Surface waters under multiple stress Peeter Nõges Centre for Limnology, Estonian University of Life Sciences

Outline Global change & water resources Dominant stressor combinations Stressor interactions EU project MARS

Global distribution of evaporation and precipitation

Redistribution of air moisture 19 May 2016Baltic Water Works Conference Dry becomes dryer and wet becomes wetter

19 May 2016Baltic Water Works Conference Rising sea surface temperature Lehmann et al., 2011 Jurgensone et al., – –2008 Average trend 1 ºC/decade

19 May 2016Baltic Water Works Conference Suursaar, 2011Jaagus & Kull, 2011 Strengthening westerlies

19 May 2016Baltic Water Works Conference Projected changes in river flow Higher winter runoff Earlier flood peak Slightly higher summer minimum Higher autumn runoff

19 May 2016Baltic Water Works Conference Main pressures Diffuse pollution Point-source pollution Toxic pollution Hydromorphological modification Damming Water abstraction Alien species Overfishing Thermal pollution

The MARS review 19 May 2016Baltic Water Works Conference Nõges et al. 2016

Stressor combinations Nõges et al. 2016

Types of stressor interaction Additive Synergistic Antagonistic 2+2 = = = 5

Pressures on surface waters in Estonia Source: Ministry of the Environment

Point source loading in Estonia Source: Ministry of the Environment

Mean pollutant concentrations in Estonian rivers in Source: Ministry of the Environment

Mean total nitrogen concentration in Estonian rivers vs amount of precipitation in Source: Ministry of the Environment

19 May 2016 Baltic Water Works Conference Temperature & nitrogen affect cyanobacteria In warmer climate, elevated nitrogen concentrations will have a stronger stimulating effect on cyanobacteria. Jeppesen et al Kosten et al. 2012

19 May 2016Baltic Water Works Conference Global warming reinforces eutrophication Moss et al. 2012

19 May 2016 Fish-kills in Lake Peipsi-Pihkva A. Kangur et al., 2007 Baltic Water Works Conference

Dams on Estonian rivers 19 May 2016Baltic Water Works Conference 966 man-made dams on Estonian rivers. About 300 of them hinder fish passage. 17 dams have a fish ladder (1,8%)

Hydropower stations in Estonia 19 May 2016 Baltic Water Works Conference

Mesocosm experiments Case study catchments Scenario modelling Diagnostic tools 19 May 2016 Baltic Water Works Conference

What will MARS do 19 May 2016Baltic Water Works Conference WFD assessment ? Bayesian Belief Networks

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