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2.
Adv Mar Biol ; 89: xxxi-xxxii, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34583817
4.
Biol Lett ; 17(5): 20210038, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33975488

RESUMO

There are major concerns about the ecological impact of extreme weather events. In the oceans, marine heatwaves (MHWs) are an increasing threat causing, for example, recent devastation to coral reefs around the world. We show that these impacts extend to adjacent terrestrial systems and could negatively affect the breeding of endangered species. We demonstrate that during an MHW that resulted in major coral bleaching and mortality in a large, remote marine protected area, anomalously warm temperatures also occurred on sea turtle nesting beaches. Granger causality testing showed that variations in sea surface temperature strongly influenced sand temperatures on beaches. We estimate that the warm conditions on both coral reefs and sandy beaches during the MHW were unprecedented in the last 70 years. Model predictions suggest that the most extreme female-biased hatchling sex ratio and the lowest hatchling survival in nests in the last 70 years both occurred during the heatwave. Our work shows that predicted increases in the frequency and intensity of MHWs will likely have growing impacts on sea turtle nesting beaches as well as other terrestrial coastal environments.


Assuntos
Antozoários , Tartarugas , Animais , Recifes de Corais , Feminino , Oceanos e Mares , Temperatura
6.
Mar Pollut Bull ; 154: 111075, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32319906

RESUMO

The global decline of reef corals has been driven largely by several marine heatwaves. This has greatly reduced coral cover but has reduced coral diversity also. While there is a lack of data in most locations to detect coral species losses, reefs of the Chagos Archipelago, central Indian Ocean, have long term monitoring data extending back to the late 1970s. Severe declines in cover have occurred since the 1970s, with regional extinctions of some species and key species assemblages. There is a severe decline in coral settlement, along with a substantial loss of habitat quality which has reduced the habitat available for settlement. This is a clear precursor to positive feedback. Regional species extinctions here occur mainly when total coral cover is <10% of pre-warming levels. Climate models predict more frequent and more severe marine heatwaves, and even if this ecosystem recovers it will contain fewer species.


Assuntos
Antozoários , Animais , Clima , Recifes de Corais , Ecossistema , Oceano Índico
7.
Glob Chang Biol ; 24(6): 2447-2462, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29504709

RESUMO

As in the tropical Atlantic, Acropora populations in the southern Persian/Arabian Gulf plummeted within two decades after having been ecosystem engineers on most wave-exposed reefs since the Pleistocene. Since 1996/1998 live coral cover in the Gulf declined by over 90% in many areas, primarily due to bleaching and diseases caused by rising temperatures. In the formerly dominant table-coral species A. downingi, population dynamics corresponding to disturbance regimes was quantified in three transition matrices (lower disturbance pre-1996; moderate disturbance from 1998 to 2010 and 2013 to 2017, disturbed in 1996/1998, 2010/11/12, 2017). Increased disturbance frequency and severity caused progressive reduction in coral size, cover, and population fecundity. Small size-classes were bolstered more by partial colony mortality than sexual recruitment. Some large corals had a size refuge and resisted die-back but were also lost with increasing disturbance. Matrix and biophysical larval flow models suggested one metapopulation. Southern, Arabian, populations could be connected to northern, Iranian, populations but this connectivity was lost under assumptions of pelagic larval duration at rising temperatures shortened to a third. Then, the metapopulation disintegrated into isolated populations. Connectivity required to avoid extinctions increased exponentially with disturbance frequency and correlation of disturbances across the metapopulation. Populations became unsustainable at eight disturbances in 15 years, when even highest theoretical recruitment no longer compensated mortality. This lethal disturbance frequency was 3-fold that of the moderately disturbed monitoring period and 4-fold of the preceding low-disturbance period-suggesting ongoing shortening of the disturbance-free period. Observed population collapse and environmental changes in the Gulf suggest that A. downingi is heading toward at least functional extinction mainly due to increasingly frequent temperature-induced mortality events, clearly linked to climate change.


Assuntos
Antozoários/fisiologia , Mudança Climática , Recifes de Corais , Temperatura Alta , Animais , Oceano Índico , Irã (Geográfico) , Dinâmica Populacional , Temperatura
8.
Emerg Radiol ; 25(3): 275-280, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29330668

RESUMO

PURPOSE: The regionalization of trauma in the USA results in frequent transfers of patients from a primary hospital ED to a higher level trauma facility. While many hospitals have a Picture Archive Communication System (PACS) which captures digital radiological images, these are often not available to the receiving institution resulting in duplicate imaging. The state of Arkansas instituted a trauma image repository (TIR) in July 2013. We examined whether implementation of this repository would impact CT scan duplication in the trauma system. METHODS: This was a retrospective analysis of trauma patients transferred from outlying hospitals in Arkansas and Missouri to a single level 1 trauma hospital in Missouri between July 2012 and June 2015. We compared the duplicate CT rate for patients transferred from Arkansas and Missouri hospitals before and after the repository was implemented for Arkansas. RESULTS: Prior to implementation (July 2012-June 2013) of Arkansas TIR, duplicate CT rates were similar for patients transferred from Arkansas (11.5% ± 2.8) or Missouri (16.3% ± 7.5). Following implementation (July 2013-June 2014), the duplicate CT rate for patients transferred from Arkansas was significantly lower (Arkansas = 10.1% vs. Missouri 16.2%; CI 95%, p = 0.02), and significance continued (Arkansas = 9.0% vs. Missouri = 17.8%; CI 95%, p = 0.02) during follow-up (July 2014-June 2015). CONCLUSION: Fewer patients received duplicated scans within the Arkansas as compared with the Missouri-based trauma referral systems regardless of Injury Severity Scores (ISS). Our findings suggest that TIR adoption coupled with PACS improved transferability of radiographic studies and could improve patient care while reducing costs in trauma transfers.


Assuntos
Transferência de Pacientes , Sistemas de Informação em Radiologia , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Centros de Traumatologia , Ferimentos e Lesões/diagnóstico por imagem , Adulto , Idoso , Arkansas , Feminino , Humanos , Escala de Gravidade do Ferimento , Masculino , Pessoa de Meia-Idade , Missouri , Estudos Retrospectivos
9.
RSC Adv ; 8(70): 39837-39848, 2018 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-35558230

RESUMO

Mn substituted Mn x Zn1-x Co2O4 (x = 0, 0.3, 0.5, 0.7, 1) oxides were synthesized by a facile co-precipitation method followed by calcination at 600 °C. The presence of manganese ions causes appreciable changes in the structural and magnetic properties of the Mn-substituted ZnCo2O4. The morphologies, structures, and electronic properties of Mn-Zn-Co oxide microspheres were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The X-ray diffraction and Fourier transform infrared spectroscopy results confirmed the formation of spinel Mn x Zn1-x Co2O4. It was shown that the Mn-Zn-Co oxide microspheres increase in size and become regular in shape with increasing Mn concentration with the crystal size lying in the range from 19.1 nm to 51.3 nm. Magnetization measurements were carried out using a vibrating sample magnetometer at room temperature and 10 K. The saturation magnetization is observed to increase with increasing Mn concentration from x = 0 to x = 1.

10.
Mar Pollut Bull ; 105(2): 593-8, 2016 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-26490413

RESUMO

This article discusses two key issues: firstly, the demise of reefs in the Gulf which is happening probably more rapidly than elsewhere; and secondly, the reasons why this remains such an intractable problem. Most reasons for this decline are scientifically well understood, though clearly not by the region's managers. Several factors may cause people to ignore the problem, even though habitat loss is vastly costly to the region. About 70% of the Gulf's reefs have essentially disappeared in a few decades, and although scientific indicators confirm that this is happening, it is commonly discounted as even being a possibility. Management of human interactions with the Gulf's marine systems remains very inadequate, to the detriment of the Gulf's marine systems and its people. It is clear that this not a scientific issue any longer but rather it is a political problem and failure.


Assuntos
Antozoários/crescimento & desenvolvimento , Conservação dos Recursos Naturais , Recifes de Corais , Animais , Antozoários/efeitos dos fármacos , Barein , Mudança Climática , Conservação dos Recursos Naturais/legislação & jurisprudência , Conservação dos Recursos Naturais/métodos , Ecossistema , Sedimentos Geológicos/química , Regulamentação Governamental , Humanos , Oceano Índico , Água do Mar/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
12.
Mar Pollut Bull ; 85(1): 8-23, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-24997002

RESUMO

Over 1.3 billion people live on tropical coasts, primarily in developing countries. Many depend on adjacent coastal seas for food, and livelihoods. We show how trends in demography and in several local and global anthropogenic stressors are progressively degrading capacity of coastal waters to sustain these people. Far more effective approaches to environmental management are needed if the loss in provision of ecosystem goods and services is to be stemmed. We propose expanded use of marine spatial planning as a framework for more effective, pragmatic management based on ocean zones to accommodate conflicting uses. This would force the holistic, regional-scale reconciliation of food security, livelihoods, and conservation that is needed. Transforming how countries manage coastal resources will require major change in policy and politics, implemented with sufficient flexibility to accommodate societal variations. Achieving this change is a major challenge - one that affects the lives of one fifth of humanity.


Assuntos
Mudança Climática , Conservação dos Recursos Naturais , Ecossistema , Animais , Antozoários , Simulação por Computador , Demografia , Ecologia , Monitoramento Ambiental/métodos , Pesqueiros , Geografia , Humanos , Oceanos e Mares
13.
14.
Mar Pollut Bull ; 77(1-2): 7-10, 2013 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-24246654

RESUMO

On the 20th anniversary of the Convention on Biological Diversity, a network of very large marine protected areas (the Big Ocean network) has emerged as a key strategy in the move to arrest marine decline and conserve some of the last remaining relatively undisturbed marine areas on the globe. Here we outline the ecological, economic and policy benefits of very large-scale MPAs and show their disproportionate value to global marine conservation targets. In particular we point out that very large-scale MPAs are a critical component of reaching the Aichi targets of protecting 10% of global marine habitats by 2020, because in addition to encompassing entire ecosystems, they will bring forward the expected date of achievement by nearly three decades (2025 as opposed to 2054). While the need for small MPAs remains critical, large MPAs will complement and enhance these conservation efforts. Big Ocean sites currently contain more than 80% of managed area in the sea, and provide our best hope for arresting the global decline in marine biodiversity.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais/métodos , Ecossistema , Animais , Oceanos e Mares
15.
Mar Pollut Bull ; 74(2): 526-39, 2013 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-23816307

RESUMO

Most reviews concerning the impact of climate change on coral reefs discuss independent effects of warming or ocean acidification. However, the interactions between these, and between these and direct local stressors are less well addressed. This review underlines that coral bleaching, acidification, and diseases are expected to interact synergistically, and will negatively influence survival, growth, reproduction, larval development, settlement, and post-settlement development of corals. Interactions with local stress factors such as pollution, sedimentation, and overfishing are further expected to compound effects of climate change. Reduced coral cover and species composition following coral bleaching events affect coral reef fish community structure, with variable outcomes depending on their habitat dependence and trophic specialisation. Ocean acidification itself impacts fish mainly indirectly through disruption of predation- and habitat-associated behavior changes. Zooxanthellate octocorals on reefs are often overlooked but are substantial occupiers of space; these also are highly susceptible to bleaching but because they tend to be more heterotrophic, climate change impacts mainly manifest in terms of changes in species composition and population structure. Non-calcifying macroalgae are expected to respond positively to ocean acidification and promote microbe-induced coral mortality via the release of dissolved compounds, thus intensifying phase-shifts from coral to macroalgal domination. Adaptation of corals to these consequences of CO2 rise through increased tolerance of corals and successful mutualistic associations between corals and zooxanthellae is likely to be insufficient to match the rate and frequency of the projected changes. Impacts are interactive and magnified, and because there is a limited capacity for corals to adapt to climate change, global targets of carbon emission reductions are insufficient for coral reefs, so lower targets should be pursued. Alleviation of most local stress factors such as nutrient discharges, sedimentation, and overfishing is also imperative if sufficient overall resilience of reefs to climate change is to be achieved.


Assuntos
Aclimatação , Antozoários/fisiologia , Mudança Climática , Conservação dos Recursos Naturais/métodos , Recifes de Corais , Animais , Dióxido de Carbono/análise , Dióxido de Carbono/toxicidade , Oceanos e Mares , Alga Marinha/fisiologia , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Poluição Química da Água/estatística & dados numéricos
16.
Mar Pollut Bull ; 72(2): 406-16, 2013 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-23643407

RESUMO

Expert opinion was assessed to identify current knowledge gaps in determining future changes in Arabian/Persian Gulf (thereafter 'Gulf') coral reefs. Thirty-one participants submitted 71 research questions that were peer-assessed in terms of scientific importance (i.e., filled a knowledge gap and was a research priority) and efficiency in resource use (i.e., was highly feasible and ecologically broad). Ten research questions, in six major research areas, were highly important for both understanding Gulf coral reef ecosystems and also an efficient use of limited research resources. These questions mirrored global evaluations of the importance of understanding and evaluating biodiversity, determining the potential impacts of climate change, the role of anthropogenic impacts in structuring coral reef communities, and economically evaluating coral reef communities. These questions provide guidance for future research on coral reef ecosystems within the Gulf, and enhance the potential for assessment and management of future changes in this globally significant region.


Assuntos
Conservação dos Recursos Naturais , Recifes de Corais , Pesquisa , Animais , Antozoários/crescimento & desenvolvimento , Biodiversidade , Mudança Climática , Previsões , Oceano Índico
17.
Sci Rep ; 3: 1520, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23519209

RESUMO

Stylophora pistillata is a widely used coral "lab-rat" species with highly variable morphology and a broad biogeographic range (Red Sea to western central Pacific). Here we show, by analysing Cytochorme Oxidase I sequences, from 241 samples across this range, that this taxon in fact comprises four deeply divergent clades corresponding to the Pacific-Western Australia, Chagos-Madagascar-South Africa, Gulf of Aden-Zanzibar-Madagascar, and Red Sea-Persian/Arabian Gulf-Kenya. On the basis of the fossil record of Stylophora, these four clades diverged from one another 51.5-29.6 Mya, i.e., long before the closure of the Tethyan connection between the tropical Indo-West Pacific and Atlantic in the early Miocene (16-24 Mya) and should be recognised as four distinct species. These findings have implications for comparative ecological and/or physiological studies carried out using Stylophora pistillata as a model species, and highlight the fact that phenotypic plasticity, thought to be common in scleractinian corals, can mask significant genetic variation.


Assuntos
Antozoários/genética , Código de Barras de DNA Taxonômico , Complexo IV da Cadeia de Transporte de Elétrons/genética , Animais , Variação Genética , Filogenia , Padrões de Referência , Especificidade da Espécie
19.
PLoS One ; 7(8): e43499, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22927975

RESUMO

BACKGROUND: Understanding the limits and population dynamics of closely related sibling species in the marine realm is particularly relevant in organisms that require management. The crown-of-thorns starfish Acanthaster planci, recently shown to be a species complex of at least four closely related species, is a coral predator infamous for its outbreaks that have devastated reefs throughout much of its Indo-Pacific distribution. METHODOLOGY/PRINCIPAL FINDINGS: In this first Indian Ocean-wide genetic study of a marine organism we investigated the genetic structure and inferred the paleohistory of the two Indian Ocean sister-species of Acanthaster planci using mitochondrial DNA sequence analyses. We suggest that the first of two main diversification events led to the formation of a Southern and Northern Indian Ocean sister-species in the late Pliocene-early Pleistocene. The second led to the formation of two internal clades within each species around the onset of the last interglacial. The subsequent demographic history of the two lineages strongly differed, the Southern Indian Ocean sister-species showing a signature of recent population expansion and hardly any regional structure, whereas the Northern Indian Ocean sister-species apparently maintained a constant size with highly differentiated regional groupings that were asymmetrically connected by gene flow. CONCLUSIONS/SIGNIFICANCE: Past and present surface circulation patterns in conjunction with ocean primary productivity were identified as the processes most likely to have shaped the genetic structure between and within the two Indian Ocean lineages. This knowledge will help to understand the biological or ecological differences of the two sibling species and therefore aid in developing strategies to manage population outbreaks of this coral predator in the Indian Ocean.


Assuntos
Estrelas-do-Mar/genética , Migração Animal , Animais , DNA Mitocondrial/genética , Oceano Índico , Filogeografia , Dinâmica Populacional , Análise de Sequência de DNA
20.
PLoS One ; 7(6): e36921, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22679482

RESUMO

We explore impacts on pristine atolls subjected to anthropogenic near-field (human habitation) and far-field (climate and environmental change) pressure. Using literature data of human impacts on reefs, we parameterize forecast models to evaluate trajectories in coral cover under impact scenarios that primarily act via recruitment and increased mortality of larger corals. From surveys across the Chagos, we investigate the regeneration dynamics of coral populations distant from human habitation after natural disturbances. Using a size-based mathematical model based on a time-series of coral community and population data from 1999-2006, we provide hind- and forecast data for coral population dynamics within lagoons and on ocean-facing reefs verified against monitoring from 1979-2009. Environmental data (currents, temperatures) were used for calibration. The coral community was simplified into growth typologies: branching and encrusting, arboresent and massive corals. Community patterns observed in the field were influenced by bleaching-related mortality, most notably in 1998. Survival had been highest in deep lagoonal settings, which suggests a refuge. Recruitment levels were higher in lagoons than on ocean-facing reefs. When adding stress by direct human pressure, climate and environmental change as increased disturbance frequency and modified recruitment and mortality levels (due to eutrophication, overfishing, pollution, heat, acidification, etc), models suggest steep declines in coral populations and loss of community diversification among habitats. We found it likely that degradation of lagoonal coral populations would impact regeneration potential of all coral populations, also on ocean-facing reefs, thus decreasing reef resilience on the entire atoll.


Assuntos
Antozoários , Monitoramento Ambiental/métodos , Animais , Ecossistema , Humanos , Modelos Teóricos
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