High detritus/phytoplankton content in net-plankton samples from coral reef water: source of over-estimation in zooplankton biomass by measuring seston weight

Abstract

We examined the bias in the estimation of zooplankton biomass in net-samples in coral reef waters by measuring seston weight, which contains non-living matter (or detritus) and net-phytoplankton in addition to zooplankton. Net-samples were collected at a coral reef at Tioman Island, Malaysia, and divided them into two aliquots to be used for both measurements of seston weight and zooplankton biomass. Seston weight was on average 2.2 times higher than net-zooplankton biomass, and non-zooplankton content (detritus/phytoplankton) contributed on average 49.2% to the seston weight. Consequently, measurement of net-plankton seston weight as zooplankton biomass in coral reef waters is inadequate due to the highly variable contribution of detritus/phytoplankton content and involves the possibility of over-estimation of zooplankton biomass.