After the closure of this part of the Rhine/Maas estuary in 1971, the deepest areas of the Grevelingenmeer (Netherlands) have been affected by bottom water hypoxia. In order to be able to reconstruct the oxygenation history of the basin, we are developing a range of paleo-oxygenation proxies based on the characteristics of recent benthic foraminifera:

1) Foraminiferal density, diversity and assemblage composition,

2) Benthic foraminiferal pore patterns,

3) Trace metal ratios in benthic foraminiferal tests

Our presentation will concentrate on the very complex observations made in the recent Grevelingenmeer, which seriously complicate the calibration of these proxies. Finally, we will show preliminary results of the application of the newly developed proxies on a 90 cm long sediment record, representing the last 50 years.