158 research outputs found

    Record of Little Ice Age sea surface temperatures at Bermuda using a growth-dependent calibration of coral Sr/Ca

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    Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 20 (2005): PA4016, doi:10.1029/2005PA001140.Strontium to calcium ratios (Sr/Ca) are reported for a massive brain coral Diploria labyrinthiformis collected from the south shore of Bermuda and are strongly correlated with both sea surface temperature (SST) and mean annual skeletal growth rate. High Sr/Ca ratios correspond with cold SSTs and slow skeletal growth rate and vice versa. We provide a quantitative calibration of Sr/Ca to extension rate and SST along the axis of maximum growth and derive a growth-dependent Sr/Ca–SST calibration equation to reconstruct western subtropical North Atlantic SSTs for the past 223 years. When the influence of growth rate is excluded from the calibration, Sr/Ca ratios yield SSTs that are too cold during cool anomalies and too warm during warm anomalies. Toward the end of the Little Ice Age (∼1850), SST changes derived using a calibration that is not growth-dependent are exaggerated by a factor of 2 relative to those from the growth-corrected model that yields SSTs ∼1.5°C cooler than today. Our results indicate that incorporation of growth rate effects into coral Sr/Ca calibrations may improve the accuracy of SSTs derived from living and fossil corals.A Stanley Watson Foundation Fellowship (N.F.G.), and grants from NSF (OCE-0402728) and WHOI (K.A.H., A.L.C., and M.S.M.) supported this work

    Deep Reef Benthos of Bermuda: Field Identification Guide

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    Deep Reef Benthos of Bermuda builds on the video and imagery data collected during Nekton’s Mission – the XL Catlin Deep Ocean Survey - and provides a photographic guide for the visual identification of many of the corals, marine plants and other common invertebrates that inhabit Bermuda’s outer deep reefs.This guide is designed to aid marine biologists, divers and naturalists with the identification of organisms as seen in underwater footage or live in the field.</div

    Low connectivity between shallow, mesophotic and rariphotic zone benthos

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    © 2019 Massachussetts Medical Society. All rights reserved. Worldwide coral reefs face catastrophic damage due to a series of anthropogenic stressors. Investigating how coral reefs ecosystems are connected, in particular across depth, will help us understand if deeper reefs harbour distinct communities. Here, we explore changes in benthic community structure across 15-300 m depths using technical divers and submersibles around Bermuda. We report high levels of floral and faunal differentiation across depth, with distinct assemblages occupying each depth surveyed, except 200-300 m, corresponding to the lower rariphotic zone. Community turnover was highest at the boundary depths of mesophotic coral ecosystems (30-150 m) driven largely by taxonomic turnover and to a lesser degree by ordered species loss (nestedness). Our work highlights the biologically unique nature of benthic communities in the mesophotic and rariphotic zones, and their limited connectivity to shallow reefs, thus emphasizing the need to manage and protect deeper reefs as distinct entities

    Testing the Utility of Geochemical Proxies to Reconstruct Holocene Coastal Environments and Relative Sea Level: A Case Study from Hungry Bay, Bermuda

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    On low-lying, tropical and sub-tropical coastlines freshwater marshes may be replaced by salt-tolerant mangroves in response to relative sea-level rise. Pollen analysis of radiocarbon-dated sediment cores showed that such a change occurred in Hungry Bay, Bermuda during the late Holocene. This well-established paleoenvironmental trajectory provides an opportunity to explore if geochemical proxies (bulk-sediment δ13C and Rock-Eval pyrolysis) can reconstruct known environmental changes and relative sea level. We characterized surface sediment from depositional environments in Bermuda (freshwater wetlands, saline mangroves, and wrack composed of Sargassum natans macroalgae) using geochemical measurements and demonstrate that a multi-proxy approach can objectively distinguish among these environments. However, application of these techniques to the transgressive sediment succession beneath Hungry Bay suggests that freshwater peat and mangrove peat cannot be reliably distinguished in the sedimentary record, possibly because of post-depositional convergence of geochemical characteristics on decadal to multi-century timescales and/or the relatively small number of modern samples analyzed. Sediment that includes substantial contributions from Sargassum is readily identified by geochemistry, but has a limited spatial extent. Radiocarbon dating indicates that beginning at –700 CE, episodic marine incursions into Hungry Bay (e.g., during storms) carried Sargassum that accumulated as wrack and thickened through repeated depositional events until ~300 CE. It took a further ~550 years for a peat-forming mangrove community to colonize Hungry Bay, which then accumulated sediment rapidly, but likely out of equilibrium with regional relative sea-level rise

    The caribbean coastal marine productivity program (CARICOMP)

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    CARICOMP is a regional scientific program to study land-sea interaction processes in the Caribbean coastal zone. It has been collecting data since 1992, when a Data Management Centre was established at the University of the West Indies in Jamaica. Initially it focuses on documenting the structure and productivity of major coastal communities (mangrove forests, seagrass meadows and coral reefs) at relatively undisturbed sites in diverse physical settings. Second, by regular recording of physical and biological parameters, it monitors for change, seeking to distinguish natural from anthropogenic disturbance. Third, it constitutes a regional network of observers, able to collaborate on studies of region-wide events. Examples are presented of the diverse data sets collected by the Program.Fil: Alcolado, Pedro M.. Instituto de Oceanología; CubaFil: Alleng, Gerard. No especifíca;Fil: Bonair, Kurt. No especifíca;Fil: Bone, David. Universidad Simón Bolívar; VenezuelaFil: Buchan, Kenneth. No especifíca;Fil: Bush, Phillippe G.. Protection and Conservation Unit; Islas CaimánFil: De Meyer, Kalli. No especifíca;Fil: Garcia, Jorge R.. Universidad de Puerto Rico; Puerto RicoFil: Garzón Ferreira, Jaime. Instituto de Investigaciones Marinas y Costeras; ColombiaFil: Gayle, Peter M. H.. Discovery Bay Marine Laboratory; JamaicaFil: Gerace, Donald T.. Bahamian Field Station; BahamasFil: Geraldes, Francisco X.. Universidad Autonoma de Santo Domingo.; República DominicanaFil: Dahlgren, Eric Jordán. Universidad Nacional Autónoma de México; MéxicoFil: Kjferve, Björn. University of South Carolina; Estados UnidosFil: Klein, Eduardo. Universidad Simón Bolívar; VenezuelaFil: Koltes, Karen. Smithsonian Institution; Estados UnidosFil: Laydoo, Richard S.. No especifíca;Fil: Linton, Dulcie M.. University of the West Indies ; JamaicaFil: Ogden, John C.. Florida Institute of Oceanography; Estados UnidosFil: Oxenford, Hazel A.. McGill University; BarbadosFil: Parker, Christoph. McGill University; BarbadosFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Pors, Leon P. P. J.. Universidad Simón Bolívar; VenezuelaFil: Ramírez Ramírez, Javier. Instituto Politécnico Nacional. Centro de Investigación y de Estudios Avanzados. Departamento de Física; MéxicoFil: Ruiz Rentería, Francisco. Universidad Nacional Autónoma de México; MéxicoFil: Ryan, Joseph D.. Centro de Investigación y Documentación de la Costa Atlántica; NicaraguaFil: Smith, Struan R.. Bermuda Biological Station for Research; BermudasFil: Tschirky, John. Latin American and Caribbean Division; Estados UnidosFil: Varela, Ramon. Estación de Investigaciones Marinas de Margarita; VenezuelaFil: Walker, Susan. No especifíca;Fil: Weil, Ernesto. Universidad de Puerto Rico; Puerto RicoFil: Wiebe, William J.. University of Georgia; Estados UnidosFil: Woodley, Jeremy D.. University of the West Indies; JamaicaFil: Zieman, Joseph C.. University of Virginia; Estados Unido

    Recent Region-wide Declines in Caribbean Reef Fish Abundance

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    Profound ecological changes are occurring on coral reefs throughout the tropics, with marked coral cover losses and concomitant algal increases, particularly in the Caribbean region. Historical declines in the abundance of large Caribbean reef fishes likely reflect centuries of overexploitation. However, effects of drastic recent degradation of reef habitats on reef fish assemblages have yet to be established. By using meta-analysis, we analyzed time series of reef fish density obtained from 48 studies that include 318 reefs across the Caribbean and span the time period 1955–2007. Our analyses show that overall reef fish density has been declining significantly for more than a decade, at rates that are consistent across all subregions of the Caribbean basin (2.7% to 6.0% loss per year) and in three of six trophic groups. Changes in fish density over the past half-century are modest relative to concurrent changes in benthic cover on Caribbean reefs. However, the recent significant decline in overall fish abundance and its consistency across several trophic groups and among both fished and nonfished species indicate that Caribbean fishes have begun to respond negatively to habitat degradation

    Current knowledge, status and future for plant and fungal diversity in Great Britain and the UK Overseas Territories

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    Societal Impact Statement We rely on plants and fungi for most aspects of our lives. Yet plants and fungi are under threat, and we risk losing species before we know their identity, roles, and potential uses. Knowing names, distributions, and threats are first steps toward effective conservation action. Accessible products like field guides and online resources engage society, harnessing collective support for conservation. Here, we review current knowledge of the plants and fungi of the UK and UK Overseas Territories, highlighting gaps to help direct future research efforts toward conserving these vital elements of biodiversity. Summary This review summarizes current knowledge of the status and threats to the plants and fungi of Great Britain and the UK Overseas Territories (UKOTs). Although the body of knowledge is considerable, the distribution of information varies substantially, and we highlight knowledge gaps. The UK vascular flora is the most well studied and we have a relatively clear picture of its 9,001 native and alien taxa. We have seedbanked 72% of the native and archaeophyte angiosperm taxa and 78% of threatened taxa. Knowledge of the UKOTs flora varies across territories and we report a UKOTs flora comprising 4,093 native and alien taxa. We have conserved 27% of the native flora and 51% of the threatened vascular plants in Kew's Millennium Seed Bank, UK. We need a better understanding of the conservation status of plants in the wild, and progress toward completion or updating national red lists varies. Site‐based protection of key plant assemblages is outlined, and progress in identifying Important Plant Areas analyzed. Knowledge of the non‐vascular flora, especially seaweeds remains patchy, particularly in many UKOTs. The biggest gaps overall are in fungi, particularly non‐lichenized fungi. Considerable investment is needed to fill these knowledge gaps and instigate effective conservation strategies

    Discovery and fine-mapping of adiposity loci using high density imputation of genome-wide association studies in individuals of African ancestry: African Ancestry Anthropometry Genetics Consortium

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    Genome-wide association studies (GWAS) have identified >300 loci associated with measures of adiposity including body mass index (BMI) and waist-to-hip ratio (adjusted for BMI, WHRadjBMI), but few have been identified through screening of the African ancestry genomes. We performed large scale meta-analyses and replications in up to 52,895 individuals for BMI and up to 23,095 individuals for WHRadjBMI from the African Ancestry Anthropometry Genetics Consortium (AAAGC) using 1000 Genomes phase 1 imputed GWAS to improve coverage of both common and low frequency variants in the low linkage disequilibrium African ancestry genomes. In the sex-combined analyses, we identified one novel locus (TCF7L2/HABP2) for WHRadjBMI and eight previously established loci at P < 5×10−8: seven for BMI, and one for WHRadjBMI in African ancestry individuals. An additional novel locus (SPRYD7/DLEU2) was identified for WHRadjBMI when combined with European GWAS. In the sex-stratified analyses, we identified three novel loci for BMI (INTS10/LPL and MLC1 in men, IRX4/IRX2 in women) and four for WHRadjBMI (SSX2IP, CASC8, PDE3B and ZDHHC1/HSD11B2 in women) in individuals of African ancestry or both African and European ancestry. For four of the novel variants, the minor allele frequency was low (<5%). In the trans-ethnic fine mapping of 47 BMI loci and 27 WHRadjBMI loci that were locus-wide significant (P < 0.05 adjusted for effective number of variants per locus) from the African ancestry sex-combined and sex-stratified analyses, 26 BMI loci and 17 WHRadjBMI loci contained ≤ 20 variants in the credible sets that jointly account for 99% posterior probability of driving the associations. The lead variants in 13 of these loci had a high probability of being causal. As compared to our previous HapMap imputed GWAS for BMI and WHRadjBMI including up to 71,412 and 27,350 African ancestry individuals, respectively, our results suggest that 1000 Genomes imputation showed modest improvement in identifying GWAS loci including low frequency variants. Trans-ethnic meta-analyses further improved fine mapping of putative causal variants in loci shared between the African and European ancestry populations

    Large-Scale Gene-Centric Meta-Analysis across 39 Studies Identifies Type 2 Diabetes Loci

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    To identify genetic factors contributing to type 2 diabetes (T2D), we performed large-scale meta-analyses by using a custom similar to 50,000 SNP genotyping array (the ITMAT-Broad-CARe array) with similar to 2000 candidate genes in 39 multiethnic population-based studies, case-control studies, and clinical trials totaling 17,418 cases and 70,298 controls. First, meta-analysis of 25 studies comprising 14,073 cases and 57,489 controls of European descent confirmed eight established T2D loci at genome-wide significance. In silico follow-up analysis of putative association signals found in independent genome-wide association studies (including 8,130 cases and 38,987 controls) performed by the DIAGRAM consortium identified a T2D locus at genome-wide significance (GATAD2A/CILP2/PBX4; p = 5.7 x 10(-9)) and two loci exceeding study-wide significance (SREBF1, and TH/INS; p <2.4 x 10(-6)). Second, meta-analyses of 1,986 cases and 7,695 controls from eight African-American studies identified study-wide-significant (p = 2.4 x 10(-7)) variants in HMGA2 and replicated variants in TCF7L2 (p = 5.1 x 10(-15)). Third, conditional analysis revealed multiple known and novel independent signals within five T2D-associated genes in samples of European ancestry and within HMGA2 in African-American samples. Fourth, a multiethnic meta-analysis of all 39 studies identified T2D-associated variants in BCL2 (p = 2.1 x 10(-8)). Finally, a composite genetic score of SNPs from new and established T2D signals was significantly associated with increased risk of diabetes in African-American, Hispanic, and Asian populations. In summary, large-scale meta-analysis involving a dense gene-centric approach has uncovered additional loci and variants that contribute to T2D risk and suggests substantial overlap of T2D association signals across multiple ethnic groups
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