Sweep net, surface sediment, and down core relative Cladocera assemblages from Finnish Lapland

DOI

Aim: To understand modern and past aquatic community responses to climate-induced shifts in productivity and ultraviolet radiation (UV) exposure.Location: Treeline ecotone from north boreal forest to subarctic tundra in northeastern Finnish Lapland.Taxon: Cladocera (Crustacea: Branchiopoda).Methods: 31 small and shallow lakes were examined for summer epilimnetic communities (SEC) and surface sediment fossil integrative communities (FIC) of Cladocera for species distribution and their environmental correlations. A 700-year down-core sediment sequence from a treeline lake (Námmájávri) was analyzed for FICs and cladoceran-inferred UV-absorbance (ABSUV, indicative of melanin pigmentation) for evidence of long-term community and photoprotective responses and compared with records of paleotemperature, solar intensity, and composite sediment biogeochemistry by variance partitioning analysis.Results: The SECs were primarily correlated with specific UV absorbance (indicative of UV exposure) and total phosphorus and FICs by mean July air temperature and total nitrogen. The Námmájávri FICs showed subtle changes with a directional shift between the 19th and 21st centuries and were mostly explained by solar intensity. ABSUV exhibited increases during the 18th and 20th centuries, being related to variation in sediment biogeochemistry, which was indicative of changes in auto- vs. allochthonous production.Main conclusions: The ecotonal distribution of cladocerans is sensitive to temperature, nutrients, and allochthonous carbon, which is closely linked with UV exposure. The long-term community shifts and photoprotection have been governed by solar intensity and biogeochemical shifts through lake water optics, attributable to direct UV impact or climate-mediated intensification in photodegradation of allochthonous carbon. Estimations of the dual effects and mechanisms of increasing temperatures and UV on subarctic lakes and their biota remain challenging as their individual impacts on key species were partly contradictory.

Supplement to: Nevalainen, Liisa; Rantala, Marttiina V; Rautio, Milla; Luoto, Tomi P (2018): Spatio-temporal cladoceran (Branchiopoda) responses to climate change and UV radiation in subarctic ecotonal lakes. Journal of Biogeography, 45(8), 1954-1965

Identifier
DOI https://doi.org/10.1594/PANGAEA.890563
Related Identifier https://doi.org/10.1111/jbi.13371
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.890563
Provenance
Creator Nevalainen, Liisa ORCID logo; Rantala, Marttiina V ORCID logo; Rautio, Milla; Luoto, Tomi P ORCID logo
Publisher PANGAEA
Publication Year 2018
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 3 datasets
Discipline Earth System Research
Spatial Coverage (26.523W, 68.792S, 27.505E, 69.912N)