Effects of natural and human-induced hypoxia on coastal benthos
Coastal hypoxia (defined here as <1.42 ml L −1 62.5 μM; 2 mg L −1 , approx. 30% oxygen saturation) develops seasonally in many estuaries, fjords, and along open coasts as a result of natural upwelling or from anthropogenic eutrophication induced by riverine nutrient inputs. Permanent hypoxia occu...
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ftdoajarticles:oai:doaj.org/article:f50e8a28b27349cb9d5c5922ae7da3fd 2023-05-15T17:36:05+02:00 Effects of natural and human-induced hypoxia on coastal benthos L. A. Levin W. Ekau A. J. Gooday F. Jorissen J. J. Middelburg S. W. A. Naqvi C. Neira N. N. Rabalais J. Zhang 2009-10-01T00:00:00Z https://doaj.org/article/f50e8a28b27349cb9d5c5922ae7da3fd EN eng Copernicus Publications http://www.biogeosciences.net/6/2063/2009/bg-6-2063-2009.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 https://doaj.org/article/f50e8a28b27349cb9d5c5922ae7da3fd Biogeosciences, Vol 6, Iss 10, Pp 2063-2098 (2009) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2009 ftdoajarticles 2022-12-31T02:54:59Z Coastal hypoxia (defined here as <1.42 ml L −1 62.5 μM; 2 mg L −1 , approx. 30% oxygen saturation) develops seasonally in many estuaries, fjords, and along open coasts as a result of natural upwelling or from anthropogenic eutrophication induced by riverine nutrient inputs. Permanent hypoxia occurs naturally in some isolated seas and marine basins as well as in open slope oxygen minimum zones. Responses of benthos to hypoxia depend on the duration, predictability, and intensity of oxygen depletion and on whether H 2 S is formed. Under suboxic conditions, large mats of filamentous sulfide oxidizing bacteria cover the seabed and consume sulfide. They are hypothesized to provide a detoxified microhabitat for eukaryotic benthic communities. Calcareous foraminiferans and nematodes are particularly tolerant of low oxygen concentrations and may attain high densities and dominance, often in association with microbial mats. When oxygen is sufficient to support metazoans, small, soft-bodied invertebrates (typically annelids), often with short generation times and elaborate branchial structures, predominate. Large taxa are more sensitive than small taxa to hypoxia. Crustaceans and echinoderms are typically more sensitive to hypoxia, with lower oxygen thresholds, than annelids, sipunculans, molluscs and cnidarians. Mobile fish and shellfish will migrate away from low-oxygen areas. Within a species, early life stages may be more subject to oxygen stress than older life stages. Hypoxia alters both the structure and function of benthic communities, but effects may differ with regional hypoxia history. Human-caused hypoxia is generally linked to eutrophication, and occurs adjacent to watersheds with large populations or agricultural activities. Many occurrences are seasonal, within estuaries, fjords or enclosed seas of the North Atlantic and the NW Pacific Oceans. Benthic faunal responses, elicited at oxygen levels below 2 ml L −1 , typically involve avoidance or mortality of large species and elevated abundances of ... Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Pacific |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 L. A. Levin W. Ekau A. J. Gooday F. Jorissen J. J. Middelburg S. W. A. Naqvi C. Neira N. N. Rabalais J. Zhang Effects of natural and human-induced hypoxia on coastal benthos |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
Coastal hypoxia (defined here as <1.42 ml L −1 62.5 μM; 2 mg L −1 , approx. 30% oxygen saturation) develops seasonally in many estuaries, fjords, and along open coasts as a result of natural upwelling or from anthropogenic eutrophication induced by riverine nutrient inputs. Permanent hypoxia occurs naturally in some isolated seas and marine basins as well as in open slope oxygen minimum zones. Responses of benthos to hypoxia depend on the duration, predictability, and intensity of oxygen depletion and on whether H 2 S is formed. Under suboxic conditions, large mats of filamentous sulfide oxidizing bacteria cover the seabed and consume sulfide. They are hypothesized to provide a detoxified microhabitat for eukaryotic benthic communities. Calcareous foraminiferans and nematodes are particularly tolerant of low oxygen concentrations and may attain high densities and dominance, often in association with microbial mats. When oxygen is sufficient to support metazoans, small, soft-bodied invertebrates (typically annelids), often with short generation times and elaborate branchial structures, predominate. Large taxa are more sensitive than small taxa to hypoxia. Crustaceans and echinoderms are typically more sensitive to hypoxia, with lower oxygen thresholds, than annelids, sipunculans, molluscs and cnidarians. Mobile fish and shellfish will migrate away from low-oxygen areas. Within a species, early life stages may be more subject to oxygen stress than older life stages. Hypoxia alters both the structure and function of benthic communities, but effects may differ with regional hypoxia history. Human-caused hypoxia is generally linked to eutrophication, and occurs adjacent to watersheds with large populations or agricultural activities. Many occurrences are seasonal, within estuaries, fjords or enclosed seas of the North Atlantic and the NW Pacific Oceans. Benthic faunal responses, elicited at oxygen levels below 2 ml L −1 , typically involve avoidance or mortality of large species and elevated abundances of ... |
format |
Article in Journal/Newspaper |
author |
L. A. Levin W. Ekau A. J. Gooday F. Jorissen J. J. Middelburg S. W. A. Naqvi C. Neira N. N. Rabalais J. Zhang |
author_facet |
L. A. Levin W. Ekau A. J. Gooday F. Jorissen J. J. Middelburg S. W. A. Naqvi C. Neira N. N. Rabalais J. Zhang |
author_sort |
L. A. Levin |
title |
Effects of natural and human-induced hypoxia on coastal benthos |
title_short |
Effects of natural and human-induced hypoxia on coastal benthos |
title_full |
Effects of natural and human-induced hypoxia on coastal benthos |
title_fullStr |
Effects of natural and human-induced hypoxia on coastal benthos |
title_full_unstemmed |
Effects of natural and human-induced hypoxia on coastal benthos |
title_sort |
effects of natural and human-induced hypoxia on coastal benthos |
publisher |
Copernicus Publications |
publishDate |
2009 |
url |
https://doaj.org/article/f50e8a28b27349cb9d5c5922ae7da3fd |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Biogeosciences, Vol 6, Iss 10, Pp 2063-2098 (2009) |
op_relation |
http://www.biogeosciences.net/6/2063/2009/bg-6-2063-2009.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 https://doaj.org/article/f50e8a28b27349cb9d5c5922ae7da3fd |
_version_ |
1766135463859453952 |