Distribution of dinoflagellate cysts in the surface sediment of the coastal areas in Chonburi Province, Thailand

Abstract

Distribution of dinoflagellate cysts were investigated in rainy and dry seasons in the surface sediment of the coastal areas in Ang-sila, Bang-pra, Si-racha and Laem-chabang, Chonburi Province, Thailand. Sampling cruises were conducted in February and September 2005 that were during the dry and rainy seasons, respectively. Thirty types of cysts were found of which 28 cysts belonged to the orders Gonyaulacales, Gymnodiniales and Peridiniales and two were of unknown cyst types. The dominant species were Pheopolykrikos hartmannii and Pyrophacus steinii and the most common species were P. hartmannii, Gonyaulax spinifera (Spiniferites mirabilis), Lingulodinium polyedrum, P. steinii, Protoperidinium pentagonum and P. leonis. Dinoflagellate cysts were widely found in most stations of the study area. The total numbers of dinoflagellate cysts in dry season were higher than those in rainy season. The abundance of dinoflagellate cysts in both seasons was higher at the stations deeper than 10 meter around Ang-sila and Bang-pra areas than at the stations near Laem-chabang areas. These findings suggest that cyst abundance and distribution might be affected by seasonal changes of environment and fishery activity.Proceedings of the Horiba International Conference "New Direction of Ocean Research in the Western Pacific" : Past, Present and Future of UNESCO/IOC/WESTPAC Activity for 50 years and the JSPS Project "Coastal Marine Science"Section I: Research Articles/Harmful microalga