Bay In Brazil Research Articles

Comparing the Effects of Erosion and Accretion along the Eastern Coast of Río de Janeiro and Guanabara Bay in Brazil

Comparing the Effects of Erosion and Accretion along the Eastern Coast of Río de Janeiro and Guanabara Bay in Brazil

Upwelling-driven variation of sound speed profile in a Brazilian bay monitored by a coastal acquisition system

Upwelling-driven variation of sound speed profile in a Brazilian bay monitored by a coastal acquisition system

Species diversity, trophic structure, and taxonomic distinctness of molluscan assemblages associated with Sargassum beds in a historically impacted bay

AbstractAnthropogenic impacts on coastal habitats can result in alterations of diversity parameters in marine invertebrate assemblages. Macroalgae beds are highly susceptible to human‐induced disturbances, supporting a great diversity of molluscan species and being ecologically important for coastal ecosystems. This study investigates the diversity alterations on Sargassum‐associated molluscan assemblages from areas with different distances from a main source of pollution within a historically impacted bay in Brazil. In general, sites closer to the pollution source presented lower species diversity, trophic diversity, and taxonomic relatedness among species. Beta diversity among assemblages was highly correlated with environmental differentiations among localities due to heavy metal concentrations in algal tissue. Bittiolum varium was the dominant species and was mainly responsible for differences in community parameters. Several trophic groups were well‐represented in Sargassum‐associated molluscan fauna, but assemblages were mostly dominated by micrograzers. A seasonal trend was observed in diversity alterations, with lower diversity during warm season at most sites except Santa Rita, possibly because it is the site less affected by human impacts. The importance of other environmental variables, such as hydrodynamism, for molluscan composition is also discussed. Our results highlight the potential of Sargassum‐associated molluscan assemblages for the study of impacted areas and reinforce the importance of using multiple community metrics to understand the biodiversity patterns of marine invertebrates under anthropogenic impacts.

Microplastics in surface waters of tropical estuaries around a densely populated Brazilian bay

Brazil is the fourth largest producer of plastic waste in the world, but studies on pollution of rivers and estuaries by microplastics are still scarce. This study is located in the state of Bahia (Northeast region) in ten estuarine environments around Todos dos Santos Bay (TDB), the largest Brazilian bay, where more than 3 million Brazilians live. The aim of the study was the evaluation of the input of microplastics into the TSB by river. Microplastic abundance, size, morphology and water quality were determined during three sampling campaigns. All river samples were highly polluted with microplastics (mostly <150 μm), up to 33,000 items m−3, exceeding values observed in most estuaries worldwide. The poor quality of the river water reflect the deficient treatment of domestic wastewater in the state of Bahia (49% are not treated), and in this study is shown a correlation with the abundance of microplastics, indicating their possible main source. Artisanal fishing can also contribute locally to this pollution. Morover, the results highlight the importance of sampling small microplastics (<100 μm) to avoid important underestimation of this pollution. Based on these data, the three major rivers would discharge 3.88 trillion items into the Bay each year, equivalent to 4.75 × 105 m2 of plastic. Further research in surface water systems is essential, given that the average wastewater treatment rates in the country and in the Northeast and North regions are only 43%, 32%, and 12%, respectively.

ESTUDO DE COMPOSTOS POLIAROMÁTICOS NÃO CONVENCIONAIS E MERCÚRIO NA BAÍA DE TODOS OS SANTOS, BRASIL: AVANÇOS RECENTES E CONTRIBUIÇÃO PARA MELHOR COMPREENSÃO DO AMBIENTE MARINHO

UNCONVENTIONAL POLYAROMATICS COMPOUNDS AND MERCURY IN THE TODOS OS SANTOS BAY, BRAZIL: RECENT ADVANCES AND CONTRIBUTIONS TO BETTER UNDERSTAND OF THEIR ROLE IN THE MARINE ENVIRONMENT. Baía de Todos os Santos (BTS) is the second-largest Brazilian bay; it was the first oil producing region in Brazil, with three large industrial parks in its north-northeast portion. In addition, the BTS has two large ports and a population of around 3 million inhabitants distributed among 14 cities. In the present study, recent studies on contamination by polycyclic aromatic compounds (PACs) and Hg in sediments, water, and biota from the BTS region are presented and critically discussed. Among the PACs, studies evaluating the presence of polycyclic aromatic hydrocarbons (PAHs) and their nitrated (nitro-PAHs), oxygenated derivatives (oxy-PAHs), and those containing atoms of S as a heteroatom (PASHs) are considered, as well as the element Hg distributed in seawater, sediments, and biota. Regarding biomonitoring organisms, recent results on polychaetes, ascidians, and corals are presented. Trends for future studies are presented at the end of the text.

Sterol and PAHs fingerprint analysis of organic matter at Southeast Brazilian Bay

Southeast Brazilian bays have been increasingly degraded by untreated organic loads. Therefore, to assess fecal contamination status, sediment quality regarding polycyclic aromatic hydrocarbons (PAHs), and sources of organic matter (OM), we have determined fine-grained and total organic carbon (TOC) content and concentrations of PAHs and sterols in twenty-six surface sediment samples in Sepetiba Bay. The fine-grained (1–26 %), TOC (0.20–3.45 %), PAHs (<LQ – 78.27 ng g−1) and sterols (0.10–21.58 μg g−1) results showed a decreasing trend from the internal to the external sector of the study area. The diagnostic ratios of selected PAHs and sterols indicated a mixture with significant contribution from continental and pyrolytic OM in all stations. The fecal contamination is significant to the internal sector of Sepetiba Bay. Considering a site-specific sediment quality guidelines (SQGs) the PAHs levels with more restricted benchmark values indicate the harbor and the internal sector as contaminated.

Modern Dinoflagellate Cyst Abundance and Trace Metals as Biomonitoring Tools in a Tropical Bay in Brazil

Freitas, A.S.; Aguiar, V.M.C., and Baptista Neto, J.A., 2021. Modern dinoflagellate cyst abundance and trace metals as biomonitoring tools in a tropical bay in Brazil. Journal of Coastal Research, 37(6), 1247–1259. Coconut Creek (Florida), ISSN 0749-0208. The spatial distribution of the dinoflagellate cyst assemblages in 11 surface sediment samples collected in Guanabara Bay embayments and associated trace metals revealed the applicability of dinocysts as bioindicators of environmental conditions in estuarine systems. The surface sediment samples presented coarse to fine granulometry. The dinoflagellate cyst analysis followed the standard methodology through the elimination of carbonates and silica. Trace metals were extracted by the evaluation of 1 g of sediment plus a mixture of HNO3 and HCl in a microwave digestion system. Dinoflagellate cyst assemblages were dominated by Operculodinium centrocarpum, Spiniferites spp., and Lingulodinium machaerophorum. Trace metals (Cu, Zn, Pb, Cr, and Ni) showed variations at the different sampling points. The values obtained were Cu (6.7–82.8 mg kg–1), Zn (29.5–355.4 mg kg–1), Pb (18.3–86.2 mg kg–1), Cr (5.1–196.2 mg kg–1), and Ni (19.6–286.0 mg kg–1). Several samples showed high pseudototal concentrations of trace metals, which were above the natural concentrations found in nature. Statistical analysis showed a strong correlation between dinocysts species and some trace metals. Lingulodinium machaerophorum showed a high correlation with 4/5 analysed trace metals and is a eutrophication-sensitive species. However, Brigantedinium sp. presented a positive correlation with all trace metals analysed. The high frequency of L. machaerophorum cysts in all analysed samples associated with several trace metals is indicative of environmental eutrophication. The high availability of trace metals in the surface sediments of Guanabara Bay may be related to the untreated industrial wastes that are dumped directly into the bay.

The Fucales Index: A new tool for monitoring subtidal rocky habitats, and its application to an Atlantic bay subjected to nuclear power plant's effluents

Ecological indices are useful tools for environmental managers to monitor and detect changes caused by natural or anthropogenic disturbances. Despite the fact that descriptors of Fucales species are often included in indices for evaluating changes in coastal marine habitats, there is no index based solely on Fucales abundance. This study proposes the Fucales Index (FI), based on four classes of abundance of a selected Fucales species. The ability of FI to detect changes in the abundance of Sargassum sp. was tested in a Brazilian bay that is subjected to the effluent plume from a nuclear power plant. FI was significantly different when comparing areas inside and outside of the plume area, and it increased with increasing distance from the source of the disturbance. These findings suggest that FI is a suitable tool for assessing the effect of an effluent plume and potentially of other disturbances on rocky shores hosting Fucales.

Energy acquisition and allocation to the gonadal development of Cynoscion leiachus (Perciformes, Sciaenidae) in a tropical Brazilian bay

ABSTRACTThe process of energy acquisition and allocation to the gonadal development involves the use of reserves obtained from the food intake and/or stored in different parts of the body. Some fish species acquire and store energy prior the spawning season (capital breeders). For others species, the energy acquisition through by feeding activity continues actively throughout the spawning season (income breeders). This process of acquisition/allocation of energy to gonadal development was investigated for Cynoscion leiarchus an important fishery resource in southeastern Brazil. Monthly measurements of the gonadosomatic, hepatosomatic, condition factor and stomach repletion indices were carried out. Size at the first maturation was also assessed. Fish, mainly teleosts, were the main source of energy in the diet suggesting a carnivorous behaviour. We found evidences of use of stored body energy reserves during the spawning period, associated concomitantly with a decrease of feeding activity, suggesting a capital breeder. However, the wide spawning season, together with asynchronic oocyte development and indeterminate fecundity (typical of income breeders) suggest that the mixed-breeder strategy should be more suitable for this species. The high plasticity regarding the capital-income breeder strategy during the reproductive cycle of the genus Cynoscion is discussed.

COMPARANDO O USO DA PICARÉ E TARRAFA NA CARACTERIZAÇÃO DA ESTRUTURA DA ICTIOFAUNA DO ENTREMARÉS DE UMA BAÍA SUBTROPICAL

Embora redes-de-arrasto-de-praia (picarés) e tarrafas sejam amplamente utilizadas para amostragem de peixes em habitats marginais costeiros, ainda não há uma comparação entre tais petrechos para a determinação da estrutura da ictiofauna de planí­­cies de maré durante a maré alta. Neste estudo, comparamos a efetividade de uma picaré de multifilamento com a efetividade de uma tarrafa de monofilamento para amostrar a estrutura da ictiofauna do entre-marés de uma baí­­a subtropical do Brasil. A picaré apresentou um melhor desempenho geral. Em comparação com a tarrafa, a picaré amostrou (I) densidade substancialmente maior da espécie localmente dominante, Atherinella brasiliensis; (II) uma média densidade relativamente maior para juvenis das demais espécies localmente conspí­­cuas, i.e., Mugil curema, Eucinostomus argenteus, Harengula clupeola e Oligoplites saurus (III); maiores valores da riqueza média e total; e (IV) melhor tanto a abundí­¢ncia de oní­­voros, quanto o número e a abundí­¢ncia de bentí­­voros. A tarrafa amostrou melhor os pequenos planctí­­voros, especialmente juvenis de Sardinella brasiliensis. Tais resultados poderão dar suporte a um futuro programa de monitoramento da ictiofauna local e enfatizam a grande importí­¢ncia da avaliação do desempenho de amostradores da ictiofauna antes de se iniciar quaisquer atividades de amostragem.

The Holocene palaeoenvironmental evolution of Vitória Bay, Espírito Santo, Brazil

Micropalaeontological analyses of two sediment cores (T_A and T_D) collected from a tropical bay in Brazil were conducted. Continental palynomorphs and carbonised particle data were associated with stable isotopes (C and N) assessed using 14C dating. The main objective was to integrate these data with the results of isotopic analyses in order to establish the palaeoenvironmental dynamics of the area during the Holocene. The samples were sub-sampled every 10 cm and then submitted for standard methodological processing for each analysis. The T_A sediment core was dated at three depths, and the oldest depth, 150 cm, had an age between 7241–7339 cal yr BP. The T_D sediment core had an age between 6778 and6948 cal yr BP at its deepest depth, 370 cm. Using radiocarbon dating and micropalaeontological analyses, the integrated assessment of the two sediment cores indicated that the core with a coarser granulometry core was a continuation of the core with the finest granulometry. Consequently, both the lithological change and the preservation of the microfossils could be directly related to periods of sea level variations observed in the coastal region of Brazil.

Spectral and computational features of the binding between riparins and human serum albumin

The green Brazilian bay leaf, a spice much prized in local cuisine (Aniba riparia, Lauraceae), contains chemical compounds presenting benzoyl-derivatives named riparins, which have anti-inflammatory, antimicrobial and anxiolytic properties. However, it is unclear what kind of interaction riparins perform with any molecular target. As a profitable target, human serum albumin (HSA) is one of the principal extracellular proteins, with an exceptional capacity to interact with several molecules, and it also plays a crucial role in the transport, distribution, and metabolism of a wide variety of endogenous and exogenous ligands. To outline the HSA–riparin interaction mechanism, spectroscopy and computational methods were synergistically applied. An evaluation through fluorescence spectroscopy showed that the emission, attributed to Trp 214, at 346 nm decreased with titrations of riparins. A static quenching mechanism was observed in the binding of riparins to HSA. Fluorescence experiments performed at 298, 308 and 318 K made it possible to conduct thermodynamic analysis indicating a spontaneous reaction in the complex formation (ΔG<0). The enthalpy-entropy balance experiment with a molecular modeling calculation revealed that hydrophobic, hydrogen bond and non-specific interactions are present for riparin I–III with HSA. The set of results from fractional fluorescence changes obtained through Schatchard was inconclusive in establishing what kind of cooperativity is present in the interaction. To shed light upon the HSA-riparins complex, Hill's approach was utilized to distinguish the index of affinity and the binding constant. A correspondence between the molecular structures of riparins, due to the presence of the hydroxyl group in the B-ring, with thermodynamic parameters and index of affinity were observed. Riparin III performs an intramolecular hydrogen bond, which affects the Hill coefficient and the binding constant. Therefore, the presence of hydroxyl groups is capable of modulating the interaction between riparins and HSA. Site marker competitive experiments indicated Site I as being the most suitable, and the molecular modeling tools reinforced the experimental results detailing the participation of residues.

Applications of radon and radium isotopes to determine submarine groundwater discharge and flushing times in Todos os Santos Bay, Brazil

Todos os Santos Bay (BTS) is the 2nd largest bay in Brazil and an important resource for the people of the State of Bahia. We made measurements of radon and radium in selected areas of the bay to evaluate if these tracers could provide estimates of submarine groundwater discharge (SGD) and flushing times of the Paraguaçu Estuary and BTS. We found that there were a few areas along the eastern and northeastern shorelines that displayed relatively high radon and low salinities, indicating possible sites of enhanced SGD. A time-series mooring over a tidal cycle at Marina do Bonfim showed a systematic enrichment of the short-lived radium isotopes 223Ra and 224Ra during the falling tide. Assuming that the elevated radium isotopes were related to SGD and using measured radium activities from a shallow well at the site, we estimated groundwater seepage at about 70 m3/day per unit width of shoreline. Extrapolating to an estimated total shoreline length provided a first approximation of total (fresh + saline) SGD into BTS of 300 m3/s, about 3 times the average river discharge into the bay. Just applying the shoreline lengths from areas identified with high radon and reduced salinity results in a lower SGD estimate of 20 m3/s. Flushing times of the Paraguaçu Estuary were estimated at about 3–4 days based on changing radium isotope ratios from low to high salinities. The flushing time for the entire BTS was also attempted using the same approach and resulted in a surprisingly low value of only 6–8 days. Although physical oceanographic models have proposed flushing times on the order of months, a simple tidal prism calculation provided results in the range of 4–7 days, consistent with the radium approach. Based on these initial results, we recommend a strategy for refining both SGD and flushing time estimates.

Identification of potential fish stocks and lifetime movement patterns of Mugil liza Valenciennes 1836 in the Southwestern Atlantic Ocean

The mullet Mugil liza is the Mugilidae that lives southernmost in the western Atlantic Ocean. Knowledge about migration, movements and identification of stocks of this important fishery resource is scarce. Thus, we aim to study movement patterns and to identify the presence of different fish stocks in the southwestern region of the Atlantic Ocean, using cumulative otolith shape morphometric and microchemical analyses of sagittae otoliths. Specimens (n=99) were obtained in four coastal areas: Paranaguá Bay in Brazil, Samborombón Bay, Mar Chiquita Coastal Lagoon, and San Blas Bay in Argentina. Otolith shape indices (circularity, rectangularity, aspect ratio, percentage occupied by sulcus, ellipticity and form factor) were used for stock identification analysis; and otolith microchemistry using LA-ICP-MS (Sr/Ca and Ba/Ca ratios chronological variation) was used for both the analysis of movement behaviors and the identification of fish stocks (otolith edge ratios). Morphometrical indices did not reveal a clear separation among areas. San Blas bay individuals presented otoliths tending to be longer than wider, with a more elliptic shape than the otoliths from other studied areas; also, this area did not share individuals with the most northern one, Paranaguá Bay in Brazil. The analysis of microchemical lifetime profiles revealed three types of behavior pattern: Type I: most frequent use of estuarine environments; Type II: a fluctuating behavior between estuarine and sea/high salinity waters; Type III: most frequent use of sea/high salinity habitats. Otolith edge analysis did not reveal differences among Sr/Ca and Ba/Ca ratios for the different areas. Thus, it cannot be assured that there is more than one stock in the studied region. Mugil liza revealed different environmental migratory behaviors in the Southwestern Atlantic Ocean showing a facultative use of estuarine waters; hence, the species appears to be mostly coastal with the use of low estuaries, as seen also by the Sr/Ca otolith cores ratios; differing from the general mugilid behavior previoulsy described.

Distribution of loliginid squids in a eutrophicated tropical coastal bay

ABSTRACTGuanabara Bay is one of the most polluted bays in Brazil, although it supports some fisheries resources, among which are three species of loliginid squids: Lolliguncula brevis, Doryteuthis plei, and Doryteuthis sanpaulensis. This study aimed to assess the temporal and spatial variations of squids in the bay, relating their abundance variation to local environmental factors. We also aimed to characterize the population structure of squids, in order to establish their degree of occupancy in this estuarine system. Ten fortnightly hauls were carried out (two per area) from July 2005 to June 2007. Squids were identified, measured, weighed, sexed and classified according to maturity stage. The spatial distribution of the three species was not uniform; most individuals were found near the mouth of the bay. Abundances were significantly different among seasons due to the presence of SACW (South Atlantic Central Water) during the spring–summer season. Most of the populations of the three species consist of juveniles, and most adult Doryteuthis were also immature, which reinforces the role of Guanabara Bay as a nursery ground for loliginid squids. Concerning the degree of occupancy of squids in Guanabara Bay, L. brevis is considered an estuarine resident, D. plei uses the estuarine system as a nursery area for feeding and growth, and juveniles of D. sanpaulensis enter the bay with the flood tide to feed, generally following the SACW intrusion. This is the first study on squids in this estuarine system, which despite the high degree of environmental impact is shown to be an important area for the loliginid species.

Structural and functional losses in macroalgal assemblages in a southeastern Brazilian bay over more than a decade

Changes in macroalgae assemblages over more than a decade are described for Sepetiba Bay, Brazil. Variations in macroalgae abundances and functional diversity were compared with older data to test the hypothesis that their diversity decreases following anthropogenic stress that negatively impact environmental characteristics. Four field sampling excursions were undertaken at two different sites from December/2012 to May/2014. Destructive sampling per effort used six box cores (25×25cm) distributed randomly along a shallow sublittoral rocky shore. Biomass was used to quantify macroalgae assemblages identified to the species level. Multivariate analyses demonstrated decreases in total biomass at both sites as well as changes in community physiognomies. The predominant corticated algae found were classified as Ecological Status Group IIA, characteristic of sites in the process of degradation and indicating that anthropogenic stress had negatively affected the macroalgae communities as evaluated by the Ecological Evaluation Index.

Nursery areas and connectivity of the adults anadromous catfish (Genidens barbus) revealed by otolith-core microchemistry in the south-western Atlantic Ocean

The anadromous catfish, Genidens barbus, is a commercial and vulnerable species from South America. The aims of the present study were to assess whether the nursery areas can be discriminated by using microchemical signatures of lapillus otoliths, to assess the accuracy of classifying fish in relation to natal nursery area and to discuss the possibility of existence of homing behaviour. Thus, the otolith-core chemical signatures (barium (Ba):calcium (Ca), lithium (Li):Ca, magnesium (Mg):Ca, manganese (Mn):Ca, strontium (Sr):Ca, and zinc (Zn):Ca ratios) of adult fish were compared among different estuaries (De La Plata River in Argentina, and Patos Lagoon, Paranaguá Bay and Guanabara Bay in Brazil). PERMANOVA analysis showed significant differences in the multi-element signatures of the otolith core among sampling sites for all cohorts (2002, 2003, 2006 and 2007), indicating that the technique has considerable potential for use in future assessments of population connectivity and nursery areas of G. barbus. Via quadratic discriminant function analysis, fish were classified to natal nursery areas with 80–100% cross-validation classification accuracies. These results suggested that a high level of spatial segregation exists in adult catfish life and homing behaviour could not be ruled out on the basis of our data.

Assessment of mercury contamination based on mercury distribution in sediment, macroalgae, and seagrass in the Todos os Santos bay, Bahia, Brazil.

The Todos os Santos bay (TSB) is the second largest Brazilian bay. Despite the large number of potential anthropogenic sources of mercury (Hg) in the bay, data on this element in this marine environment are very scarce. Total Hg concentrations were therefore determined in sediment, macroalgae, and seagrass species collected during dry and rainy seasons, from eight locations. In ~45% of the sediment samples, Hg concentration was two to four times higher than the upper value considered the regional Hg background (15μgkg(-1)). Geoaccumulation index indicated that Hg contamination was at none to heavily contaminated. In Padina sp., Caulerpa sp., Hypnea sp., and Halodule wrigthii, Hg concentrations ranged from 10.61-297.61, 15.59-74.50, 12.84-158.03, and 4.02-67.25μgkg(-1), respectively.

Simulations of nutrient emissions from a net cage aquaculture system in a Brazilian bay.

Hydrodynamics and transport simulations were conducted with the modeling software TELEMAC-2D on Icó-Mandantes bay, a branch of the Itaparica reservoir. The bay has a maximal operational water level amplitude of 5 m and is suffering from eutrophication and algae bloom. Therefore, we investigated low and high water level scenarios with two different high resolution meshes, with the purpose to deeper understand their impact on transport of substances and to improve the watershed management. In particular, nutrient emissions from a hypothetical net cage aquaculture system located in the bay were investigated on half-year cycles. We observed a relevant impact on water quality for a tilapia production of 130 t y(-1); i.e. after 6 months' simulation we obtained around 8 μgP L(-1) and 6 μgP L(-1) at the source of emissions, for low and high water scenarios, respectively.

Inter-decadal changes in fish communities of a tropical bay in southeastern Brazil

Long-term evaluations of coastal fish communities worldwide have in many cases showed a decrease in the species richness and abundance as a result of anthropogenic impacts. Fish communities in two zones (inner and outer) of a tropical bay in southeastern Brazil were sampled monthly during six years over two decades (1983–1985, 1993–1995, 1999–2001) using identical sampling methods. Over time, an increase in temperature and a decrease in water transparency were detected, while salinity remained stable. Fish assemblage was dominated by benthivorous species both migrant and resident species. The fish assemblage structure differed significantly between the two bay zones. Significant decreases in the fish richness, abundance and biomass were detected over time. The highest decreases in the species richness was recorded between 1983–1985 and 1993–1995 for the marine migrants in both bay zones and for the resident and marine straggler species in the outer zone. Dominant species such as the clupeoids Anchoajanuaria, Anchoa tricolor,Harengula clupeola, the gerreid Eucinostomos argenteus,the sciaenid Micropogonias furnieri, the atherinopsid Atherinella brasiliensis and the ariid Genidens barbus decreased over time, whereas the mugilid Mugil liza increased. Persistent differences in the fish assemblage structure between the two bay zones over the three periods can be attributed at least in part to differences in environmental variables between the zones and seem to be a key ecological element to maintenance of biodiversity. This is the first study to examine long-term changes in the fish community of a tropical bay in Brazil.