Cumulative stressors reduce the self-regulating capacity of coastal ecosystems.

Autor: Thrush SF; Institute of Marine Science, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand., Hewitt JE; Department of Statistics, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.; National Institute of Water and Atmospheric Research, PO Box 11-115, Hillcrest Hamilton, 3251, New Zealand., Gladstone-Gallagher RV; Institute of Marine Science, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.; School of Science, University of Waikato, Private Bag 3105, Hamilton, 3240, New Zealand., Savage C; Department of Marine Science, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.; Department of Biological Sciences, University of Cape Town, Private Bag, Rondebosch, 7700, South Africa., Lundquist C; Institute of Marine Science, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.; National Institute of Water and Atmospheric Research, PO Box 11-115, Hillcrest Hamilton, 3251, New Zealand., O'Meara T; Institute of Marine Science, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.; Smithsonian Environmental Research Center, 647 Contees Wharf Road, Edgewater, Maryland, 21037-0028, USA., Vieillard A; Institute of Marine Science, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand., Hillman JR; Institute of Marine Science, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand., Mangan S; School of Science, University of Waikato, Private Bag 3105, Hamilton, 3240, New Zealand., Douglas EJ; National Institute of Water and Atmospheric Research, PO Box 11-115, Hillcrest Hamilton, 3251, New Zealand.; School of Science, University of Waikato, Private Bag 3105, Hamilton, 3240, New Zealand., Clark DE; School of Science, University of Waikato, Private Bag 3105, Hamilton, 3240, New Zealand.; Cawthron Institute, Private Bag 2, Nelson,, 7042, New Zealand., Lohrer AM; National Institute of Water and Atmospheric Research, PO Box 11-115, Hillcrest Hamilton, 3251, New Zealand., Pilditch C; School of Science, University of Waikato, Private Bag 3105, Hamilton, 3240, New Zealand.
Jazyk: angličtina
Zdroj: Ecological applications : a publication of the Ecological Society of America [Ecol Appl] 2021 Jan; Vol. 31 (1), pp. e02223. Date of Electronic Publication: 2020 Oct 29.
DOI: 10.1002/eap.2223
Abstrakt: Marine ecosystems are prone to tipping points, particularly in coastal zones where dramatic changes are associated with interactions between cumulative stressors (e.g., shellfish harvesting, eutrophication and sediment inputs) and ecosystem functions. A common feature of many degraded estuaries is elevated turbidity that reduces incident light to the seafloor, resulting from multiple factors including changes in sediment loading, sea-level rise and increased water column algal biomass. To determine whether cumulative effects of elevated turbidity may result in marked changes in the interactions between ecosystem components driving nutrient processing, we conducted a large-scale experiment manipulating sediment nitrogen concentrations in 15 estuaries across a national-scale gradient in incident light at the seafloor. We identified a threshold in incident light that was related to distinct changes in the ecosystem interaction networks (EIN) that drive nutrient processing. Above this threshold, network connectivity was high with clear mechanistic links to denitrification and the role of large shellfish in nitrogen processing. The EIN analyses revealed interacting stressors resulting in a decoupling of ecosystem processes in turbid estuaries with a lower capacity to denitrify and process nitrogen. This suggests that, as turbidity increases with sediment load, coastal areas can be more vulnerable to eutrophication. The identified interactions between light, nutrient processing and the abundance of large shellfish emphasizes the importance of actions that seek to manage multiple stressors and conserve or enhance shellfish abundance, rather than actions focusing on limiting a single stressor.
(© 2020 The Authors. Ecological Applications published by Wiley Periodicals LLC on behalf of Ecological Society of America.)
Databáze: MEDLINE
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