Research in the Elbe estuary by the ECOBE research group . Fieldwork can be quite different and challenging between seasons: frozen field conditions in February 2017 at -9 Â°C (right) and hot summer days in September 2016 at 27 Â°C (left). Estuaries form the transition zones from a river to the sea and are influenced by the tides. These interesting and highly dynamic ecosystems form one of the study areas of research group ECOBE. Most research is done in the Scheldt estuary, but ECOBE studies estuaries all over the world such as the Sundarbans in Bangladesh, the Chesapeake Bay in the USA and the Elbe estuary in Germany (shown in the picture).