Verrill's modern Mussismilia (the ‘brain corals’) were described in the 19th century, being hitherto considered endemic reef-building species to Brazil. Contrasting with the original diagnoses, highly variable morphological patterns have been observed among the congeners. Interspecific overlapping of major taxonomical characters has resulted in quite inconclusive use of the skeleton macromorphology for the genus. Intending to corroborate the Mussismilia taxonomy, a comparative morphological approach was developed, combining skeleton macro- and micromorphology. A total of 132 colonies was collected between 13°S and 17°S latitude (Mussismilia hispida = 53, Mussismilia harttii = 41, and Mussismilia braziliensis = 38). Qualitative (n = 9) and quantitative characters (n = 7) were selected (the latter was analysed with Kruskal–Wallis and a principal component analysis). A non-parametric test was adopted due to heteroscedasticity and the irregular sampling among populations. As a result, the corallite diameter and number of septa were significantly distinct among the species (α = 0.05). Micromorphology also differs interspecifically, being distribution and size of septal spines diagnostic for the congeners. Intraspecific variation and morphs are approached, ensuring the relevance of the skeleton for the interspecific delimitation and the species identities. Finally, field identification and/or methods based on image analyses from video transects should be adopted with caution. These practices may provide unreliable data, once the information is restricted to the view of the colony top, resulting in biased identification – majorly if the morphotypes of M. harttii and M. hispida share closely spaced corallites.

The field of Atlantic history initially focused exclusively on the Anglo-American North Atlantic, largely ignoring the South Atlantic and Africa. This approach, dominant after World War II, portrayed a “Western civilization” based on North Atlantic liberal values, akin to a postwar Mediterranean. Over time, historians of the Anglo-American Atlantic criticized this narrow focus, recognizing the broader interconnectedness of the Atlantic world. Recent decades have seen a shift, with more historians acknowledging the Atlantic as a complex, interconnected space involving four continents. Particularly notable is the rise of studies on the South Atlantic, especially regarding science and empire in the Iberian world. These studies highlight the significant role of Spain and Portugal, challenging the previously North Atlantic-centered narrative. This research has revealed that the Atlantic world was as much, if not more, shaped by Spanish and Portuguese influences as by English ones. The reviewed works exemplify this shift, focusing on the South Atlantic's imperial entanglements and the African diaspora in the Caribbean.

The brittle stars of the family Ophiocomidae inhabit shallow waters and coral reefs of tropical regions. The species of Ophiocoma are difficult to identify due to high morphological variation, especially when different stages of development are observed. Here, based on morphological analyses, two Brazilian morphotypes of Ophiocoma were studied and characterized, Ophiocoma sp. NB (Northeastern Brazil) and Ophiocoma sp. TMV (Trindade and Martin Vaz Archipelago), and subsequently thoroughly analysed to confirm whether they were the same species or not. After the morphological studies, including external morphology, morphometry and microstructural characters, and analysis of molecular data, involving the 16S gene, it was concluded that Ophiocoma sp. NB and Ophiocoma sp. TMV do not correspond to the same species, the first being identified as Ophiocoma echinata (Lamarck, 1816) and the latter being a new species. This new species is characterized by two tentacle scales on the first arm segment and then one on all following segments, and the dorsalmost arm spines are robust and rounded, as wide as long or almost as wide as long.

The life history and oceanic impact of three very large icebergs that escaped together from the Weddell Sea sea ice, near the tip of the Antarctic Peninsula, are traced from March 2014. Despite the initial proximity of these three icebergs, they followed very different trajectories across the South Atlantic until their eventual break-up and melting 1 year later. The largest, giant iceberg, B17a, spent extensive periods grounded near two different islands. The triplet's gradual melting is examined through the impact on the icebergs' dimensions, but also the meltwater's oceanic influence on the local salinity and primary productivity. It is found that there was generally a significant local surface and mixed-layer freshening of a few tenths of a practical salinity unit, up to several hundred kilometres away from the 10–20 km-sized icebergs. In contrast, the chlorophyll impact was highly temporally variable, although it tended to be larger in the summer. Break-up of these large icebergs did not occur until near the end of their life. We also show that modelling the trajectories of individual very large icebergs can be reasonable for up to 2 weeks if the characteristics of the iceberg and the local ocean and atmospheric forcing are well known.

Between 1845 and 1850, the Congo coast became the most important source of slaves for the coffee growing areas in the Brazilian Empire. This essay develops a new methodology to understand the making of the ‘nations’ of 290 Africans found on the slave ship Jovem Maria, which boarded slaves in the Congo river and was captured by the Brazilian Navy near Rio de Janeiro in 1850. A close reading of such ‘nations’ reveals a complex overlapping between languages and forms of identification that alters the historian's use of concepts such as ‘ethnolinguistic group’ and ‘Bantu-based lingua franca’ in the Atlantic world. Building on recent developments in Central African linguistics, the article develops a social history of African languages in the Atlantic that foregrounds how recaptives negotiated commonalities and boundaries in the diaspora by drawing on a political vocabulary indigenous to their nineteenth-century homes in Central Africa.

The changes in the Antarctic Circumpolar Current system associated with the Polar, sub-Antarctic and Subtropical Fronts in the Atlantic are examined in a ten-member ensemble using the Community Earth System Model. Results for the ensemble average mean show that the Polar Front at 25°W shifts to the south by 0.8° during 1970–2000 compared to its mean latitude over the period 1050–1950. This shift is significant because it is more than twice the standard deviation of the mean latitude time series during 1050–1950. The shift is caused by a slight southward displacement of the Antarctic Circumpolar Current, which in turn is caused by a southward shift in the latitude of the maximum zonal wind stress. The sub-Antarctic Front also shows a small southward shift after 1970, with a maximum latitudinal displacement of 0.2°. However, this shift is not significant compared to the standard deviation of the time series during 1050–1950. The Subtropical Front does not change its latitude during 1970–2000 compared to 1050–2000 because there is very little change in the wind-stress curl in the subtropics. Differences in temperature and salinity throughout the water column at 25°W reveal that during 1970–2000 there is freshening of Antarctic Intermediate Water, whereas the Circumpolar Deep Water becomes saltier.

A taxonomic revision of the Nystiellidae from Brazil, including samples from the Rio Grande Rise, South Atlantic, was performed based on shell morphology. Five genera and 17 species were recognized. For the richest genus, Eccliseogyra, the three species previously recorded from Brazil were revised: E. brasiliensis and E. maracatu, previously known only from their respective type series, were re-examined. Newly available material of E. maracatu expanded the known geographic range of this species to off south-east Brazil. Eccliseogyra nitida is now recorded from north-eastern to south-eastern Brazil, as well as from the Rio Grande Rise. Three species of Eccliseogyra are newly recorded from the South Atlantic: E. monnioti, previously known from the north-eastern Atlantic, occurs off eastern Brazil and on the Rio Grande Rise; its protoconch is described for the first time, confirming its family allocation. Eccliseogyra pyrrhias occurs off eastern Brazil and on the Rio Grande Rise, and E. folini off eastern Brazil. The genus Iphitus is newly recorded from the South Atlantic. Iphitus robertsi was found off northern Brazil, although the shells show some differences from the type material, with less-pronounced spiral keels. Additional new finds showed that Iphitus cancellatus ranges from eastern Brazil to the Rio Grande Rise, and Iphitus notios sp. nov. is restricted to the Rio Grande Rise. Narrimania, previously recorded from Brazil based on dubious records, is confirmed, including the only two living species described for the genus: N. azelotes, previously only known from the type locality in Florida, and N. concinna, previously known from the Mediterranean. A third species, Narrimania raquelae sp. nov. is described from eastern Brazil, diagnosed by its numerous and thinner cancellate sculpture. To the three species of Opaliopsis previously known from Brazil, a fourth species, O. arnaldoi sp. nov., is added from eastern Brazil, and diagnosed by its very thin spiral sculpture, absence of a varix, and thinner microscopic parallel axial striae. Papuliscala nordestina, originally described from north-east Brazil, is recorded off eastern Brazil and synonymized with P. elongata, a species previously known only from the North Atlantic.

Antarctic surface waters were warm and ice free between 10,000 and 5000 cal yr B.P., as judged from ice-rafted debris and microfossils in a piston core at 53°S in the South Atlantic. This evidence shows that about 5000 cal yr B.P., sea surface temperatures cooled, sea ice advanced, and the delivery of ice-rafted detritus (IRD) to the subantarctic South Atlantic increased abruptly. These changes mark the end of the Hypsithermal and onset of Neoglacial conditions. They coincide with an early Neoglacial advance of mountain glaciers in South America and New Zealand between 5400 and 4900 cal yr B.P., rapid middle Holocene climate changes inferred from the Taylor Dome Ice Core (Antarctica), cooling and increased IRD in the North Atlantic, and the end of the African humid period. The near synchrony and abruptness of all these climate changes suggest links among the tropics and both poles that involved nonlinear response to gradual changes in Northern Hemisphere insolation. Sea ice expansion in the Southern Ocean may have provided positive feedback that hastened the end of the Hypsithermal and African humid periods in the middle Holocene.

The present paper investigates standing stock variations of Halimeda opuntia on a sandstone reef of the South-west Atlantic Ocean, in order to better understand the role of this seaweed as a CaCO3 producer. The study was conducted over two 3-month periods, using photo quadrats to analyse the coverage area, and destructive sampling to quantify area-specific biomass and CaCO3 percentage. The alga occupied 2.4% of the substrate (4464 m2), growing as clumps with an average biomass of 1.59 kg m−2, resulting in a standing stock of 7097.8 kg of alga. This standing stock varied with environmental conditions, particularly wind speed. Assuming an exponential model for these variations, H. opuntia produced at least 13,050.14 kg (54.37 g m−2 day−1) of carbonate sediments. There was a positive correlation between changes in standing stock and coverage, but not with area-specific biomass. This suggests that net algal growth results in the occupation of new spaces, with minimal increases in height or segment density. Therefore monitoring coverage should complement traditional individual-based methods for estimating Halimeda growth and production. Combined, these approaches should result in more accurate models of the role of this alga on marine carbonate budgets.

Swordfish (Xiphias gladius) is heavily exploited in the Atlantic Ocean by several European fleets and age and growth studies are essential for the accomplishment of the stock assessments carried out by ICCAT. The present study aims to validate the periodicity of growth increments on swordfish fin spines and provide first estimates of the growth parameters of South Atlantic swordfish. A total of 502 (231 males and 271 females) spine samples were collected from swordfish specimens onboard commercial longline vessels, from 2006 to 2009. Estimated ages ranged between 0 and 12 years, with age groups 3 and 4 dominating the samples. Marginal increment analysis suggested that growth bands were deposited annually in mid-spring. Fitted standard von Bertalanffy growth parameters (sexes combined) were L∞ = 317.133, k = 0.085 and t0 = −2.488. Minor, but insignificant, growth differences were observed between sexes.

The common dolphinfish (Coryphaena hippurus) is widely distributed and represents an important part of the currently exploited fishery resources. This species’ feeding behaviour, however, is poorly understood. This study aimed to investigate the feeding behaviour of dolphinfish and the effect of body size (and the consequently aggregated learning experience) on the strategies used for capturing their prey. Observations were made from an oil platform in north-eastern Brazil. Dolphinfish length was visually estimated and classified into three size classes. The following foraging strategies were observed in our study: ‘active chasing’, ‘leaping out’, ‘swimming in circles’, ‘surf’, ‘using floating objects’ and ‘cleaning turtle carapaces’. The most frequently used foraging strategy was ‘active chasing’, suggesting a strong preference of dolphinfish in using visual cues during predation. Smaller size-classes of dolphinfish did not perform the ‘swimming in circles’ and ‘surf’ strategy, probably due to a lack of learning experience, since further social interactions could be needed in order to show this strategy. Smaller dolphinfish regularly showed the ‘using floating objects’ as a foraging strategy, probably reflecting an opportunistic behaviour. The smallest individuals were using more simple strategies, to chase smaller prey that could have different and less complex escape strategies. It indicates learning experience could play an important role into the dolphinfish ontogeny, moving towards more complex foraging strategies throughout their lives. Independently of the age class, the dolphinfish displayed a varied repertory of foraging strategies, maximizing hunting success in the open ocean, a hostile pelagic environment with a low prey availability.

Based on material collected during oceanographic campaigns in the western Atlantic from 1958 to 2011, two species of primnoid octocorals belonging to the genus Callogorgia were identified: Callogorgia americana and Callogorgia arawak sp. nov. These species are described and illustrated herein and their geographic and bathymetric are given. This is the first record of the genus in the south-western Atlantic. Additionally, the elevation of C. americana americana and C. a. delta to species level is proposed, keeping Callogorgia gilberti, C. delta and C. americana as separate species.

The reef-building fire coral Millepora alcicornis is reported from Ascension Island (South Atlantic). This record, based on a recent expedition to Ascension, is the first in which the identification of a Millepora coral is supported by photographic evidence from the field and by morphological and molecular analyses of collected specimens. This finding is discussed in relation to earlier Millepora records from Ascension and the biogeographic range of this particular species in the Atlantic.

Ascension Island in the South Atlantic Ocean is renowned for its globally-important nesting population of green turtles (Chelonia mydas) that has been the subject of long-term research. By comparison, very little is known about the apparently small population of hawksbill turtles (Eretmochelys imbricata) that have been recorded in its waters, thousands of kilometres from known nesting beaches. Here, we collate 10 years of in-water tagging data, opportunistic public sighting records and underwater observations to provide a baseline for future research, and present preliminary data on habitat use derived from two individuals fitted with GPS transmitters. Although public sightings were inevitably biased towards popular recreation areas, the resulting distribution suggests that hawksbill turtles occur year round in Ascension Island's waters along the entire 65 km of coastline. Hawksbills were observed feeding on benthic algae and encrusting sponges, and were frequently seen scavenging on fish discards around the Island's pier at night aided by anthropogenic lighting. Between 2003 and 2013, 35 turtles were captured, measured, tagged and then released. Curved carapace lengths ranged from 33.5 to 85 cm (mean = 48.8 cm) indicating that most (if not all) individuals encountered around Ascension are post-pelagic juveniles. Four individuals were recaptured at least once giving a mean minimum residence time of 4.2 yr (range: 2.8–7.3 yr) and a mean growth rate of 2.8 cm yr−1. Turtles fitted with Fastloc™ GPS devices remained at Ascension Island for the duration of the study (>90 days) and occupied restricted home ranges with an average area of 2.5 km2 and an average ‘core use area’ (50% utilization distribution) of 0.05 km2. Together, these results suggest that Ascension Island serves as a mid-Atlantic developmental habitat for benthic-feeding, juvenile hawksbill turtles on extended oceanic migrations before recruiting to their adult foraging grounds, likely to be located in Brazil or tropical West Africa.

The spatial and temporal variations of planktonic cnidarians were studied across the inner continental shelf (≤40 m) off the State of Paraná in southern Brazil. Monthly zooplankton samples were taken between November 1997 and March 1999 at five stations. The holoplanktonic Liriope tetraphylla and Muggiaea kochi dominated during the entire period, comprising >80% of the specimens. The coast–ocean gradient became evident due to a near-coastal (≤20 m) assemblage formed by L. tetraphylla, Solmaris corona and meroplanktonic medusae, and a distinct outer (25–40 m) assemblage formed by the medusae Corymorpha gracilis and Aglaura hemistoma and siphonophores. The estuarine runoff during warm rainy periods lowered the salinity (~30) at the inner stations (1, 2 and 3), providing appropriate conditions for the estuarine/coastal species. Wind-driven onshore advection of outer-shelf species to the inner isobaths occurred from late autumn to winter, when the rainfall decreased and salinity increased (>35). Population peaks occurred in both summer and winter at the inner stations. For most species, the seasonal patterns were inconsistent with other studies conducted in the Southern Brazilian Bight, suggesting irregular and unpredictable seasonal distributions of abundance. Whereas in high-latitude ecosystems the dynamics of cnidarian populations follows the seasonal productivity cycle, here, complex hydrographic processes seem to be more important in determining the structure and seasonal dynamics of this community.

Seven species of antipatharian corals (Cnidaria: Anthozoa: Antipatharia) are recorded from Ascension Island; five of these for the first time. Tanacetipathes spinescens and Stichopathes occidentalis were the two most commonly collected species.

The stalked barnacle Dosima fascicularis is reported from Uruguayan waters for the first time based on stranded specimens. It is suggested that the Subtropical Front is the main area of occurrence of D. fascicularis in the South Atlantic and its occurrence on the Uruguayan coast was found to be sporadic and mainly related to singular atmospheric and oceanographic factors that cast ‘blue plankton’ ashore (e.g. easterly and south-easterly winds, and prevalence of tropical waters).

Rocas is the only atoll in the south-western Atlantic and comprises a shallow platform area of about 360 km2, distant 230 km from the continent and 130 km from Fernando de Noronha Archipelago, in Brazil. Since the 1970s, its marine flora has received the attention of several authors, giving rise to considerable and well-established knowledge about its algal biodiversity, with a total of 143 seaweed species reported for the area. Previous efforts stressed the interesting absence of the green algae Halimeda, usually abundant in tropical reefs and one of the most important seaweed groups in the structure of the tropical benthic community. Herein, we report for the first time the presence of Halimeda opuntia at Rocas, collected during an expedition in January 2012. Based on phylogenetic analysis, was proposed that H. opuntia was originated in the Indo-Pacific Ocean and that its establishment in Brazil was independent from populations of the Caribbean as a whole and the Bahamas in particular. Another hypothesis is the current scenario of increased frequency and intensity of extreme events along the Brazilian coast, which could explain the transport of propagules from adjacent areas towards the atoll.

Two new records of sponges are registered from Ilha Grande Bay (Rio de Janeiro, Brazil), which is an important area in Angra dos Reis for its tourist, economic and environmental contributions. Two species are redescribed in order to elucidate their morphological variations in relation to the known Caribbean specimens: Iotrochota arenosa, a new record to Brazil; and Echinodictyum dendroides, which have now been recorded on the south-east coast of Brazil for the first time. Furthermore, the genus Echinodictyum is redefined.