cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14325746
title: Evaluating the gravity wave energy potential off the Brazilian coast

description: Abstract The wave energy potential on the Brazilian coast is estimated using in-situ buoy data and model data. The results present a greater potential on the southern-southeastern coast than on the northeastern coast, but the variance is also larger. These seem to be associated with the different atmospheric regimes. While in the northeastern portion the trade winds determine the wave regime, in the south the passage of cold front systems plays a major role. For almost all regions and throughout the year, the energy potential oscillates between 10 and 30 kW/m, the most efficient range to implement wave energy converters. The occurrence of sea states is also assessed, showing that the passage of cold front systems also creates different sea states in the S-SW area. Finally, the most common sea states and energy flux are estimated, showing a shift towards longer periods and higher waves for the latter. On the S-SW coast, although the most frequent sea states have waves with periods around 8 s, the energy flux has a more balanced distribution between these and the waves with periods around 11s, the common period for waves generated by cold front systems. This result shows that the most common sea state is not necessarily the one that should be considered when planning wave energy converters for the region.
DOI: 10.6084/m9.figshare.14325746.v1
title: Evaluating the gravity wave energy potential off the Brazilian coast

description: Abstract The wave energy potential on the Brazilian coast is estimated using in-situ buoy data and model data. The results present a greater potential on the southern-southeastern coast than on the northeastern coast, but the variance is also larger. These seem to be associated with the different atmospheric regimes. While in the northeastern portion the trade winds determine the wave regime, in the south the passage of cold front systems plays a major role. For almost all regions and throughout the year, the energy potential oscillates between 10 and 30 kW/m, the most efficient range to implement wave energy converters. The occurrence of sea states is also assessed, showing that the passage of cold front systems also creates different sea states in the S-SW area. Finally, the most common sea states and energy flux are estimated, showing a shift towards longer periods and higher waves for the latter. On the S-SW coast, although the most frequent sea states have waves with periods around 8 s, the energy flux has a more balanced distribution between these and the waves with periods around 11s, the common period for waves generated by cold front systems. This result shows that the most common sea state is not necessarily the one that should be considered when planning wave energy converters for the region.
DOI: 10.6084/m9.figshare.7367801
title: Tidal and subtidal oscillations in a shallow water system in southern Brazil

description: ABSTRACT Sea level oscillations in time scales between hours and days have a great vertical amplitude regarding the low lying coastal gradient of the beaches in the Rio Grande do Sul coast. However, the mechanism of oscillations is poorly understood since the scarcity of observational data makes it impossible to determine the forces that control sea level oscillations. Therefore, hourly sea level and wind time series with a time period of 650 days were examined. It has been found that the mean tidal and subtidal amplitudes were very similar to each other and that a considerable portion of the energy from sea level oscillations was due to astronomical forces. A new perspective was introduced when high and low frequencies were compared, leading to the comprehension that astronomical tides should be considered in coastal studies in southern Brazil. The sea level time series analyzed in this study showed that the maximum amplitude of the high spring tide was 0.53m, and that the subtidal rise caused by the wind reached up to 0.66m. In general, when large tidal and subtidal amplitudes are added, it can generate extreme events of sea level rise on the coast, which constitute a direct threat to coastal communities and habitats.
DOI: 10.6084/m9.figshare.7367801.v1
title: Tidal and subtidal oscillations in a shallow water system in southern Brazil

description: ABSTRACT Sea level oscillations in time scales between hours and days have a great vertical amplitude regarding the low lying coastal gradient of the beaches in the Rio Grande do Sul coast. However, the mechanism of oscillations is poorly understood since the scarcity of observational data makes it impossible to determine the forces that control sea level oscillations. Therefore, hourly sea level and wind time series with a time period of 650 days were examined. It has been found that the mean tidal and subtidal amplitudes were very similar to each other and that a considerable portion of the energy from sea level oscillations was due to astronomical forces. A new perspective was introduced when high and low frequencies were compared, leading to the comprehension that astronomical tides should be considered in coastal studies in southern Brazil. The sea level time series analyzed in this study showed that the maximum amplitude of the high spring tide was 0.53m, and that the subtidal rise caused by the wind reached up to 0.66m. In general, when large tidal and subtidal amplitudes are added, it can generate extreme events of sea level rise on the coast, which constitute a direct threat to coastal communities and habitats.
DOI: 10.6084/m9.figshare.7368101
title: Subtidal soft sediments of the Paranaguá Bay inlet: mapping habitats and species distribution at a landscape scale

description: ABSTRACT This study aimed to map habitats and species distribution in a benthoscape section of the Paranaguá Bay inlet, Paraná State, Southern Brazil. The degree of correspondence between maps independently generated through sidescan imagery and macrofauna and sediment samples was also evaluated. The study area had approximately 9km2 and was chosen considering both diverse landscape features and proximity to future port developments. Sampling was performed in 67 evenly distributed and unreplicated sites. Patterns related to backscatter intensity (high and low) and the presence or absence of bedforms were observed, as well as other large-scale features like sand waves and beach rock outcrops. Local sedimentary environments were represented in a mosaic used for comparisons with sedimentary and faunistic data. Cluster analysis using grain size data formed four groups with similar particle size distribution. A strong correspondence between habitats and grain size distribution was found in only one habitat class. Macrofauna around the deeper Poço Point region and the Mel Island shallower banks presented high species richness and number of individuals. These were considered habitats of high biological relevance. Regions with bedforms indicate higher rates of sand transport in which a few species can thrive. The navigation channel had the lowest number of species and individuals when compared to vicinal regions, indicating persistent impacts. The study evidenced local estuarine bottom heterogeneity and contributed to the understanding of local processes of both bottom sediments dynamics and their associate faunal components.
DOI: 10.6084/m9.figshare.7368101.v1
title: Subtidal soft sediments of the Paranaguá Bay inlet: mapping habitats and species distribution at a landscape scale

description: ABSTRACT This study aimed to map habitats and species distribution in a benthoscape section of the Paranaguá Bay inlet, Paraná State, Southern Brazil. The degree of correspondence between maps independently generated through sidescan imagery and macrofauna and sediment samples was also evaluated. The study area had approximately 9km2 and was chosen considering both diverse landscape features and proximity to future port developments. Sampling was performed in 67 evenly distributed and unreplicated sites. Patterns related to backscatter intensity (high and low) and the presence or absence of bedforms were observed, as well as other large-scale features like sand waves and beach rock outcrops. Local sedimentary environments were represented in a mosaic used for comparisons with sedimentary and faunistic data. Cluster analysis using grain size data formed four groups with similar particle size distribution. A strong correspondence between habitats and grain size distribution was found in only one habitat class. Macrofauna around the deeper Poço Point region and the Mel Island shallower banks presented high species richness and number of individuals. These were considered habitats of high biological relevance. Regions with bedforms indicate higher rates of sand transport in which a few species can thrive. The navigation channel had the lowest number of species and individuals when compared to vicinal regions, indicating persistent impacts. The study evidenced local estuarine bottom heterogeneity and contributed to the understanding of local processes of both bottom sediments dynamics and their associate faunal components.
DOI: 10.6084/m9.figshare.7368242
title: Genesis of submerged sandstones in Paraná State continental shelf, Southern Brazil, based on cementation patterns, ages and stable isotopes

description: ABSTRACT Beachrocks are a common feature along the Brazilian coast and although their occurrence in intertidal zones is concentrated in tropical regions, similar formations have been described submerged on the continental shelf in subtropical regions. In the state of Paraná, submerged sandstones are present on the continental shelf and their formation could be associated with the cementation of beach sediments. This would provide an excellent indicator of the stabilization of the coastline during lower sea-level periods. In this study, samples were identified and collected in Paraná State, Southern Brazil, at depths between 18 and 33 meters in the continental shelf and at 6 meters depth in the Paranaguá Bay inlet. As in situ observations proved problematic, analysis relied mainly on their petrography, mineralogy, ages and isotopic values (δ13C and δ18O). Whole rock dating demonstrated that the oldest acquired sample was formed 28109-26406 cal. years BP, being exposed to atmospheric conditions during the Last Glacial Maximum. This exposure is reflected in its cements, composed uniquely of microcrystalline and spar calcite, and on its δ18O/δ13C values, which indicates formation on a fresh water environment. Contrarily to most carbonate cemented products described along Brazilian coastline, δ13C values ranged between -26.36 and -51.07‰ on all other samples, interpreted as a result of cement precipitation prompted by methane, either: in a paleo-estuarine/ paleo-lagunar to transgressive environment buried under a pile of coarser material or; after transgression and drowning of organic-rich sediments by coarser sediments, and due to upward migration of methane on the sedimentary column. Both processes would result in cements identified on these samples, apart from the one collected closer to shore which indicates some freshwater influence. Two of the samples separated by 15km distance perpendicularly to the actual coastline and 11m depth difference yielded max and minimum ages of 7913 and 7452 cal. years BP. Such a short time span between these samples could be either the result of their formation on a linked environment or older carbon signature from drowned environments being present on younger cements.
DOI: 10.6084/m9.figshare.7368242.v1
title: Genesis of submerged sandstones in Paraná State continental shelf, Southern Brazil, based on cementation patterns, ages and stable isotopes

description: ABSTRACT Beachrocks are a common feature along the Brazilian coast and although their occurrence in intertidal zones is concentrated in tropical regions, similar formations have been described submerged on the continental shelf in subtropical regions. In the state of Paraná, submerged sandstones are present on the continental shelf and their formation could be associated with the cementation of beach sediments. This would provide an excellent indicator of the stabilization of the coastline during lower sea-level periods. In this study, samples were identified and collected in Paraná State, Southern Brazil, at depths between 18 and 33 meters in the continental shelf and at 6 meters depth in the Paranaguá Bay inlet. As in situ observations proved problematic, analysis relied mainly on their petrography, mineralogy, ages and isotopic values (δ13C and δ18O). Whole rock dating demonstrated that the oldest acquired sample was formed 28109-26406 cal. years BP, being exposed to atmospheric conditions during the Last Glacial Maximum. This exposure is reflected in its cements, composed uniquely of microcrystalline and spar calcite, and on its δ18O/δ13C values, which indicates formation on a fresh water environment. Contrarily to most carbonate cemented products described along Brazilian coastline, δ13C values ranged between -26.36 and -51.07‰ on all other samples, interpreted as a result of cement precipitation prompted by methane, either: in a paleo-estuarine/ paleo-lagunar to transgressive environment buried under a pile of coarser material or; after transgression and drowning of organic-rich sediments by coarser sediments, and due to upward migration of methane on the sedimentary column. Both processes would result in cements identified on these samples, apart from the one collected closer to shore which indicates some freshwater influence. Two of the samples separated by 15km distance perpendicularly to the actual coastline and 11m depth difference yielded max and minimum ages of 7913 and 7452 cal. years BP. Such a short time span between these samples could be either the result of their formation on a linked environment or older carbon signature from drowned environments being present on younger cements.
DOI: 10.6084/m9.figshare.7367684
title: Structure of microphytoplankton community and environmental variables in a macrotidal estuarine complex, São Marcos Bay, Maranhão - Brazil

description: ABSTRACT São Marcos Bay is an estuarine complex with semidiurnal tides that can reach more than 7 m during equinoctial spring tides. It is situated in the second largest Brazilian coastline and is subjected to continuous human activities holding an important port complex of Latin America. In order to contribute to the knowledge about the structure of the phytoplankton in a macrotidal systems, this study aims to evaluate the phytoplankton community and its relationship with environmental conditions in the São Marcos Bay. Five surveys in 2010 and 2011 were carried out on four sampling points during the rainy and dry seasons. Samples were taken during the flood and ebb phases at neap tides. Hydrological parameters were correlated with biological data (phytoplankton composition, abundance and biomass) using statistical analysis. The phytoplankton biomass (chlorophyll a) characterized the bay as quite productive (10.43±7.62 mg m-3) with the nanophytoplankton as the dominant fraction. Seasonal variation was observed in phytoplankton abundance with higher values (34,262±18,422 cells L-1) in the rainy season. Diatoms were the most important phytoplankton group, pointing out Nitzschia sp., Diploneis weissflogii and Synedra sp. as the dominant species. This study revealed that the composition of phytoplankton community was mainly influenced by the local dynamics, governed by macrotides, and precipitation regime that mostly contributed to the seasonal fluctuations of the environmental conditions, such as salinity, dissolved oxygen, and nutrients.
DOI: 10.6084/m9.figshare.7367684.v1
title: Structure of microphytoplankton community and environmental variables in a macrotidal estuarine complex, São Marcos Bay, Maranhão - Brazil

description: ABSTRACT São Marcos Bay is an estuarine complex with semidiurnal tides that can reach more than 7 m during equinoctial spring tides. It is situated in the second largest Brazilian coastline and is subjected to continuous human activities holding an important port complex of Latin America. In order to contribute to the knowledge about the structure of the phytoplankton in a macrotidal systems, this study aims to evaluate the phytoplankton community and its relationship with environmental conditions in the São Marcos Bay. Five surveys in 2010 and 2011 were carried out on four sampling points during the rainy and dry seasons. Samples were taken during the flood and ebb phases at neap tides. Hydrological parameters were correlated with biological data (phytoplankton composition, abundance and biomass) using statistical analysis. The phytoplankton biomass (chlorophyll a) characterized the bay as quite productive (10.43±7.62 mg m-3) with the nanophytoplankton as the dominant fraction. Seasonal variation was observed in phytoplankton abundance with higher values (34,262±18,422 cells L-1) in the rainy season. Diatoms were the most important phytoplankton group, pointing out Nitzschia sp., Diploneis weissflogii and Synedra sp. as the dominant species. This study revealed that the composition of phytoplankton community was mainly influenced by the local dynamics, governed by macrotides, and precipitation regime that mostly contributed to the seasonal fluctuations of the environmental conditions, such as salinity, dissolved oxygen, and nutrients.
DOI: 10.6084/m9.figshare.8292605
title: Energy budgets for juvenile Pacific whiteleg shrimp Litopenaeus vannamei fed different diets

description: Abstract Energy budgets for juvenile Pacific whiteleg shrimp, Litopenaeus vannamei (1.7-4.0 g ) fed with different diets were assessed. The energy partitioning between growth, respiration, ammonia excretion, feces and exuvia was calculated to estimate for total food energy intake. Shrimp oxygen consumption and ammonia excretion were quantified in sealed chambers (25°C, 34 ppt). Energy allocated for growth and feces were obtained from the wet combustion of whole body and feces samples, exuvia was estimated as 10% growth energy. Three diets were tested: 100% chopped fish (Fish), 100% commercial feed (Feed), and 50-50% chopped fish and commercial feed (Mix). Most of the energy from the diets was channeled into respiration (49.7-70.5%). Shrimp fed the Feed diet used more energy in growth (24.4%) than those fed Mix (13.4%) or Fish diets (13.2%), either in absolute (joule) or relative (% of ingested energy) terms. Conversely, energy loss as ammonia excretion was lower in shrimp fed Feed (1.0%) compared to shrimp fed Mix (4.2%) or Fish diets (7.8%). Less energy was lost in feces by shrimp fed Fish diet (7.3%) compared to Mix (20.2%) and Feed diets (22.2%). The calculated energy intake by shrimp fed Fish, Mix and Feed were 0.995, 1.100, and 1.255 kJ ind-1day-1, respectively. According to the O:N atomic ratios (oxygen consumed to nitrogen excreted), protein tented to be the predominant substrate catabolized by shrimp fed Fish (O:N=16±5.2), and Mix (O:N=25±11.6), with increasing use of carbohydrates and/or lipids in the Feed (O:N=74±37.3). Results suggest diet composition may affect energy budget and partitioning differently between metabolism and growth either in absolute or relative terms, as shrimp fed Fish and Mix diets used protein as main substrate for metabolism, whereas shrimp fed Feed diet channeled protein for growth, and lipids and carbohydrates for other metabolic functions.
DOI: 10.6084/m9.figshare.8292605.v1
title: Energy budgets for juvenile Pacific whiteleg shrimp Litopenaeus vannamei fed different diets

description: Abstract Energy budgets for juvenile Pacific whiteleg shrimp, Litopenaeus vannamei (1.7-4.0 g ) fed with different diets were assessed. The energy partitioning between growth, respiration, ammonia excretion, feces and exuvia was calculated to estimate for total food energy intake. Shrimp oxygen consumption and ammonia excretion were quantified in sealed chambers (25°C, 34 ppt). Energy allocated for growth and feces were obtained from the wet combustion of whole body and feces samples, exuvia was estimated as 10% growth energy. Three diets were tested: 100% chopped fish (Fish), 100% commercial feed (Feed), and 50-50% chopped fish and commercial feed (Mix). Most of the energy from the diets was channeled into respiration (49.7-70.5%). Shrimp fed the Feed diet used more energy in growth (24.4%) than those fed Mix (13.4%) or Fish diets (13.2%), either in absolute (joule) or relative (% of ingested energy) terms. Conversely, energy loss as ammonia excretion was lower in shrimp fed Feed (1.0%) compared to shrimp fed Mix (4.2%) or Fish diets (7.8%). Less energy was lost in feces by shrimp fed Fish diet (7.3%) compared to Mix (20.2%) and Feed diets (22.2%). The calculated energy intake by shrimp fed Fish, Mix and Feed were 0.995, 1.100, and 1.255 kJ ind-1day-1, respectively. According to the O:N atomic ratios (oxygen consumed to nitrogen excreted), protein tented to be the predominant substrate catabolized by shrimp fed Fish (O:N=16±5.2), and Mix (O:N=25±11.6), with increasing use of carbohydrates and/or lipids in the Feed (O:N=74±37.3). Results suggest diet composition may affect energy budget and partitioning differently between metabolism and growth either in absolute or relative terms, as shrimp fed Fish and Mix diets used protein as main substrate for metabolism, whereas shrimp fed Feed diet channeled protein for growth, and lipids and carbohydrates for other metabolic functions.
DOI: 10.6084/m9.figshare.8292617.v1
title: Distribution patterns of meiofauna on a tropical macrotidal sandy beach, with special focus on nematodes (Caixa d’Água, Amazon Coast, Brazil)

description: Abstract Spatial distribution patterns (both horizontal and vertical) of meiofauna, with special focus on nematodes, on a tropical macrotidal beach across different climatic periods were analyzed in this study. Samplings were carried out at five stations in the intertidal zone in June (rainy season) and December (dry season), 2011. At each station, three samples were taken using a corer with 3cm diameter, which was thrust 10cm into the substrate and stratified in 0-2, 2-5, and 5-10cm. Meiofauna was comprised of 16 groups and Nematoda was the dominant. Meiofauna density during rainy season was higher at the central intertidal station and during dry season it was lower near the high tide mark, followed by an increasing trend towards the low tide mark. Meiofauna was more concentrated in the upper sediment layer during rainy season. However, during dry season, the highest density occurred in the lower sediment layer at both stations near the high tide mark. Nematoda association was comprised of 72 genera, with Daptonema and Theristus (both from the family Xyalidae) as the dominant ones in most stations and strata. The genera richness and diversity increased towards the low tide mark, with lower richness in the upper stratum at most stations. Non-selective deposit-feeders predominated during rainy season, while at dry season there was an alternation of dominance between non-selective deposit-feeders and epistrate feeders. Significant differences were found in the meiofauna community, as well as in the Nematoda association in regard to the months, stations, and sediment layers. The distribution patterns of interstitial organisms found in this study, in part, follow what is already known for microtidal beaches but other differential aspects were observed even if compared to environments of macrotidal beaches in temperate regions.