Colonization of a bomb crater on the bunker Valentin, Bremen, Germany, with Ostracoda (Crustacea) during the last decades

In 2017 several sediment cores were extracted from a water-filled bomb crater of World War II on the roof of the bunker Valentin in Bremen-Farge, Germany. The drill cores have a length of up to 55 cm, although the lower part of the cores could not be retrieved. Dating was carried out using the isotopes 210Pb and 137Cs and revealed that oldest sample dates back to ca. AD 1976, resulting in an average sedimentation rate of ca. 1.3 cm/yr. Regarding the ostracod assemblage, almost all species that are currently found alive in this bomb crater were already present even in the oldest sample. There is no uniform trend in the abundance of each species within the core. Eucypris virens is given special attention. This species was not found in the analyzed sediment samples, but only once living juveniles are detected in the years between 2013 and 2015 in this bomb crater.