Northeast Coast Of Brazil Research Articles

Interaction of non-native bivalves and exotic dendrophylliid corals (Scleractinia, Dendrophylliidae) in the Brazilian Northeast coast

Interaction of non-native bivalves and exotic dendrophylliid corals (Scleractinia, Dendrophylliidae) in the Brazilian Northeast coast

Circulation in a tropical embayment with two inlets and complex geometry: The Itamaracá-Itapessoca system, Brazil

Along the northeast coast of Brazil, numerous estuaries with intricate morphologies, characterized by multiple channels, islands, and intertidal areas, are found. These estuaries undergo significant seasonal variations, experiencing pronounced wet and dry periods. While some of these systems have small drainage basins with minimal freshwater inflow and sediment production, they boast extensive intertidal mangrove areas. This study focuses on assessing the hydrodynamics and residual circulation of the Itamaracá-Itapessoca Estuarine System (IIES) to elucidate the impact of residual circulation on estuary-shelf exchange dynamics. The IIES comprises two main islands and two inlets surrounded by extensive intertidal areas. Field observations collected during the wet season were used to calibrate and validate a numerical model. Two model scenarios were examined: a 'dry' scenario, considering hydrodynamics driven solely by interactions between morphology and tides, and a 'wet' scenario, incorporating freshwater inflow. Key findings include: (a) the inclusion of freshwater inflow minimally alters system dynamics; (b) tidal dynamics are amplified within the system, resulting in a null zone between the inlets; and (c) residual circulation circulates around the islands, with net importation through the larger inlet and net exportation through the smaller one. The intensity of exchange is heightened under wet conditions.

Density and abundance estimation of West Indian manatee, Trichechus manatus, between the states of Ceará and Piauí, Northeast Brazil, using active acoustics

The West Indian manatee is one of the most threatened species in Brazil. The species has currently a patchy distribution from the state of Alagoas to the state of Amapá. The difficulty of observing manatees, especially in estuarine waters, is a challenge for conservation. Therefore, it is necessary to use new methodologies and technologies to solve manatee detection problems in their natural habitats. The goal of this study was to use an active acoustic method of detection to estimate manatee density and abundance in the estuarine complex of the Timonha and Ubatuba rivers, between the states of Ceará and Piauí, northeast Brazil. Data collection was conducted from a wooden boat with an outboard motor using a side-scan sonar. Sonar images were collected along line transects in three regions within the study area. Manatee abundance was calculated using distance sampling (Distance 6.0 software). There were 1,396 transection lines that totaled 863.6 km traveled in the study area. The observed general encounter rate was 0.089 group detected per kilometer traveled. The best detection model was the hazard-rate with no adjustment terms, resulting in a detection probability of 33.7%, and an estimated density for the entire study area of 9.19 manatees per km2. Abundance of manatees in the estuary was estimated to be 37 animals (CV% = 30.2, 95% CI = 21 - 66). The methodology using side-scan sonar proposed here was successful in the detection of manatees in the study area and in defining parameters for its use to estimate the population size using the distance sampling method. This study provides an estimate of manatee density and abundance in a key estuarine system along the northeast coast of Brazil, which can serve as a baseline for future studies and aid in the development of conservation strategies for the species. This is the first time this methodological approach has been used for manatee detection and abundance estimation in Brazil. We recommend the use of side-scan sonar in future West Indian manatee research.

Profile of inorganic elements of seaweed from the Brazilian Northeast coast

The contents of 24 elements were determined in seven species of macroalgae collected in Ceara-Brazil, in the rainy and dry seasons of 2022. The samples were digested, and the analytes were quantified by ICP-OES and Hg by direct analyzer. The CRM CD-200 was analyzed for accuracy and obtained recoveries were higher than 95 %. The seaweed species have different inorganic element profiles with predominant elements being: Ca, K, Na, Mg and P. The Sargassum vulgare species stood out for its Hg and As contents (1.479 ± 0.005 mg kg−1 and 172 ± 6 mg kg−1, both in the rainy seasons). Ulva lactuca attracted attention for its high concentration of V (46.4 ± 3.4 mg kg−1, rainy season). In general, the elemental content levels in the macroalgae samples were higher in the rainy season. Long-term studies to comprehend the effect of seasonality on the elemental composition of seaweed must be carried out.

NURSERY AREA FOR THE THREATENED GUIANA DOLPHIN, SOTALIA GUIANENSIS, ON THE NORTHEAST COAST OF BRAZIL

Cetacean calves are considered fragile and vulnerable, especially in the first year of life. To guarantee safety and increase the likelihood of survival, females with calves use habitats with unique characteristics, called nursery areas. In the present study, we investigated whether the Guiana dolphin Sotalia guianensis, considered a threatened species in Brazil, uses the Tibau do Sul Coastal Wildlife Reserve (REFAUTS) as a nursery area. We identified the Guiana dolphins through photographs and recorded the composition of the groups during the 41-day sampling period, between 2013 and 2019. We identified 17 adults/juveniles in the company of calves, five of which were recorded in three or more years of the study. The average size of the Guiana dolphin groups (mean±SE) was 2.4±0.08 individuals, ranging from 2 to 5 individuals (n = 98). Groups with calves were recorded in every year of the study and on 53.7% of the sampling days. A total of 35.8% of the Guiana dolphin groups had calves. These results suggest that REFAUTS is an important nursery area for Guiana dolphins on the Northeast coast of Brazil.

Sea breeze-driven effects on wind down-ramps: Implications for wind farms along the north-east coast of Brazil

This research focuses on understanding a meteorological phenomenon that is related to operational disruptions in a wind power plant on the North-East coast of Brazil. The study employed enhanced weather observations based on SODAR and LIDAR wind profilers, micrometeorological masts, ERA-5 reanalysis data, wind power production data from Brazilian power grid operators, and GOES-16 thermal and visible imagery. On August 15, 2023, Brazil experienced a widespread blackout, which was largely caused by down-ramp events that affected several wind farms at the same time. The factors leading to the phenomenon were categorized into three driven-dependent categories: i) a sharp fall in dew-point temperature, ii) the presence of a cumulus cloud line just above the coastline in the early morning, and/or iii) rainfall over the adjoining sea, providing the feasibility to nowcasting this severe wind ramp. The results derived from the conceptual model suggest that sea-breezes play a significant role in the net wind at the turbine hub-height, and often exceed the influence of large-scale flow. The net wind is considered to be caused by the interplay between trade winds and consistent breezes. It is hoped this research can provide a valuable insight into the complex interactions between local meteorological phenomena and wind energy production on the North-East coast of Brazil, and that its application has the potential to improve the operational forecasting of wind power plants.

Structural Characterization of Biomass from Crassiphycus birdiae in natura and Residual

Macroalgae contains micro and macromolecules of great interest for various sectors, for example, food, cosmetics, and pharmaceuticals. These compounds can be obtained through different extraction methods, among them the use of organic solvents with varying polarities. In this study, materials were characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy, infrared spectrometry, X-ray diffraction and differential scanning calorimetry in the seaweed biomasses before and after an extraction process with organic solvents. The red macroalgae Crassiphycus birdiae, cultivated on the northeast coast of Brazil, appeared, after extraction, as an amorphous material with some porosity. Its composition includes the elements carbon, oxygen, sodium, magnesium, sulfur, chlorine, potassium, aluminum, silicon, calcium, and iron. The presence of the agar polysaccharide was also verified by infrared spectroscopy. The decomposition of this polysaccharide was observed using differential scanning calorimetry.

Geochemical Assessment of Tar Balls That Arrived in 2022 along the Northeast Coast of Brazil and Their Relationship with the 2019 Oil Spill Disaster

Geochemical Assessment of Tar Balls That Arrived in 2022 along the Northeast Coast of Brazil and Their Relationship with the 2019 Oil Spill Disaster

A custom, low-cost, continuous flow chamber built for experimental Sargassum seaweed decomposition and exposure of small rodents to generated gaseous products

Since 2011, Sargassum events have increased in frequency along the Caribbean and Atlantic coasts. The accumulation and decomposition of large amounts of Sargassum seaweed on beaches pose socio-economic, ecological, and health risks due to the emission of hydrogen sulfide (H2S), methane, and ammonia. However, limited research exists on the emission processes and the health effects of subchronic and chronic exposure to low levels of H2S. Additionally, the absence of emission factor data for Sargassum decomposition on-site makes health risk assessments challenging. This study aimed to create a custom chamber to simulate real-world Sargassum decomposition, exposing experimental animals to the generated gases. Metal content was analyzed, and emission rates were estimated in a controlled environment. The decomposition-exposure system replicated reported environmental gas emissions from the Caribbean region, except for NH3. H2S bursts were observed during the decomposition process at intervals of 2–10 days, with higher frequency associated with larger masses of decomposing Sargassum. The decomposed gas was transferred to the exposure chamber, resulting in an 80–87% reduction in H2S concentration. The maximum H2S emission was 156 ppm, with a concentration ranging from 50.4 to 56.5 ppm. An estimated emission rate of 7–8 g/h for H2S was observed, and significant levels of lead, arsenic, and aluminum were found in beached Sargassum from the northeast coast of Brazil. This study's developed model provides an opportunity to investigate the effects and risks to human health associated with exposure to gases produced during the environmental decomposition of Sargassum seaweed.

Influence of the invasive bivalve Isognomon bicolor on the native community found in northeast Brazilian coast

The Caribbean bivalve Isognomon bicolor (C. B. Adams, 1845) is currently among the main invasive species along the Brazilian coast. The present study evaluated the co-occurrence, influence, and relationship of the native macrobenthic community with I. bicolor. The study was performed on samples collected from two sandstone reefs located in Northeast Brazil. We observed that the macrobenthic community differed significantly across reefs, zones, and seasons. The higher density of I. bicolor in the lower intertidal zone (347.7 ind/m² ± 800.8) was one of the main differentiation factors of zonation. The results indicated that the evenness of the community and some gastropods had a negative effect on I. bicolor. We found a negative correlation between the co-occurrence of I. bicolor with the macroalgae Hypnea sp. and Gracilaria caudata J. Agardh 1852 and the microgastropod Eulithidium affine (C. B. Adams, 1850). This study provides data on the relationship between I. bicolor and the native community of sandstone reefs, which could be applied to monitor the expansion of I. bicolor to the Northeast region of Brazil.

Weathering impacts on petroleum biomarker, aromatic, and polar compounds in the spilled oil at the northeast coast of Brazil over time

After the wide oil spill reached the northeast of Brazil, the resurgence of oil was recorded and to evaluate this oil in detail, two samples collected in the state of Pernambuco in 2019 and 2021 were submitted to multiple analytical techniques. For both, we have found similar saturated biomarkers and triaromatic steroid ratios, implying that they are from the same spilled source. The n-alkanes, isoprenoids, and cycloalkanes were almost completely degraded due to evaporation, photooxidation, and/or biodegradation processes. The preferential loss of less alkylated PAHs than the more alkylated ones suggests that biodegradation was the most active process. This hypothesis is reinforced by the formation of mono and dicarboxylic acids assessed by GC × GC-TOFMS and ESI(−) FT-ICR MS high-resolution techniques. Furthermore, based on the ESI(−) FT-ICR MS results, three new ratios were proposed to evaluate the progress of the biodegradation process over time: Ox>2/O, SOx/SO, and SOx/N.

Red Marine Algae Lithothamnion calcareum Supports Dental Enamel Mineralization

The current management of oral conditions such as dental caries and erosion mostly relies on fluoride-based formulations. Herein, we proposed the use of the remaining skeleton of Lithothamnion calcareum (LC) as an alternative to fluorides. LC is a red macroalgae of the Corallinales order, occurring in the northeast coast of Brazil, whose unique feature is the abundant presence of calcium carbonates in its cell walls. Two experimental approaches tested the general hypothesis that LC could mediate enamel de-remineralization dynamics as efficiently as fluorides. Firstly, the effect of LC on enamel de-mineralization was determined in vitro by microhardness and gravimetric measurements to test the hypothesis that LC could either prevent calcium/phosphate release from intact enamel or facilitate calcium/phosphate reprecipitation on an artificially demineralized enamel surface. Subsequently, an in situ/ex vivo co-twin control study measured the effect of LC on the remineralization of chemical-demineralized enamel using microhardness and quantitative light-induced fluorescence. With this second experiment, we wanted to test whether outcomes obtained in experiment 1 would be confirmed by an in situ/ex vivo co-twin control model. Both experiments showed that LC exhibited equivalent or superior ability to modulate enamel de-remineralization when compared to fluoride solution. LC should be explored as an alternative to manage oral conditions involving the enamel demineralization.

Microcotylidae (Monogena) parasites of snappers (Perciformes: Lutjanidae) collected from the northeast coast of Brazil.

Monogeneans are a diverse group of flatworms, being ectoparasites of marine and freshwater fish, with great morphological and ecological variety. Analyzes of monogenetics in fish with great habitat diversity such as snappers are scarce in the literature, which already emphasizes the need for an update in this regard. The presente study found, morphologically characterized and mapped the geographic distribution and in known hosts the species Microcotyloides incisa and Microcotyloides impudicus, describing the first occurrence of these monogeneans for South America and in new hosts. The survey of hosts in the literature shows that M. incisa seems to have a greater Affinity with congener species of Lutjanidae and fish from other families, which may indicate a preference or specificity for fish of this family because they are congeners of their host type. The introduction of these parasites into South American waters may have occurred due to the migratory behavior of snappers, which are well distributed along the Mexican coast, where the parasites are usually reported. Here, we also bring the first occurrence of M. incisa for Lutjanus analis and Lutjanus jocu and M. impudicus for Ocyurus chrysurus and Lutjanus synagris, helping in the mapping and distribution of these monogenetic species in the Americas.

Mitigation Actions by the Marine Epas Against the Oil Spill on the Northeast Brazilian Coast

Mitigation Actions by the Marine Epas Against the Oil Spill on the Northeast Brazilian Coast

Distribution and New Records of the Bluntnose Sixgill Shark, Hexanchus griseus (Hexanchiformes: Hexanchidae), from the Tropical Southwestern Atlantic

The bluntnose sixgill shark, Hexanchus griseus, is a widely distributed demersal species found in tropical and temperate waters of the Pacific, Atlantic, and Indian Oceans, inhabiting continental shelves and slopes, islands, and mid-ocean ridges at depths ranging from 200 to 1100 m. In the Southwestern Atlantic, this species has been recorded from northeastern to southern Brazil, Argentina, and Uruguay. Despite this, the known distribution of this species in the Southwestern Atlantic is very patchy and, in some cases, still mostly ignored in the literature, such as in northeastern Brazil. This study, therefore, aimed to report 23 new records of Hexanchus griseus in the Tropical Southwestern Atlantic and highlight the presence of this species off the northeastern Brazilian coast. So far, Hexanchus griseus was officially reported from the Fernando de Noronha Archipelago, Saint Peter and Saint Paul Archipelago, and the state of Ceará along the northeast coast of Brazil. Herein, the known distribution is extended to the continental shelf breaks and upper slopes of other Brazilian states, reinforcing the previously reported occurrence of the species near the Saint Peter and Saint Paul Archipelago.

Long-term monitoring projects of Brazilian marine and coastal ecosystems.

Biodiversity assessment is a mandatory task for sustainable and adaptive management for the next decade, and long-term ecological monitoring programs are a cornerstone for understanding changes in ecosystems. The Brazilian Long-Term Ecological Research Program (PELD) is an integrated effort model supported by public funds that finance ecological studies at 34 locations. By interviewing and compiling data from project coordinators, we assessed monitoring efforts, targeting biological groups and scientific production from nine PELD projects encompassing coastal lagoons to mesophotic reefs and oceanic islands. Reef environments and fish groups were the most often studied within the long-term projects. PELD projects covered priority areas for conservation but missed sensitive areas close to large cities, as well as underrepresenting ecosystems on the North and Northeast Brazilian coast. Long-term monitoring projects in marine and coastal environments in Brazil are recent (<5 years), not yet integrated as a network, but scientifically productive with considerable relevance for academic and human resources training. Scientific production increased exponentially with project age, despite interruption and shortage of funding during their history. From our diagnosis, we recommend some actions to fill in observed gaps, such as: enhancing projects' collaboration and integration; focusing on priority regions for new projects; broadening the scope of monitored variables; and, maintenance of funding for existing projects.

Productive performance of ‘Pera’ sweet orange grafted onto 37 rootstocks in tropical cohesive soils under rainfed condition

• Cumulative fruit yield was decisive for identify promising rootstocks to ‘Pera’;. • Rangpur, Volkamer x Rangpur, Maravilha Sunki and Indio induced higher yield to ‘Pera’;. • Florida Sunki x citrange 13–012 and Sunki x Swingle-041 perform similar to Rangpur. • The citrus rootstocks induced no significant change on the fruit's quality. In tropical cohesive soils of Brazil, ‘Rangpur’ lime provide high fruit yield to ‘Pera’ sweet oranges. However, the predominance of a single rootstock puts the citrus industry in this region at risk. To identify promising rootstocks for diversification of ‘Pera’ sweet orange orchard's in the tropical cohesive soils of Brazil, a trial was established with 37 citrus rootstocks on the northeast coast of Brazil. The horticultural performance, fruit yield up to the tenth year, and physic-chemical fruit quality attributes were evaluated. The rootstocks induced changes in the tree size, cumulative fruit yield fresh mass and size of fruit, but had not significant influence on chemical fruit quality. The Hierarchical Cluster Analysis allowed group rootstocks into three classes, in which the accumulated fruit yield was the attribute that most contributed. A group with 15 rootstocks was chosen due to the best productive performance and fruits with 193.75–218.5 g, 57.36–62.65% of juice with 9.85–13.08° brix, which meets the requirement of the Brazilian market. Among these 15, the hybrid of ‘Volkamer’ lemon (VKL) with ‘Rangpur’ lime (RL), ‘Maravilha Sunki’ mandarin, ‘Indio’ citrandarin and the local selection of RL stood out by inducing the highest yield . VKL × RL – 030 produced fruits later, but favored the highest fruit yield at the tenth year. Trees grafted on these four rootstocks and also onto RLCNPMF, TSKC × CTQT1434 – 001, MXWL × LHA – 004, ‘Santa Cruz’ Rangpur, ‘San Diego’ citrandarin,– 004 and trifoliate TRH-208 had greater production regularity across the harvests, although the last three showed lower cumulative yield. The earliest fruit bearing was induced by TSKFL × CTC13 – 012, followed by the ‘Sunki' mandarin hybrids TSKC × CTQT1434 – 001, RL, TSKC x TRFD -007 and TSKC x CTSW-041. It is concluded that the most promising rootstocks for diversification of citrus orchards under rainfed condition on the northeast coast of Brazil are VKL x RL-030, ‘Maravilha Sunki’ , ‘Indio’, TSKFL × CTC13 – 012 and TSKC × CTQT1434 – 001, RLCNPMF – 004, TSKC x TRFD -007, TSKC x CTSW-041 and MXWL × LHA – 004.

Reproduction and population dynamics of the invasive bivalves Mytilopsis sallei and Isognomon bicolor on the Northeast coast of Brazil

Knowing the reproductive biology and population dynamics of invasive species are essential for environmental conservation and protection of native species. The success of these invasive species is directly linked to their reproductive strategy. Therefore, this study aimed to describe the reproductive cycles and evaluate population parameters of the invasive bivalves Mytilopsis sallei and Isognomon bicolor, and to estimate if those characteristics would favor their population growths in the northeast coast of Brazil. The bivalves were sampled monthly from June 2016 to May 2017, respectively from the Sanhauá River estuary and Jacarapé beach, State of Paraíba, Northeast Brazil. Through histological analyses, reproductive parameters were determined in order to identify sex, gonadal development, minimum size at maturity, and mean gonadal index. The asymptotic growth (L∞) and growth rate (K) parameters were estimated using the von Bertalanffy growth curve, and recruitment patterns and cohorts were projected based on shell length frequency distributions. Mytilopsis sallei presented more than 50% spawning individuals in most months, while animals showing gametogenic gonads were predominant during the season of greatest precipitation. Isognomon bicolor had ripe gonads (about 30%) and spawning individuals (more than 40%) in all months of the year, but unlike M. sallei, it had the highest concentration of ripe individuals in the months of greatest precipitation. Both species showed equal and high growth rates (K = 1.1 yr-¹) and analysis of the cohorts indicated that these populations are established and expanding. The results confirmed the great invasive potential of the two species in their local environments (estuary and marine) in Northeast Brazil and, therefore, their harmful potential for the conservation of native species and the environment in the invaded areas.

Biometric relationships and sex ratio of the crab Callinectes ornatus (Ordway, 1863) (Decapoda, Portunidae) captured as bycatch in the northeast coast of Brazil.

Biometric relationships and sex ratio of the crab Callinectes ornatus (Ordway, 1863) (Decapoda, Portunidae) captured as bycatch in the northeast coast of Brazil.

FOSTERING CONSERVANCY THROUGH BIOPROSPECTION: THE PHARMACEUTICAL VALUE OF THE BRAZILIAN ASCIDIAN FAUNA

The inherent value of nature is immeasurable. That being said, through bioprospection – the systematic search for functional products or processes from living organisms –, the oceans and marine life have emerged as a relevant source of biodiscoveries that hold significant economic worth. Particularly considering the pharmaceutical industry, an increasing number of natural molecules of marine origin have been making their way into pipelines and receiving approval for clinical use. Still, in its earliest days, this had become an extractivist practice, putting marine environments at risk and nearly driving species to extinction through over-collecting. While it is now well understood that exploration of the oceans' living resources must withstand a sustainable agenda, thus, protecting the environment from unnatural genetic losses, it was the developments towards achieving more efficient bioprospective strategies and non-destructive but feasible means to assure product supply that pushed for the greatest advances in this field. Herein, we present our assessment of this story by telling it through the 20-year journey – and few detours –we took in the chemical and pharmacological study of the ascidian Eudistoma vannamei, a species endemic to the northeast coast of Brazil that retains novel natural products with remarkable modes of action. Indeed, ascidians figure among the most pharmacologically talented marine organisms, having yielded the active principles of three new anticancer drugs, one of which is being considered for repositioning towards the treatment of Covid-19. Finally, we argue that emphasizing the unceasing biotechnological potential of marine biological diversity, exemplified herein by Brazilian ascidians, but certainly true worldwide for this and many other groups, would work in favor of raising awareness and supporting strategies to foster conservation of the oceans.&#x0D; Keywords: blue biotechnology, marine biodiversity, ascidians, bioproducts, innovation.