A Holocene high‐resolution record of aquatic productivity, seasonal anoxia and meromixis from varved sediments of Lake Łazduny, North‐Eastern Poland: insight from a novel multi‐proxy approach

Sanchini, Andrea; Szidat, Sönke; Tylmann, Wojciech; Vogel, Hendrik; Wacnik, Agnieszka; Grosjean, Martin (2020). A Holocene high‐resolution record of aquatic productivity, seasonal anoxia and meromixis from varved sediments of Lake Łazduny, North‐Eastern Poland: insight from a novel multi‐proxy approach. Journal of quaternary science JQS, 35(8), pp. 1070-1080. John Wiley & Sons, Ltd. 10.1002/jqs.3242

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Anthropogenic eutrophication and spreading anoxia in freshwater systems is a global concern. Little is known about anoxia in earlier historic times under weaker human impact, or under prehistoric natural conditions with different trophic, land cover and climatic regimes. We use a novel approach that combines high‐resolution hyperspectral imaging with μ‐XRF and HPLC‐pigment data, which allows us to assess chloropigments (productivity) and bacteriopigments (anoxia) at seasonal subvarve‐scale resolution. Our ~9700 cal a BP varved sediment record from NE Poland suggests that productivity increased stepwise from oligotrophic Early Holocene conditions (until ~9200 cal a BP) to mesotrophic conditions in the Mid‐ and Late Holocene. Natural eutrophication was mainly a
function of progressing landscape evolution with intense weathering under dense forest and warm‐moist climatic conditions. Generally, anoxia increased with increasing productivity. Seasonal anoxia and some multi‐decadal periods of meromixis were the common mixing patterns throughout the Holocene except for a period of persisting meromixis between ~5200 and 2000 cal a BP. Anthropogenic deforestation around 400 cal a BP resulted in substantially better lake oxygenation despite high productivity. In this small lake, aquatic productivity and lakeshore forest cover (wind shield) were more important factors controlling oxic/anoxic conditions than Holocene temperature
variability.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)
08 Faculty of Science > Institute of Geological Sciences
08 Faculty of Science > Institute of Geography

UniBE Contributor:

Sanchini, Andrea; Szidat, Sönke; Vogel, Hendrik and Grosjean, Martin

Subjects:

500 Science > 540 Chemistry
500 Science > 550 Earth sciences & geology
900 History > 910 Geography & travel

ISSN:

0267-8179

Publisher:

John Wiley & Sons, Ltd.

Language:

English

Submitter:

Hendrik Vogel

Date Deposited:

18 Nov 2020 17:21

Last Modified:

15 Dec 2020 12:45

Publisher DOI:

10.1002/jqs.3242

BORIS DOI:

10.7892/boris.148132

URI:

https://boris.unibe.ch/id/eprint/148132

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