Chitin determination on marine seston in a shallow temperate estuary (Argentina)

ABSTRACT Chitin is one of the most abundant biopolymers in the planet. Chitin was quantified in seston fractions in order to obtain the first characterization of this polymer in the Bahía Blanca Estuary. Sampling was conducted at two sites: a non- impacted tidal channel -Bahía del Medio (BM)- and a sewage discharge sector -Canal Vieja (CV)-, during winter and summer. The highest values of chitin were observed in the seston fraction <20 µm (6.1 mg L-1 in BM in summer). The remaining larger fractions (20-60, 60-200, 200-500 and >500 µm) did not exceed ~1% of total chitin.. The higher concentration of chitin in seston <20 µm suggests that this fraction is a large reservoir of this biopolymer contributing to organic matter for microorganisms in the food web of the Bahía Blanca Estuary. This study is also the first report on the possible sources of chitin in Argentina marine ecosystems.