A sediment record of recent nutrient loading and trophic state change in Lake Norrviken, Sweden
2009 (English)In: Journal of Paleolimnology, ISSN 0921-2728, E-ISSN 1573-0417, Vol. 42, no 3, 325-341 p.Article in journal (Refereed) Published
Human-induced perturbations in the Lake Norrviken catchment, Sweden, over the last 100+ years have left distinctive geochemical imprints in the sediments. Disposal of sewage, industrial, and agricultural run-off into the lake since the end of the nineteenth century changed the trophic status from eutrophic to hyper-eutrophic. The primary organic matter (OM) source in the lake is in situ algal material. Total organic carbon (TOC) concentrations increased near the mid-section of a short sediment core collected from the deepest part of the lake, reflecting elevated epilimnetic productivity and consequent hypolimnetic anoxia. Accompanying shifts to lighter stable organic C and total N isotopic compositions suggest that cyanobacterial productivity increased during this period. The distribution of pigments in the core indicates a shift in the phytoplankton community to a cyanobacteria-dominated system. Moreover, pigments confirm that N-2-fixing versus non-N-2-fixing phytoplankton varied depending upon the external inputs of N and P. Conditions in the lake improved after sewage input was diverted and the lake is currently mesotrophic.
Place, publisher, year, edition, pages
2009. Vol. 42, no 3, 325-341 p.
Eutrophication, TOC/N ratios, C and N isotopes, n-Alkanes, Phytoplankton pigments
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:su:diva-59960DOI: 10.1007/s10933-008-9279-2ISI: 000269918300003OAI: oai:DiVA.org:su-59960DiVA: diva2:432550
authorCount :42011-08-042011-08-022011-08-04Bibliographically approved