SHORT-TERM PROCESSES AND PATTERNS IN THE FORAMINIFERAL RESPONSE TO ORGANIC FLUX RATES

The measurement of the benthic response to the input of organic matter derived from the photic zone gives insight into the relationship between sea surface productivity and growth, reproduction and population fluctuations of benthic foraminifera. At Kieler Bucht (Kiel Bight), biomass and reproduction cycles of Elphidium excavatum clavatum are directly related to the development and sedimentation of phytoplankton biomass over the entire year. Deep-sea foraminifera from the Norwegian Sea fed in a microcosm show a lag time of food ingestion and growth rates quite similar to what has been observed in shallow water communities. In response to the food pulse, Cribrostomoides subglobosum nearly doubled individual bodymass (org. C) over a period of 72 hours by ingestion of organic matter into food vacuoles. In both studies, approximately 6 to 10% of the total organic flux arriving on the sediment surface is ingested by benthic foraminifera, indicating that foraminifera play an important role in the cycling of organic matter in marine benthic environments.