Marked recent declines in boron in Baltic Sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system?

Abstract 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.

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• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch

Verweise und Beziehungen

• Erschienen in: Marked recent declines in boron in Baltic Sea cod otoliths – a bellwether of incipient acidification in a vast hypoxic system? ; volume:20 ; number:23 ; year:2023 ; pages:4751-4760 ; extent:10 ; Biogeosciences ; 20, Heft 23 (2023), 4751-4760 (gesamt 10)

Beteiligte, Orts- und Zeitangaben

• Urheber: Limburg, Karin E. ; Heimbrand, Yvette ; Kuliński, Karol

Weitere Informationen

• DOI: 10.5194/bg-20-4751-2023
• URN: urn:nbn:de:101:1-2023120703443791449468
• Rechteinformation: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.