37 research outputs found
Pathologies Affecting Reef Corals at the Flower Garden Banks, Northwestern Gulf of Mexico
The Flower Garden Banks are high-latitude reefs consisting of coral caps on the top of salt domes in the northwestern Gulf of Mexico. Limited studies to date report low incidence of coral disease on these reefs. Surveys were conducted to document the extent of coral diseases throughout the Flower Garden Banks, including types of disease present, species affected, percentage of recent colony mortality, cases of false disease, and descriptions of new pathologies. Very few of the known (or reported) Western Atlantic diseases were found, and they occurred at extremely low frequencies. Tissue-skeletal anomalies were common. Several conditions resembled known diseases, although their appearance was not wholly consistent with described pathologies and they may represent different conditions. Both ridge-mortality disease and rapid wasting disease were confirmed to be the result of fish biting activities. Several novel pathologic conditions that do not fit the description or known etiology of any currently described coral disease were discovered at relatively high prevalence rates. Because of an absence of standardized coral disease nomenclature and the unknown etiology of these novel syndromes, they are tentatively named pale ring, pale patch, and mottling syndromes on the basis of field characteristics
How U.S. Ocean Policy and Market Power Can Reform the Coral Reef Wildlife Trade
As the world’s largest importer of marine ornamental species for the aquaria, curio, home décor, and jewelry industries, the United States has an opportunity to leverage its considerable market power to promote more sustainable trade and reduce the effects of ornamental trade stress on coral reefs worldwide. Evidence indicates that collection of some coral reef animals for these trades has caused virtual elimination of local populations, major changes in age structure, and promotion of collection practices that destroy reef habitats. Management and enforcement of collection activities in major source countries such as Indonesia and the Philippines remain weak. Strengthening US trade laws and enforcement capabilities combined with increasing consumer and industry demand for responsible conservation can create strong incentives for improving management in source countries. This is particularly important in light of the March 2010 failure of the parties to the Convention on International Trade in Endangered Species (CITES) to take action on key groups of corals
Engineered nonlinear materials using gold nanoantenna array
Gold dipole nanoantennas embedded in an organic molecular film provide strong local electromagnetic fields to enhance both the nonlinear refractive index (n(2)) and two-photon absorption (2PA) of the molecules. An enhancement of 53x for 2PA and 140x for nonlinear refraction is observed for BDPAS (4,4'-bis(diphenylamino) stilbene) at 600 nm with only 3.7% of gold volume fraction. The complex value of the third-order susceptibility enhancement results in a sign change of n(2) for the effective composite material relative to the pure BDPAS film. This complex nature of the enhancement and the tunability of the nanoantenna resonance allow for engineering the effective nonlinear response of the composite film8119Agências de fomento estrangeiras apoiaram essa pesquisa, mais informações acesse artig
Preserving and Using Germplasm and Dissociated Embryonic Cells for Conserving Caribbean and Pacific Coral
Coral reefs are experiencing unprecedented degradation due to human activities, and protecting specific reef habitats may not stop this decline, because the most serious threats are global (i.e., climate change), not local. However, ex situ preservation practices can provide safeguards for coral reef conservation. Specifically, modern advances in cryobiology and genome banking could secure existing species and genetic diversity until genotypes can be introduced into rehabilitated habitats. We assessed the feasibility of recovering viable sperm and embryonic cells post-thaw from two coral species, Acropora palmata and Fungia scutaria that have diffferent evolutionary histories, ecological niches and reproductive strategies. In vitro fertilization (IVF) of conspecific eggs using fresh (control) spermatozoa revealed high levels of fertilization (>90% in A. palmata; >84% in F. scutaria; P>0.05) that were unaffected by tested sperm concentrations. A solution of 10% dimethyl sulfoxide (DMSO) at cooling rates of 20 to 30°C/min most successfully cryopreserved both A. palmata and F. scutaria spermatozoa and allowed producing developing larvae in vitro. IVF success under these conditions was 65% in A. palmata and 53% in F. scutaria on particular nights; however, on subsequent nights, the same process resulted in little or no IVF success. Thus, the window for optimal freezing of high quality spermatozoa was short (∼5 h for one night each spawning cycle). Additionally, cryopreserved F. scutaria embryonic cells had∼50% post-thaw viability as measured by intact membranes. Thus, despite some differences between species, coral spermatozoa and embryonic cells are viable after low temperature (−196°C) storage, preservation and thawing. Based on these results, we have begun systematically banking coral spermatozoa and embryonic cells on a large-scale as a support approach for preserving existing bio- and genetic diversity found in reef systems
Implications of coral harvest and transplantation on reefs in northwestern Dominica
In June, 2002, the government of Dominica requested assistance in evaluating the coral culture and transplantation activities being undertaken by Oceanographic Institute of Dominica (OID), a coral farm culturing both western Atlantic and Indo-Pacific corals for restoration and commercial sales. We assessed the culture facilities of OID, the condition of reefs, potential impacts of coral collection and benefits of coral transplantation. Coral reefs (9 reefs, 3-20m depth) were characterized by 35 species of scleractinian corals and a live coral cover of 8-35%. Early colonizing, brooders such as Porites astreoides (14.8% of all corals), P. porites (14.8%), Meandrina meandrites (14.7%) and Agaricia agaricites (9.1%) were the most abundant corals, but colonies were mostly small (mean=25cm diameter). Montastraea annularis (complex) was the other dominant taxa (20.8% of all corals) and colonies were larger (mean=70cm). Corals (pooled species) were missing an average of 20% of their tissue, with a mean of 1.4% recent mortality. Coral diseases affected 6.4% of all colonies, with the highest prevalence at Cabrits West (11.0%), Douglas Bay (12.2%) and Coconut Outer reef (20.7%). White plague and yellow band disease were causing the greatest loss of tissue, especially among M. annularis (complex), with localized impacts from corallivores, overgrowth by macroalgae, storm damage and sedimentation. While the reefs appeared to be undergoing substantial decline, restoration efforts by OID were unlikely to promote recovery. No Pacific species were identified at OID restoration sites, yet species chosen for transplantation with highest survival included short-lived brooders (Agaricia and Porites) that were abundant in restoration sites, as well as non-reef builders (Palythoa and Erythropodium) that monopolize substrates and overgrow corals. The species of highest value for restoration (massive broadcast spawners) showed low survivorship and unrestored populations of these species were most affected by biotic stressors and human impacts, all of which need to be addressed to enhance survival of outplants. Problems with culture practices at OID, such as high water temperature, adequate light levels and persistent overgrowth by macroalgae could be addressed through simple modifications. Nevertheless, coral disease and other stressors are of major concern to the most important reef builders, as these species are less amenable to restoration, collection could threaten their survival and losses require decades to centuries to replace. Rev. Biol. Trop. 58 (Suppl. 3): 111-127. Epub 2010 October 01.<br>En junio del año 2002 el gobierno de Dominica solicitó asistencia para evaluar el Instituto Oceanográfico de Dominica (OID), una operación de cultivo de corales del océano Atlántico y del Indo Pacifico para propósitos de restauración y comercio. Evaluamos las facilidades de cultivo del OID, la condición de los arrecifes y el impacto potencial de la recolección de corales y los posibles beneficios del transplante de colonias. Los arrecifes de coral (9 arrecifes de profundidades entre 3 y 20m se caracterizaban por 35 especies escleractíneos y una cobertura viva de coral entre 8 y 35%. Las especies que liberan larvas tales como Porites astreoides (14.8 % de todos los corales), P. porites (14.8%), Meandrina meandrites (14.7%) y Agaricia agaricites (9.1%) fueron los más abundantes, pero sus colonias eran pequeñas (promedio de 25cm de diámetro). El complejo de Montastraea annularis fue otro grupo dominante (20.8% de todos los corales) y sus colonias eran mayores (promedio de 70cm de diámetro). Entre todas las especies los corales habían perdido el 20% de sus tejidos, con un promedio de 1.4% por mortandad reciente. Las enfermedades de coral afectaron 6.4% de todas las colonias, con la incidencia mayor en Cabrits Oeste (11%), Bahía Douglas (12.2%) y el arrecife de Coconut Afuera (20.7%). Plaga blanca y la enfermedad de la banda amarilla causaron la mayoría de la pérdida de tejido vivo, especialmente en el complejo de M. annularis, con impactos localizados por caracoles coralívoros, sobre crecimiento por macroalgas, impactos de tormentas y sedimentación. Mientras los arrecifes parecen estar declinando substancialmente, los esfuerzos de restauración de OID no parecen entablar su recuperación debido a que las especies escogidas para transplantar con las mayores tasas de sobrevivencia incluyen especies que liberan larvas (Agaricia y Porites) que fueron abundantes en las restauraciones, al igual que los organismos potencialmente parasíticos (Palythoa y Erythropodium) que pueden monopolizar el sustrato y sobre crecer a los corales. Las especies de mayor valor para la restauración (corales masivos de liberación de gametos) tuvieron baja sobrevivencia, sufrieron mas de las enfermedades u otros impactos biológicos e impactos antropogénicos los cuales deben ser atendidos para garantizar la sobrevivencia de los corales transplantados. Algunos problemas con la operación de cultivo de OID tales como temperaturas e irradiación altas al igual que sobre crecimiento de algas podrían ser controladas con algunos cambios en los sistemas de irrigación, iluminación y mantenimiento. Sin embargo los altos niveles de enfermedades y otros impactos (macroalgas, ausencia de herbívoros, evidencia de sobre pesca, sedimentación y eutrofización) son de mayor preocupación por sus impactos sobre los corales que proveen el armazón del arrecife ya que estas especies reciben menos beneficio de la restauración, su colección puede amenazar la sobrevivencia de sus poblaciones la recuperación de estos corales podría tomar siglo
Effects of bacterial antibiotic production on rhizosphere microbial communities from a culture-independent perspective
Diversity and Biogeography of the Scleractinian Coral Fauna of Easter Island (Rapa Nui).
v. ill. 23 cm.QuarterlyThree surveys at Easter Island (Rapa Nui) spanning the period 1999– 2005, and examination of private and museum collections, have revealed a depauperate zooxanthellate scleractinian fauna. Collections were all made off island shelf exposures, from tide pools to 70 m with scuba, and by dredging to 100 m. With synonymies, reassignments, and two new records in the families Pocilloporidae and Faviidae, the Easter Island coral fauna now comprises 13 species. Pocilloporid and poritid coral abundances were generally high on all island shelves protected from southern swells. A cluster analysis of the coral fauna relationships of 19 south, central, and far-eastern Pacific sites indicates a strong affinity between those of Easter Island and the far-eastern Pacific equatorial region (e.g., Colombia, Ecuador, Panama´, and the Gala´pagos Islands). The precipitous drop in coral species richness from the Pitcairn Island group (61 species) to Easter Island suggests the presence of a dispersal barrier between these two remote southeastern Pacific areas, separated by @1,800 km of deep ocean waters. Consideration of the surface circulation based on satellite-tracked surface drifters confirms this conclusion. Surface currents are from east to west along the topography on which Easter and Sala-y-Go´mez Islands sit, suggesting a substantial barrier to recruitment from the west
Engineered nonlinear materials using gold nanoantenna array
This article describes the use of a gold nanoantenna array to enhance both the nonlinear refractive index and two-photon absorption (2PA) of the organic dye 4,4'-bis(diphenylamino)stilbene (BDPAS), which is known as a dye with relatively large 2PA