The document discusses using the chemistry of freshwater mussel shells as a proxy for reconstructing late Holocene river conditions. It outlines a study that analyzed stable oxygen isotopes and trace element concentrations in modern and late Holocene mussel shells from the Rhine and Meuse Rivers. The results showed seasonal patterns in the shell chemistry that corresponded to predicted values based on environmental factors. This indicates the shell chemistry can be used as a proxy to reconstruct river discharge, flood and drought frequencies over the past 5000 years. Future work involves further isotope and trace element analyses to better resolve seasonal patterns and growth lines in order to study variations related to factors like the North Atlantic Oscillation.

1. The chemistry of freshwater mussels as a proxy for late Holocene river conditions Emma Versteegh Simon Troelstra Hubert Vonhof

6. Stable oxygen isotopes

7. Rivers Rhine and Meuse

8.  18 O Rhine and Meuse

14. Late Holocene shells

16. Results: 20 th century shells

20. Predicted  18 O

21. Predicted  18 O shell vs.  18 O shell  18 O shell corresponds well with predicted values   18 O shell is useful proxy

23. Calculated  18 O water vs. monthly mean  18 O water

24. Trace elements

25. Trace elements Winter Winter Winter Winter

26. Results: Late-Holocene shells

30. Preliminary results LA-ICPMS

31. Preliminary results LA-ICPMS

32. Polymesoda