Macrobenthic community structure in a Brazilian chocked lagoon system under environmental stress

Abstract

ABSTRACT. Saquarema-Jaconé lagoonal system (SJLS) comprises a sequence of five interconnected shallow brackish lagoons with access to the sea by a single permanent tidal channel. It is a eutrophic system, receiving constant input of organic load from its urbanized catchments. The relationship between several environmental variables and the spatialtemporal distribution of the benthic macrofauna was assessed during four seasonal samplings (dry and wet periods of [2007][2008][2009]. Sediment replicates were sampled at seven sites for biological identification and analyzes of organic matter, carbonates, phytopigments, grain size and heavy metals. Salinity, dissolved oxygen and redox potential were measured in situ. SJLS was characterized by sandy bottoms with very reducing conditions. Redox potential significantly discriminated between the dry and wet periods and anoxic conditions were observed in the latter. No significant seasonal differences were observed in the macrofauna. A total of 37 taxa were identified, of which Capitella sp, oligochaetes and Laeonereis culveri (Webster, 1880) were the dominant, representing the early stage of community recovery following dystrophic crises. The faunistic pattern seems to be determined by complex combinations of silt+clay with salinity, organic matter and redox potential. On the other hand, the low concentrations of heavy metals found did not seem to influence the structure and distribution of the biota. SJLS is undergoing persistent environmental stress, dominated by first-order opportunistic species linked to organically enriched sediments.

Predicting ecological changes on benthic estuarine assemblages through decadal climate trends along Brazilian Marine Ecoregions

“…The Southeastern region is a climatic transicional area, where changes in climate conditions are expected to be higher. Also, estuaries from this study were represented by widely varying environmental conditions including heavily polluted bays and chocked lagoons (Santi and Tavares, 2009;Mendes and Soares-Gomes, 2011), and preserved estuaries. There is still very limited information on the effects of pollution and other stressors on benthic communities from most Brazilian estuaries.…”

“…There is still very limited information on the effects of pollution and other stressors on benthic communities from most Brazilian estuaries. Effects of anthropogenic disturbance are well known at estuaries and bays within metropolitan areas that are heavily impacted by wastewater discharges, organic and chemical pollutants, dredging for commercial activities and those areas that have had their margins cleared for urbanization (Bemvenuti et al, 2003;Santi and Tavares, 2009;Mendes and Soares-Gomes, 2011;Aviz et al, 2012;Soares-Gomes et al, 2012). The number of Brazilian estuaries subject to nutrient discharge and eutrophication is likely larger than currently acknowledged.…”

Biomonitoring of the Application of Monoculture and Integrated Multi-Trophic Aquaculture (IMTA) Using Macrobenthic Structures at Tembelas Island, Kepulauan Riau Province, Indonesia

“…is related to its feeding type as a sub-surface deposit feeder. They are well known to respond to changes in sediment organic content and are therefore considered an opportunistic taxa [11,25]. Finally, Nereis sp.…”

Benthic estuarine communities in Brazil: moving forward to long term studies to assess climate change impacts

“…As has been revealed for temperate and tropical estuaries in the Northern hemisphere, significant differences in community structure, succession and trophic processes occur between vegetated and unvegetated sediments in subtropical estuaries (LANA and GUISS, 1992;NETTO and LANA, 1999). Manipulative and mensurative experiments also revealed the responses of benthic communities to nutrient loading and pollution effects, which greatly improved our understanding of mechanisms of community resilience and succession after disturbance (FARACO and LANA, 2003;MENDES and SOARES-GOMES, 2011;GERN and LANA, 2013;SOUZA et al, 2013). Recognising these patterns on local and regional scales allows for better predictive models of benthic community responses to habitat modification, species invasion and subsequent changes in sediment biogeochemistry (NEIRA et al, 2005;DEMOPOULOS et al, 2007;CANNICCI et al, 2008;DEMOPOULOS and SMITH, 2010;SWEETMAN et al, 2010).…”