Dinoflagellate Cyst Assemblage and Marine Sediment Characteristics of Colombo Port, Sri Lanka

Abstract

The present study was to investigate dinoflagellate cyst assemblage in relation to characteristics of sediments in Colombo Port. Sampling was conducted between June and October 2013. Sediment samples collected using small (2cm) and large (18cm) core samplers and analyzed for occurrence of dinoflagellate cysts, particle size and organic content of the sediment. Sea Surface Temperature (SST) and Sea Surface Salinity (SSS) were also measured at each sampling site. Eight dinoflagellate cysts were recorded from the sediment samples. They were Protoperidinium leonis, Protoperidinium pentagonum, three other Protoperidinium spp., Scrippsiella spp., Spiniferites spp. and Polykrikos spp. The Scrippsiella spp. is known to form harmful algal blooms which lead to fish mortality. The mean SST varied between 28-29.50C and SSS between 15.5-33.5 ppt. Organic content was between 6.63-14.02% and sediment texture ranged from very fine sand to coarse sand. The study revealed that the dinoflagellate cysts were associated with fine sediments and showed inverse relationships with organic content. Port environment and adjacent coastal environments should be closely monitored for non-indigenous species which would otherwise cause deleterious effects on native biota.