Geography and Environmental Science
Freshwater bivalves as archives of environmental
variability in the Rhine-Meuse delta
Emma A. A. Versteegh
H. B. Vonhof, S. R. Troelstra, D. Kroon
Low δ18O values in winter
precipitation with little
High δ18O values during
evaporation and summer
precipitation enriched in
Additional factor: Melt
water from the Alps
during summer → low
δ18O values of the rivers
• Do these unionids record δ18O values of river water in
• Can we use this as a proxy for past river dynamics?
• Monitoring experiment
• 20th century shells (museum
• Late Holocene shells
Monitoring experiment: collection and tagging of shells
Freshwater mussels record ambient water 18O
values in their shell.
Shell 18O values can be used to determine from
which river a shell originates.
It is not possible to quantitatively reconstruct river
Extreme droughts and possibly melt water peaks
can be detected.
NAO-variability during the Middle Ages??