[1] Norwegian Inst Water Res, N-0411 Oslo, Norway
[2] Trent Univ, Environm & Resources Studies Programme, Peterborough, ON K9J 7B8, Canada
[3] Swedish Agr Univ, Dept Environm Assessment, SE-75007 Uppsala, Sweden
[4] CSIC, Ctr Estudis Avancats Blanes, E-17300 Blanes, Spain
[5] Univ Virginia, Dept Environm Sci, Charlottesville, VA 22904 USA
[6] Ctr Ecol & Hydrol, Bangor LL57 2UP, Gwynedd, Wales
[7] Finnish Environm Inst, FIN-00251 Helsinki, Finland
[8] Charles Univ, Inst Environm Studies, CZ-12801 Prague 2, Czech Republic
[9] Macaulay Land Use Res Inst, Aberdeen AB15 8QH, Scotland
[10] Czech Geol Survey, CZ-11821 Prague, Czech Republic
[11] Ctr Ecol & Hydrol, Wallingford XO10 8BB, Oxon, England
[12] Acad Sci Czech Republ, Inst Hydrobiol, CZ-37005 Ceske Budejovice, Czech Republic
[13] USB, Fac Biol Sci, CZ-37005 Ceske Budejovice, Czech Republic
[14] Swedish Environm Res Inst, SE-40014 Gothenburg, Sweden
[15] Netherlands Environm Assessment Agcy, NL-3720 AH Bilthoven, Netherlands
[16] CNR, Inst Ecosyst Study, Sect Hydrobiol & Ecol Inland Waters, I-28922 Verbani Pallanza, Italy