Variations in the dominant algal bloom-forming species in the western South China Sea from 1993 to 2007

Abstract

The study investigated the spatial and temporal variations of harmful algal bloom (HAB) species in the western South China Sea (SCS) for the period 1993–2007, using in situ HAB and remotely sensed datasets. A  significant change in the dominant bloom species occurred during the study period. Trichodesmium erythraeum (Cyanophyta) was the dominant species from 1993 to 1999, usually occurring between March and July in the coastal waters of Binh Thuan Province, South Vietnam. Phaeocystis globosa (Haptophyta) dominated blooms from 2002 to 2007, usually occurring between June and September in the coastal waters of Ninh Thuan Province. Furthermore, most HAB species observed in the earlier period (1993–1999) were absent in latter period (2002–2007). These changes are attributable to environmental influences. Warm oligotrophic conditions likely favoured T. erythraeum whereas cooler eutrophic conditions favoured P. globosa.

Keywords: Chl a concentration; harmful algal blooms (HABs); Phaeocystis globosa; South China Sea; Trichodesmium erythraeum; upwelling

African Journal of Marine Science 2009, 31(3): 373–380