The Odra estuary as a filter and transformation area

The Odra Estuary is one of the most polluted coastal waters of the southern Baltic. To investigate how and whether the estuary acts asa filter and tra nsformation area For the fluviogenic material, different models were develo ped and an intensive monitoring programme was carried out. Summarizing diff erent methodological approaches, it could be shown that the total system fi lter capacity reaches 2...5% for nutrients and 10...15% for some heavy meta ls related to the current mean annual input. In the western part of the est uary, the retention is more important and amounts to 10...40% of the annual nutrient yield. Carbon flux studies revealed that both a reduction of the inputs and more internal and external nutrient sinks are needed to reverse the anthropogenic eutrophication process.