Spatial patterns of macrozoobenthos diversity on sewage-impacted intertidal rocky shores in Central Patagonia, Argentina

• Published in: Marine pollution bulletin 2025-02, Vol.211, p.117358, Article 117358
• Main Authors: Verga, Romina N., Tolosano, Javier A., Cazzaniga, Néstor J., Gil, Damián G.
• Format: Article
• Language: English
• Subjects: ABC curves; Argentina; Benthos; biomass; fauna; habitats; Hill's numbers; Intertidal; littoral zone; marine pollution; mussels; Polychaeta; Sewage; species; species richness; wastewater
• ISSN: 0025-326X; 1879-3363; 1879-3363
• DOI: 10.1016/j.marpolbul.2024.117358

The effects of untreated wastewater and shore levels on zoobenthic diversity, species accumulation, and abundance-biomass relationships were studied on intertidal rocky shores of central Patagonia, Argentina. Winter samples (2015) from two sewage-impacted and two reference sites showed that pollution disrupted macrozoobenthic diversity and zonation. A total of 83 taxa were identified, with polychaetes (31 species), mollusks (22), and crustaceans (21) being the most diverse. Impacted sites had greater intra-environmental diversity heterogeneity and higher abundance at the lower midlittoral level, indicating a shift towards lower intertidal levels. Species richness was lower and evenness was higher in the polluted mid-littoral level. ABC curves in the stressed areas showed moderate disturbances with variability across shore zones, while non-polluted rocky shores typically exhibit a higher cumulative faunal biomass than abundance. In impacted areas, chronic habitat changes and disturbances to the mussel matrix by Perumytilus purpuratus are likely responsible for differences in diversity and abundance-biomass relationships. •Small-scale interactions on zoobenthic diversity were examined in central Patagonia.•Fewer species were evenly distributed across the upper shore levels at all sites.•At lower zones, species richness and abundance increased, but evenness and equitability decreased.•Diversity changes and intra-environmental heterogeneity occurred at impacted sites.•ABC curves partly fit dominance models for stressed ecosystems, varying by level.