Natural factors and chemical contamination control the structure of macrobenthic communities in the Santos Estuarine System (SP, Brazil)

Abstract

The Santos Estuarine System (SES) is a complex of bays, islands, estuarine channels, and rivers located on the Southeast coast of Brazil, in which multiple contaminant sources are situated in close proximity to mangroves and other protected areas. In this study, the composition and structure of the macrobenthic communities of SES were described and ninetynine species were identified, with the predominance of polychaetes and bivalve mollusks. The benthic assemblages also showed strong signs of stress, as indicated by the low abundance, richness and diversity, and the dominance of opportunistic species. Integrated analysis including sediment characteristics related to natural and anthropogenic factors (e.g., sediment chemistry, and toxicity) indicated that benthic fauna from the inner portions of the SES and vicinities of the SSOS diffusers as Santos Bay were affected. Some locations at the mouths of Santos and Sao Vicente estuaries exhibited moderate disturbance. In other sites from the mouth of São Vicente and Bertioga channels, and Santos Bay, the benthic fauna were considered not degraded. Our results suggest that a combination of both environmental factors and contaminants were responsible for the benthic community structure.

Population biology of the fiddler crab Uca maracoani (Crustacea, Ocypodidae) inhabiting an impacted mangrove area on the southern coast of São Paulo state, Brazil

“…The study area has several observable sources of anthropogenic impacts, which are mostly related to the existence of houses, a recreational marina, and paved roads separating mangrove patches (Mano-Clara and Schmiegelow, 2015). Previous studies reported low to moderate levels of contaminants and improper disposal of solid residues (mainly plastic and wood) in the São Vicente Channel (Abessa et al, 2008;Cordeiro and Costa, 2010), which are all capable of negatively affecting the benthic communities (Abessa et al, 2019). Despite the anthropogenic influence, at least seven fiddler crab species are found in the study area (Checon and Costa, 2017).…”

Influence of water quality on the macroinvertebrate community in a tropical estuary (Buenaventura Bay)

“…This challenge is referred to as “the estuarine quality paradox” because of the similarities in the characteristics of organisms and assemblages between relatively unaffected and anthropogenically impacted estuaries (Elliott & Quintino, 2007 ). Accordingly, the Buenaventura Bay macroinvertebrate assemblage was affected by the convergence of anthropogenic pollution and natural stressors (Abessa et al, 2019 ; Dauvin & Ruellet, 2009 ; Elliott & Quintino, 2007 ). The most relevant anthropogenic stressors were nitrate and phosphate concentrations, whereas the most relevant natural stressors were salinity, pH, and water temperature.…”

Living benthic foraminiferal assemblages monitored monthly in a tide-dominated estuary, Bertioga Channel, Brazil

“…The natural stress typical of coastal zones is intensified in Santos estuarine system, area where we can find the largest harbor of South America and the largest industrial pole of Brazil with petrochemicals, pharmaceuticals, and steel industries (Kim et al 2016). Abessa et al (2019) showed that most critical area of their studying the chemical contamination in the Santos Estuary System was the inner portion of Santos Channel (Piaçaguera Channel), due to the presence of the industrial complex.…”