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

DOI

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 combining high-resolution hyperspectral imaging with µ-XRF and HPLC-pigment data, which allows us to assess chloropigments (productivity) and bacteriopheophytin (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.

Identifier
DOI https://doi.org/10.1594/PANGAEA.914847
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.914847
Provenance
Creator Sanchini, Andrea ORCID logo
Publisher PANGAEA
Contributor Universität Bern
Publication Year 2020
Funding Reference Swiss National Science Foundation https://doi.org/10.13039/501100001711 Crossref Funder ID 172586 https://data.snf.ch/grants/grant/172586 Exploring VNIR/SWIR Hyperspectral Imaging of Varved Lake Sediments: Methods and Applications in Paleoclimatology and Paleoecology
Rights Creative Commons Attribution 4.0 International; https://creativecommons.org/licenses/by/4.0/
OpenAccess true
Representation
Resource Type Publication Series of Datasets; Collection
Format application/zip
Size 15 datasets
Discipline Earth System Research
Spatial Coverage (21.952 LON, 53.855 LAT)
Temporal Coverage Begin 2017-02-18T00:00:00Z
Temporal Coverage End 2017-08-31T00:00:00Z