 |
 |
|
Environmental Change Research Unit - ECRU
Navigation:Contact information:Environmental Change Research Unit (ECRU) Phone: +358-9-1911 Maintenance
|
 |
Mutual
MULTIPROXY APPROACH TO ESTIMATE CHANGES IN UV EXPOSURE IN ARCTIC LAKES
The project contributes directly to the key research priorities in the field of arctic global change research as defined in Finland 's Arctic Research Strategy. It will also form a key component of Finland 's contribution to global initiatives and programmes dealing with the protection of arctic environment. Active national and international co-operation will guarantee the maximal expertise in the project. Specific objectives: The overall objective of the study is to achieve information on the functioning of the northern nature in respect to parameters that determine and reflect the underwater light environment in subarctic and arctic lakes. The main objectives of the project are:
Figure 1. Schematic presentation of the factors determining and reflecting underwater UV regime. The objective is to quantify links between different boxes and analyse how changes within the parameters influence these interactions. Expected results and their significance: • Long-term UV time series for the research areas in northern Finland and in arctic Canada using the existing meteorological data series and novel modelling tools and methods. This will be the first long-term times series produced for remote Arctic areas. • Bio-optical characterisation of lakes in arctic Lapland and Canada using the state-of-the-art measuring techniques. This will produce new and highly relevant data on the characteristics of northern lakes and their sensitivity to global changes. • Establishment of relationships between various aquatic organisms and UV radiation fluxes in more than 50 lakes in Finnish Lapland and arctic Canada . This forms a huge database for future studies. • Detailed model to relate plant and zooplankton pigments to underwater light conditions and UV penetration. This will allow ecosystem responses to UV radiation to be modelled both back in time and for the future. • A diatom-based model to predict changes in DOC and colour of lake water in Lapland and Canada . This will allow underwater light conditions in lakes to be reconstructed with a great accuracy • Detailed and validated reconstruction of past UV radiation fluxes and underwater light milieu in Lapland and arctic Canada . This will produce the first times series of decadal to century-scale changes in UV conditions that allow conclusion when changes began, and what was the starting point prior to anthropogenic impact. Project partners: Laval University : Warwick F. Vincent, Reinhard Pienitz , Claude Belzile CNR-ISE (Consiglio Nazionale delle Ricerche, Instituto per lo Studio degli Ecosistimi) : Piero Guillizzoni, Andrea Lami Rolf Nevanlinna Institute: Lasse Holmström, Panu Erästö Finnish research team: |
The effect of stratospheric ozone depletion on increases in ambient levels of solar ultraviolet (UV) radiation in high-latitude regions has raised concerns about the response of northern ecosystems to global change. Unfortunately, meteorological and biological monitoring studies are usually too brief to record the magnitudes of past changes in UV radiation fluxes and their effects. The current project is an innovative study in which we combine long time-series of modelled UV radiation data with the high resolution record of environmental changes recorded in lake sediments in Finnish Lapland and arctic Canada to hindcast the long-term changes in UV radiation fluxes that have taken place in northern high-latitude regions. To achieve this we will use the latest bio-optical instruments, biological sampling, and meteorological models that utilise long sunshine duration, total ozone and other meteorological data to establish relationships between biological indicators and UV penetration. We then present probabilistic estimates of past UV exposures from three representative proxy sources: the concentration of UV-photoprotective melanin pigments in the subfossil remains of Cladocera, the concentration of UV-sensitive algal pigments in the sediment, and the past concentration of UV-attenuating dissolved organic carbon (DOC) of the water column, derived from the transfer function between subfossil diatom algae and DOC. The results from the project will enable long-term impacts of UV radiation on various aspects of northern aquatic ecosystem structure to be evaluated. 