Distribution of suspended sediments and pollen in the northern south China sea: Implications for pollen source, transport, and deposition in surface ocean waters

Abstract

Pollen and spores of terrestrial plants found in marine sediments are excellent proxies for paleovegetation and paleoclimate reconstructions of surrounding areas. Ascertaining the pollen transport mechanism from terrestrial to oceanic environments is crucial for the interpretation of pollen data from marine sediments. In this study, we present the distribution of suspended sediments and pollen from 59 surface ocean water samples collected during September and October of 2013, in the northern South China Sea (SCS). The results suggest that there is a difference between the transmission mechanisms of suspended sediment and pollen/spores. Suspended sediment (silt, coarse sand, and gravel) settle quickly in nearshore and continental shelf waters due to their density. Alternately, small, light-weight pollen grains can be carried over long distances in a marine setting. The density of suspended sediment has a high correlation with the concentrations of Pinus, evergreen Quercus, Poaceae and Cyperaceae pollen as well as fern spores (e.g., Dicranopteris), but no correlation with total pollen concentration. This finding will broaden the understanding of the relationships between suspended sediments and pollen in the northern SCS and help to better interpret pollen records extracted from marine sediment cores from the SCS.