Recovery from multi-millennial natural coastal hypoxia in the Stockholm Archipelago, Baltic Sea, terminated by modern human activity.

Autor: van Helmond NAGM; Department of Earth Sciences, Faculty of Geosciences Utrecht University Utrecht The Netherlands.; Department of Geology Lund University Lund Sweden., Lougheed BC; Department of Earth Sciences Uppsala University Uppsala Sweden.; Laboratoire des Sciences du Climat et de l'Environnement LSCE/IPSL, CEA CNRS-UVSQ, Université Paris-Saclay Gif-sur-Yvette France., Vollebregt A; Department of Earth Sciences, Faculty of Geosciences Utrecht University Utrecht The Netherlands., Peterse F; Department of Earth Sciences, Faculty of Geosciences Utrecht University Utrecht The Netherlands., Fontorbe G; Department of Geology Lund University Lund Sweden., Conley DJ; Department of Geology Lund University Lund Sweden., Slomp CP; Department of Earth Sciences, Faculty of Geosciences Utrecht University Utrecht The Netherlands.
Jazyk: angličtina
Zdroj: Limnology and oceanography [Limnol Oceanogr] 2020 Dec; Vol. 65 (12), pp. 3085-3097. Date of Electronic Publication: 2020 Aug 18.
DOI: 10.1002/lno.11575
Abstrakt: Enhanced nutrient input and warming have led to the development of low oxygen (hypoxia) in coastal waters globally. For many coastal areas, insight into redox conditions prior to human impact is lacking. Here, we reconstructed bottom water redox conditions and sea surface temperatures (SSTs) for the coastal Stockholm Archipelago over the past 3000 yr. Elevated sedimentary concentrations of molybdenum indicate (seasonal) hypoxia between 1000 b.c.e. and 1500 c.e. Biomarker-based (TEX 86 ) SST reconstructions indicate that the recovery from hypoxia after 1500 c.e. coincided with a period of significant cooling (∼ 2°C), while human activity in the study area, deduced from trends in sedimentary lead and existing paleobotanical and archeological records, had significantly increased. A strong increase in sedimentary lead and zinc, related to more intense human activity in the 18 th and 19 th century, and the onset of modern warming precede the return of hypoxia in the Stockholm Archipelago. We conclude that climatic cooling played an important role in the recovery from natural hypoxia after 1500 c.e., but that eutrophication and warming, related to modern human activity, led to the return of hypoxia in the 20 th century. Our findings imply that ongoing global warming may exacerbate hypoxia in the coastal zone of the Baltic Sea.
Competing Interests: None declared.
(© 2020 The Authors. Limnology and Oceanography published by Wiley Periodicals LLC on behalf of Association for the Sciences of Limnology and Oceanography.)
Databáze: MEDLINE
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