Hydrobiologia

, Volume 667, Issue 1, pp 255–270

Increased nutrient loading and rapid changes in phytoplankton expected with climate change in stratified South European lakes: sensitivity of lakes with different trophic state and catchment properties

  • Peeter Nõges
  • Tiina Nõges
  • Michela Ghiani
  • Fabrizio Sena
  • Roswitha Fresner
  • Maria Friedl
  • Johanna Mildner
Primary research paper

DOI: 10.1007/s10750-011-0649-9

Cite this article as:
Nõges, P., Nõges, T., Ghiani, M. et al. Hydrobiologia (2011) 667: 255. doi:10.1007/s10750-011-0649-9

Abstract

We hypothesised that increasing winter affluence and summer temperatures, anticipated in southern Europe with climate change, will deteriorate the ecological status of lakes, especially in those with shorter retention time. We tested these hypotheses analysing weekly phytoplankton and chemistry data collected over 2 years of contrasting weather from two adjacent stratified lakes in North Italy, differing from each other by trophic state and water retention time. Dissolved oxygen concentrations were higher in colder hypolimnia of both lakes in the second year following the cold winter, despite the second summer was warmer and the lakes more strongly stratified. Higher loading during the rainy winter and spring increased nutrient (N, P, Si) concentrations, and a phytoplankton based trophic state index, whilst the N/P ratio decreased in both lakes. The weakened Si limitation in the second year enabled an increase of diatom biovolumes in spring in both lakes. Chlorophyll a concentration increased in the oligo-mesotrophic lake, but dropped markedly in the eutrophic lake where the series of commonly occurring cyanobacteria blooms was interrupted. The projected increase of winter precipitation in southern Europe is likely to increase the nutrient loadings to lakes and contribute to their eutrophication. The impact is proportional to the runoff/in-lake concentration ratio of nutrients rather than to the retention time, and is more pronounced in lakes with lower trophy.

Keywords

Climate change Anoxia Phosphorus release Silicon limitation Change of dominant species Flushing 

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • Peeter Nõges
    • 1
    • 2
  • Tiina Nõges
    • 1
    • 2
  • Michela Ghiani
    • 1
  • Fabrizio Sena
    • 1
  • Roswitha Fresner
    • 3
  • Maria Friedl
    • 3
  • Johanna Mildner
    • 3
  1. 1.Joint Research Centre, Institute for Environment and SustainabilityEuropean CommissionIspraItaly
  2. 2.Centre for Limnology, Institute of Agricultural and Environmental SciencesEstonian University of Life SciencesRannu, TartumaaEstonia
  3. 3.Carinthian Institute for Lake ResearchKlagenfurtAustria

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