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University of Helsinki Faculty of XXX

Environmental Change Research Unit - ECRU


Tracking carbon dynamic patterns and climate forcing through post-glacial mire development history by combining modern flux measurements and palaeoecological information
Impacts of climate change on Arctic environment, ecosystem services and society (CLICHE)
Biomarkers – a new potential method to study highly humified peat components
Past water table fluctuations and related changes in carbon accumulation rates in mires – a quantitative multi proxy-based reconstruction from different climate regimes
Impacts of multiple environmental stressors on subarctic lake food web dynamics (MESS)
Climate variability in NW Europe during the past 4000 years and its ecological consequences (CLIM-ECO)
Science workshop on past, present and fututure climate change
Long-term changes in lake ice conditions in northern Finland
Responses of Boreal ecosystem carbon exchange to changing environment in different spatio-temporal scales
Former Projects

Contact information:

Environmental Change Research Unit (ECRU)
Department of Environmental Sciences
P.O. Box 65 (Viikinkaari 1)
FIN-00014 University of Helsinki

Phone: +358-9-1911
(main switch board)
or see People


Jan Weckström



Paimionlahti, Photo: Sanna Vaalgamaa


Duration: 2003-2006

Academy of Finland

Bireme-logoGeneral description:

Coastal marine eutrophication has become a significant and wide-spread problem in recent decades. The same trend can be observed in the Baltic Sea, where the nutrient load has strongly increased from its natural level. In developing a strategy for the sustainable use of coastal ecosystems it is important to understand how a system has varied through time, and, in particular, how far it has departed from baseline conditions. The new EU Water Framework Directive (WFD) requires all surface waters in Europe to fulfill the criterion of “good ecological status” by the end of 2015. This status is defined with reference to undisturbed conditions. However, the implementation of the WFD in coastal areas will be challenged by the difficulty of assessing these reference conditions, as in most cases the systems were already heavily impacted before the start of monitoring programmes.

Bay Halikonlahti, southern Finland, Photo:Sanna VaalgamaaIn the absence of historical water chemistry data the paleolimnological record preserved in coastal sediments can be used to address long-term changes in the trophic status. By combining chemical and biological proxies it is possible to reconstruct changes in the ecological structure of ecosystems affected by eutrophication. The development of new numerical approaches that allow quantitative reconstruction of ecological changes on the basis of modern reference data has been a major recent advance in paleolimnology. These approaches have been successfully used in fresh water ecosystems with regard to surface water acidification, eutrophication, and climate change. Preliminary studies have demonstrated that the multi-proxy approach and organism-based transfer functions are also applicable to coastal environments and suggest that palaeolimnology can offer powerful tools for coastal management.

Kaarina and Sanna sampling, Photo:Janne SuomelaSpecific objectives:

We will

  • expand an already existing dataset of modern water chemistry data and diatom assemblages from 64 sites along the southern coast of Finland by the addition of 20 new sites in the Archipelago Sea (Fig.1)
  • describe the pre-industrial reference status of these 20 new sites in terms of their biota (diatoms, cladocera), and the pigment, stable isotope (d 15 N and d 13 C) and elemental composition of the sediment and further assess the difference between the reference and the present status
  • define reference levels for epilimnetic nitrogen and phosphorus concentrations and the present departure from these background levels at 40 sites using a diatom-nutrient calibration model
  • determine the exact time scales and patterns of eutrophication over the past 150 years at 6 carefully selected sites
  • develop a parsimonious sampling strategy, which provides a fast and cost-effective tool for coastal management with clear implications for future restoration programmes such as the EU Water Framework Directive

Fig.1. Location of the diatom-nutrient training set (outlined area). The 40 reference sites are indicated by circles and the six long core sites by stars .

Research team:


Atte Korhola, Ph.D., co-ordination of the project
Paul Leeson, B.Sc., cladoceran analysis
Sanna Vaalgamaa,M.Sc., geochemical and isotopic analyses
Kaarina Weckström,M.Sc., diatom analysis

Southwest Finland Regional Environment Centre:

Harri Helminen, Doc., Ph.D.
Janne Suomela, Ph.D.

Dating Laboratory, Finnish Museum of Natural History:

Högne Jungner, Ph.D.
National Environmental Research Institute (NERI), Denmark: Daniel Conley, Senior Scientist. Ph.D.
Nina Reuss, pigment analysis

The University of Newcastle, Newcastle upon Tyne (UNEW), United Kingdom:

Stephen Juggins, Ph.D.

Ph.D. theses under preparation:

  • Eutrophication of coastal waters in Southern Finland as indicated by sediment geochemistry ( Sanna Vaalgamaa )