Analysis of the composition and selective preservation of organic matter in surficial deep-sea sediments from a high-productivity area (Banda Sea, Indonesia)
Abstract Palynological analysis of box-core samples from surficial deep-sea sediments along three transects in the Banda Sea (Indonesia), demonstrates that associations of palynomorphs, palynodebris and diffuse organic aggregates are mainly composed of terrigenous and zooplanktonic constituents. Organic remains of phytoplankton and benthos play a subordinate role in this area. The presence of surprisingly high proportions of notably egg-envelopes and exoskeleton fragments of copepods indicates that areas with seasonally enhanced high productivity can serve as an important sink of organic carbon derived from primary consumers. These zooplankton remains, as well as a considerable part of the terrigenous organic matter originate from animal and plant tissues that are chemically characterized by a high polysaccharide (chitin, cellulose) content. The quantitative prominence of such labile components can be explained by high organic matter influx in combination with high sedimentation rates in the area. Considering the positive relationship between organic matter preservability and sedimentation rate, variations in the amount of transparent palynodebris derived from crustacean exoskeletons may serve as a proxy indicatpr for spatical variations in organic carbon burial efficiency in surficial sediments. It is emphasized that occurrences of structurally preserved organic matter with a presumed chitinous and cellulosic composition are not restricted to young sediments. For reasons not yet fully understood, some structures may even remain preserved under conditions of thermal maturation, so that their records may go well back into the Palaeozoic.