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1.
PeerJ ; 11: e15556, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37465150

RESUMO

Skin microbial communities are an essential part of host health and can play a role in mitigating disease. Host and environmental factors can shape and alter these microbial communities and, therefore, we need to understand to what extent these factors influence microbial communities and how this can impact disease dynamics. Microbial communities have been studied in amphibian systems due to skin microbial communities providing some resistance to the amphibian chytrid fungus, Batrachochytrium dendrobatidis. However, we are only starting to understand how host and environmental factors shape these communities for amphibians. In this study, we examined whether amphibian skin bacterial communities differ among host species, host infection status, host developmental stage, and host habitat. We collected skin swabs from tadpoles and adults of three Ranid frog species (Lithobates spp.) at the Mianus River Gorge Preserve in Bedford, New York, USA, and used 16S rRNA gene amplicon sequencing to determine bacterial community composition. Our analysis suggests amphibian skin bacterial communities change across host developmental stages, as has been documented previously. Additionally, we found that skin bacterial communities differed among Ranid species, with skin communities on the host species captured in streams or bogs differing from the communities of the species captured on land. Thus, habitat use of different species may drive differences in host-associated microbial communities for closely-related host species.


Assuntos
Quitridiomicetos , Microbiota , Animais , RNA Ribossômico 16S/genética , Quitridiomicetos/genética , Anuros/genética , Ranidae/genética , Microbiota/genética , Bactérias/genética
2.
PeerJ ; 10: e13788, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36164598

RESUMO

Carnivores are currently colonizing cities where they were previously absent. These urban environments are novel ecosystems characterized by habitat degradation and fragmentation, availability of human food, and different prey assemblages than surrounding areas. Coyotes (Canis latrans) established a breeding population in New York City (NYC) over the last few decades, but their ecology within NYC is poorly understood. In this study, we used non-invasive scat sampling and DNA metabarcoding to profile vertebrate, invertebrate, and plant dietary items with the goal to compare the diets of urban coyotes to those inhabiting non-urban areas. We found that both urban and non-urban coyotes consumed a variety of plants and animals as well as human food. Raccoons (Procyon lotor) were an important food item for coyotes within and outside NYC. In contrast, white-tailed deer (Odocoileus virginianus) were mainly eaten by coyotes inhabiting non-urban areas. Domestic chicken (Gallus gallus) was the human food item found in most scats from both urban and non-urban coyotes. Domestic cats (Felis catus) were consumed by urban coyotes but were detected in only a small proportion of the scats (<5%), which differs markedly from high rates of cat depredation in some other cities. In addition, we compared our genetic metabarcoding analysis to a morphological analysis of the same scat samples. We found that the detection similarity between the two methods was low and it varied depending on the type of diet item.


Assuntos
Carnívoros , Coiotes , Cervos , Humanos , Animais , Gatos , Coiotes/genética , Cidade de Nova Iorque , Ecossistema , Código de Barras de DNA Taxonômico
3.
Genes (Basel) ; 13(9)2022 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-36140828

RESUMO

Coyotes are ubiquitous on the North American landscape as a result of their recent expansion across the continent. They have been documented in the heart of some of the most urbanized cities, such as Chicago, Los Angeles, and New York City. Here, we explored the genomic composition of 16 coyotes in the New York metropolitan area to investigate genomic demography and admixture for urban-dwelling canids in Queens County, New York. We identified moderate-to-high estimates of relatedness among coyotes living in Queens (r = 0.0-0.5) and adjacent neighborhoods, suggestive of a relatively small population. Although we found low background levels of domestic-dog ancestry across most coyotes in our sample (5%), we identified a male suspected to be a first-generation coyote-dog hybrid with 46% dog ancestry, as well as his two putative backcrossed offspring that carried approximately 25% dog ancestry. The male coyote-dog hybrid and one backcrossed offspring each carried two transposable element insertions that are associated with human-directed hypersociability in dogs and gray wolves. An additional, unrelated coyote with little dog ancestry also carried two of these insertions. These genetic patterns suggest that gene flow from domestic dogs may become an increasingly important consideration as coyotes continue to inhabit metropolitan regions.


Assuntos
Coiotes , Lobos , Animais , Coiotes/genética , Elementos de DNA Transponíveis , Cães , Genômica , Humanos , Masculino , Cidade de Nova Iorque , Lobos/genética
4.
Ecology ; 103(10): e3775, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35661139

RESUMO

Managing wildlife populations in the face of global change requires regular data on the abundance and distribution of wild animals, but acquiring these over appropriate spatial scales in a sustainable way has proven challenging. Here we present the data from Snapshot USA 2020, a second annual national mammal survey of the USA. This project involved 152 scientists setting camera traps in a standardized protocol at 1485 locations across 103 arrays in 43 states for a total of 52,710 trap-nights of survey effort. Most (58) of these arrays were also sampled during the same months (September and October) in 2019, providing a direct comparison of animal populations in 2 years that includes data from both during and before the COVID-19 pandemic. All data were managed by the eMammal system, with all species identifications checked by at least two reviewers. In total, we recorded 117,415 detections of 78 species of wild mammals, 9236 detections of at least 43 species of birds, 15,851 detections of six domestic animals and 23,825 detections of humans or their vehicles. Spatial differences across arrays explained more variation in the relative abundance than temporal variation across years for all 38 species modeled, although there are examples of significant site-level differences among years for many species. Temporal results show how species allocate their time and can be used to study species interactions, including between humans and wildlife. These data provide a snapshot of the mammal community of the USA for 2020 and will be useful for exploring the drivers of spatial and temporal changes in relative abundance and distribution, and the impacts of species interactions on daily activity patterns. There are no copyright restrictions, and please cite this paper when using these data, or a subset of these data, for publication.


Assuntos
COVID-19 , Animais , Animais Selvagens , Aves , COVID-19/epidemiologia , Humanos , Mamíferos , Pandemias , Estados Unidos
5.
Ecology ; 102(6): e03353, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33793977

RESUMO

With the accelerating pace of global change, it is imperative that we obtain rapid inventories of the status and distribution of wildlife for ecological inferences and conservation planning. To address this challenge, we launched the SNAPSHOT USA project, a collaborative survey of terrestrial wildlife populations using camera traps across the United States. For our first annual survey, we compiled data across all 50 states during a 14-week period (17 August-24 November of 2019). We sampled wildlife at 1,509 camera trap sites from 110 camera trap arrays covering 12 different ecoregions across four development zones. This effort resulted in 166,036 unique detections of 83 species of mammals and 17 species of birds. All images were processed through the Smithsonian's eMammal camera trap data repository and included an expert review phase to ensure taxonomic accuracy of data, resulting in each picture being reviewed at least twice. The results represent a timely and standardized camera trap survey of the United States. All of the 2019 survey data are made available herein. We are currently repeating surveys in fall 2020, opening up the opportunity to other institutions and cooperators to expand coverage of all the urban-wild gradients and ecophysiographic regions of the country. Future data will be available as the database is updated at eMammal.si.edu/snapshot-usa, as will future data paper submissions. These data will be useful for local and macroecological research including the examination of community assembly, effects of environmental and anthropogenic landscape variables, effects of fragmentation and extinction debt dynamics, as well as species-specific population dynamics and conservation action plans. There are no copyright restrictions; please cite this paper when using the data for publication.


Assuntos
Animais Selvagens , Mamíferos , Animais , Aves , Dinâmica Populacional , Estados Unidos
6.
Mil Med ; 184(9-10): e522-e530, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30941415

RESUMO

INTRODUCTION: In military populations, physician burnout has potential to adversely affect medical readiness to deploy in support of joint operations. Burnout among Graduate Medical Education (GME) faculty may further threaten the welfare of the medical force given the central role these officers have in training and developing junior physicians. The primary aim of this investigation was to estimate the prevalence of burnout among faculty physicians in United States (US) Army, Navy, and Air Force GME programs. MATERIALS AND METHODS: We conducted a cross-sectional study of faculty physicians at US military GME training programs between January 2018 and July 2018. Through direct coordination with Designated Institutional Officials, we administered the Maslach Burnout Inventory Health Services Survey (MBI-HSS) via online web link to faculty physicians listed in Accreditation Data System at each sponsoring institution. In addition to the MBI-HSS, we collected demographic data and queried physicians about common occupational stressors in order to assist institutional leaders with identifying at-risk physicians and developing future interventions to address burnout. RESULTS: Sixteen of 21 institutions that currently sponsor military GME programs agreed to distribute the MBI-HSS survey to core faculty. We received completed assessments from 622 of the 1,769 (35.1%) reported physician core faculty at these institutions. Of the 622 physician respondents, 162 demonstrated high levels of emotional exhaustion and depersonalization for an estimated 26% prevalence of burnout. We identified only one independent risk factor for burnout: increasing numbers of deployments (OR 1.38, 95% CI 1.07-1.77). Physicians in our cohort who reported a desire to stay beyond their initial active duty service obligation were less likely to be classified with burnout (OR 0.45, 95% CI 0.26-0.77). The most common drivers of occupational distress were cumbersome bureaucratic tasks, insufficient administrative support, and overemphasis on productivity metrics. CONCLUSIONS: We estimate that 26% of physician faculty in military GME programs are experiencing burnout. No specialty, branch of service, or specific demographic was immune to burnout in our sample. Institutional leaders in the MHS should take action to address physician burnout and consider using our prevalence estimate to assess effectiveness of future interventions.


Assuntos
Esgotamento Profissional/diagnóstico , Docentes de Medicina/psicologia , Prevalência , Adulto , Esgotamento Profissional/epidemiologia , Esgotamento Profissional/psicologia , Estudos Transversais , Educação de Pós-Graduação em Medicina/métodos , Educação de Pós-Graduação em Medicina/normas , Educação de Pós-Graduação em Medicina/estatística & dados numéricos , Docentes de Medicina/estatística & dados numéricos , Feminino , Humanos , Satisfação no Emprego , Masculino , Medicina/estatística & dados numéricos , Pessoa de Meia-Idade , Militares/psicologia , Militares/estatística & dados numéricos , Médicos/psicologia , Médicos/estatística & dados numéricos , Psicometria/instrumentação , Psicometria/métodos , Psicometria/estatística & dados numéricos , Inquéritos e Questionários , Estados Unidos/epidemiologia , United States Department of Defense/organização & administração , United States Department of Defense/estatística & dados numéricos
7.
J Spec Oper Med ; 17(4): 56-62, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29256196

RESUMO

Many anesthesiologists and CRNAs are provided little training in preparing for a humanitarian surgical mission. Furthermore, there is very little published literature that outlines how to plan and prepare for anesthesia support of a humanitarian surgical mission. This article attempts to serve as an in-depth planning guide for anesthesia support of humanitarian surgical missions. Recommendations are provided on planning requirements that most anesthesiologists and CRNAs do not have to consider on routinely, such as key questions to be answered before agreeing to support a mission, ordering and shipping supplies and medications, travel and lodging arrangements, and coordinating translators in a host nation. Detailed considerations are included for all the phases of mission planning: advanced, mission-specific, final, mission-execution, and postmission follow-up planning, as well as a timeline in which to complete each phase. With the proper planning and execution, the anesthetic support of humanitarian surgical missions is a very manageable task that can result in an extremely satisfying sense of accomplishment and a rewarding experience. The authors suggest this article should be used as a reference document by any anesthesia professional tasked with planning and supporting a humanitarian surgical mission.


Assuntos
Anestesiologia/instrumentação , Anestesiologia/organização & administração , Missões Médicas/organização & administração , Socorro em Desastres/organização & administração , Atenção à Saúde , Cirurgia Geral/organização & administração , Guias como Assunto , Humanos , Assistência Perioperatória , Técnicas de Planejamento , Viagem , Recursos Humanos
8.
Mil Med ; 182(3): e1747-e1751, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28290953

RESUMO

INTRODUCTION: The San Antonio Uniformed Services Health Education Consortium (SAUSHEC) is the largest group of residency programs in the Department of Defense. In an effort to provide improved Quality Improvement and Patient Safety (QI/PS) training for its residents, SAUSHEC created the position of Chief of QI/PS for Residents in the academic year 2014-2015. The Chief of QI/PS for Residents was based in the Internal Medicine residency program but also assisted with SAUSHEC-wide QI/PS projects. This is the first such job in the Department of Defense. METHODS: Here, we detail the accomplishments during this first academic year, including the alignment of the job with the stated QI/PS-related goals of the Accreditation Council for Graduate Medical Education Clinical Learning Environment Review. Efforts focused within the Internal Medicine residency program included QI/PS curriculum development, improvement upon monthly morbidity and mortality (M&M) conferences, and facilitating resident participation in QI projects. The 2014-2015 academic year Internal Medicine residency QI/PS project focused on increasing comfort and discussions with patients regarding advance directives; this also served to emphasize the humanistic side of potential QI/PS projects. The Chief of QI/PS for Residents also spearheaded hospital-wide initiatives, including the creation of a quarterly hospital-wide M&M conference, coordinating resident involvement in QI/PS-related committees, and facilitating feedback of patient safety report responses to trainees. RESULTS: We focus on the portion of the QI/PS curriculum involving the presentation of a mock Root Cause Analysis (RCA) and provide the results of a pre- and postpresentation survey of resident knowledge of RCAs. In order to quantify the efforts over the entire academic year, we also report the results of a resident self-assessment of QI/PS aptitude and competencies, including changes in these measures over the academic year. Finally, we discuss challenges faced and outline future goals for the position. CONCLUSION: The SAUSHEC Chief of QI/PS for Residents is the first such designated position in the Department of Defense. As QI/PS continues to increase as a focus area for physician training, we anticipate that other programs will create similar positions. We provide ideas for how a Chief of QI/PS for Residents can be involved at a program and hospital-wide level and quantify the success of different efforts.


Assuntos
Medicina Interna/educação , Internato e Residência , Segurança do Paciente/normas , Melhoria de Qualidade , Competência Clínica/normas , Currículo/tendências , Educação de Pós-Graduação em Medicina/métodos , Educação de Pós-Graduação em Medicina/tendências , Humanos , Medicina Interna/tendências , Internato e Residência/tendências , Inquéritos e Questionários , Ensino/normas , Recursos Humanos
9.
Mil Med ; 182(1): e1514-e1520, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28051967

RESUMO

The purposes of this study are to (1) introduce our novel Applicant Ranking Tool that aligns with the Accreditation Council for Graduate Medical Education competencies and (2) share our preliminary results comparing applicant rank to current performance. After a thorough literature review and multiple roundtable discussions, an Applicant Ranking Tool was created. Feasibility, satisfaction, and critiques were discussed via open feedback session. Inter-rater reliability was assessed using weighted kappa statistic (κ) and Kendall coefficient of concordance (W). Fisher's exact tests evaluated the ability of the tool to stratify performance into the top or bottom half of their class. Internal medicine and anesthesiology residents served as the pilot cohorts. The tool was considered user-friendly for both data input and analysis. Inter-rater reliability was strongest with intradisciplinary evaluation (W = 0.8-0.975). Resident performance was successfully stratified into those functioning in the upper vs. lower half of their class within the Clinical Anesthesia-3 grouping (p = 0.008). This novel Applicant Ranking Tool lends support for the use of both cognitive and noncognitive traits in predicting resident performance. While the ability of this instrument to accurately predict future resident performance will take years to answer, this pilot study suggests the instrument is worthy of ongoing investigation.


Assuntos
Sucesso Acadêmico , Avaliação Educacional/métodos , Internato e Residência/tendências , Critérios de Admissão Escolar/tendências , Desempenho Profissional/normas , Anestesiologia/educação , Competência Clínica/normas , Educação de Pós-Graduação em Medicina/métodos , Educação de Pós-Graduação em Medicina/normas , Humanos , Medicina Interna/educação , Candidatura a Emprego , Otolaringologia/educação , Determinação da Personalidade , Projetos Piloto , Reprodutibilidade dos Testes , Inquéritos e Questionários
10.
J Clin Anesth ; 31: 60-3, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27185679

RESUMO

Ex utero intrapartum treatment (EXIT) procedures are therapeutic interventions for fetuses with life-threatening airway abnormalities and/or other prenatally diagnosed congenital malformations requiring immediate neonatal extracorporeal membrane oxygenation support. Although certain anesthetic goals are common among EXIT procedures, many different approaches to their management have been described in the literature. Herein, we present a novel anesthetic approach to an EXIT procedure for fetal micrognathia and retrognathia. We also review the indications and anesthetic considerations for these procedures and highlight the need for multidisciplinary collaboration to optimize clinical outcomes.


Assuntos
Obstrução das Vias Respiratórias/terapia , Anestesia Obstétrica/métodos , Cesárea/métodos , Doenças Fetais/terapia , Assistência Perinatal/métodos , Obstrução das Vias Respiratórias/etiologia , Anestesia Geral/métodos , Feminino , Doenças Fetais/diagnóstico por imagem , Humanos , Recém-Nascido , Imageamento por Ressonância Magnética , Micrognatismo/complicações , Micrognatismo/diagnóstico por imagem , Micrognatismo/terapia , Gravidez , Diagnóstico Pré-Natal/métodos , Retrognatismo/complicações , Retrognatismo/diagnóstico por imagem , Retrognatismo/terapia , Adulto Jovem
11.
MedEdPORTAL ; 12: 10508, 2016 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-30984850

RESUMO

INTRODUCTION: Physician wellness has garnered significant recent national attention within graduate medical education (GME). Unfortunately, the resources to proactively address burnout, depression, and suicide are lacking. The "Time to Talk About It: Physician Depression and Suicide" video/discussion session is specifically designed for the GME community. METHODS: The primary focus of this 60-minute video/discussion session is to promote an open dialogue among interns, residents, and fellows about depression and suicide within the profession of medicine. The centerpiece of the session is a 7-minute video featuring personal accounts from physicians at the San Antonio Uniformed Services Health Education Consortium (SAUSHEC). The materials associated with the publication include the video, a guide for facilitating group discussion following the video, a list of questions to guide small-group discussions, a session evaluation form, and examples of mental health resources for distribution at the end of the session. RESULTS: A field test of the video/discussion session with 22 trainees from the pediatrics residency program at SAUSHEC was very well received. Their average response to "This session was an effective first step in promoting an open dialogue among physicians about depression and suicide within the profession" was 4.5 out of 5 (i.e., Strongly Agree). One hundred percent of participants answered "Yes" to the question "Would you recommend this session to other physicians?" DISCUSSION: We hope that this resource will be useful to other institutions around the country as they confront physician burnout, depression, and suicide.

15.
PeerJ ; 2: e310, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24688884

RESUMO

Severe fragmentation is a typical fate of native remnant habitats in cities, and urban wildlife with limited dispersal ability are predicted to lose genetic variation in isolated urban patches. However, little information exists on the characteristics of urban green spaces required to conserve genetic variation. In this study, we examine whether isolation in New York City (NYC) parks results in genetic bottlenecks in white-footed mice (Peromyscus leucopus), and test the hypotheses that park size and time since isolation are associated with genetic variability using nonlinear regression and information-theoretic model selection. White-footed mice have previously been documented to exhibit male-biased dispersal, which may create disparities in genetic variation between males and females in urban parks. We use genotypes of 18 neutral microsatellite data and four different statistical tests to assess this prediction. Given that sex-biased dispersal may create disparities between population genetic patterns inferred from bi- vs. uni-parentally inherited markers, we also sequenced a 324 bp segment of the mitochondrial D-loop for independent inferences of historical demography in urban P. leucopus. We report that isolation in urban parks does not necessarily result in genetic bottlenecks; only three out of 14 populations in NYC parks exhibited a signature of a recent bottleneck at 18 neutral microsatellite loci. Mouse populations in larger urban parks, or parks that have been isolated for shorter periods of time, also do not generally contain greater genetic variation than populations in smaller parks. These results suggest that even small networks of green spaces may be sufficient to maintain the evolutionary potential of native species with certain characteristics. We also found that isolation in urban parks results in weak to nonexistent sex-biased dispersal in a species known to exhibit male-biased dispersal in less fragmented environments. In contrast to nuclear loci, mitochondrial D-loop haplotypes exhibited a mutational pattern of demographic expansion after a recent bottleneck or selective sweep. Estimates of the timing of this expansion suggest that it occurred concurrent with urbanization of NYC over the last few dozens to hundreds of years. Given the general non-neutrality of mtDNA in many systems and evidence of selection on related coding sequences in urban P. leucopus, we argue that the P. leucopus mitochondrial genome experienced recent negative selection against haplotypes not favored in isolated urban parks. In general, rapid adaptive evolution driven by urbanization, global climate change, and other human-caused factors is underappreciated by evolutionary biologists, but many more cases will likely be documented in the near future.

17.
J Educ Perioper Med ; 16(7): E073, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-27175404

RESUMO

BACKGROUND: Anesthesiology residency programs will be expected to have Milestones-based evaluation systems in place by July 2014 as part of the Next Accreditation System. METHODS: The San Antonio Uniformed Services Health Education Consortium (SAUSHEC) anesthesiology residency program developed and implemented a Milestones-based feedback and evaluation system a year ahead of schedule. It has been named the Milestone-specific, Observed Data points for Evaluating Levels of performance (MODEL) assessment strategy. RESULTS: The "MODEL Menu" and the "MODEL Blueprint" are tools that other anesthesiology residency programs can use in developing their own Milestones-based feedback and evaluation systems prior to ACGME-required implementation. Data from our early experience with the streamlined MODEL blueprint assessment strategy showed substantially improved faculty compliance with reporting requirements. CONCLUSIONS: The MODEL assessment strategy provides programs with a workable assessment method for residents, and important Milestones data points to programs for ACGME reporting.

18.
J Educ Perioper Med ; 16(1): E067, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-27175397

RESUMO

BACKGROUND: We sought to determine the relationship between residents' Anesthesia Knowledge Test 6 (AKT-6) scores and their first-time success/failure on the American Board of Anesthesiology written licensing examination. Reliable early identification of residents at risk for failing the ABA exam would be an invaluable screening tool for program leadership and facilitate timely remediation for struggling residents. METHODS: Program directors were invited to submit anonymous data regarding their residents' performance on the AKT-6 and their subsequent first-time success/failure on the American Board of Anesthesiology written licensing examination. RESULTS: Eight residency programs responded with AKT6 percentile scores and ABA part 1 first-time pass/fail status from 306 residents spanning 2004-2011. Of these, 292 also included AKT6% correct scores. AKT-6 performance was significantly better for trainees who went on to pass the ABA exam on their first attempt compared to those who failed. Trainees who scored at or below the 4(th) percentile (or answered ≤42% of questions correctly) failed the ABA exam while all those scoring above the 84(th) percentile (or answered >68% of questions correctly) passed. A Mantel-Haenszel common odds ratio estimate revealed significantly increased odds of failure below the thresholds of AKT-6 scores ≤ 36(th) percentile (≤56% correct). CONCLUSIONS: Observations from this work help to validate educators' use of AKT-6 exam performance as a marker for likelihood of success/failure on the ABA written licensing exam. Our analysis, based on data from eight training programs, yielded definitive cut points for ABA exam failure and passing. ROC analysis of our data supports a recommendation for educators to intervene with trainees scoring at or below the 36(th) percentile or 56% correct on AKT-6 testing. Our results likely require confirmation in a larger subset of anesthesiology residency programs.

19.
Mil Med ; 177(3): 243-4, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22479909

RESUMO

Military residency training programs are unique in a number of ways, none more significant than the fact that our graduates become our colleagues and future teammates on lengthy deployments. We have a fundamental responsibility to make sure that they are up to the task. Although certainly not a panacea, a well-crafted military-unique curriculum goes a long way toward creating the kind of institutional culture and training mindset that enables a successful transition from active duty resident to deployable physician.


Assuntos
Anestesiologia/educação , Currículo , Internato e Residência , Medicina Militar , Militares/educação , Humanos , Estados Unidos
20.
Nature ; 455(7211): 383-6, 2008 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-18800137

RESUMO

Terrestrial ecosystems control carbon dioxide fluxes to and from the atmosphere through photosynthesis and respiration, a balance between net primary productivity and heterotrophic respiration, that determines whether an ecosystem is sequestering carbon or releasing it to the atmosphere. Global and site-specific data sets have demonstrated that climate and climate variability influence biogeochemical processes that determine net ecosystem carbon dioxide exchange (NEE) at multiple timescales. Experimental data necessary to quantify impacts of a single climate variable, such as temperature anomalies, on NEE and carbon sequestration of ecosystems at interannual timescales have been lacking. This derives from an inability of field studies to avoid the confounding effects of natural intra-annual and interannual variability in temperature and precipitation. Here we present results from a four-year study using replicate 12,000-kg intact tallgrass prairie monoliths located in four 184-m(3) enclosed lysimeters. We exposed 6 of 12 monoliths to an anomalously warm year in the second year of the study and continuously quantified rates of ecosystem processes, including NEE. We find that warming decreases NEE in both the extreme year and the following year by inducing drought that suppresses net primary productivity in the extreme year and by stimulating heterotrophic respiration of soil biota in the subsequent year. Our data indicate that two years are required for NEE in the previously warmed experimental ecosystems to recover to levels measured in the control ecosystems. This time lag caused net ecosystem carbon sequestration in previously warmed ecosystems to be decreased threefold over the study period, compared with control ecosystems. Our findings suggest that more frequent anomalously warm years, a possible consequence of increasing anthropogenic carbon dioxide levels, may lead to a sustained decrease in carbon dioxide uptake by terrestrial ecosystems.


Assuntos
Dióxido de Carbono/metabolismo , Clima , Ecossistema , Temperatura Alta , Desastres , Fatores de Tempo
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