Das Projekt "Ablagerung von Vulkanasche in der Tiefsee: Biogene Sedimentstrukturen dokumentieren die Reaktion des Makrobenthos auf den Ausbruch des Pinatubo" wird vom Umweltbundesamt gefördert und von Universität Basel, Geologisch-Paläontologisches Institut durchgeführt. Leading Questions: - How many trace fossils are known from the pre-ash as well as the ash habitat? How many opportunistic immigrants occur not known from the pre-ash ichnofabrics? - What is the population density of the macrobenthos after the events (estimated from open holes in the 'sero' surface of the ash)? - How do the macro-organisms mix the event layer? - How do ash and background sediment differ in some physical properties which affect the 'burrowbility' of the sediment? Abstract: Most of the ash erupted by the Pinatubo in 1991 was deposited in the South China Sea. Sediment cores taken in 1994, 1996, and planned for 1998 provide the unique opportunity to study various aspects of the faunal response to this giant natural environmental disturbance. The response of the macrobenthos is documented by traces and ichnofabrics, but it has not been analysed yet. The proponent of the proposal is invited to perform such a study. During the course of this investigation, the following aspects will be addressed (see below). This study is based on visual observations, analysis of x-ray radiographs, measurements of physical properties, and quantification of the vertical distribution of ash.