Cabo Frio Research Articles

Seasonal spatial distribution of groundwater suitability in the Cabo Frio shallow coastal aquifer, Rio de Janeiro, Brazil: applying groundwater quality index and GIS approaches

Seasonal spatial distribution of groundwater suitability in the Cabo Frio shallow coastal aquifer, Rio de Janeiro, Brazil: applying groundwater quality index and GIS approaches

Deciphering the complex history of the cabo frio high – SE brazilian continental margin

Extensive seismic reflection interpretation of the Cabo Frio High allowed better understanding of its proximal and distal structure. Seismic lines helped map the salt base and recognize the primary geological interfaces, unconformities, faults, and volcanic intrusions. The proximal Cabo Frio High is a continental basement uplift extending mainly into the Campos Basin. The Cabo Frio Outer High, which is of volcanic origin, lies between Santos and Campos Basins. This volcanism is concentrated at the crossing of two significant structures: Cruzeiro do Sul Lineament and Rio de Janeiro Fracture Zone. The Cabo Frio High fits an NW-SE fold axis, which is well correlated with distension along NW-SE direction generating a regional E-W sinistral plate movement, mainly related to the ENE-WNW sinistral Rio de Janeiro transfer zones. The accumulated uplift is approximately 4 km, achieved by at least four uplifting pulses. The uplifting starts in the Albian-Santonian, characterized by the elevation of the northeast portion of Cabo Frio High, followed by erosion. The sill and dikes intruded in the Upper Cretaceous, and the uplift of the southwest portion of the Cabo Frio High characterizes the second uplift pulse. Subaerial Eocene volcanos characterize the third uplifting pulse. The uplifting of the Blue Marker horizon (Oligocene) characterizes the last pulse.

Early warning indicators of decadal shifts in the planktonic assemblage of the Cabo Frio upwelling ecosystem

Long-term monitoring of coupled environmental and biological components in upwelling ecosystems is critical for early warning under the global warming context. Temperature, salinity, nutrients, and plankton populations are promising indicators of the ecosystem state that help us to address the current status of the oceans and construct better predictions for the future. The Cabo Frio Upwelling System (CFUS) is a regionally productive wind-driven coastal upwelling ecosystem on the northern boundary of the South Brazilian Shelf sustaining diverse marine life including large stocks of fish and squid. Like other cold marine ecosystems, most of its functioning is likely threatened by ocean warming which emphasizes the need for ecological indicators. This study aimed to analyze the causal relationships between the temporal changes in the physical and chemical properties and the dominant planktonic communities leveraging long-term observations (20 years). The results suggested a link between the temporal changes in the ecosystem conditions and the composition of the plankton assemblage, notably an increasing proportion of dinoflagellates relative to diatoms and cladocerans relative to copepods. This increase in the proportional abundance of dinoflagellates and cladocerans over time suggests a regime shift in the plankton assemblages during the 2000s, highlighting some large phytoplankton and zooplankton groups as early indicators of productivity shifts in upwelling ecosystems.

Taphonomy and taphofacies of the bioclastic accumulations of Baía Formosa Paleolagoon (Quaternary), Rio de Janeiro state, Brazil

The study of taphofacies is extremely relevant in Paleontology as it provides support for paleoenvironmental interpretation by associating the preservation state of fossil content with sedimentological and stratigraphic characteristics. Despite its importance, there are few analyses of taphofacies in bioclastic accumulations of invertebrates in Brazilian sedimentary basins or Quaternary sedimentary accumulations. Therefore, this article aims to identify taphofacies in Holocene bioclastic accumulations distributed along the coastal plains of Armação de Búzios, Rio de Janeiro State, Brazil. After qualitative observations and taphonomic analysis of material from two outcrops located in the Canal Marina Porto Búzios, three distinct taphofacies were identified. Taphofacies 1 was interpreted as a beach environment related to strandlines; taphofacies 2 was interpreted as a shallow lagoon environment; and taphofacies 3 was interpreted as a lagoon margin. The taphofacies identified in this study are related to the maximum Holocene transgression, which occurred in the region about 6000 years BP, and the subsequent marine regression. This study presents relevant and unprecedented data, enabling a better understanding of the coastal evolution of Armação dos Búzios and Cabo Frio.

25 YEARS OF THE NATIONAL ENVIRONMENTAL EDUCATION POLICY (PNEA): A CASE STUDY ON THE IMPLEMENTATION OF FORMAL ENVIRONMENTAL EDUCATION IN THE DAILY SCHOOL LIFE OF 120 PUBLIC SCHOOL TEACHERS IN THE MUNICIPALITY OF CABO FRIO, RJ

Objective: The objective of this study is to carry out a critical analysis of the National Environmental Education Policy based on a Case Study with 120 Teachers who are in the classroom, in Public Schools of the Education Network in the Municipality of Cabo Frio, RJ, Brazil. Theoretical Reference: There are several theories and authors who research and write about EA. Historically, it can be said that the first person studied to describe and teach about AE was Raquel Carson, in her book “Silecious Spring” where she described the problems caused by pesticides. Subsequently, there were several international meetings that gave rise to treaties and guidelines on the predatory way in which man deals with the environment in his capitalist model of production. Among the multilateral documents signed by Brazil is the EA Treaty. Currently, we have in practice the EAF resulting from philosophical understandings arising from Federal Law No. 9,795/99 “the EA law”. In contrast to the traditional EA model, our main source of analysis is the theories of “Critical EA”, aimed at building knowledge, awareness, critical cognitions and autonomy of people in relation to their interaction with environmental goods in a sustainable and sustainable way. perennial. Method: The methodology adopted for this research comprises exploratory field research. The technique used in the research was the “Case Study”. The quantitative method was used in the analysis of data obtained from the application of the field research instrument, namely: the questionnaire. Being applied to this statistical analysis. Each proposed question generated a table and a graph where the statistical percentages of the responses of the Teachers who answered the questionnaire are presented. A quantitative and qualitative analysis of the results was then carried out. Results and Discussion: The results obtained confirm the hypotheses raised, as they demonstrate a lack in the training of undergraduates in undergraduate courses in relation to the EA theme, as well as an incipient and ineffective practice of formal EA in the daily lives of the Teachers surveyed. Implications of the Research: The practical and theoretical implications of this research are visible given the demonstration of a reality of the researched that is replicated throughout the education network of the researched municipality and possibly of Public School Teachers throughout the State of RJ. Originality/Value: This study significantly contributes to enriching the theory and practice of EAF, as it portrays the current scenario of teaching practice in relation to EAF in municipal schools with actuality and truth, demonstrating the obstacles, flaws and ways to be taken to make a constitutional right effective, namely the right to EA.

The education of fishing workers about accidents caused by marine animals: a study in the Região dos Lagos of Rio de Janeiro

Fishing exposes workers to various occupational risks, including accidents caused by poisonous, venomous and traumatizing marine animals. With this in mind, the aim of this study is to present educational activities for people working in the fishing activities in the Região dos Lagos (Lakes Region) of Rio de Janeiro, southeastern Brazil, with a focus on accidents caused by marine animals (ACMA). The protocol was approved by the Human Research Ethics Committee of the Universidade Federal de Viçosa (CAAE: 53959421.8.0000.5153). The activities were carried out in the municipalities of Armação dos Búzios, Arraial do Cabo and Cabo Frio and included a workshop on the subject, lasting an average of four hours, preceded (pre-test) and followed (post-test) by an assessment consisting of objective questions on the ACMA. A total of 47 workers (with an average working time of 15.2±12.8 years) took part in the activity. Each professional suffered an average of three ACMA. A comparison of the pre-test and post-test results showed a higher percentage of correct answers to almost all the questions. Further studies are needed to estimate the risks of ACMA among fishing workers and to improve educational actions to minimize the impact of these injuries on this population.

Using single-beam bathymetric data in digital depth models, for viewing the Sargassum furcatum bed in Cabo Frio Island

Single-beam bathymetric surveys are used in several areas, namely, in the assessment of underwater geography as determining factor for navigation; conducting scientific studies and exploration of oil and natural resources. The data acquired in this type of surveys offers a grid of X, Y and Z sample points. For the correct spatial visualization in a continuous data grid, it is necessary to apply mathematical interpolators to estimate the depth value in the points not covered by the survey. The​​​​​​​ Sargassum furcatum bed presents on Cabo Frio island is the target of several studies due the importance of its primary productivity and biodiversity. It was verified after the elaboration of the digital depth models, characteristics regarding the location and spatial distribution of the Sargassum furcatum bed. Based on results obtained in the construction of the digital depth models, it was possible to demonstrate that the association of surveys, mining and interpolation methods for single-beam bathymetry data, developed during this study, were suitable to assess the visualization the Sargassum furcatum bed in Cabo Frio Island, Arraial do Cabo - RJ.

Salinity Fronts in the South Atlantic

Monthly climatology data for salinity fronts in the South Atlantic have been created from satellite SMOS sea surface salinity (SSS) measurements taken from 2011–2019, processed at the Barcelona Expert Center of Remote Sensing (BEC), and provided as high-resolution (1/20°) daily SSS data. The SSS fronts have been identified with narrow zones of enhanced horizontal gradient magnitude (GM) of SSS, computed using the Belkin–O’Reilly algorithm (BOA). The SSS gradient fields generated by the BOA have been log-transformed to facilitate feature recognition. The log-transformation of SSS gradients markedly improved the visual contrast of gradient maps, which in turn allowed new features to be revealed and previously known features to be documented with a monthly temporal resolution and a mesoscale (~100 km) spatial resolution. Monthly climatologies were generated and analyzed for large-scale open-ocean SSS fronts and for low-salinity regions maintained by the Rio de la Plata discharge, Magellan Strait outflow, Congo River discharge, and Benguela Upwelling. A 2000 km-long triangular area between Africa and Brazil was found to be filled with regular quasi-meridional mesoscale striations that form a giant ripple field with a 100 km wave length. South of the Tropical Front, within the subtropical high-salinity pool, a trans-ocean quasi-zonal narrow linear belt of meridional SSS maximum (Smax) was documented. The meridional Smax belt shifts north–south seasonally while retaining its well-defined linear morphology, which is suggestive of a yet unidentified mechanism that maintains this feature. The Subtropical Frontal Zone (STFZ) consists of two tenuously connected fronts, western and eastern. The Brazil Current Front (BCF) extends SE between 40 and 45°S to join the subantarctic front (SAF). The STFZ trends NW–SE across the South Atlantic, seemingly merging with the SAF/BCF south of Africa to form a single front between 40 and 45°S. In the SW Atlantic, the Rio de la Plata plume migrates seasonally, expanding northward in winter (June–July) from 39°S into the South Brazilian Bight, up to Cabo Frio (23°S) and beyond. The inner Plata front moves in and out seasonally. Farther south, the Magellan Strait outflow expands northward in winter (June–July) from 53°S up to 39–40°S to nearly join the Plata outflow. In the SE Atlantic, the Congo River plume spreads radially from the river mouth, with the spreading direction varying seasonally. The plume is often bordered from the south by a quasi-zonal front along 6°S. The diluted Congo River water spreads southward seasonally down to the Angola–Benguela Front at 16°S. The Benguela Upwelling is delineated by a meridional front, which extends north alongshore up to 20°S, where the low-salinity Benguela Upwelling water forms a salinity front, which is separate from the thermal Angola–Benguela Front at 16°S. The high-salinity tropical water (“Angola water”) forms a wedge between the low-salinity waters of the Congo River outflow and Benguela Upwelling. This high-salinity wedge is bordered by salinity fronts that migrate north–south seasonally.

Deep Structure of the Santos Basin, Offshore Brazil From 3D Inversion of magnetotelluric Data

AbstractThe relationship between deep crustal structure and the deformation in the overlying sedimentary wedge in Santos basin, Brazil is not well understood, and the origin and evolution of the salt‐related “Albian Gap (AG)” remain a topic of debate. We investigate the deep structure using three‐dimensional inversion of full tensor marine magnetotelluric (MT) data (of 10−1 to 104 s period bandwidth) from 92 stations along three NW–SE lines in 50–1,700 m water depth, one crossing the Cretaceous hinge line (CHL), AG, and Cabo Frio Fault (CFF). The geological validity of the resulting MT resistivity models was determined using resistivity logs from 11 wells and seismic data. The model shows two regionally persistent electrically conductive layers (C2 and C3) related to key Cenozoic and Cretaceous unconformities in the upper part of the sedimentary wedge. Beneath this wedge, the resistive continental crust is ∼35 km thick across the CHL until the 200 m isobath and thereafter thins rapidly seaward to ∼21 km over a lateral distance of ∼80 km defining a domain of highly extended and faulted crust. Our models show a mantle‐associated basement high and evidence of significant uplift of the lower part of the sedimentary wedge at 100–150 km distance along our central profile which spatially coincides with the AG and a previously proposed Moho high. This implies a mantle‐driven deformation of the crust and basin fill. We propose that mantle flow and magmatism may have played a significant role in the inferred displacement at the AG.

Lobatozoum woodi n. sp. (Digenea: Didymozoidae) parasitizing Euthynnus alletteratus (Scombriformes: Scombridae) in the coast of the State of Rio de Janeiro, Brazil.

The aim of this study was to describe a new species of Didymozoidae (Trematoda) found in the mesentery of Euthynnus alletteratus (Rafinesque) off Cabo Frio, in the coastal area of the state of Rio de Janeiro, Brazil. Thirty specimens of E. alletteratus were obtained between August 2023 and June 2024, directly from traders who sell fresh fish in markets. The parasites were fixed in AFA (93% ethanol 70%, 5% formaldehyde and 2% glacial acetic acid) with or without compression, stained with Langeron's hydrochloric carmine, dehydrated in an alcohol series, clarified in clove oil and mounted in Canada balsam as permanent slides. The new species was assigned to the genus Lobatozoum Ishii, 1935, mainly by the presence of lobes in the posterior region of the body and by the arrangement of the testes, ovary and vitellaria. Lobatozoum woodi n. sp. differs from all congeneric species mainly by presenting three testicular tubules, by the size of pharynx, larger than the oral sucker, and by the absence of digestive glands cells in esophagus and initial portion of caeca. The finding of a new species of Lobatozoum represents the eleventh valid species in the genus.

Seston biomass in plankton assemblages in the Southwestern Atlantic Ocean: spatial, vertical, and temporal variations.

Bioseston is a heterogeneous assemblage of bacterioplankton, phytoplankton, zooplankton, and planktonic debris. A detailed knowledge of biosestons is essential for understanding the dynamics of trophic flows in marine ecosystems. The distributional features of seston biomass in plankton (micro- and mesoplankton) in the Southwest Atlantic Ocean (Rio de Janeiro State, Brazil) were analyzed using stratified samples gathered to a depth of 2,400 m during night time. The horizontal pattern of biomass distribution was analyzed vis-a-vis station depth during both wet and dry periods, with higher values recorded in the continental shelf than in the slope, confirming the terrestrial contribution of nutrient sources to the marine environment. This horizontal variation reinforces the occurrence of seasonal vortices in Cabo Frio and Cabo de São Tomé on the central coast of Brazil. Environmental variables reflect the hydrological signatures of the water masses along the Brazilian coast. The largest seston biomass was related to high temperatures, salinities, and low inorganic nutrient concentrations in tropical and South Atlantic central waters. The observed distribution patterns suggest that seston biomass in plankton in the region may be structured based on partitioned horizontal and vertical habitats and food resources.

New U-Pb and Hf data of the contact region between the Oriental and Cabo Frio terranes, Central Ribeira Belt, Brazil: Implications for the closure of the Ediacaran-Cambrian oceanic space

The Ribeira Belt represents a deeply eroded orogen which exposes rocks from the different stages of magmatic arcs and associated metasedimentary basins. This contribution focus on the last collisional episode between the Outer Magmatic Arc System (OMAS) and the Cabo Frio Terrane (Angola craton). The OMAS represents a long-lived magmatic arc that collided against the Inner Magmatic System (IMAS) at ca. 590 Ma (M1 metamorphism), and against the Cabo Frio Terrane at ca. 530 Ma (M2 metamorphism). The nature of the magmatism recorded in the first collisional episode, and the subduction polarity of the second is a current topic of debate. New U-Pb age and Lu-Hf analyses in zircon grains from units close to the contact are presented to propose a tectonic model for the closure of the oceanic space between the OMAS and the Cabo Frio Terrane. The results in combination with published data suggest that the metasedimentary rocks of the São Fidélis Group are in a back-arc position of the OMAS and were affected by both the M1 and M2 metamorphic episodes, reflected by the presence of metamorphic zircons with ages between ca. 592–553 Ma and 543–533 Ma. The orthogneiss of the Tinguí Complex intrusive in the back-arc metasedimentary units yielded a crystallization age of 578 ± 9 Ma, coeval with the syn-collisional stage M1. A younger metamorphic overprint at 529 ± 7 Ma was also detected (syn-M2). The orthogneiss of the Região dos Lagos Complex (Cabo Frio Terrane) rendered a crystallization age of 1968 ± 26 and a M2 metamorphic overprint at 522 Ma. Zircon analyses from folded leucosomes in the orthogneiss also indicated a crystallization age of 523 ± 10 Ma, which constrain the time of folding after thrusting. Undeformed post-collisional granitoids and pegmatites yielded crystallization ages between 496 and 499 Ma, closing the tectonic evolution of the belt with the orogen collapse. Our results corroborate with terrane accretion model for the Central Segment of the Ribeira Belt.

Evaluation of chloride deposition using the wet candle method: a study in the city of Cabo Frio, RJ

In a context of durability design of reinforced concrete structures, it is necessary to establish the divisions of the aggressiveness classes of the different maritime and coastal environments, in order to contribute to the study of the classification of environmental aggressiveness. In this paper, the deposition of aggressive ions and the general climatic aspects of the coastal region of the city of Cabo Frio, RJ are evaluated. For the analysis, the wet candle method (Brazilian NBR 6211:2001) was adopted. The exhibitions were held at five different points throughout the city, each with three wet candles. To quantify the chloride content, the conductimetry method was used, which is done by measuring the electrical conductivity of an electrolyte solution, due to ion migration. The results point to a high level of chlorides in the initial range of distance from the sea and a considerable decrease from approximately 900 meters from the seashore. In this way, it was possible to verify that the city, in its interior, is under moderate to minimal aggressiveness. In the initial distances of the seashore, there is high aggressiveness. These results show the importance of considering micro exposure environments during the design phase of reinforced concrete structures.

South Atlantic Central Water Intrusion in the Southeast Brazil Bight and its impacts

The responses of biogeochemical cycles and ecosystems are influenced by a variety of physical conditions, including but not limited to temperature, moisture, and nutrient availability. The ecological significance of cold and nutrient-rich water inflow into coastal embayments is well-established and is often attributed to the presence of an upwelling system in the adjacent area. The Southeast Brazil Bight (SBB) provides a sheltered environment for both the Cabo Frio upwelling system and Guanabara Bay. The water mass from the Cabo Frio upwelling system is known as the South Atlantic Central Water (SACW), and cold water events related to it have a particular impact on Guanabara Bay. To understand the ecosystem’s response to cold water events in the SBB during the 2014–2015 austral summer, a compilation of datasets including temperature time series, satellite chlorophyll-a data, meteorological station data, tidal gauge readings, and biogeochemical model results were used. The results revealed an east-to-west cold water flow, with a 43-hour delay in the response observed in Guanabara Bay after it was observed in Cabo Frio. There was no indication of a second upwelling system near Guanabara Bay. The biogeochemical analysis indicated that each area presents a different limitant nutrient, resulting in unique and distinct trophic webs in both areas.

PERSPECTIVE FOR ENERGY EXPLOITATION ALONG THE BRAZILIAN COAST

The constant need to supply the growing global energy demand, leads to an increase in the generation of greenhouse gases. To circumvent this problem, more and more alternative means of energy generation have been used to compose the energy grid. One of the alternatives, which in recent decades has received great attention from researchers, is the conversion of wave energy into electrical energy. In Brazil, studies have also gained momentum, and the possibility of implementing wave energy converters on the Brazilian coast is increasingly recognized. With this in mind, the present work aims to determine the regions on the Brazilian coast that are most capable of being explored through wave energy. For this, a simulation of 37 years of the Brazilian sea state, is used in conjunction with a multicriterial methodology, where the logistical and energetic conditions of the Brazilian coast are quantified. Subsequently, power matrices of 8 wave converters are used to quantify the theoretical potential generated in the improved locations. The results showed that, in energy terms, the South and Southeast regions of Brazil have the greatest potential. This factor also proved to be the cause of the presence of lower logistical indexes in these regions, when comparing them with the North and Northeast regions of Brazil. After parameterization of the indices, three zones of interest were observed on the Brazilian coast: Cabo Frio, Imbituba and São José do Norte. When applying the conversion matrices in these locations, average daily generation power between 1.5 and 230kW were observed, the largest being located in the Cabo Frio region, using the BHBA model of converter. Variability in energy production was also discussed, and it should be a primary factor in the choice of the convert model, as well as in its design. Finally, all results were consistent with previous work, however, the path to implementing a wave energy conversion site in Brazil is still long, and should be focused on optimizing devices for Brazilian waters.

Temperature stratification in the Guanabara Bay and its relationship with wind-induced coastal upwelling off Cabo Frio, Brazil

This study investigates the mechanisms that control the occurrence of cold water intrusion events observed in Guanabara Bay, Rio de Janeiro, Brazil. To achieve this, we used multiple time-series data comprising in-situ temperatures recorded at depths of 5 m and 20 m in three sites in the Guanabara Bay region, wind velocities from three meteorological stations along the Brazilian coast, and sea level data from a tidal gauge located in the interior of Guanabara Bay. We found that from October 2014 to May 2016, near-bed temperatures in Guanabara Bay were dominated by subinertial variability. We identified subinertial cold water events, defined by temperature values below 18 °C, that were associated with South Atlantic Central Water intrusions. We obtained a total of 21 cold water events during the 18-month (545-day) sampling period, corresponding to 92.5 days or 17% of the time. Additionally, we found statistically significant lag-adjusted correlation coefficients (0.37-0.95) between near-bed (20 m) temperatures in Guanabara Bay and alongshore winds from the Arraial do Cabo meteorological station, which act in the well-known Cabo Frio upwelling system along the coast. These upwelling-favorable winds led near-bed temperature values in Guanabara Bay by 12 to 56 h and provided the remote forcing mechanism for the cold water intrusions in Guanabara Bay. Locally, the shelf-bay intrusion velocity values ranged from 0.04 to 0.50 m⋅s−1, consistent with a gravity current enhanced by baroclinic pressure gradient, the local forcing mechanism. The cold water intrusions caused an increase in the vertical temperature stratification within Guanabara Bay, as verified for all analyzed events. We also identified subinertial oscillations due to Coastal Trapped Waves (CTWs) propagation from our sea level data records and evaluated their impacts on cold water events.

Coastal upwelling influences population structure of dusky grouper Epinephelus marginatus: An integrative approach based on otolith chemistry and muscle stable isotopes

The dusky grouper (Epinephelus marginatus) is an overfished and threatened fish species with coastal distribution. In the Southwestern Atlantic, it occurs across a broad region influenced by two major oceanographic features: the Cabo Frio (23°S) and the Cabo Santa Marta (28°S) upwelling systems. Along the Brazilian coast, the species may present continuous or discrete populations, depending on the methodological approach used. In this study we combined otolith chemistry and muscle stable isotope analyses to examine the population structure of dusky groupers and its association with the two upwelling systems. Fish were collected in shallow coastal waters of the Southwest Atlantic Ocean, covering the southeastern and southern Brazilian coasts, among Macaé (22°S), Santos (24°S), Florianópolis (27°S), and in Rio Grande (32°S). The results show three statistically well-separated population groups along the region. We named these population groups as North (north of Cabo Frio); Center (between upwelling regions); and South (south of the Cabo Santa Marta system). Our findings allow to suggest that the upwelling systems may influence the distribution of E. marginatus stocks along the Brazilian south-western coast, even though a causal effect may not be attributed at this point. Overall, this combined approach, leveraging information from distinct natural tags, and reflecting variability of water chemistry and food webs with latitude, allowed us to enhance our understanding on how major upwelling systems influence the structuring of fish populations along the southwestern Atlantic Ocean.

The southern Ribeira Belt in Western Gondwana: a record of a long-lived continental margin and terrane collage

The Ribeira Belt is an ENE-trending orogen in southeastern South America associated with the Neoproterozoic and Early Cambrian assembly of Western Gondwana. Its final configuration results from the amalgamation of several Statherian to Neoproterozoic continental margin tectonostratigraphic terranes. This contribution provides a revision of the southern Ribeira Belt, encompassing the São Roque, Apiaí, Embu, Costeiro, Curitiba, and Paranaguá terranes, bounded by branches of long-lived Tonian–Ediacaran shear zone systems. An initial Statherian rifting (1750 Ma) associated with anorogenic magmatism and sedimentation is followed by Calymmian to Ectasian (1600–1200 Ma) large carbonate platforms as well turbiditic volcanosedimentary successions, including both passive and active continental margins, and possible island arc collision, making up the Apiaí and São Roque composite terranes. The Tonian is represented by the Embu Terrane accretion and orogenesis at 850–760 Ma. The Brasiliano orogeny in the terranes north of the Lancinha–Cubatão shear zone is mainly represented by 630–600 Ma granitic magmatism associated with a Barrovian metamorphism, related to a tectonic scenario evolving from subduction to oblique collisional and final post-collisional stabilization. Terranes south of the Lancinha-Cubatão shear zone display evidence of an early Ediacaran suture zone, including a high-grade complex, ultramafic suites, a paired low-P and high-P belt corresponding to a back-arc basin, and an accretionary wedge, with a metamorphic collisional peak between 590 and 585 Ma. Terrane dispersion along strike-slip shear zones occurred after 590 Ma, resulting in the final configuration of the southern Ribeira Belt, associated with anorogenic A-type granitic magmatism and pull-apart continental sedimentary and volcanic basins. The deformation in this final period may reflect a far-field stress related to continental collisions that proceed south and southeast as the docking of the Costeiro (Oriental) and Paranaguá terranes, and later the Cabo Frio Terrane collision, as well the southernmost Dom Feliciano and Kaoko final collisional process, until the upper Cambrian (500–490 Ma).

Nonlinear features in whistles produced by the short-beaked common dolphin (Delphinus delphis) off southeastern Brazil.

Animal vocalizations have nonlinear characteristics responsible for features such as subharmonics, frequency jumps, biphonation, and deterministic chaos. This study describes the whistle repertoire of a short-beaked common dolphin (Delphinus delphis) group at Brazilian coast and quantifies the nonlinear features of these whistles. Dolphins were recorded for a total of 67 min around Cabo Frio, Brazil. We identify 10 basic categories of whistle, with 75 different types, classified according to their contour shape. Most (45) of these 75 types had not been reported previously for the species. The duration of the whistles ranged from 0.04 to 3.67 s, with frequencies of 3.05-29.75 kHz. Overall, the whistle repertoire presented here has one of the widest frequency ranges and greatest level of frequency modulation recorded in any study of D. delphis. All the nonlinear features sought during the study were confirmed, with at least one feature occurring in 38.4% of the whistles. The frequency jump was the most common feature (29.75% of the whistles) and the nonlinear time series analyses confirmed the deterministic chaos in the chaotic-like segments. These results indicate that nonlinearities are a relevant characteristic of these whistles, and that are important in acoustic communication.

Carbonate system in the Cabo Frio upwelling

The quantitative assessment of the carbonate system represents one of the biggest challenges toward the "Sustainable Development Goals" defined by the United Nations in 2015. In this sense, the present study investigated the Spatio-temporal dynamics of the carbonate system and the effects of the El Niño and La Niña phenomena over the Cabo Frio upwelling area. The physical characterization of the site was carried out through data on wind speed and sea surface temperature. Water samples were also collected during the oceanographic cruise onboard the Diadorim R/V (Research Vessel). From these samples, the parameters of absolute and practical salinity, density, pH, total alkalinity, carbonate, calcite, aragonite, bicarbonate dissolved inorganic carbon, carbon dioxide, partial pressure of carbon, calcium, and total boron were obtained. The highest average concentration of bicarbonate in S1 (2018 µmol/kg) seems to contribute to the dissolved inorganic carbon values (2203 µmol/kg). The values of calcite saturation state, aragonite saturation state, and carbonate were higher on the surface of each station (calcite saturation state = 4.80–5.48; aragonite saturation state = 3.10–3.63, and carbonate = 189–216 µmol/kg). The mean values of pH were similar in the day/night samples (7.96/7.97). The whole carbonate system was calculated through thermodynamic modeling with the Marine Chemical Analysis (AQM) program loaded with the results of the following parameters: temperature, salinity, total alkalinity, and pH parameters. This manuscript presents original data on the carbonate system and the "acidification" process influenced by the Cabo Frio upwelling, which directly depends on the El Niño and La Niña phenomena oscillations in the sea surface temperature.