Effect of Marine Hypoxia on Baltic Sea Cod Gadus morhua: Evidence From Otolith Chemical Proxies
The Baltic Sea contains the world’s largest anthropogenic deoxygenated zone, with increasing episodes and areal extent of hypoxia/anoxia. Atlantic cod in the Baltic has suffered a loss in condition which has been attributed mainly to hypoxia. Otoliths, the aragonitic structures that form part of the...
Published in: | Frontiers in Marine Science |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Frontiers Media S.A.
2018
|
Subjects: | |
Online Access: | https://doi.org/10.3389/fmars.2018.00482 https://doaj.org/article/175520f596f542ce837dfccaa080f611 |
id |
ftdoajarticles:oai:doaj.org/article:175520f596f542ce837dfccaa080f611 |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:175520f596f542ce837dfccaa080f611 2023-05-15T15:27:45+02:00 Effect of Marine Hypoxia on Baltic Sea Cod Gadus morhua: Evidence From Otolith Chemical Proxies Karin E. Limburg Michele Casini 2018-12-01T00:00:00Z https://doi.org/10.3389/fmars.2018.00482 https://doaj.org/article/175520f596f542ce837dfccaa080f611 EN eng Frontiers Media S.A. https://www.frontiersin.org/article/10.3389/fmars.2018.00482/full https://doaj.org/toc/2296-7745 2296-7745 doi:10.3389/fmars.2018.00482 https://doaj.org/article/175520f596f542ce837dfccaa080f611 Frontiers in Marine Science, Vol 5 (2018) Baltic cod hypoxia otolith microchemistry manganese magnesium growth effects Science Q General. Including nature conservation geographical distribution QH1-199.5 article 2018 ftdoajarticles https://doi.org/10.3389/fmars.2018.00482 2022-12-31T01:41:21Z The Baltic Sea contains the world’s largest anthropogenic deoxygenated zone, with increasing episodes and areal extent of hypoxia/anoxia. Atlantic cod in the Baltic has suffered a loss in condition which has been attributed mainly to hypoxia. Otoliths, the aragonitic structures that form part of the hearing/balance system in fishes, accumulate Mn in the presence of hypoxia and other reducing environments. Otoliths grow over the lifetime of fishes, and thus life-long records of hypoxia exposure exist for each individual fish. However, otolith Mn/Ca ratios are also sensitive to growth effects. We tested a new proxy to at least partially account for growth: Mn/Mg, since Mg levels reflect metabolic activity but not hypoxia. This and other elemental proxies were parsed annually from the otoliths to reconstruct lifetime histories of mean, maximum, and cumulative values of this proxy as well as others (Sr/Ca) that inform us about salinity conditions. We analyzed cod from five different time periods: Neolithic (4500 YBP, a normoxic baseline), 1980s, 1990s, 2000s, and 2010s – under different hypoxia intensities, assessing fish growth and condition in relation to hypoxia experience recorded by otolith proxies. Fish growth decreased with increasing hypoxia exposure; condition at capture (measured by Fulton’s K index) showed a strongly positive relation to growth indexed by magnesium (Mg/Ca). We conclude that cod otolith chemistry proxies not only inform about the hypoxia, growth, and metabolic status of cod, retrospectively throughout life, but also reflect the worsening situation for cod in the Baltic. Article in Journal/Newspaper atlantic cod Gadus morhua Directory of Open Access Journals: DOAJ Articles Frontiers in Marine Science 5 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Baltic cod hypoxia otolith microchemistry manganese magnesium growth effects Science Q General. Including nature conservation geographical distribution QH1-199.5 |
spellingShingle |
Baltic cod hypoxia otolith microchemistry manganese magnesium growth effects Science Q General. Including nature conservation geographical distribution QH1-199.5 Karin E. Limburg Michele Casini Effect of Marine Hypoxia on Baltic Sea Cod Gadus morhua: Evidence From Otolith Chemical Proxies |
topic_facet |
Baltic cod hypoxia otolith microchemistry manganese magnesium growth effects Science Q General. Including nature conservation geographical distribution QH1-199.5 |
description |
The Baltic Sea contains the world’s largest anthropogenic deoxygenated zone, with increasing episodes and areal extent of hypoxia/anoxia. Atlantic cod in the Baltic has suffered a loss in condition which has been attributed mainly to hypoxia. Otoliths, the aragonitic structures that form part of the hearing/balance system in fishes, accumulate Mn in the presence of hypoxia and other reducing environments. Otoliths grow over the lifetime of fishes, and thus life-long records of hypoxia exposure exist for each individual fish. However, otolith Mn/Ca ratios are also sensitive to growth effects. We tested a new proxy to at least partially account for growth: Mn/Mg, since Mg levels reflect metabolic activity but not hypoxia. This and other elemental proxies were parsed annually from the otoliths to reconstruct lifetime histories of mean, maximum, and cumulative values of this proxy as well as others (Sr/Ca) that inform us about salinity conditions. We analyzed cod from five different time periods: Neolithic (4500 YBP, a normoxic baseline), 1980s, 1990s, 2000s, and 2010s – under different hypoxia intensities, assessing fish growth and condition in relation to hypoxia experience recorded by otolith proxies. Fish growth decreased with increasing hypoxia exposure; condition at capture (measured by Fulton’s K index) showed a strongly positive relation to growth indexed by magnesium (Mg/Ca). We conclude that cod otolith chemistry proxies not only inform about the hypoxia, growth, and metabolic status of cod, retrospectively throughout life, but also reflect the worsening situation for cod in the Baltic. |
format |
Article in Journal/Newspaper |
author |
Karin E. Limburg Michele Casini |
author_facet |
Karin E. Limburg Michele Casini |
author_sort |
Karin E. Limburg |
title |
Effect of Marine Hypoxia on Baltic Sea Cod Gadus morhua: Evidence From Otolith Chemical Proxies |
title_short |
Effect of Marine Hypoxia on Baltic Sea Cod Gadus morhua: Evidence From Otolith Chemical Proxies |
title_full |
Effect of Marine Hypoxia on Baltic Sea Cod Gadus morhua: Evidence From Otolith Chemical Proxies |
title_fullStr |
Effect of Marine Hypoxia on Baltic Sea Cod Gadus morhua: Evidence From Otolith Chemical Proxies |
title_full_unstemmed |
Effect of Marine Hypoxia on Baltic Sea Cod Gadus morhua: Evidence From Otolith Chemical Proxies |
title_sort |
effect of marine hypoxia on baltic sea cod gadus morhua: evidence from otolith chemical proxies |
publisher |
Frontiers Media S.A. |
publishDate |
2018 |
url |
https://doi.org/10.3389/fmars.2018.00482 https://doaj.org/article/175520f596f542ce837dfccaa080f611 |
genre |
atlantic cod Gadus morhua |
genre_facet |
atlantic cod Gadus morhua |
op_source |
Frontiers in Marine Science, Vol 5 (2018) |
op_relation |
https://www.frontiersin.org/article/10.3389/fmars.2018.00482/full https://doaj.org/toc/2296-7745 2296-7745 doi:10.3389/fmars.2018.00482 https://doaj.org/article/175520f596f542ce837dfccaa080f611 |
op_doi |
https://doi.org/10.3389/fmars.2018.00482 |
container_title |
Frontiers in Marine Science |
container_volume |
5 |
_version_ |
1766358162553700352 |