Sedimentology,palaeoenvironments and biostratigraphy of the Pliocene–Pleistocene carbonate platform of Grande‐Terre (Guadeloupe,Lesser Antilles forearc)

Pliocene and Pleistocene deposits from Grande‐Terre (Guadeloupe archipelago, French Lesser Antilles) provide a remarkable example of an isolated carbonate system built in an active margin setting, with sedimentation controlled by both rapid sea‐level changes and tectonic movements. Based on new field, sedimentological and palaeontological analyses, these deposits have been organized into four sedimentary sequences (S1 to S4) separated by three subaerial erosion surfaces (SB0, SB1 and SB2). Sequences S1 and S2 (‘Calcaires inférieurs à rhodolithes’) deposited during the Late Zanclean to Early Gelasian (planktonic foraminiferal Zones PL2 to PL5) in low subsidence conditions, on a distally steepened ramp dipping eastward. Red algal‐rich deposits, which dominate the western part of Grande‐Terre, change to planktonic foraminifer‐rich deposits eastward. Vertical movements of tens of metres were responsible for the formation of SB0 and SB1. Sequence S3 (‘Formation volcano‐sédimentaire’, ‘Calcaires supérieurs à rhodolithes’ and ‘Calcaires à Agaricia’) was deposited during the Late Piacenzian to Early Calabrian (Zones PL5 to PT1a) on a distally steepened, red algal‐dominated ramp that changes upward into a homoclinal, coral‐dominated ramp. Deposition of Sequence S3 occurred during a eustatic cycle in quiet tectonic conditions. Its uppermost boundary, the major erosion surface SB2, is related to the Cala1 eustatic sea‐level fall. Finally, Sequence S4 (‘Calcaires à Acropora’) probably formed during the Calabrian, developing as a coral‐dominated platform during a eustatic cycle in quiet tectonic conditions. The final emergence of the island could then have occurred in Late Calabrian times.     

Spatial variability in beach biogeomorphology in a tropical archipelago

Beaches of tropical island coasts exhibit high levels of diversity in composition and form in comparison with their continental counterparts. To investigate the nature and origin of this diversity, individual beach morphology and sedimentology was investigated in the British Virgin Islands (BVI), a Caribbean archipelago of > 60 high volcanic and low reef islands. The islands exhibit a diversity of orientations (some facing the Atlantic and some the Caribbean), elevation and gradient, rock type and wave energy. An examination of 100 beaches in the archipelago revealed a first-order division into sand (70 beaches) and coral rubble (30 beaches). These beaches occur in seven planform types (determined by the antecedent geological framework) and are further subdivided according to shoreface type (seagrass, sandy shoreface, or reef). Mainland-attached headland-embayment beaches are the most common form of sand beach while coral rubble beaches usually occur as barriers that enclose salt ponds and wetlands. Among sand beaches, carbonate content is greatest on Atlantic-facing beaches, and coral rubble beaches are more common on Caribbean-facing beaches. Grain size characteristics on sandy beaches are highly variable and range from fine to very coarse sands while coral rubble beaches range up to boulder-sized clasts. The local source material is a primary determinant of sediment composition. The local factors such as the underlying geology, source and availability of sediments are the primary determinants of beach form, composition and texture in the BVI. Oceanographic and climatic conditions such as the prevailing easterly trade winds and waves which seasonally range in direction from east-northeast to southeast as well as beach orientation to Atlantic- or Caribbean-facing waves also contribute to the variability, but in a secondary role. © 2019 John Wiley & Sons, Ltd.     

Marine dependent livelihoods and resilience to environmental change: A case study of Anguilla

There is increasing concern over the consequences of environmental change for people and communities that depend on already fragile marine resources, given the mounting evidence of sustained over-exploitation and climate change impacts on marine systems. In order to explore the potential social resilience of marine-dependent livelihoods to environmental change, interviews with fishers and marine-based tourism operators in the Caribbean island of Anguilla were undertaken, to identify the impacts of hurricane events on marine livelihoods, the perceptions of resource-users and their potential adaptability to future change. For both sectors of resource-users, there is evidence that they have diversified livelihoods to achieve financial security, which may provide resilience to future climate related impacts or resource variability. In addition, specific behavioural changes that have been developed following previous hurricane events, e.g. removal of fish pots during hurricane months, or bringing boats to shore, indicate fishers' flexibility to changing conditions. However, strong personal and cultural attachment to occupations, particularly among fishers, may hinder resilience. Additionally, the reliance of all of these marine resource-users on the climate-dependent tourism industry may undermine their capacity to cope with future environmental change. Many of these problems are common throughout the Caribbean, as thousands of marine-dependent livelihoods are vulnerable to marine degradation and climate change impacts. Urgent attention is therefore required to support the development of adaptive, sustainable management of marine resources that may enhance resilience to environmental change.     

Early Benthic Organism Colonization on a Caribbean Coral Reef (Barbados, West Indies): a Plate Experimental Approach

Abstract. Macrofaunal colonization was studied using coral plates fixed at 10 m depth on a fringing reef in Barbados, West Indies. Two sites were compared: Spring Garden, a site that is affected by eutrophication, and Six Men's Bay which is relatively free of this effect. Two sets of plates were immersed in winter and spring 1990 at each site and monitored for 28 and 19 weeks, respectively. Green and brown algae colonized first, followed 2 weeks later by ostracods, cumaceans, amphipods and polychaetes: terebellids, nereidids and syllids. Most colonizers either nestled or encrusted. A total of 11 017 invertebrates belonging to 145 species were collected. Polychaetes were the most abundant and diverse zoological group. Considering polychaetes, crustaceans and molluscs, the study sites shared around 75% of the species. Overall, densities were higher on lower (shaded) surfaces while diversities were higher on upper (illuminated) sides. Similarity coefficients and correspondence analysis showed different macrobenthic assemblages and colonization patterns in light and shaded and in polluted and unpolluted sites. Coral plates were associated according to their 'immersion time' and were closely linked to their stage of development. Spring Garden (polluted) presented a higher number of soft-bottom and deposit-feeder species ( e.g. , Capitella capitata ).     

Tectonic controls on carbonate sequence formation in an active strike–slip setting: Serranilla Basin, Northern Nicaragua Rise, Western Caribbean Sea

The Serranilla Basin is a flat-floored, semi-circular bathymetric depression (100×100 km; 1100–1200 m deep) at the western end of the northern Nicaragua Rise (NNR) in the Caribbean Sea. It is bound to the north by the Cayman Trough, an area of active sea floor spreading, and is part of the Northern Caribbean Plate Boundary Zone (NCPBZ). Single-channel, high-resolution seismic data were calibrated to rock dredges and ODP Site 1000 to define the geologic evolution and attempt to tie sequence formation within the basin to tectonic developments in this part of the Caribbean. Five seismic sequences were identified within the basin. The two lower sequences (A and B) are interpreted as neritic and shallow periplatform deposits which infill three distinct basins that make up the early to late Miocene Serranilla Basin. The three upper sequences (C through E) are interpreted as periplatform and pelagic deposits interspersed with turbidites, and in some areas, megabreccias. Faulting is prevalent in sequences A through C in the central basin, and becomes progressively younger toward the south, disrupting the seafloor in places and perhaps indicating renewed activity along the Pedro Fracture Zone. The timing of sequence boundary formation has been correlated to tectonic activity along the NCPBZ and closure of the Central American Seaway. Possible mechanisms of sequence boundary formation include tectonic tilting within the basin in conjunction with increased turbidite deposition, carbonate platform drowning and subsequent back-stepping associated with circulation changes resulting from tectonic ‘gateway' closure, and megabreccia deposition associated with bank demise. Although a direct genetic relationship is not proven, regional tectonic changes are considered more important than eustatic sea-level changes in controlling depositional sequence formation in the Serranilla Basin.     

The Boreholes of the Sea Urchin Genus Echinometra (Echinodermata: Echinoidea: Echinometridae) as a Microhabitat in Tropical South America*

Abstract. Members of the genus Echinometru (Echinoideu: Echinometridue) inhabit hard substrata in shallow waters where they live in self-excavated dwellings. Boring by Echinometru spp. causes a secondary structure of the surface, thus forming additional microhabitats. In this study the effects of boring activities of Echinometru lucunter (L.) along the Caribbean coast of Colombia and of Echinometra vunbrunri A. Agassu in the Colombian Pacific is examined. Several species inhabit the boreholes occupied by these urchins. The associates live underneath the echinoid on the bottom of the borehole, where they find shelter from exposure and predators. The co-inhabitants of E. lucunter include the porcellanid Clusroroechus vunderhorsri (Schmitt ), the recently described brit-tlestar Ophiorhrix synoecim (Schoppe ), and the clingfish Acyrrus rubiginosus (Poey ). The species co-occumng with E. vunbrunti include the porcellanid crab Clusroroechus gorgonensis Werding amp; Haig and the clingfish Arcos decoris Briggs . With the exception of A. decoris, all of these species are obligatorily associated with the Echinomerra host.     

Abyssal geography†

Today, we are held to live in the Anthropocene, bringing to an end modern binary imaginaries, such as the separation between Human and Nature, and with them Western assumptions of progress, linear causality and human exceptionalism. Much Western critical theory, from new or vital materialism to post- and more-than-human thinking, unsurprisingly reflects this internal crisis of faith in Eurocentric or Enlightenment reasoning. At the same time, a radically different critique of modernity has gained prominence in recent years, emerging from critical Black studies, which places the Caribbean at the centre of the development of a new and distinct mode of critical thought. In attempting to grasp the ways in which Caribbean thought and practice have been seen to enable a distinctive alternative non-Eurocentric imaginary, this paper heuristically sets out a paradigmatic framing of ‘abyssal geography’. We emphasize two key points. The first is that abyssal thought is not grounded in abstract and timeless philosophical assumptions but figuratively draws upon aspects of Caribbean practices of resistance and survival, for example, from the Middle Passage, Plantation, carnival, creolization, dance forms and speculative fiction. The second is that abyssal work engages the legacies of modernity and coloniality by explicitly seeking to question the lure of ontology: seeking to disrupt, suspend and to problematize the modern project of the human and the world.     

Ontogenetic patterns of concentration indicate lagoon nurseries are essential to common grunts stocks in a Puerto Rican bay

Estimates of abundance and size of three commercially exploited grunt species indicate ontogenetic changes in habitat utilization concentrate their juveniles within the lagoon of the Bay of La Parguera, Puerto Rico. Eleven biotopes, defined by four benthic structures (reef, mangrove, vegetation beds and unconsolidated sediments) and three geographic zones (inner lagoon, outer lagoon and bank shelf) were sampled randomly by visual surveys. French, bluestriped and white grunt (Haemulon flavolineatum, Haemulon sciurus and Haemulon plumeri) were common in the bay and appeared to exhibit similar life history patterns of cross-shelf migration and habitat selection. Recently settled grunts were dispersed over vegetated and unconsolidated soft-bottom sediments of the bay. The juvenile stage occurred in highest densities in shallow lagoon biotopes among the submerged prop-roots of mangrove stands and on inshore reefs. Length data indicates that grunts migrate offshore to adult habitat via increasingly deep reefs. Indices of biotope nursery function based on standing stock estimates of juveniles identified three biotopes, all within the inner lagoon as essential habitat for juveniles of 5–10 cm length interval. This concentration of juveniles within biotopes of the lagoon could represent a bottleneck to recruitment for grunt stocks. Evidence that quantity and quality of lagoon nurseries may limit recruitment indicates that these areas represent a key component of a marine protected area designed to restore fisheries within the bay.     

Long‐term trends in the recreational lobster fishery of Florida,United States: Landings,effort, and implications for management

In Florida, United States, the Caribbean spiny lobster, Panulirus argus, supports an important commercial fishery and also perhaps the most intensive recreational fishery of any lobster species, with sales of recreational lobster fishing permits exceeding 100 000 annually. For the past decade, we have used mail surveys of recreational lobster license holders to estimate spatially explicit landings and fishing effort when recreational fishers are most active—during the state's “Special Two‐Day Sport Season”, which takes place just before the opening of the commercial season, and during the first month of the regular recreational season, which coincides with the commercial season. From 1993 through 2002, fishing effort during the Special Two‐Day Sport Season has ranged from 60 000 to 112 000 person‐days, and landings have ranged from c. 112 to 255t. Both fishing effort and landings have varied without trend. Fishing effort during the regular season over the same period has ranged from 261 000 to 514 000 person‐days, and landings have ranged from 434 to 825 t. Fishing effort has shown a marginally statistically significant decreasing trend, the result of a progressive decrease in effort since 1999. The largest proportion of both fishing effort and landings was concentrated along the south‐east coast. Despite the recent decrease in landings, the proportion of total landings made by the recreational fishery has increased. From 1993 through 1998, the fishery was responsible for c. 30% of commercial landings; by 2001, that percentage increased to nearly 40%. Such a shift in landings away from the commercial trap fishery toward the recreational fishery was recognised as a potential but unintended effect of the ongoing management plan of restricting effort in the commercial trap fishery. Our 2001 surveys revealed that recreational lobster fishers spent more on a person‐day basis than the general visitor to the Florida Keys did, but less than those visitors using the region's coral reefs. Consequently, managers must establish management strategies that allow the coexistence of this resource's user groups and also incorporate the social and environmental concerns of nonuser groups.