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Journal of Paleolimnology

, Volume 42, Issue 3, pp 325–341 | Cite as

A sediment record of recent nutrient loading and trophic state change in Lake Norrviken, Sweden

  • Joyanto Routh
  • Preetam Choudhary
  • Philip A. Meyers
  • Bhishm Kumar
Original Paper

Abstract

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 N2-fixing versus non-N2-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.

Keywords

Eutrophication TOC/N ratios C and N isotopes n-Alkanes Phytoplankton pigments 

Notes

Acknowledgements

We thank Gunnel Ahlgren and Ingemar Ahlgren for providing references on Lake Norrviken and discussing the lake’s early history. Supriyo Das helped with the pigment analysis. We are grateful to both reviewers for providing valuable suggestions and Mark Brenner for editorial handling. Funding for this study was provided by the J. Rickert stiftelsen and KVA to JR.

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Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • Joyanto Routh
    • 1
  • Preetam Choudhary
    • 2
  • Philip A. Meyers
    • 3
  • Bhishm Kumar
    • 4
  1. 1.Department of Geology and GeochemistryStockholm UniversityStockholmSweden
  2. 2.Department of Earth SciencesIndian Institute of TechnologyRoorkeeIndia
  3. 3.Department of Geological SciencesUniversity of MichiganAnn ArborUSA
  4. 4.National Institute of HydrologyRoorkeeIndia

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