Succession of organisms following <i>Trichodesmium</i> phenomenon

Abstract

Enrichment caused by <i>Trichodesmium</i> phenomenon is manifested in the environment by the appearance of a series of organisms in succession. In April and May, when <i>Trichodesmium</i> bloom is on the decline in Goa waters (Arabian Sea) and the sea conditions are still fairly uniform, a mixed diatom bloom comprising largely of <i>Chaetoceros</i> appears. This is followed by swarms of cladocerans mostly consisting of <i>Evadne</i>. Soon afterwards the cladocerans are succeeded by dinoflagellates and green algae. At this stage, <i>Noctiluca</i> becomes the most predominant organism. The dinoflagellates are soon followed by swarms of copepods and finally the carnivores (siphonophores and <i>Sagitta</i>) make their appearance in large numbers. Thus, within 2 months, concomitant with the decline of <i>Trichodesmium</i> bloom, rapid changes occur in the population density of planktonic life of the sea when one set of organisms gets replaced by another and each time the community gets reorganized.