland Current is a key factor in controlling sea-ice conditions, and both diatom phenology and production in northeastern Baffin Bay. Our proxy record notably shows that changes in sea-surface conditions initially forced by Neoglacial cooling were dynamically amplified by the shift in the dominant phase of the Arctic Oscillation (AO) mode that occurred at ca. 3000 yrs BP, and caused drastic changes in community composition and a decline in diatom production at the study site. In the future, with projected dominant positive AO conditions favored by Arctic warming, increased water column stratification may counteract the positive effect of a longer open-water growth season and negatively impact diatom production.

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