Assessment of chitin variation in seston of a temperate estuary (Bahía Blanca, Argentina)

Chitin was quantified in seston samples to determine its seasonal and spatial distribution in the estuary of Bahia Blanca. Sampling was conducted at three sites: Puerto Cuatreros, Maldonado, and Canal Vieja in autumn, winter, spring, and summer (2012–2013). Chitin concentrations were 3.79 ± 0.75 and 0.61 ± 0.36 chitin mg L −1 in autumn and winter, respectively. The proportion of chitin in the suspended particular matter (SPM) reached a maximum of 4% in autumn. There were statistical differences in chitin between seasons but not between sampling points. The particulate organic carbon (POC) ranged from 337.25 ± 30.52 µM in winter to 54.93 ± 26.10 µM in summer. The SPM varied from a maximum of 1172.17 ± 17.53 mg L −1 in spring to a minimum 71.42 ± 5.59 mg L −1 in autumn. In both cases, statistical differences were found between seasons but not between sampling points. The results indicated that the concentration of chitin as well as SPM and POC had a strong seasonal trend. The principal component analysis and the canonical analysis on the principal coordinates of environmental variables also highlighted the seasonal variation. The micro-detritus and planktonic organisms (fungi, diatoms, and copepods) in SPM and POC represent a chitinaceous substrate with a great importance for the study of the incorporation of compounds of nitrogen and carbon to the Bahía Blanca system.