Marked recent declines in boron in Baltic Sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system?
Ocean acidification is spreading globally as a result of anthropogenic CO 2 emissions, but the Baltic Sea has until recently been thought to be relatively well-buffered by terrigenous inputs of alkalinity from its watershed. We discovered a 3- to 5-fold decline in boron (as B : Ca) in otoliths of ea...
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ftcopernicus:oai:publications.copernicus.org:egusphere110265 2023-12-31T10:21:37+01:00 Marked recent declines in boron in Baltic Sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system? Limburg, Karin E. Heimbrand, Yvette Kuliński, Karol 2023-11-30 application/pdf https://doi.org/10.5194/egusphere-2023-512 https://egusphere.copernicus.org/preprints/2023/egusphere-2023-512/ eng eng doi:10.5194/egusphere-2023-512 https://egusphere.copernicus.org/preprints/2023/egusphere-2023-512/ eISSN: Text 2023 ftcopernicus https://doi.org/10.5194/egusphere-2023-512 2023-12-04T17:24:18Z Ocean acidification is spreading globally as a result of anthropogenic CO 2 emissions, but the Baltic Sea has until recently been thought to be relatively well-buffered by terrigenous inputs of alkalinity from its watershed. We discovered a 3- to 5-fold decline in boron (as B : Ca) in otoliths of eastern Baltic cod (EBC) between the late 1990s and 2021. Examining a time series of EBC otoliths, we found varying levels of B : Ca starting in the 1980s, with the most recent years showing an all-time low for this period. This trend correlates with declines in pH and dissolved oxygen but not with changes in salinity. We examined possible physiological influences on B : Ca by including a collection of Icelandic cod as an “out-group”. Icelandic cod otoliths showed strongly positive correlations of B : Ca with physiologically regulated P : Ca; this was not the case for EBC. Finally, B : Ca in EBC otoliths is negatively correlated, to some extent, with Mn : Mg, a proposed proxy for hypoxia exposure. This negative relationship is hypothesized to reflect the dual phenomena of hypoxia and acidification as a result of decomposition of large algal blooms. Taken together, the otolith biomarkers Mn : Mg and B : Ca in cod suggest a general increase in both hypoxia and acidification within the Baltic intermediate and deep waters in the last decade. Text Ocean acidification Copernicus Publications: E-Journals |
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English |
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Ocean acidification is spreading globally as a result of anthropogenic CO 2 emissions, but the Baltic Sea has until recently been thought to be relatively well-buffered by terrigenous inputs of alkalinity from its watershed. We discovered a 3- to 5-fold decline in boron (as B : Ca) in otoliths of eastern Baltic cod (EBC) between the late 1990s and 2021. Examining a time series of EBC otoliths, we found varying levels of B : Ca starting in the 1980s, with the most recent years showing an all-time low for this period. This trend correlates with declines in pH and dissolved oxygen but not with changes in salinity. We examined possible physiological influences on B : Ca by including a collection of Icelandic cod as an “out-group”. Icelandic cod otoliths showed strongly positive correlations of B : Ca with physiologically regulated P : Ca; this was not the case for EBC. Finally, B : Ca in EBC otoliths is negatively correlated, to some extent, with Mn : Mg, a proposed proxy for hypoxia exposure. This negative relationship is hypothesized to reflect the dual phenomena of hypoxia and acidification as a result of decomposition of large algal blooms. Taken together, the otolith biomarkers Mn : Mg and B : Ca in cod suggest a general increase in both hypoxia and acidification within the Baltic intermediate and deep waters in the last decade. |
format |
Text |
author |
Limburg, Karin E. Heimbrand, Yvette Kuliński, Karol |
spellingShingle |
Limburg, Karin E. Heimbrand, Yvette Kuliński, Karol Marked recent declines in boron in Baltic Sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system? |
author_facet |
Limburg, Karin E. Heimbrand, Yvette Kuliński, Karol |
author_sort |
Limburg, Karin E. |
title |
Marked recent declines in boron in Baltic Sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system? |
title_short |
Marked recent declines in boron in Baltic Sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system? |
title_full |
Marked recent declines in boron in Baltic Sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system? |
title_fullStr |
Marked recent declines in boron in Baltic Sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system? |
title_full_unstemmed |
Marked recent declines in boron in Baltic Sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system? |
title_sort |
marked recent declines in boron in baltic sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system? |
publishDate |
2023 |
url |
https://doi.org/10.5194/egusphere-2023-512 https://egusphere.copernicus.org/preprints/2023/egusphere-2023-512/ |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
eISSN: |
op_relation |
doi:10.5194/egusphere-2023-512 https://egusphere.copernicus.org/preprints/2023/egusphere-2023-512/ |
op_doi |
https://doi.org/10.5194/egusphere-2023-512 |
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1786832467270828032 |