1. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund PALEOLIMNOLOGICAL STUDIES IN THE WEL LAKES Sigrid Haande, NIVA DeWELopment workshop, Oslo 21.-22.06 2010

2. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund DeWELopment: OBJECTIVE Validation of reference conditions in selected lakes in the WEL catchment area by using paleolimnological methods –Dating 210 Pb –Dry weight/Loss of ignition –Algal pigments –Diatoms

3. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund BACKGROUND Palaeolimnology provides powerful tools to determine reference conditions and to assess the deviation from reference conditions Analyse a number of slices from different levels of a sediment core, corresponding to different periods in the history of the lake the palaeo-record potentially allows the structural and functional characteristics of pre-pollution aquatic ecosystems to be reconstructed

4. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund THE WEL LAKES

5. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund METHODS Each slice was divided in four parts: 1.Dry weight and loss of ignition 2.Dating 210 Pb (DHI, Denmark) 3.Pigment analyses (NIVA) 4.Diatom analysis (UCL, England)

6. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund METHODS: Diatom inferred-Total Phosphorous reconstructions Diatom analyses from each core (25 sub samples from the full cores; top/bottom samples) A diatom-total phosphorous (TP) transfer function was applied to the diatom data for each core. A reconstruction of diatom-inferred total phosphorous (DI-TP) were produced by using a Northwest European training set of 152 relatively small, shallow lakes (<10 m max depth) with a median value of the dataset fo 104 µg TP L -1.

7. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund RESULTS: Lake Rumian Dating 210 Pb Pigments

8. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund RESULTS: Diatoms

9. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund RESULTS: Lake Lidzbaskie Dating 210 Pb Pigments

10. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund RESULTS: Diatom analyses

11. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund RESULTS: Lake Kielpinskie Dating 210 Pb Pigments

12. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund RESULTS: Diatom analyses

13. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund RESULTS: Other WEL lakes

14. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund RESULTS: Other lakes-Diatom analyses

15. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund RESULTS

16. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund SUMMARY All lakes have been nutrient rich Pre-reference communities could not be defined for the three lakes The sediment cores cover a relatively short period (30-120 years) Lake Rumian (30 years) Nutrient rich for the whole period May show some degree of recovery Lake Lidzbarskie (60 years) Nutrient rich for the whole period Enrichment 1960-1990 Slight decrease in enrichment the last 10 years Lake Kielpinskie (120 years) Nutrient rich for the whole period Enrichment in the early 1900, Slight decline in productivity the last 10 years Other lakes, just indicative results

17. Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund