Marked recent declines in boron in Baltic Sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system?
<p>Ocean acidification is spreading globally as a result of anthropogenic CO<span class="inline-formula"><sub>2</sub></span> emissions, but the Baltic Sea has until recently been thought to be relatively well-buffered by terrigenous inputs of alkalinity from i...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-11-01
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| Series: | Biogeosciences |
| Online Access: | https://bg.copernicus.org/articles/20/4751/2023/bg-20-4751-2023.pdf |
| _version_ | 1797447459128999936 |
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| author | K. E. Limburg K. E. Limburg Y. Heimbrand K. Kuliński |
| author_facet | K. E. Limburg K. E. Limburg Y. Heimbrand K. Kuliński |
| author_sort | K. E. Limburg |
| collection | DOAJ |
| description | <p>Ocean acidification is spreading globally as a result of anthropogenic CO<span class="inline-formula"><sub>2</sub></span> 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.</p> |
| first_indexed | 2024-03-09T13:56:15Z |
| format | Article |
| id | doaj.art-908c362346394c68a5a43e7af9502536 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-03-09T13:56:15Z |
| publishDate | 2023-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-908c362346394c68a5a43e7af95025362023-11-30T16:14:26ZengCopernicus PublicationsBiogeosciences1726-41701726-41892023-11-01204751476010.5194/bg-20-4751-2023Marked recent declines in boron in Baltic Sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system?K. E. Limburg0K. E. Limburg1Y. Heimbrand2K. Kuliński3Department of Environmental Biology, College of Environmental Science and Forestry, State University of New York, Syracuse, NY, USADepartment of Aquatic Resources, Swedish University of Aquatic Sciences, Uppsala, SwedenDepartment of Aquatic Resources, Swedish University of Aquatic Sciences, Uppsala, SwedenDepartment of Marine Chemistry and Biochemistry, Institute of Oceanology of the Polish Academy of Sciences, Sopot, Poland<p>Ocean acidification is spreading globally as a result of anthropogenic CO<span class="inline-formula"><sub>2</sub></span> 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.</p>https://bg.copernicus.org/articles/20/4751/2023/bg-20-4751-2023.pdf |
| spellingShingle | K. E. Limburg K. E. Limburg Y. Heimbrand K. Kuliński Marked recent declines in boron in Baltic Sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system? Biogeosciences |
| title | 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_short | 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 |
| url | https://bg.copernicus.org/articles/20/4751/2023/bg-20-4751-2023.pdf |
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