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Simple Summary: The Southwest Atlantic Ocean (SAO) is a biodiversity hotspot for elasmobranchs. This marine subclass of animals is deeply threatened by anthropogenic activities and many species are at imminent risk of extinction, such as sharks of the genus Mustelus. Scientific reports on the biology, ecology and genetic identity of the narrownose (Mustelus schmitti), the smalleye (Mustelus higmani) and the striped (Mustelus fasciatus) smooth-hound sharks from the family Triakidae are few in the literature. This study describes the sequencing of the first complete mitochondrial genome of a Chondrichthyes from the SAO coast (Mustelus schmitti, a shark classified as critically endangered by the International Union for Conservation of Nature—IUCN) and presents the phylogenetic analysis of this species. The scientific knowledge obtained here will help in elasmobranch conservation programs, in future studies on population ecology and genetics and in fisheries control for this and other small coastal shark species at risk in SAO. Southern Brazil is home to a large biodiversity of elasmobranchs from the Brazilian coast. Several genera and species of small sharks of the Triakidae family live in this marine environment. Studies on these shark species are scarce, with few genetic data and little information on animal population structures. The present study aimed to sequence the complete mitochondrial genome (mtDNA) of the endangered species Mustelus schmitti (narrownose smooth-hound shark) and to perform a phylogenetic analysis of the Triakidae family. The mtDNA sequenced here was 16,764 bp long and possessed the usual 13 mitochondrial protein coding genes (PCGs), 22 tRNAs, two rRNAs (12S and 16S) and a large D-loop DNA sequence, presenting an overall organization similar to other species from the genus Mustelus. Phylogenetic analyses were performed using a dataset containing this new mtDNA and 59 other mitochondrial genomes of the Carcharhiniformes species (including 14 from the Triakidae family), using the Maximum Likelihood (ML) method. All the species of the Triakidae family were clustered into a monophyletic topology group. In addition, polyphyly was observed in Galeorhinus galeus, Hemiatrakis japanica, Triakis megalopterus and Triakis semifasciata. In conclusion, this study contributes to a deeper understanding of the genetic diversity of sharks and represents an important step towards the conservation of these endangered animals. [ABSTRACT FROM AUTHOR]

Close relationship exists between the Mg/Ca ratio in foraminiferal shells and the calcification temperature. Even when most paleoceanographic studies focused on near-surface property reconstructions leaving the deep ocean less explored, during the last years, new Mg/Ca-temperature calibrations were established for the benthic genera Uvigerina and Cibicidoides. Among the main conclusions, it has been established that secondary factors exist affecting the Mg incorporation into the benthic shells, particularly at low temperatures. In order to establish a potential relationship between the Mg/Ca ratios of the aforementioned genera for the western South Atlantic and tropical Atlantic, 38 core-top samples are analyzed here. Our results confirm the existence of other parameters than just temperature affecting Cibicidoides and Uvigerina Mg/Ca, suggesting that the effect of all these other parameters together produces a variable "offset" between both genera that can be linearly approached. We develop an algorithm that allows transforming the Mg/Ca data measured on one of these two genera into the other. This not only would allow performing a continuous Mg/Ca record independent of which benthic genera is available for study but also potentially leads to new and more accurate Mg/Ca-temperature calibrations allowing to get more, high-resolution bottom water temperature reconstructions. [ABSTRACT FROM AUTHOR]

Micropaleontological analyses from the western South Atlantic core AU_Geo02_GC20 (45° 55' S; 58° 30' W, 2589 m water depth) revealed changes in the primary productivity and sea surface temperature (SST) during MIS 3 that point to significant changes in the Brazil Malvinas Confluence Zone dynamics. These changes led to a marked increase in the SST and the primary productivity between 44.0-36.1 ka BP, as indicated by the quantitative reconstruction of the subsurface temperature and the high relative abundance of the planktonic foraminifera Globigerina bulloides and the eutrophic index. The increase in the SST and the primary productivity could indicate frequent or more persistent southward penetration of subtropical waters over the north Patagonian margin due to a southward extension of the Brazil Current and a weakening of the Malvinas Current. The high primary productivity resulted in the intensive use of phosphate during spring. Conversely, benthic assemblages do not reflect high surface productivity. The dominance of calcareous nannoplankton over diatoms as primary producers, which allows inferring the shoaling of the nutricline and the thermocline, justifies the decoupling between planktonic and benthic communities as a consequence of reduced efficiency of the biological pump. The deposition of the pelagites during the period of enhanced primary productivity indicates a slowing down of the bottom circulation, probably due to a weakening of the Atlantic Meridional Overturning Circulation. [ABSTRACT FROM AUTHOR]

Extreme near-surface winds and ocean waves affect several activities over coastal and oceanic regions, such as offshore oil and gas industry, management of port operations, installation of renewable energy systems, and navigation. Our objective is to evaluate the ability of reanalysis/satellite data to reproduce local features of wind speed at 10 m height and significant wave height (SWH), and to assess the climatology (mean and extreme) of regional downscalings using WRF and RegCM4 for the atmosphere and WW3 for the ocean waves over the western South Atlantic. For the present climate, WRF and RegCM4 are forced by two CMIP5 global climate models (HadGEM2-ES and MPI-ESM-MR) and reanalysis, while WW3 is forced by the winds from the downscalings. We found that: (i) CCMP and WAVERYS have a more realistic representation of, respectively, the wind speed and SWH observed by buoys and platforms over the southeastern Brazilian basins; (ii) near the southeastern coast of Brazil, austral spring and winter have the more intense wind and wave extremes; (iii) RegCM4 and WRF present opposite biases over the southwestern South Atlantic, i.e., RegCM4 (WRF) overestimates (underestimates) the wind speed extremes, except for the region of Santos basin where both overestimate the extremes in austral summer and spring; and (iv) the SWH is closer to reanalysis when WW3 is forced by winds from WRF. This first assessment of the mean and extreme winds and oceanic waves from regional climate downscaling provides confidence and knowledge for further investigation on climate projections over the region. [ABSTRACT FROM AUTHOR]

Sounds produced by dolphins can be grouped into tonal (whistles) and pulsed sounds (e.g., echolocation clicks and burst sounds). Clicks are broadband pulses temporarily spaced to allow echo processing between the sound source and the object. Echolocation is related mainly to prey detection and environmental recognition. Echolocation click trains tend to present a decreasing inter-click interval due to a continuous changing of the target's location when the animal approaches to capture the prey. In addition to foraging and feeding contexts, burst pulsed sounds have been associated with short social communication. Although echolocation clicks are relatively well documented, there is no consensus regarding the broad variety of the burst pulsed signals. The present study analyzed time-frequency characteristics by conducting a clustering and discrimination analysis to classify pulsed sounds. A total of 64 click trains were analyzed from short-beaked common dolphins recorded in the slope region of the western South Atlantic Ocean. Three analyses (time; frequency; and combined time-frequency parameters) were compared through k-means clustering and posterior cluster validation using Random forest analysis. The k-means clustering resulted in four clusters for all groups of analysis. The time parameters were the most accurate among the comparisons, with the first two-dimensional axis corresponding to 87 % (Dim1 = 70.2 % and Dim2 = 17.2 %). The random forest analysis showed that the time-frequency dataset was the best classification of pulsed sounds in D. delphis (Accuracy = 84.6 %; confidence interval CI = 65.1 %-95.6 %; p < 0.01). This result considers the animal an acoustical identity, emphasizing the importance of certain parameters that influence this identity and thus reflecting the energy-cost optimization for sound production. [Display omitted] • Pulsed sounds constitute one of the main parts of dolphins repertoire. • Characterizing pulsed sounds improve our knowledge on its functional significance. • Time-frequency parameters provided best classification of D. Delphis pulsed sounds. • D. delphis produces four distinct types of pulsed sounds. • The quantitative classification may represent with greater accuracy the variation of a repertoire. [ABSTRACT FROM AUTHOR]

Inputs of new nitrogen by cyanobacterial diazotrophs are critical to ocean ecosystem structure and function. Relative to other ocean regions, there is a lack of data on the distribution of these microbes in the western South Atlantic. Here, the abundance of six diazotroph phylotypes: Trichodesmium, Crocosphaera, UCYN-A, Richelia associated with Rhizosolenia (Het-1) or Hemiaulus (Het-2), and Calothrix associated with Chaetoceros (Het-3) was measured by quantitative PCR (qPCR) of the nifH gene along a transect extending from the shelf-break to the open ocean along the Vitória-Trindade seamount chain (1200 km). Using nifH gene copies as a proxy for phylotype abundance, Crocosphaera signals were the most abundant, with a broad distribution throughout the study region. Trichodesmium signals were the second most abundant, with the greatest numbers confined to the warmer waters closer to the coast, and a significant positive correlation with temperature. The average signals for the host-associated diazotrophs (UCYN-A, Het-1, and Het-2) were consistently lower than for the other phylotypes. These findings expand measurements of cyanobacterial diazotroph distribution in the western South Atlantic, and provide a new resource to enhance modeling studies focused on patterns of nitrogen fixation in the global ocean.

Planktonic foraminifera census data have been widely used to reconstruct changes in ocean ecosystems as well as ocean chemistry and circulation through calibration functions. Here we analyse new core‐top census data from 22 sites in the western South Atlantic, improving the geographical coverage and spatial resolution of the environmental gradients from the region covered by the Brazil–Malvinas Confluence (˜38°S–53°W). We combine them with previous data to provide an up‐to‐date compilation of the western South Atlantic planktonic foraminifera–calibration data set. We study the relationship between the assemblages present in the core‐top samples and the most dynamic environmental variables from the region to establish the environmental variable(s) more resolved by the assemblages. Therefore, we develop and assess a new calibration function using the data set and testing several statistical models at different water depths. Our results reveal that the distribution and abundance of the species in the Brazil–Malvinas Confluence region mainly reflect the influence of two environmental variables: the mixed layer temperature and mixed layer depth (57% of total variance). The most precise reconstructions were obtained when using sub‐surface temperatures between 40 and 50 m water depth. The application of the calibration function to a Holocene sediment core at ˜37°S–53°W revealed mean annual sub‐surface temperature reconstructions between 8°C and 11°C, confirming the northward displacement of the Brazil–Malvinas Confluence during the onset of the Holocene and suggesting a major influence of the Malvinas Current during the entire Holocene at the studied site. [ABSTRACT FROM AUTHOR]

Here we present a record of coccolith variation over the past 14 kyr BP from core KF-02 (25.84°S, 45.2°W; 827 m water depth) collected from the continental slope of the São Paulo Bight (SPB), located in the subtropical western South Atlantic. Additionally, we estimated primary productivity based on Florisphaera profunda nannoliths and compared it with other published investigations on the productivity based on different proxies. The coccolith assemblages varied and agreed with the main regional oceanic and atmospheric changes since the latest deglaciation, likely in response to the terrestrial influence and nutricline depth variations. Among eutrophic species, Gephyrocapsa oceanica was more abundant during times with enhanced productivity promoted by the input of terrestrial material. Emiliania huxleyi and small Gephyrocapsa dominated the middle Holocene samples and probably benefitted from the more stable oceanic conditions and the enhanced light availability promoted by the Brazil Current. The paleoproductivity estimates indicated that moderate levels of productivity persisted since the latest deglaciation with a decreasing trend after the middle Holocene, delaying the productivity reduction that was indicated by other regional studies based on planktonic foraminifera. Apparently, seasonal regional hydrographic conditions were responsible for changing coccolith assemblages, and these were not reflected by the planktonic foraminifera G. bulloides variations. • Paleoproductivity in the subtropical Brazilian margin based on Florisphaera profunda. • Higher levels of primary productivity during late deglaciation in the São Paulo Bight. • Primary productivity declined since the middle Holocene in western South Atlantic. • Late Holocene productivity tends to oligotrophy at the subtropical Brazilian margin. • Seasonal hydrographic variability potentially influenced the coccolith assemblages. [ABSTRACT FROM AUTHOR]

The franciscana is endemic to subtropical coastal waters of Brazil, Uruguay, and Argentina, and is the only living species of the family Pontoporiidae. It is regarded as the most endangered cetacean in the western South Atlantic. Five management units are recognized (Franciscana Management Areas, FMAs – sensu Secchi et al., 2003a), with abundance estimates ranging from a few hundred to around 15,000 dolphins. Low reproductive potential and short life span make this species highly susceptible to current non-natural removal rates. Bycatch in gillnet fisheries occurs in high levels since the 1960s in Uruguay and 1980s in Brazil and Argentina. Although other threats exist, such as habitat degradation that includes physical (noise) and chemical pollution, depletion of fish stocks and climate change, incidental mortality in gillnets is currently the greatest threat to franciscanas. Fishing-related mortality ranges from approximately 100, in FMA I, to more than 1,000 in FMA III, and exceed from near two (in FMA IV) to more than five times (in FMA III) the maximum allowed sustainable mortality rate, based on potential biological removal (PBR) approach. These numbers indicate that the species is unlikely to cope with the current levels of bycatch and that urgent and extreme reduction on fishing practice and effort are required to avoid collapse of the franciscana and to lower its risk of extinction. Current mortality levels and projected declines resulted in the listing of the franciscana as “Vulnerable” in the IUCN Red List. Recent fisheries regulations were implemented in areas with extensive bycatch in Brazil and were expected to improve the species’ conservation status. There is evidence, however, that this regulation is insufficient to reduce fishing-related mortality to sustainable levels due to either or both lack of compliance and inadequate regulation strategies. Here we provide a comprehensive review on the franciscana ecology and threats and discuss perspectives for its conservation.

A single specimen of Bassozetus mozambiquensis Tomiyama, Takami, and Fukui, 2016, collected off southern Brazil in the western South Atlantic and held in the University of Hamburg ichthyological collection, was re-examined. Because the species was previously known only from the western Indian Ocean, solely on the basis of the holotype, the present specimen represents not only the first Atlantic record of the species, but also a ca. 8300 km westward extension of the distributional range. A detailed description of the Atlantic specimen and an updated diagnosis of the species are provided. [ABSTRACT FROM AUTHOR]

The franciscana dolphin (Pontoporia blainvillei) is a coastal dolphin endemic to the western South Atlantic Ocean. The dolphin is listed as vulnerable in the IUCN Red List, with incidental catches in gillnet fisheries the greatest conservation concern for this species. Insights into the feeding habits of this dolphin are essential to understand its distribution, movements and use of habitat, which are fundamental for effective management of the species. The feeding habits of franciscana dolphins were investigated from analyses of stomach contents of animals incidentally caught by two fishing operations from southern and northern regions of the southern Brazilian coast. In this study we investigate the existence of intrapopulation (sexual maturity and sex-related) variation in the diet of the franciscana dolphin, evaluating the spatial (northern and southern geographic areas) and seasonal influences. The analyses were based on Linear and Generalized Linear Models (LM and GLM). The majority of identified prey species were bottom-dwelling teleosts and the squid Doryteuthis sanpaulensis. The most important prey differed spatially and seasonally between northern and southern regions of the study area, and our results revealed significant differences between sexes and sexual maturity stages, mainly related to prey species sizes. This variation might indicate differences in prey selection, availability or habitat use patterns among these groups. In any case, these dietary differences are likely to minimize intraspecific competition for food resources, and/or indicate spatio-temporal variation in prey availability. [ABSTRACT FROM AUTHOR]

Magnetic signals in deep‐sea sediments have the potential to unravel past continental environmental changes, via changes in primary terrigenous magnetic supply, but also record past marine environmental conditions, via in situ formation of secondary magnetic minerals, particularly when complemented by independent proxies. By combining environmagnetic, geochemical, and siliciclastic grain size data, we investigated marine sediment core GL‐1090 (24.92°S, 42.51°W, 2,225 m water depth) aiming to unravel changes in terrigenous sediment input and bottom water conditions during the last ∼184 ka at the western South Atlantic middepth. The Al/Si, Fe/κ and siliciclastic grain size data show that terrigenous sediments at this core location derived from the Plata River (southeastern South America). This material was transported northwards by the Brazilian Coastal Current and their delivery to our core site was modulated by sea‐level oscillations. Periods of low sea‐level were characterized by the input of coarser and more abundant terrigenous sediments. Environmagnetic parameters indicate significant downcore variations in the magnetic domain state, which we interpret as changes in the content of biogenic magnetite following glacial‐interglacial cycles. Coeval negative excursions in magnetic grain size and benthic δ13C suggests that concentrations of single domain magnetite (possibly magnetotactic bacterial magnetite) vary in response to middepth water ventilation. We suggest that reduced ventilation in the middepth western South Atlantic bottom waters during peak glaciations triggered a decrease in the production of biogenic magnetite. Peak glaciations were, in turn, linked with increases in the residence time of North Atlantic Deep Water (or its glacial counterpart). Key Points: Multi‐proxy approach points to the Plata River as the main lithogenic sediment source to tropical SE South American continental margin, modulated by sea‐levelReduced biogenic magnetite formation coeval with negative benthic δ13C anomalies during glaciationsBiogenic magnetite formation hampered by decreased bottom water ventilation during glaciations [ABSTRACT FROM AUTHOR]

Abstract A variety of gravel‐ to cobble‐sized rocks, recovered from the Mar del Plata (MdP) Canyon area (Western South Atlantic at 38°S) and interpreted as ice‐rafted debris, represent the first evidence that large icebergs have floated in the Falkland (Malvinas) Current from the southern polar high latitudes far northward. Detailed petrographic analyses identified the Antarctic Peninsula, sub‐Antarctic islands in the Scotia Sea, and Tierra del Fuego as plausible source areas. The drift process could have started as early as at the beginning of the last deglaciation, according to an age obtained from a cold‐water coral fragment associated with one of the dropstones. At the end of the Last Glacial Maximum, large icebergs have been supplied to the Antarctic Circumpolar Current, captured by those ocean current branches that circumvent the Falkland (Malvinas) Islands and entered the Argentine Margin. When the iceberg fleets approached the Brazil‐Falkland (Malvinas) Confluence Zone with its steep latitudinal temperature gradient, the icebergs got oceanographically trapped and melted off rapidly. The sediment load sinking down to the seafloor formed a dropstone blanket particularly where the MdP Canyon had incised into the continental slope. Here, mass‐flow processes, induced by local slope instability, and along‐slope sediment resorting, due to the erosional effects of strong and persistent contouritic bottom currents, favored local enrichment in dropstones in the form of a loose, coarse sediment drape inside morphological depressions. The bottom current velocity would be locally strong enough to rework this sediment, leaving coarse rafted debris as a lag deposit.

The Serra Spanish Mackerel, Scomberomorus brasiliensis is one of the principal fishery resources found in the tropical and subtropical waters of the western South Atlantic. Declining catches of S. brasiliensis off the coast of northeastern Brazil indicate that this species is being overfished. Despite the importance of this species to local fisheries, few data are available on its genetic diversity or population parameters. Given this scenario, the present study evaluated the genetic variability of S. brasiliensis off the coast of the western South Atlantic, based on mitochondrial genes. We compiled two databases, one with partial sequences of the MT-CYB gene (N = 105), and the other of the MT-ND4 gene of the Serra Spanish Mackerel, sampled from eight localities, ranging from Cumana in Venezuela to Paranaguá, in southern Brazil. The results of the analysis indicate low levels of genetic diversity in the study. Samples from Cumana, on the coast of Venezuela were the most differentiated, although the results of the AMOVA were not significant. The PhiST values, the genetic divergence, and the haplotype network all indicate the widespread sharing of haplotypes by the mackerel from all the different localities. Analyses of the historical demography, based on both markers, indicate the occurrence of past population expansion, coinciding with fluctuations in sea level that occurred 10,000 years ago. The demographic and phylogeographic analyses of the mitochondrial DNA revealed the existence of a single genetic stock of S. brasiliensis on the coast of the western South Atlantic according to. These findings are fundamental to the development of effective conservation strategies.

A variety of gravel‐ to cobble‐sized rocks, recovered from the Mar del Plata (MdP) Canyon area (Western South Atlantic at 38°S) and interpreted as ice‐rafted debris, represent the first evidence that large icebergs have floated in the Falkland (Malvinas) Current from the southern polar high latitudes far northward. Detailed petrographic analyses identified the Antarctic Peninsula, sub‐Antarctic islands in the Scotia Sea, and Tierra del Fuego as plausible source areas. The drift process could have started as early as at the beginning of the last deglaciation, according to an age obtained from a cold‐water coral fragment associated with one of the dropstones. At the end of the Last Glacial Maximum, large icebergs have been supplied to the Antarctic Circumpolar Current, captured by those ocean current branches that circumvent the Falkland (Malvinas) Islands and entered the Argentine Margin. When the iceberg fleets approached the Brazil‐Falkland (Malvinas) Confluence Zone with its steep latitudinal temperature gradient, the icebergs got oceanographically trapped and melted off rapidly. The sediment load sinking down to the seafloor formed a dropstone blanket particularly where the MdP Canyon had incised into the continental slope. Here, mass‐flow processes, induced by local slope instability, and along‐slope sediment resorting, due to the erosional effects of strong and persistent contouritic bottom currents, favored local enrichment in dropstones in the form of a loose, coarse sediment drape inside morphological depressions. The bottom current velocity would be locally strong enough to rework this sediment, leaving coarse rafted debris as a lag deposit. Plain Language Summary: Icebergs can transport sand‐ to cobble‐sized sediment while drifting with the ocean currents over large distances away from the high latitudes. When seawater temperature forces the ice to melt, this "ice‐rafted debris" will sink down as "dropstones" to the seabed. Offshore dropstone deposits are common in polar regions but rarely found in lower latitudes because icebergs barely survive if the ocean water is not extremely cold. We found evidence of dropstone deposits along the Argentine Margin at the relatively low latitude of 38°S. They rest inside morphological seafloor depressions at the continental slope in association with the Mar del Plata Canyon. Here, also the oceanic Brazil‐Falkland (Malvinas) Confluence Zone is located, which acts as a barrier for northward drifting icebergs. The presence of icebergs in the Argentine Sea was already known; we, however, describe the first finding of rocks that clearly had originated from the Antarctic Peninsula, sub‐Antarctic islands in the Scotia Sea, and Tierra del Fuego, the southern tip of the South American continent. These dropstones are often found together with fragments of cold‐water corals, suggesting that the imported rocks have locally served as hard substrate for coral colonies to establish. Key Points: Rocks recovered from the Mar del Plata Canyon area, 38°S in the Western South Atlantic, are interpreted as ice‐rafted debrisAntarctic Peninsula, sub‐Antarctic islands in the Scotia Sea and Tierra del Fuego are identified as plausible source areasDropstones lie as a coarse sediment drape inside morphological depressions [ABSTRACT FROM AUTHOR]

Aim: We evaluated traditional biogeographic boundaries of coastal marine regions in Southwestern Atlantic using DNA sequence data from common, rocky‐shore inhabiting, marine mites of the genera Agauopsis and Rhombognathus, family Halacaridae. Methods: We investigated geographic population genetic structure using CO1 gene sequences, estimated divergence times using a multigene dataset and absolute time‐calibrated molecular clock analyses, and performed environmental niche modeling (ENM) of common marine mite species. Results: Agauopsis legionium has a shallow history (2.01 Ma) with four geographically differentiated groups. Two of them corresponded to the traditional Amazonian and Northeastern ecoregions, but the boundary between the two other groups was inferred at the Abrolhos Plateau, not Cabo Frio. Rhombognathus levigatoides s. lat. was represented by two cryptic species that diverged 7.22 (multilocus data) or 10.01 Ma (CO1‐only analyses), with their boundary, again at the Abrolhos Plateau. ENM showed that A. legionium has suitable habitats scattered along the coast, while the two R. levigatoides cryptic species differ considerably in their niches, especially in parameters related to upwelling. This indicates that genetic isolation associated with the Abrolhos Plateau occurred in both lineages, but for the R. levigatoides species complex, ecological niche specialization was also an important factor. Main conclusions: Our study suggests that the major biogeographic boundary in the Southwestern Atlantic lies not at Cabo Frio but at the Abrolhos Plateau. There two biogeographically relevant factors meet (a) changes in current directions (which limit dispersal) and (b) abrupt changes in environmental parameters associated with the South Atlantic Central Waters (SACW) upwelling (offering distinct ecological niches). We suggest that our result represents a general biogeographic pattern because a barrier at the Abrolhos Plateau was found previously for the fish genus Macrodon (phylogeographic data), prosobranch mollusks, ascidians, and reef fishes (community‐level data). [ABSTRACT FROM AUTHOR]

This study reports the occurrence of the oceanic basslet (Howellidae) in Brazilian waters. Bathysphyraenops simplex Parr, 1933, a rare species with a worldwide distribution, is recorded for the first time in Brazilian waters, based on three specimens collected off Rocas Atoll and Rio Grande do Norte. Howella atlantica Post & Quéro, 1991, known from the western and eastern Atlantic Ocean (64°N to 21°S), including waters around the Trindade Island, is reported off Rio Grande do Norte, Pernambuco, Rocas Atoll, and the Fernando de Noronha Archipelago. In addition, specimens previously reported in the literature as Howella brodie Ogilby, 1899 are reidentified as H. atlantica, extending the known distribution of this species to northeastern and southeastern Brazil. Measurements and counts for all specimens examined are provided. [ABSTRACT FROM AUTHOR]

The manefishes of the family Caristiidae are rare, poorly known deep-sea species with broad geographical distribution. This study provides new information on the diversity and distribution of this family around the oceanic islands and seamounts off northeastern Brazil, reporting the first records of Paracaristius nudarcus, Platyberyx andriashevi, Platyberyx paucus and Platyberyx pietschi in Brazilian waters. Measurements and counts for all specimens examined are provided and compared with those available in the literature. In addition, the identity of caristiids previously reported from Brazil is discussed. [ABSTRACT FROM AUTHOR]

Abstract: Sea surface height data from multiple satellite altimetric missions are analyzed in order to investigate the surface manifestation of internal tides generated at the Vitória‐Trindade Ridge (VTR), in the western South Atlantic Ocean. The VTR is formed by a sequence of submerged seamounts disposed in a west‐east alignment around 20.5°S, extending for over 1,000 km from the Brazilian continental margin to the Trindade and Martim Vaz islands. Point‐wise harmonic analysis of the along‐track sea surface height data, combined with a two‐dimensional plane wave fitting at selected subregions, depicts well‐organized northbound and southbound wave beams radiating from the VTR, and propagating as far as ~1,000 km from the ridge. Energy convergence is observed at a focal point located circa 300 km south of the VTR, associated with a lens effect due to the arc‐shaped ridge. Wavenumber spectra show highest energy associated with wavelengths of 140 and 70 km, close to the theoretical values expected for the first and second baroclinic modes, respectively. Energy fluxes for the mode 1 principal lunar (M2) constituent reach values of 2 to 3 kW/m for the southward beams and 1 kW/m north of the VTR. Judging from its surface signature, the VTR appears to be the most significant internal tide generation site in the western South Atlantic. [ABSTRACT FROM AUTHOR]

A survey of the distribution and abundance of the invasive orange cup coral Tubastraea coccinea Lesson, 1829 was conducted using photoquadrats during 2014/2015, fifteen years after its first documented introduction in a Cabo Frio upwelling area in the western South Atlantic (42º00'W-22º44'S). These data were related to local currents and to a dispersion model of particles and with sea surface temperatures (SST). The objective was to investigate how variations in environmental conditions (local currents and temperatures) influence the dispersion and survival of T. coccinea. Complementary laboratory experiments were performed to investigate the effects of low temperatures on the survival of this species. T. coccinea has expanded its distribution and larval dispersion seems to be driven by the local currents. Furthermore, higher densities of colonies and recruits were observed within areas with higher water temperatures (>20 °C), while no coral was found in the area of direct upwelling influence, suggesting that cold waters limited the distribution of T. coccinea. These findings were corroborated by laboratory experiments that showed a negative effect of cold water (≤ 12.5 °C) on colony survival. The present data contribute to our understanding of the worldwide geographical expansion of T. coccinea and could be particularly important for management decisions to prevent new invasions. [ABSTRACT FROM AUTHOR]

The São Paulo state (SP) coast (23º18'S, 44º42'W; 25º14'S, 48º01'W) is of approximately 600 km in length, bordering the Western Atlantic Ocean, in southeastern Brazil. Cetacean sightings and strandings have long been observed throughout this area. Scattered data from scientific publications, skeletal remains in museums, photographs and articles from newspaper files, universities and aquaria have been organised and updated since 1993. Field investigations on strandings and sightings have also been conducted. A total of 29 cetacean species have been recorded, including 7 baleen whales (Mysticeti) and 22 toothed whales (Odontoceti), as follows: Balaenoptera physalus, B. borealis, B. edeni, B. acutorostrata, B. bonaerensis, Megaptera novaeangliae, Eubalaena australis, Physeter macrocephalus, Kogia breviceps, K. sima, Berardius arnuxii, Mesoplodon europaeus, M. mirus, Ziphius cavirostris, Orcinus orca, Feresa attenuata, Globicephala melas, G. macrorhynchus, Pseudorca crassidens, Delphinus capensis, Lagenodelphis hosei, Steno bredanensis, Tursiops truncatus, Stenella frontalis, S. longirostris, S. coeruleoalba, Lissodelphis peronii, Sotalia guianensis and Pontoporia blainvillei. Several species have been observed only once and include strays from their areas of common distribution, as well as species with known preferences for offshore distribution. Others, such as P. blainvillei and S. guianensis, are common coastal dwellers year-round. Z. cavirostris, P. crassidens and L. hosei are reported for the first time on the SP coast.A costa do Estado de São Paulo (SP) (23º18'S, 44º42'O; 25º14'S, 48º01'O) apresenta aproximadamente 600 km de extensão voltada para o Oceano Atlântico Ocidental no sudeste do Brasil. Registros de encalhes e de avistamentos de cetáceos vêm sendo realizados ao longo desse litoral. Desde 1993, dados obtidos em literatura científica, material osteológico encontrado em museus, fotografias e artigos de arquivos de jornais, universidades e aquários foram organizados e atualizados. Investigações efetuadas em campo referentes a encalhes e avistamentos de cetáceos também foram conduzidas. Um total de 29 espécies de cetáceos foi registrado, incluindo 7 misticetos e 22 odontocetos, como indicados a seguir: Balaenoptera physalus, B. borealis, B. edeni, B. acutorostrata, B. bonaerensis, Megaptera novaeangliae, Eubalaena australis, Physeter macrocephalus, Kogia breviceps, K. sima, Berardius arnuxii, Mesoplodon europaeus, M. mirus, Ziphius cavirostris, Orcinus orca, Feresa attenuata, Globicephala melas, G. macrorhynchus, Pseudorca crassidens, Delphinus capensis, Lagenodelphis hosei, Steno bredanensis, Tursiops truncatus, Stenella frontalis, S. longirostris, S. coeruleoalba, Lissodelphis peronii, Sotalia guianensis e Pontoporia blainvillei. Algumas espécies foram observadas apenas em uma ocasião e incluem tanto vagantes de suas áreas comuns de distribuição, assim como de conhecidas áreas de distribuições preferenciais oceânicas. Outras, como P. blainvillei e S. guianensis, são comumente encontradas em águas rasas o ano todo. Z. cavirostris, P. crassidens e L. hosei são listados pela primeira vez para a costa de SP.

Calcareous microfossils have potential in the biostratigraphy of Pleistocene sediments and a clear relationship with paleoceanographic studies. Conversely, there are few quantitative biostratigraphic studies of chronologically-tuned events or sections in the western South Atlantic. In order to improve the stratigraphical framework for South Atlantic paleoceanographic studies, the present work attempts to review the last 772,000 years by carrying out a quantitative analysis of the calcareous nannofossil and planktonic foraminiferal assemblages by comparing them with a high resolution marine isotopic record (δ 18 O). This work is based on the analysis of two piston cores obtained from the continental slope of the Santos Basin in the Santos Drift, southeastern Brazilian Continental Margin. Twelve Pleistocene calcareous nannofossil events and twenty planktonic foraminifera events calibrated with oxygen isotopes and correlated with literature stratigraphies are discussed. This is the first calcareous plankton biochronology study for the last 772 kyr in the western South Atlantic Ocean. More studies in this region will help to establish a more precise biochronology for these calcareous microfossils. This study also presents six new biostratigraphic events of isotopically-caibrated planktonic foraminifera which can be used as markers in the western South Atlantic. [ABSTRACT FROM AUTHOR]

Background: Humpback whales Megaptera novaeangliae are cosmopolitan and highly migratory animals that rarely feed in low latitude waters during their breeding seasons. The western South Atlantic humpback whale population breeds off the Brazilian coast, from Natal (4°S) to Cabo Frio (23°S) and migration to their feeding grounds is known to be undertaken through offshore waters. Results: Here we report on an unusual stranding of a young humpback whale that was feeding in the coastal waters of Santa Catarina state (27°S), in October 2014. Evidence of a ship strike and that the animal had fed in no more than a few hours before death are also presented. Additionally, it is the first time that Peisos petrunkevitchi, a sergestid shrimp species, is described as prey for large whales. Conclusions: Although more information is required before we can further discuss whether the area could provide an important source of food for young humpback whales, the present ship strike highlights a possibly important threat in case this ecological feature is confirmed in the future. [ABSTRACT FROM AUTHOR]

A variação no padrão das placas de dentes vômero-palatinas de Genidens barbus e Genidens machadoi é revista e as espécies redescritas com base na análise de 46 caracteres morfológicos. Genidens machadoi pode ser diferenciada de Genidens barbus pela: margem lateral do esfenótico recortada (vs. margem lateral do esfenótico retilínea); escudo cefálico mais estreito na região dos esfenóticos (vs. escudo cefálico mais estreito na região dos frontais); distância entre a margem lateral do escudo cefálico, na porção mais estreita, e a margem posterior da órbita cabendo 0,681,0 na menor largura do escudo cefálico (vs. 1,21,7); menor largura do processo occipital, na porção posterior, cabendo 2,03,4 no comprimento do processo occipital (vs. 3,34,7); um ou dois pares de placas de dentes na região do palato, par anterior arredondado e pequeno, par posterior ovalado às vezes confluente ou fusionado com o par anterior (vs. placas de dentes na região do palato formando um conjunto com aspecto de uma ferradura, as placas totalmente fusionadas ou confluentes e distintas, mas sempre com uma projeção posterior); maior comprimento das placas de dentes cabendo 3,24,9 na altura da cabeça (vs. 1,93,4); granulação no escudo cefálico espessa e irregularmente distribuída (vs. fina e distribuída em série regulares).Variation in the pattern of the vomero-palatine tooth patches of Genidens barbus and Genidens machadoi is reviewed and the species redescribed based on the analysis of 46 morphological characters. Genidens machadoi can be distinguished from Genidens barbus by: the notched lateral margin of the sphenotic (vs. lateral margin of the sphenotic straight); the cephalic shield narrowest in the sphenotic (vs. cephalic shield narrowest in the frontal); distance between the lateral margin of the cephalic shield, at narrowest portion, and the posterior margin of the orbit 0.681.0 of the smallest width of the cephalic shield (vs. 1.21.7); width of the posterior extremity of the supra-occipital process 2.03.4 of the length of the supra-occipital process (vs. 3.34.7); one or two groups of tooth patches on roof of mouth, anterior patch small and round, posterior patch oval, sometimes confluent or fused with the front group (vs. patches a with horseshoe shape, patches totally fused or divided in confluent groups, always with a posterior projection); longest length of the tooth patches 3.24.9 of the height of the head (vs. 1.93.4); granulation on cephalic shield coarse and irregularly distributed (vs. smooth and distributed in regular series).

Hybridization between hawksbill (Eretmochelys imbricata) and loggerhead (Caretta caretta) breeding groups is unusually common in Bahia state, Brazil. Such hybridization is possible because hawksbill and loggerhead nesting activities overlap temporally and spatially along the coast of this state. Nevertheless, the destinations of their offspring are not yet known. This study is the first to identify immature hawksbill × loggerhead hybrids (n = 4) from this rookery by analyzing the mitochondrial DNA (mtDNA) of 157 immature turtles morphologically identified as hawksbills. We also compare for the first time modeled dispersal patterns of hawksbill, loggerhead, and hybrid offspring considering hatching season and oceanic phase duration of turtles. Particle movements varied according to season, with a higher proportion of particles dispersing southwards throughout loggerhead and hybrid hatching seasons, and northwards during hawksbill season. Hybrids from Bahia were not present in important hawksbill feeding grounds of Brazil, being detected only at areas more common for loggerheads. The genetic and oceanographic findings of this work indicate that these immature hybrids, which are morphologically similar to hawksbills, could be adopting behavioral traits typical of loggerheads, such as feeding in temperate waters of the western South Atlantic. Understanding the distribution, ecology, and migrations of these hybrids is essential for the development of adequate conservation and management plans.

Copyright of Revista de Biologia Marina y Oceanografía (RBMO) is the property of Universidad de Valparaiso, Facultad de Ciencias del Mar and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study analyses depredation by killer whales (Orcinus orca) and false killer whales (Pseudorca crassidens) on catches of the Uruguayan pelagic longline fishery in the Southwestern Atlantic Ocean between 1998 and 2007. Data were collected by scientific observers from the National Observer Program of the Tuna Fleet operating in the area between 19°-40.5°S and 20°-54°W. Depredation occurred in 67 of the 1029 sets and was restricted to the area from 25°-40.5°S to 27°-53°W, though larger proportions of depredation (DP: percentage of total fish caught damaged by cetaceans) were observed in the Brazil-Malvinas (Falkland) Confluence area (34°-37°S and 51°-53°W) where most of the fishing effort was concentrated. Depredation occurred year-round though intra-annual variability in its intensity was recorded. The overall DP was 0.37% and was slightly higher in autumn. The spatial analysis showed that DP within grids of 1 x 1° was homogeneous and generally <2.5%. Ten out of 57 fish species caught by the fishery were depredated by cetaceans. Swordfish (Xiphias gladius) showed the highest DP per species (1.17%). Using the frequency of resources selectivity index of Ivlev, it was determined that swordfish was selected as a preferred prey in 43.9% of the sets with depredation. Generalized linear models indicated that distance to coast, year, and vessel were significant variables in explaining the number of fish depredated per fishing event. The presence of killer whales in the fishing ground seems not to affect the catch per unit effort by the longline fishery. The losses caused by depredation of cetaceans on the catch are low with probably minor economic effects to the Uruguayan longline fishing industry. [ABSTRACT FROM AUTHOR]

Bycatch is one of the main causes of human-caused mortality and population decline of many marine mammals. Monitoring bycatch is the first step to understand the impact of the fisheries on the species affected. Understanding how the interaction between marine mammals and fishing operations varies in space and time, and how it is influenced by environmental variables, is essential for designing mitigation strategies to reduce bycatch mortality. In this paper, we use data gathered by scientific observers and a fishing skipper to analyse marine mammals bycatch by the Uruguayan pelagic longline fishery operating in the Southwestern Atlantic Ocean from 1996 to 2007. The total bycatch per unit effort (Bcpue) was 0.0150 marine mammals/1000 hooks and the highest values (~0.2) were recorded between 37°-38°S and 49°-51°W. Total cetacean Bcpue during the study period was low (0.0051 cetacean/1000 hooks) and occurred between 32°-37°S and 46°-54°W. Generalized additive models showed that cetaceans' bycatch was mainly affected by the depth, sea surface temperature, and season. Although cetaceans were captured year-round, the highest values were registered in spring months, most bycatch events occurred over the continental slope (median = 619 m) and in waters with a median temperature of 19.7°C. The bycatch of pinnipeds was influenced by depth, location, and season. Pinniped bycatch occurred mainly in winter, in waters ranging from 80 to 5000 m of depth (median = 2366 m) between 34°-37°S (median = 35.9°S) and 54°-49°W (median = 51.8°W). The spatial analysis showed that most bycatch events occurred within the Brazil-Malvinas Confluence zone, an area of high productivity where the pelagic longline fleet concentrates its fishing effort and where marine mammals probably concentrate to feed. [ABSTRACT FROM AUTHOR]

We provide a new multivariate calibration-function based on South Atlantic modern assemblages of planktonic foraminifera and atlas water column parameters from the Antarctic Circumpolar Current to the Subtropical Gyre and tropical warm waters (i.e., 60°S to 0°S). Therefore, we used a dataset with the abundance pattern of 35 taxonomic groups of planktonic foraminifera in 141 surface sediment samples. Five factors were taken into consideration for the analysis, which account for 93% of the total variance of the original data representing the regional main oceanographic fronts. The new calibration-function F141-35-5 enables the reconstruction of Late Quaternary summer and winter sea-surface temperatures with a statistical error of ~ 0.5°C. Our function was verified by its application to a sediment core extracted from the western South Atlantic. The downcore reconstruction shows negative anomalies in sea-surface temperatures during the early–mid Holocene and temperatures within the range of modern values during the late Holocene. This pattern is consistent with available reconstructions. [ABSTRACT FROM AUTHOR]

Although the circulation of the western South Atlantic tightly controls the meridional heat and salt transport, our knowledge about its long-term past changes is still fragmented and sparse. While many studies focused their attention on the last glacial and deglaciation periods, Holocene studies mostly lack of an integrated analysis from the subtropical and midlatitude regions. The analysis of selected regionally distributed palaeoceanographic records along the western South Atlantic between 27° and 39°S reveals that, although weaker in amplitude than the dramatic shifts of the last glacial cycle, the Brazil-Malvinas Confluence region showed substantial changes throughout the Holocene. The shift in the location of both southern and northern source waters in the Atlantic implied a strengthening of the Southern Atlantic Meridional Overturning Circulation since the Mid-Holocene. This, together with the progressive southward displacement of the Brazil-Malvinas Confluence confirms the progressive weakening of the Atlantic Meridional Overturning Circulation towards the preindustrial times. • Regional analysis of selected palaeoceanographic records distributed along the western South Atlantic. • The Brazil-Malvinas Confluence region showed substantial changes throughout the Holocene. • Southern and northern source waters' shift location implied a strengthening of the SAMOC since Mid-Holocene. • The Brazil-Malvinas Confluence southward displacement confirms AMOC's progressive weakening towards the preindustrial times. [ABSTRACT FROM AUTHOR]

Two Limnohalacarus species are reported from the southern Brazilian state of Rio Grande do Sul, Limnohalacarus cultellatus Viets, 1940 and L. mamillatus Fain & Lambrechts, 1987, originally described on the basis of individuals from the Caribbean region and aquaria in Belgium, respectively. The former species is also known from Madagascar, Hungary, North America, and was referred to Brazil and El Salvador in the literature. The latter species is also known from Western Australia. [ABSTRACT FROM AUTHOR]

The western South Atlantic along the Brazilian margin is an important region for the Atlantic Meridional Overturning Circulation (AMOC) because surface currents in this area transfer warm and salty waters from the Southern Hemisphere to the North Atlantic. Although the number of sea surface temperature (SST) reconstructions has grown in this region, it has been challenging to explain changes in different and sometimes proximal cores. To understand the SST evolution of the Brazilian margin from the Last Glacial Maximum (LGM) to the late Holocene, we present the first SST stack (BR SST stack) for this region. We compare the BR SST stack with the outputs of the transient climate model simulation TraCE-21ka. The BR SST stack shows an LGM cooling of 1.43 °C (from −1.31 to −1.55 °C, 2σ) relative to the late Holocene, followed by deglacial warming starting at ∼ 18.8 ka. TraCE-21ka simulates this early onset of the last deglaciation. Sensitivity experiments suggest that the input of meltwater from retreating ice sheets in the Northern Hemisphere triggered the post-LGM warming, which was subsequently sustained by increasing atmospheric CO 2. Deglacial millennial-scale events of AMOC slowdown produced large-scale warming of the Brazilian margin not clearly distinguished by some previous studies. Analyzing our stack in its segregated components, i.e., the North Brazil Current (NBC SST stack) and Brazil Current (BC SST stack) – we noted in-phase warming at the onset of the last deglaciation, which is not found in TraCE-21ka simulations. We attributed this to underestimating the meltwater influence over the tropical Brazilian margin by the model. BR SST stack also presents episodes of abrupt cooling near periods of fast sea-level rise during the last deglaciation, which may be due to rapid AMOC reinvigoration or freshening of the Southern Ocean. Holocene climate resembles that recorded by other compilations, with no clear Holocene thermal maximum but presenting a cooling trend during the late Holocene possibly related to intensified volcanic activity. Our study indicates that the future human-induced SST change expected for the end of the 21st-century will overcome the background of natural climate variability of the last 22,000 years for the Brazilian margin. • We present the first SST compilation (BR SST stack) of the Brazilian margin. • The BRS ST stack describes the SST evolution from the LGM to Holocene. • TraCE-21ka suggests the meltwater input and rising CO 2 as drivers of SST evolution. • Future human-induced SST change overcomes the natural background of SST variability. [ABSTRACT FROM AUTHOR]

The article discusses the potential of the Hawksbill sea turtle as the new host of the parasite Hapalotrema (H) postorchis. The study was done on a female turtle that was found dead in October 2011 on Conceição de Barra Beach in Brazil, where the parasites were found in her heart chambers and evaluated through light microscopy and computerized image analysis. Results of the study confirmed the first infection of H. postorchis on a Hawksbill sea turtle in the South Atlantic Ocean.

Abstract: Surface currents and sediment distribution of the SE South American upper continental margin are under the influence of the South American Monsoon System (SAMS) and the Southern Westerly Wind Belt (SWWB). Both climatic systems determine the meridional position of the Subtropical Shelf Front (STSF) and probably also of the Brazil–Malvinas Confluence (BMC). We reconstruct the changing impact of the SAMS and the SWWB on sediment composition at the upper Rio Grande Cone off southern Brazil during the last 14cal kyr BP combining sedimentological, geochemical, micropaleontological and rock magnetic proxies of marine sediment core GeoB 6211-2. Sharp reciprocal changes in ferri- and paramagnetic mineral content and prominent grain-size shifts give strong clues to systematic source changes and transport modes of these mostly terrigenous sediments. Our interpretations support the assumption that the SAMS over SE South America was weaker than today during most of the Late Glacial and entire Early Holocene, while the SWWB was contracted to more southern latitudes, resembling modern austral summer-like conditions. In consequence, the STSF and the BMC were driven to more southern positions than today's, favoring the deposition of Fe-rich but weakly magnetic La Plata River silts at the Rio Grande Cone. During the Mid Holocene, the northern boundary of the SWWB migrated northward, while the STSF reached its northernmost position of the last 14cal kyr BP and the BMC most likely arrived at its modern position. This shift enabled the transport of Antarctic diatoms and more strongly magnetic Argentinean shelf sands to the Rio Grande Cone, while sediment contributions from the La Plata River became less important. During the Late Holocene, the modern El Niño Southern Oscillation set in and the SAMS and the austral tradewinds intensified, causing a southward shift of the STSF to its modern position. This reinforced a significant deposition of La Plata River silts at the Rio Grande Cone. These higher magnetic silts with intermediate Fe contents mirror the modern more humid terrestrial climatic conditions over SE South America. [Copyright &y& Elsevier]

Abstract: Fragments of mitochondrial (COI and rRNA 16S) and nuclear (Tmo-4C4) genes were sequenced to evaluate the phylogenetic relationships among 15 genera of the western South Atlantic Sciaenidae, two freshwater genera and the northwest Pacific Larimichthys crocea. Our results suggest a great diversification for the western Atlantic assemblage; the monophyly of Macrodon, Menticirrhus and Plagioscion genera; the distinctiveness of Bardiella, Stellifer and Ophioscion as belonging to the same clade; the possible existence of two distinct groups in Stellifer; the closer relationship between Lonchurus and Paralonchurus; the non-monophyly of Cynoscion; and the remarkable diversification of Larimus breviceps populations in the Brazilian coast. This is the most comprehensive study evaluating the phylogenetic relationships of the western Atlantic sciaenid and provides a guide for future studies within this family. [Copyright &y& Elsevier]

A dual stable isotope approach (δ13C and δ15N) was used to investigate inter- and intra-specific variations in feeding ecology and habitat use of 7 delphinids from coastal/estuarine, continental shelf and offshore marine environments from southern Brazil: Tursiops sp., Orcinus orca, Stenella frontalis, Steno bredanensis, Delphinus delphis, Pseudorca crassidens and Lagenodelphis hosei. Teeth from 50 specimens acquired from stranded animals were analysed in this study. Tursiops sp. and O. orca are the most coastal species, and had the highest δ13C values followed by the continental shelf species S. frontalis, S. bredanensis and D. delphis. Lagenodelphis hosei showed the lowest δ13C value, demonstrating its typical offshore habitat. One group of P. crassidens had the lowest δ15N values, indicating their low trophic level feeding habit while two specimens of the same species showed the highest mean nitrogen isotope value. This first study on stable isotope values of delphinids from southern Brazil provides substantial new information about the trophic ecology, habitat use and feeding environments of these animals. [ABSTRACT FROM PUBLISHER]

Copyright of Neotropical Biology & Conservation is the property of Pensoft Publishers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Brazilian Journal of Oceanography is the property of Instituto Oceanografico da Universidade de Sao Paulo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Iron (Fe) and other trace elements such as Zn, Mn, Ni and Cu are known as key-factors in marine biogeochemical cycles. It is believed that ocean primary productivity blooms in iron deficient regions can be triggered by iron in aeolian dust. Up to now, scarce aerosol elemental composition, based on measurements over sea at the Western South Atlantic (WSA), exist. An association between the Patagonian semi-desert dust/Fe and chlorophyll-a variability at the Argentinean continental shelf is essentially inferred from models. We present here experimental data of Fe enriched aerosols over the WSA between latitudes 22°S–62°S, during 4 oceanographic campaigns between 2002 and 2005. These data allowed inferring the atmospheric Fe flux onto different latitudinal bands which varied from 30.4 to 1688 nmolFe m−2 day−1 (October 29th–November 15th, 2003); 5.83–1586 nmolFe m−2 day−1 (February 15th–March 6th, 2004) and 4.73–586 nmolFe m−2 day−1(October 21st–November 5th, 2005). [Copyright &y& Elsevier]

This is the first study in Argentine waters on the abundance of the threatened Franciscana dolphin, Pontoporia blainvillei. During 2003–2004 we carried out 17 aerial surveys using line transect sampling methodology. We observed 101 Franciscanas in 71 sightings. In northern areas density was estimated at 0.106 individual/km2. Density was lower in southern areas (0.055/km2) and declined with depth beyond 30-m isobaths (0.05/km2). A correction factor for submerged dolphins was applied to density and then extrapolated to the strip between the coastline and the 30-m isobath. Abundance in the northern area was estimated at 8,279 (4,904–13,960) individuals, while in the southern area it was estimated at 5,896 (1,928–17,999) individuals. Considering an annual mortality of about 500–800 individuals, about 3.5%–5.6% of the stock may be removed each year by the fishery and over the 2% recommended by the International Whaling Commission (IWC) and may not be sustainable by the population. Higher densities in coastal areas make Franciscanas more vulnerable to coastal fishing camps, which increased mortality in recent years. A remarkable finding was that while density decreases to the south, values of catch per unit effort (CPUE) increases, indicating different catchability of dolphins between areas. [ABSTRACT FROM AUTHOR]