123 research outputs found

    Effects of natural gas pipeline condensate and crude oil spills, and comments on remediation, with emphasis on south Louisiana salt marshes: a review

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    This report reviews some of the natural ecological processes at work within a salt marsh as they relate to a spill of natural gas condensate - a mixture of aliphatic hydrocarbons, n-hexane, benzene, toluene, and xylene. It also reviews the environmental impacts of some of the components of natural gas condensate as well as related compounds (crude oil, higher molecular weight hydrocarbons, polycyclic aromatic hydrocarons - PAHs, linear alkyl-benzenes - LABs, etc.) on salt marsh ecosystems in southern Louisiana and elsewhere in the world. The behavior and persistence of these compounds once they have entered the environment is also considered

    Variation in Morphology vs Conservation of a Mitochondrial Gene in Montastraea cavernosa (Cnidaria, Scleractinia)

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    Skeletal morphology of many scleractinian corals may be influenced by environmental factors and may thus result in substantial intraspecific phenotypic plasticity and, possibly, in overlapping morphologies between species. Environmentally induced variation can also mask phenotypic variation that is genetically based. Morphological analyses and DNA sequence analyses were performed on Montastraea cavernosa from the Flower Garden Banks, Texas, and from the Florida Keys in order to assess variation within and between geographic regions. Skeletal characters, including corallite diameter, columella width, theca thickness, nearest-neighbor distance, length of first septa cycle, and width of first septa cycle, varied within colonies, among colonies, and between the Flower Garden Banks and the Florida Keys. Morphological variation may be controlled by environmental and genetic influences at different levels. If phenotype is under genetic control, it is not influenced by the mitochondrial cytochrome oxidase subunit I gene, because analysis of a 708 base pair fragment revealed identical sequences of M. cavernosa from these geographic regions. This high level of nucleotide sequence similarity may result from functional constraints, efficient DNA repair mechanisms, or other processes. This gene was not found to exhibit any variation in association with that observed in the morphology, and we suggest that it is an inappropriate genetic marker to use to assess intraspecific variation within this species and possibly other scleractinian species as well. Analysis via other molecular techniques will be necessary in order to assess the factors that influence morphological variation and that distinguish populations within this species

    Genetic Connectivity in Scleractinian Corals across the Northern Gulf of Mexico: Oil/Gas Platforms, and Relationship to the Flower Garden Banks

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    The 3,000 oil/gas structures currently deployed in the northern Gulf of Mexico (GOM) provide hard substratum for marine organisms in a region where such has been rare since the Holocene. The major exception to this are the Flower Garden Banks (FGB). Corals are known to have colonized oil/gas platforms around the FGB, facilitating biogeographic expansion. We ask the question, what are the patterns of genetic affinity in these coral populations. We sampled coral tissue from populations of two species occurring on oil and gas platforms: Madracis decactis (hermatype) and Tubastraea coccinea (invasive ahermatype). We sampled 28 platforms along four transects from 20 km offshore to the continental shelf edge off 1) Matagorda Island, TX; 2) Lake Sabine, TX; 3) Terrebonne Bay, LA; and 4) Mobile, AL. The entire population of M. decactis was sampled between depths of 5 m and 37 m. T. coccinea populations were sub-sampled. Genetic variation was assessed using the PCR-based Amplified Fragment Length Polymorphisms (AFLPs). Data were analyzed via AFLPOP and STRUCTURE. Genetic connectivity among M. decactis platform populations was highest near the FGB and decreased to the east. Connectivity increased again in the eastern sector, indicating isolation between the populations from different sides of the Mississippi River (Transects 3 and 4). A point-drop in genetic affinity (relatedness) at the shelf edge south of Terrebonne Bay, LA indicated a population differing from all others in the northern GOM. Genetic affinities among T. coccinea were highest in the west and decreased to the east. Very low genetic affinities off Mobile, AL indicated a dramatic difference between those populations and those west of the Mississippi River, apparently a formidable barrier to larval dispersal

    Grazing and control of coral reef community structure by Diadema antillarum Philippi (Echinodermata: Echinoidea): A preliminary study

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    The grazing activities of the tropical echinoid Diadema antillarum Philippi can markedly influence the structure of the shallow-water epibenthic coral reef community. The elimination of an entire Diadema population from a patch reef in St. Croix, U.S. Virgin Islands resulted in a great increase in macro-algal biomass, alterations in species composition, shifts in dominance, an increase in species numbers, and a decrease in equitability...

    Depuration of Macondo (MC-252) Oil Found in Heterotrophic Scleractinian Corals (Tubastrea coccinea and Tubastrea micranthus) on Offshore Oil/Gas Platforms in the Gulf

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    The impetus for this study began on 8 May 2011, when we noted sporadic mortality of colonies of orange—cup corals, Tubastrea coccinea (Lesson, 1829), and green sun corals, Tubastrea micranthus (Ehrenberg, 1834; Cnidaria, Anthozoa, Scleractinia) among colonies of coral that appeared to be in good health at the GI 90 block platforms. Colonies of T. coccinea which appeared to be healthy displayed markedly less tissue regression and were bright orange in color. The morbid polyps were dark brown or black. The corals were collected, transported to the laboratory, and segregated; healthy—appearing corals were placed in quarantine tanks. After 12 h in quarantine tanks, the coral exudate turned the tank water black and the colonies died within 48 h. After observing this unusual behavior, we decided to document subsequent collection events and analyze the discharged oil to determine its source

    Patterns of Mesophotic Benthic Community Structure on Banks Off vs Inside the Continental Shelf Edge, Gulf of Mexico

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    Information on the biodiversity and geographic patterns of mesophotic, sessile, epibenthic communities on banks around and at the edge of the continental shelf, northern Gulf of Mexico, has been limited. These communities vary in their environments and are prone to disturbance from Outer Continental Shelf oil- and gas-related activities and fishing (trawling and long-lining). We surveyed these communities on the flanks of 13 banks to determine species richness, species composition, similarities between benthic communities, and geographic patterns in community structure. We sampled to ≤ 181 m in depth via a remotely operated vehicle using a vertically mounted digital camera bearing two lasers for scale and a flash (generally 10 drop-sites/bank, 5 transects/drop-site, and ≤11 photos/transect). Data analysis via PATN revealed three main Bank Groups: the on-shelf group containing 29 Fathom and Sonnier Banks; an anomalous bank—Geyer Bank; and the shelf edge group—Horseshoe, 28 Fathom, Bright, Alderdice, Bouma, Rankin, Rezak, Elvers, McGrail, and Sidner Banks. Most species-rich banks (Bank Group 3) occurred at the shelf edge. Two of the species-poor banks (Bank Group 1) occurred further north, inside the shelf. Geyer Bank (Bank Group 2) occurred at the shelf edge but was anomalously species-poor. Box-and-whisker analyses identified four Species Groups driving the Bank Groupings. Species Group 4 (the Elatopathes abientina/Nicella sp. group) was the largest (also containing Peysonellia sp.), primarily defining Bank Group 3. Species Groups 2 (the Antipathes sp./Gorgonian G04 group) and 3 (low species abundances) were also associated with Bank Group 3. Species Group 4 (the Elatopathes abientina/Nicella sp. group) was a major contributor to Bank Group 2 (Geyer Bank). Species Group 2 (the Antipathes sp./Gorgonian G04 group) was the primary constituent of the on-shelf Bank Group 1, also characterized by low species richness. Most species had a comparative abundance of ≤20%. The high species richness and affinities exhibited by Bank Group 3 are likely due to continual exposure to warm, low-turbidity Caribbean water at the shelf edge. Banks inside the shelf likely vary from the others as a result of exposure to cooler winter temperatures and higher turbidity due to wind-forced inshore currents. The reasons for the unique community structure on Geyer Bank are as yet unknown. Shelf-edge banks tend to be more species rich than on-shelf banks

    Corals and Their Potential Applications to Integrative Medicine

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    Over the last few years, we have pursued the use and exploitation of invertebrate immune systems, most notably their humoral products, to determine what effects their complex molecules might exert on humans, specifically their potential for therapeutic applications. This endeavor, called “bioprospecting,” is an emerging necessity for biomedical research. In order to treat the currently “untreatable,” or to discover more efficient treatment modalities, all options and potential sources must be exhausted so that we can provide the best care to patients, that is, proceed from forest and ocean ecosystems through the laboratory to the bedside. Here, we review current research findings that have yielded therapeutic benefits, particularly as derived from soft and hard corals. Several applications have already been demonstrated, including anti-inflammatory properties, anticancer properties, bone repair, and neurological benefits

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    Muscle moment arm analyses applied to vertebrate paleontology: a case study using Stegosaurus stenops Marsh, 1887

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    The moment arm of a muscle defines its leverage around a given joint. In a clinical setting, the quantification of muscle moment arms is an important means of establishing the ‘healthy’ functioning of a muscle and in identifying and treating musculoskeletal abnormalities. Elsewhere in modern animal taxa, moment arm studies aim to illuminate adaptions of the musculoskeletal system towards particular locomotor or feeding behaviors. In the absence of kinematic data, paleontologists have likewise relied upon estimated muscle moment arms as a means of reconstructing musculoskeletal function and biomechanical performance in fossil species. With the application of ‘virtual paleontological’ techniques, it is possible to generate increasingly detailed musculoskeletal models of extinct taxa. However, the steps taken to derive such models of complex systems are seldom reported in detail. Here we present a case study for calculating three-dimensional muscle moment arms using Stegosaurus stenops Marsh, 1887 to highlight both the potential and the limitations of this approach in vertebrate paleontology. We find the technique to be mostly insensitive to choices in muscle modeling parameters (particularly relative to other sources of uncertainty in paleontological studies), although exceptions do exist. Of more concern is the current lack of consensus on what functional signals, if any, are contained within moment arm data derived from extant species. Until a correlation between muscle moment arm and function can be broadly identified across a range of modern taxa, the interpretation of moment arms calculated for extinct taxa should be approached with caution
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