Organochlorine contamination (PCBs, DDTs, HCB, HCHs) in sediments from Cienfuegos bay, Cuba   总被引：1，自引：0，他引：1  

I. Tolosa  M. Mesa-Albernas 《Marine pollution bulletin》2010,60(9):1619-1624

The spatial distribution of various organochlorinated compounds, e.g. PCBs, DDTs, HCB and HCHs, were investigated in sediments from Cienfuegos bay, Cuba. Their concentrations appeared to be relatively low by global standards and only sediments receiving the impact from the residual waters of the city and thermoelectrical power approached the sediment quality guidelines for PCBs and DDTs. Relatively higher ΣDDT concentrations and high DDT/DDE + DDD ratios in two sites near the outfalls of the city indicated a current DDT usage, probably linked to public health emergencies. These results contribute to the sparse regional database for organochlorinated compounds in the Caribbean marine environment.  相似文献   

Historical analysis (2000-2005) of the coastal water quality in San Andrés Island, SeaFlower Biosphere Reserve, Caribbean Colombia     

Brigitte Gavio  Shelly Palmer-Cantillo  J. Ernesto Mancera 《Marine pollution bulletin》2010,60(7):1018-1030

To understand the coastal water quality of San Andrès Island, and provide tools for the management of its marine resources, we present the historical analysis of the island monitoring, which includes ammonia, nitrites, nitrate, phosphates, fecal and total coliforms. The anthropogenic pressure on the coastal system is heavy, with water nutrification, posing at risk seagrass and coral ecosystems. During dry season, biologically available nitrogen is 3-9 times higher than the maximum recommended for coral reefs, while during wet season values are 2-6.4 times the maximum. Biologically available phosphorous is also high, 1-8 times the maximum during dry season, 2-13 times during wet season. In some sites the concentration of pathogenic bacteria is above the limits set by law for primary and secondary contact. It is urgent to improve the management of sewage discharge, the main polluting source of San Andres coastal waters.  相似文献   

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

David S. Duncan  Albert C. Hine  Andre W. Droxler 《Marine Geology》1999,160(3-4):355-382

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.  相似文献   

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

Victoria Díaz-Castañeda  & Cesar Almeda-Jauregui 《Marine Ecology》1999,20(3-4):197-220

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 ).  相似文献   

From incipient island arc to doubly‐vergent orogen: A review of geodynamic models and sedimentary basin‐fills of southern Central America          下载免费PDF全文

Christian Brandes  Jutta Winsemann 《Island Arc》2018,27(5)

Southern Central America is a Late Mesozoic/Cenozoic island arc that evolved in response to the subduction of the Farallón Plate beneath the Caribbean Plate in the Late Cretaceous and, from the Oligocene, the Cocos and Nazca Plates. Southern Central America is one of the best studied convergent margins in the world. The aim of this paper is to review the sedimentary and structural evolution of arc‐related sedimentary basins in southern Central America, and to show how the arc developed from a pre‐extensional intra‐oceanic island arc into a doubly‐vergent, subduction orogen. The Cenozoic sedimentary history of southern Central America is placed into the plate tectonic context of existing Caribbean Plate models. From regional basin analysis, the evolution of the southern Central American island arc is subdivided into three phases: (i) non‐extensional stage during the Campanian; (ii) extensional phase during the Maastrichtian‐Oligocene with rapid basin subsidence and deposition of arc‐related, clastic sediments; and (iii) doubly‐vergent, compressional arc phase along the 280 km long southern Costa Rican arc segment related to either oblique subduction of the Nazca plate, west‐to‐east passage of the Nazca–Cocos–Caribbean triple junction, or the subduction of rough oceanic crust of the Cocos Plate. The Pleistocene subduction of the Cocos Ridge contributed to the contraction but was not the primary driver. The architecture of the arc‐related sedimentary basin‐fills has been controlled by four factors: (i) subsidence caused by tectonic mechanisms, linked to the angle and morphology of the incoming plate, as shown by the fact that subduction of aseismic ridges and slab segments with rough crust were important drivers for subduction erosion, controlling the shape of forearc and trench‐slope basins, the lifespan of sedimentary basins, and the subsidence and uplift patterns; (ii) subsidence caused by slab rollback and resulting trench retreat; (iii) eustatic sea‐level changes; and (iv) sediment dispersal systems.  相似文献   

Spatial variability in beach biogeomorphology in a tropical archipelago     

Shannon Gore  J. Andrew G. Cooper  Derek W.T. Jackson  Lianna Jarecki 《地球表面变化过程与地形》2019,44(9):1860-1875

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.  相似文献   

Source processes of large (M≥6.5) earthquakes of the Southeastern Caribbean (1926–1960)     

Diane I. Doser  Shelley R. Vandusen 《Pure and Applied Geophysics》1996,146(1):43-66

We have conducted body waveform modeling studies of 13 historic earthquakes to provide a better understanding of the long-term spatial and temporal pattern of seismicity and deformation within a region extending from Barbuda, Lesser Antilles, to Cumana, Venezuela. Our results suggest that shallow earthquakes (<50 km deep) along the South American-Caribbean plate margin reflect right-lateral and extensional deformation. Intermediate depth events (100 km) show left-lateral strike-slip motion beneath the Paria peninsula of Venezuela. In the Lesser Antilles the 1960 Barbuda and 1946 Martinique earthquakes appear to be interplate thrust events, however the greatest moment release in the region has occurred at intermediate depths as a mixture of normal and strike-slip faulting, generally along trends oblique to the arc. The deformation rate estimated from the seismic moment release between 1926 and 1960 is only 1 to 10% of the estimated plate convergence rate for the region.  相似文献   

Distribution of the genus Hypoplectrus (Teleostei: Serranidae) in the Greater Caribbean Region: support for a color‐based speciation     

Alfonso Aguilar‐Perera  Carlos González‐Salas 《Marine Ecology》2010,31(2):375-387

The reef‐associated fish genus Hypoplectrus (Serranidae), endemic to the western Atlantic Ocean, represents an ideal model to study speciation within a potentially highly dispersive (marine) ecosystem, because it consists of a complex of at least 10 morphs differentiated primarily by coloration. Although several recent studies on genetics, diet, and fertilization reveal little to no difference between the Hypoplectrus color morphs, there is still not a full understanding of what keeps these morphs distinct or drives their variation. Ecological information is needed alongside the genetic information to better understand this variation. Based on presence/absence records from scientific literature and direct observations in coral reefs, this work examined the distribution of the genus Hypoplectrus in the Greater Caribbean region. Some color morphs occurred simultaneously at given locations, but others showed geographic restrictions. Using cluster and nMDS analyses, we found three major groupings according to distribution: (i) widespread (Hypoplectrus puella, Hypoplectrus unicolor, and Hypoplectrus nigricans), (ii) less widespread (Hypoplectrus indigo, Hypoplectrus gummigutta, Hypoplectrus chlorurus, Hypoplectrus aberrans, and Hypoplectrus guttavarius), and (iii) geographically confined or segregated (Hypoplectrus gemma, Hypoplectrus providencianus). Geographic sections selected for the Greater Caribbean (eastern, western and northern) were dominated by at least three widely distributed Hypoplectrus morphs. New geographic records of some color morphs were documented and compared to previous established distribution ranges in the Greater Caribbean.  相似文献   

A literature review on trace metals and organic compounds of anthropogenic origin in the Wider Caribbean Region   总被引：2，自引：2，他引：0  

Fernandez A  Singh A  Jaffé R 《Marine pollution bulletin》2007,54(11):1681-1691

About 30 studies from the published literature were reviewed to determine the pollution status regarding heavy metals and organic compounds of the Wider Caribbean Region (WCR). The literature revealed that most studies were performed in the South and Central American Caribbean Region with sparse reports on the small island states. Collectively, the most frequently analyzed heavy metals were Pb, Cu, Zn, Fe, Cd, Ni, Mn and Cr while DDT and its metabolites were the most frequently reported organic pollutants. The samples which were analyzed vary in terms of sampling schemes, parameters and analytical techniques, as well as differences in data reporting presentation (i.e. dry weight versus wet weight, sediment fraction analyzed, or % lipids). These differences make meaningful comparisons of the available data very difficult. Furthermore, there is limited data available for most of these contaminants from the majority of nations in the WCR. Therefore, any attempt to create a regional scale assessment from contaminants data available in the open literature is limited by the scarcity of available information.  相似文献   

What makes mangroves attractive to fish? Use of artificial units to test the influence of water depth,cross-shelf location,and presence of root structure     

I. Nagelkerken  C.H. Faunce   《Estuarine, Coastal and Shelf Science》2008,79(3):559-565

Mangroves are an attractive fish habitat because they provide shelter and food for juvenile fishes. However, because mangroves are almost always located in shallow water and in sheltered (i.e., lagoonal, estuarine or bay) environments, the degree to which the latter two factors contribute to the attractiveness of mangrove prop-roots as a fish habitat is unknown. Artificial Mangrove Units (AMUs) were placed at multiple depths and along a gradient from an embayment to, and including, the coral reef. Total fish density and species richness in AMUs placed in the embayment was lower at 1 m depth than at 2 and 3 m depth, suggesting that shallow water is not a prerequisite for the attractiveness of mangrove prop-roots as a fish habitat. Total fish density and species richness were equal or greater in AMUs on the coral reef than in the embayment, suggesting that placement of mangroves in a sheltered lagoonal environment is not solely responsible for the attractiveness of mangrove prop-roots either. After 3 weeks, removal of AMUs did not have a negative effect on total fish density or species richness. However, within the embayment AMU removal resulted in the complete collapse of the assemblage component comprised of species that use mangroves as juvenile habitats, highlighting the need for a species-based approach towards assessing the benefits provided by the presence of mangrove root structure for fishes.  相似文献