Zooplankton community modulated by spatial and tidal changes in the Bahía Blanca Estuary, Argentina

CHAZARRETA, JAVIER; DUTTO, SOFIA; BERASATEGUI, ANABELA A.; PANIAGUA, GUILLERMINA F.; FRITZ, LAURA J.; CUADRADO, DIANA G.; HOFFMEYER, MÓNICA S.

Regional Studies in Marine Science

Elsevier

Año: 2020 vol. 36

2352-4855

The variability of the zooplankton community over a spatial and a tidal scale, the relationship betweenphysico-chemical variables, and the abundance of zooplankton were studied in the temperate andturbid Bahía Blanca Estuary (Southwestern Atlantic, Argentina). Samples were taken by pumps during12-h tidal cycles, at 3-h intervals, from two depths and three sites across the main channel in theinner and middle estuary zones. The zooplankton was dominated by the copepods Acartia tonsa andEuterpina acutifrons, and larvae of the invasive Pacific oyster Crassostrea gigas. The physico-chemicalvariables that most influenced the zooplankton community were salinity, temperature, suspendedparticulate matter, and chlorophyll a Most taxa showed higher abundances in the inner estuary, whichcorresponds to a turbid and shallow area. The abundance of A. tonsa was higher in the inner estuarywhile that of E. acutifrons was higher in the middle estuary. This spatial distribution is consistent withthe tidal distribution of these species as in the inner estuary the abundance of A. tonsa peaked at ebbtide and that of E. acutifrons peaked at flood tide. Significant differences in the zooplankton communitystructure both across the channel and between depths were detected by multivariate analyses, butno clear patterns were found in the abundance of each taxon by a species-level analysis. The resultsprovide insight into the patterns of zooplankton distribution and abundance in a temperate, turbid, andhuman-impacted coastal ecosystem, considering different spatial and short-term scales. These resultswill be useful to design efficient sampling programmes in highly dynamic environments.