Biomass and production characteristics of the first red tide noticed in Kuwait Bay, Arabian Gulf

Abstract

Observations on the first red tide off Kuwait, Arabian Gulf, yielded high biomass [55.4-262.7 μg chlorophyll (Chl) a 1-1] and primary production (507.9-571.2 μg Ch-1 1-1), comparable with some of the highest values reported. There were contrasting changes in the carbon assimilation ratios, composition of the phytoplankton and the contribution of nanoplankton (<20 μm) between 11 and 12 May. On 11 May, carbon assimilation by nanoplankton was 2.2 μg C (μg Chl a)-1 h-1, but increased to 9.2 μg C (μg Chl a)-1 h-1 the following day. Nanoplankton contributed 56 and 9% of Chl a and production, respectively, on 11 May, while net plankton (>20 μm) accounted for >65% of the biomass and primary production on 12 May. Picoplankton (<3 μm) contributed <8% of Chl a and <3% of production. Frequent sampling will be necessary to capture such dynamic changes and ephemeral events in these waters.