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Landscape controls on nutrient stoichiometry regulate lake primary production at the margin of the Greenland ice sheet

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posted on 30.09.2021, 10:22 authored by Clay Prater, Joanna BullardJoanna Bullard, Christopher L Osburn, Sarah L Martin, Michael J Watts, Nicholas John AndersonNicholas John Anderson
Global change is reshaping the physical environment and altering nutrient dynamics across the Arctic. These changes can affect the structure and function of biological communities and influence important climate-related feedbacks (for example, carbon (C) sequestration) in biogeochemical processing hot spots such as lakes. To understand how these ecosystems will respond in the future, this study examined recent (< 10 y) and long-term (1000 y) shifts in autotrophic production across paraglacial environmental gradients in SW Greenland. Contemporary lake temperatures and light levels increased with distance from the ice sheet, along with dissolved organic C (DOC) concentrations and total nitrogen:total phosphorus (TN:TP) ratios. Diatom production measured as biogenic silica accumulation rates (BSiARs) and diatom contribution to microbial communities declined across these gradients, while total production estimated using C accumulation rates and δ13C increased, indicating that autochthonous production and C burial are controlled by microbial competition and competitive displacement across physiochemical gradients in the region. Diatom production was generally low across lakes prior to the 1800’s AD but has risen 1.5–3× above background levels starting between 1750 and 1880 AD. These increases predate contemporary regional warming by 115–250 years, and temperature stimulation of primary production was inconsistent with paleorecords for ~ 90% of the last millennium. Instead, primary production appeared to be more strongly related to N and P availability, which differs considerably across the region due to lake landscape position, glacial activity and degree of atmospheric nutrient deposition. These results suggest that biological responses to enhanced nutrient supply could serve as important negative feedbacks to global change.

Funding

Ecological effects of glacial dust deposition on remote Arctic lakes

Natural Environment Research Council

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NEIF Radiocarbon NRCF010001 (allocation number 2168.1118)

History

School

  • Social Sciences and Humanities

Department

  • Geography and Environment

Published in

Ecosystems

Volume

25

Issue

4

Pages

931 - 947

Publisher

Springer

Version

VoR (Version of Record)

Rights holder

© The Authors

Publisher statement

This is an Open Access Article. It is published by Springer under the Creative Commons Attribution 4.0 International Licence (CC BY 4.0). Full details of this licence are available at: https://creativecommons.org/licenses/by/4.0/

Acceptance date

27/07/2021

Publication date

2021-08-17

Copyright date

2021

ISSN

1432-9840

eISSN

1435-0629

Language

en

Depositor

Prof Joanna Bullard. Deposit date: 29 September 2021