Structuring of copepod communities across sub-Antarctic coastal and oceanic environments during spring

This study examines the spatial structuring of mesozooplankton communities across sub-Antarctic coastal (Beagle Channel), transitional (Staten Island), and oceanic (Burdwood Bank) environments during spring. Hydrographic (temperature and salinity), satellite-derived chlorophyll-a, and biological variables (density, biomass, size, and composition) were integrated, with emphasis on copepods as the dominant mesozooplankton group. Salinity was the environmental variable most strongly associated with copepod distribution, exhibiting a significant positive correlation with density, whereas associations with biomass, temperature, and chlorophyll-a were not significant. Four distinct copepod assemblages were identified, corresponding to regional hydrographic regimes: the inner Beagle Channel, the outer channel, the Staten Island area, and the Burdwood Bank. Copepod abundance and body size increased toward oceanic waters, suggesting enhanced secondary production linked to physical retention and upwelling processes. In contrast, coastal zones showed lower density and biomass but higher richness and evenness, likely influenced by freshwater inputs. A total of sixteen copepod species were documented, with Drepanopus forcipatus and Calanus australis widely distributed across all subregions. These species may function as ecological indicators, reflecting environmental conditions and ecosystem connectivity. Overall, the findings underscore the role of this region as a biological corridor linking coastal and oceanic systems.

http://doi.org/10.1590/2675-2824074.25255

Figure captions:

Table S1: Station depths and zooplankton sampling depths (m) at the study sites. 

Table S2: Density (ind m⁻³) of zooplankton groups at each sampling station. 

Figure S1. Spatial distribution of Drepanopus forcipatus and Calanus australis density (ind m⁻³) across sub-Antarctic coastal (Beagle Channel), transitional (Staten Island), and oceanic (BB) environments.