Eutrophication and hypoxia in four streams discharging in Guanabara Bay, RJ, Brazil, a case study

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

“…According to the latest National Survey on Basic Sanitation, 50% of Brazilian municipalities discharge most of their raw sewage into rivers. A significant population growth in the last decades associated with inefficient sewage networks has resulted in local or generalized impacts on estuarine habitats (Aguiar et al, 2011;Gern and Lana, 2013). Pollution and habitat loss in estuaries of Southeastern Brazil may be partially responsible for differences in community organization in this ecoregion.…”

Biochemical Composition and Foraminiferal Content of Sediments for Determining Bottom Sector Environments in Guanabara Bay (Rio de Janeiro, Brazil)

“…These stations are located near the Guapimirim mangrove area and near the city of Sã o Gonçalo, which may be the sources of organic matter to these areas. According to Aguiar, Neto, and Rangel (2011), the four streams of São Gonçalo city provide inexorable sources of nutrients, enhancing the severe eutrophication process in Guanabara Bay. This zone can be considered as the eutrophic sector of Guanabara Bay (biotope 5 in Figure 8).…”

Antioxidant responses of triangle sail mussel Hyriopsis cumingii exposed to harmful algae Microcystis aeruginosa and hypoxia

“…One of the more serious impacts of eutrophication on aquatic ecosystems is the disappearance of submerged macrophytes and the shift to a phytoplankton-dominated state (Korner, 2001). Over the last several decades, many regions throughout the world have experienced harmful algal blooms, which were caused by a variety of microalgal species (Karim et al, 2002;Aguiar et al, 2011). Toxic Microcystis aeruginosa, is a http://dx.doi.org/10.1016/j.chemosphere.2015.07.074 0045-6535/Ó 2015 Elsevier Ltd. All rights reserved.…”

“…Hypoxia, the condition where dissolved oxygen (DO) levels in water is less than 2.8 mg O 2 L À1 (Diaz and Rosenberg, 1995), has been observed in different water bodies around the world during the last several decades (Diaz, 2001). Although it can be a natural phenomenon caused by vertical stratification, such as formation of haloclines and thermoclines (Rosenberg et al, 1991), eutrophication makes hypoxia situations worse and more frequently (Gray et al, 2002;Aguiar et al, 2011). Bloom forming algae and hypoxia are considered to be two main stressors which are associated with eutrophication (Karim et al, 2002;Aguiar et al, 2011).…”

“…Although it can be a natural phenomenon caused by vertical stratification, such as formation of haloclines and thermoclines (Rosenberg et al, 1991), eutrophication makes hypoxia situations worse and more frequently (Gray et al, 2002;Aguiar et al, 2011). Bloom forming algae and hypoxia are considered to be two main stressors which are associated with eutrophication (Karim et al, 2002;Aguiar et al, 2011). However, very few studies documented the combined effects of the two stressors on aquatic animals.…”