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1.
Zootaxa ; 4732(4): zootaxa.4732.4.3, 2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-32230237

RESUMO

A new species of callianassid mud shrimp is described from outer continental shelf waters of the northwestern Gulf of Mexico, where it appears to commonly live in close association with sediments on or near natural hydrocarbon seeps. Recent genus-level taxonomic revisions of the Callianassidae, based on gene sequence analyses and comparative morphological studies, included specimens representing this new species, assigning it with strong support to the genus Pugnatrypaea Poore et al., 2019. The other known species of this genus are also typically found in offshore waters of continental shelves, but are all restricted in distribution to the Indo-West Pacific and are known from relatively few specimens. Collections of this new Gulf of Mexico representative of the genus are all from slightly deeper waters than for other known congeners, and commonly occur near hydrocarbon seeps, on some occasions being directly associated with sulfidic substrates that include waxy crude oil globules.


Assuntos
Decápodes , Distribuição Animal , Estruturas Animais , Animais , Crustáceos , Golfo do México , Hidrocarbonetos
2.
Zootaxa ; 4732(1): zootaxa.4732.1.5, 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32230274

RESUMO

The rare short-stemmed physonect Melophysa melo typically lives above the thermocline in warm waters of the world's oceans. In the past this species has been described from fragmented or distorted material, with the last two accounts being published in 1931 and 1954. A new description is given herein with pertinent figures based on nine samples recently collected in the Gulf of Mexico (GoM), including the first detailed illustrations of mature nectophores, and of a well-developed corm. The corm comprises a prominent pneumatophore, a narrow nectosome bearing small attachment lamellae for four nectophores and a much larger short, swollen spiral siphosome bearing eight cormidia. The last five cormidia of this corm are still attached to the pneumatophore, while the oldest three are free, with cormidium one being the oldest and eight the youngest. Two rings of bracteal muscular lamellae occur on the siphosome of this corm, one on the upper surface of each cormidium and a second on the lower surface. Laterally each cormidium supports an upper gonodendron, a zooid meridian bearing palpons and a lower gonodendron. Cormidium one has the most mature gonodendra, and all cormidia have palpons on the zooid meridian, which become progressively mature towards the base. Differences in corm structure from previously described corms are attributed to the younger age of the present two corms. Bracts are re-described from photographic images of both young and mature bracts.


Assuntos
Hidrozoários , Animais , Golfo do México , México
3.
Zootaxa ; 4731(3): zootaxa.4731.3.8, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32230300

RESUMO

Speciose populations of small xanthoid crabs on offshore banks and reefs of the northern Gulf of Mexico include a new species that is not assignable to presently named genera. Morphological diagnoses of the new genus and species are underpinned by previously published gene sequence analyses, originally misattributed to another species but now known to apply to this taxon. Herein named Guinope tiara n. gen., n. sp., the species shows molecular phylogenetic affinities with the family Linnaeoxanthidae Stevcic, 2005, an ally of panopeid and pseudorhombilid crabs. Specimens from Occulina banks off the Florida Atlantic coast, previously regarded to represent Garthiope barbadensis (Rathbun, 1921), are not that species but instead morphologically assignable to Guinope n. gen. Whether they represent variants of Guinope tiara n. gen, n. sp. or a second species of the genus awaits the collection of fresh materials for DNA analyses.


Assuntos
Braquiúros , Decápodes , Animais , Ecossistema , Golfo do México , Filogenia
4.
Zootaxa ; 4722(4): zootaxa.4722.4.1, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32230613

RESUMO

Six species of hermit crabs of the family Paguridae from the Caribbean Sea and Gulf of Mexico region, including two new species, Anisopagurus asteriscus sp. nov. and Pagurus alarius sp. nov., are documented. The two new species are described, and recognition characters summarized for the four previously known species. Reports of the latter, Nematopaguroides fagei Forest de Saint Laurent, 1968, N. karukera Lemaitre, Felder Poupin, 2017, Paguriscus robustus Lemaitre, Felder Poupin, 2017, and Pylopaguridium markhami McLaughlin Lemaitre, 2001, represent range extensions for all four species. Color photographs are included for four of the species, as well as remarks on their taxonomy and distributions. All six species included can be categorized as micro-pagurids (with shield length rarely exceeding 2.0 mm), and were collected from cryptic reef habitats in Bocas del Toro, Panama; the French Antillean island of Guadeloupe; and the Gulf of Mexico coasts of Louisiana, Yucatán, and Florida Keys. The discovery of these new or rare species supports the conclusion of recent studies that the diversity of pagurids from the Caribbean region has yet to be fully realized.


Assuntos
Anomuros , Animais , Região do Caribe , Golfo do México
5.
Environ Monit Assess ; 191(Suppl 4): 816, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32185513

RESUMO

We estimated detection probabilities of bird carcasses along sandy beaches and in marsh edge habitats in the northern Gulf of Mexico to help inform models of bird mortality associated with the Deepwater Horizon oil spill. We also explored factors that may influence detection probability, such as carcass size, amount of scavenging, location on the beach, habitat type, and distance into the marsh. Detection probability for medium-sized carcasses (200-500 g) ranged from 0.82 (SE = 0.09) to 0.93 (SE = 0.04) along sandy beaches. Within sandy beaches, we found that intact/slightly scavenged carcasses were easier to detect than heavily scavenged ones and did not find strong effects of location on the beach on detection probability. We estimated detection rate for each combination of scavenging state, carcass size, and position along sandy beaches. In marsh edge habitats, detection ranged from 0.04 (SE = 0.04) to 0.86 (SE = 0.10), with detection rates rapidly increasing from small (< 200 g) to medium carcass sizes and leveling off between medium and extra-large (> 1000 g) carcasses regardless of vegetation type (Spartina or Phragmites). Carcasses of all sizes were generally harder to locate in Spartina-dominated marshes than in Phragmites-dominated ones. A subset of the data for which we could adequately assess the effect of distance into the marsh indicated that detection rates generally declined the farther a carcass was into marsh vegetation. Based on power analyses, our ability to identify predictors that influence detection rates would be higher with larger numbers of carcasses, greater numbers of search trials per carcass, or more balanced sampling distributions across predictor values.


Assuntos
Aves , Poluição por Petróleo , Áreas Alagadas , Animais , Cadáver , Monitoramento Ambiental , Golfo do México , Probabilidade
6.
Environ Monit Assess ; 191(Suppl 4): 814, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32185518

RESUMO

In response to the Deepwater Horizon oil spill, federal and state agencies conducted field studies to develop inputs for a shoreline deposition model used to estimate nearshore avian mortality resulting from the spill. A 2011 carcass drift study was designed to generate data on the likelihood that birds that died on the water would deposit along the northern Gulf of Mexico coast (rather than becoming lost at sea). In the case of the Deepwater Horizon oil spill, carcass losses at sea accounted for a significant portion of nearshore avian mortality. We evaluate the data collected during the Deepwater Horizon carcass drift study and compare the results obtained from the use of avian carcasses versus dummy carcasses (dummies) and the differences between those deployed nearshore versus further offshore. We conclude that, although the use of dummies provided valuable confirmation on the drift patterns of dead birds, dummies drifted greater distances, for longer periods of time, and were more likely to be observed beached compared to avian carcasses, with 64.6% of dummies beaching compared to 17.2% of carcasses. In response to future spills, researchers should account for these potential biases when incorporating dummy drift data into estimates of avian carcass loss. Further, none of the avian carcasses and dummies released more than 40 km from the shoreline made it to shore. In the northern Gulf of Mexico, carcasses that die on the waters farther offshore are unlikely to make it to shore to be captured in a deposition model; therefore, it may be appropriate to utilize a separate methodology to estimate offshore mortality. The applicability of these results to other spill events should be evaluated in the context of the specific spill characteristics.


Assuntos
Aves , Poluição por Petróleo , Poluentes Químicos da Água , Animais , Cadáver , Monitoramento Ambiental , Golfo do México , Movimentos da Água , Poluentes Químicos da Água/toxicidade
7.
Environ Monit Assess ; 191(Suppl 4): 812, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32185519

RESUMO

Deposition models, such as the Shoreline Deposition Model (SDM) used to quantify nearshore avian injuries resulting from the 2010 Deepwater Horizon (DWH) oil spill, were developed to improve the estimates of nearshore avian mortality resulting from the release of oil into coastal and marine environments. Unlike earlier approaches to injury quantification, such as simple counts of carcasses on the shoreline, a modeling approach allows trustees to evaluate the precision of their estimate (i.e., to develop a confidence interval) and can inform decision-making and the likely utility of additional primary data collection activities through sensitivity analyses. In this paper, we rely on published literature, actual DWH data, and a deposition model simulation to evaluate how different model inputs and assumptions can affect the accuracy and precision of model results. We find that the precision of deposition models is strongly affected by the length of time between subsequent shoreline searches, the underlying magnitude of carcass deposition, carcass persistence probabilities, and carcass detection probabilities. In addition, the accuracy of deposition model results may be affected by natural fluctuations in deposition rates. Given these findings, we recommend that natural resource trustees include an evaluation of future model uncertainty as part of their initial data collection efforts. This will allow them to deploy resources in a way that maximizes the utility of future deposition model results. We also identify several factors that do not need to be assessed immediately following a spill event, thereby potentially freeing resources for more time critical data collection efforts.


Assuntos
Aves , Poluição por Petróleo , Poluentes Químicos da Água , Animais , Monitoramento Ambiental , Golfo do México , Modelos Teóricos , Poluentes Químicos da Água/toxicidade
8.
Environ Monit Assess ; 191(Suppl 4): 817, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32185520

RESUMO

The Natural Resource Damage Assessment and Restoration Trustees for the Deepwater Horizon oil spill assessed the external oiling of migratory bird species dependent on open water in the Gulf of Mexico following the aforementioned spill. The assessment was designed to evaluate birds that use open water during the winter within 40 km of the Gulf shoreline. We focused on the American white pelican (Pelecanus erythrorhynchos), common loon (Gavia immer), and northern gannet (Morus bassanus). Point counts (pelican, loon) or strip transects (gannet) were used and each target species was assessed for oiling (unoiled, trace, light, moderate, or heavy amounts) and photographed. Due to distance at sighting and/or poor visibility, not all visible birds were assessed. The percentage of birds oiled varied by species, with the common loon being the highest (23.6%), followed by American white pelican (16.9%), and northern gannet (6.9%). Most of the American white pelicans and common loons had trace (83% and 72%, respectively) or light levels (11% and 24%, respectively) of oiling. The northern gannet had just trace levels of oiling. Some pelicans (6%) and loons (4%) had moderate amounts of oiling. Based on expert derived-mortality estimates and our estimates of oil exposure, we used Monte Carlo simulations to predict expected decreases of 2.5%, 4%, and 11% in the observed population for the northern gannet, American white pelican, and common loon, respectively. While these values are underestimates of the true values given the long time lag (10-12 months) between the oil spill and the assessment, these data represent some of the few estimates of exposure for these species and describe minimum risk estimates to these species.


Assuntos
Aves , Poluição por Petróleo , Poluentes Químicos da Água , Animais , Monitoramento Ambiental , Golfo do México , Estações do Ano , Poluentes Químicos da Água/toxicidade
9.
Environ Monit Assess ; 191(Suppl 4): 813, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32185545

RESUMO

During a marine oil spill, injured birds often die on the water, some eventually washing ashore, but others becoming waterlogged and sinking or being scavenged before reaching the shoreline. Birds that disappear before they can be deposited on the shoreline are difficult to enumerate, but they commonly represent a large fraction of total oil spill-related mortality. As part of the process of quantifying the overall impact to seabirds resulting from the Deepwater Horizon oil spill, it was necessary to estimate the number of dead birds lost at sea. We conducted a study to estimate the beaching probability of birds that died at sea in the Gulf of Mexico in the areas most heavily used by seabirds and impacted by the spill. Using a mark-recapture analysis to derive the beaching probability from our field study data, we estimated that dead birds afloat at sea had about a 0.1414 probability of beaching in areas searched during the Deepwater Horizon oil spill. Sensitivity analyses of our model and requisite assumptions suggested that if our assumptions were violated, the "true" beaching probability could be anywhere between 0.11 and 0.16. These estimates are much lower than beaching probabilities estimated for seabirds killed during the Exxon Valdez oil spill in the waters of Alaska, for example, likely reflect higher rates of decomposition and scavenging in the warmer waters of the Gulf of Mexico. Our estimate suggests that bird carcasses that washed onshore during the Deepwater Horizon oil spill represented only 14% of those killed at sea during the spill.


Assuntos
Aves , Poluição por Petróleo , Poluentes Químicos da Água , Alaska , Animais , Monitoramento Ambiental , Golfo do México , Mortalidade , Dinâmica Populacional , Probabilidade , Poluentes Químicos da Água/toxicidade
10.
Environ Monit Assess ; 191(Suppl 4): 815, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32185585

RESUMO

As part of the natural resource damage assessment for the Deepwater Horizon oil spill, a mathematical model was used to estimate the total number of bird carcasses deposited on shorelines based on the number of carcasses collected and adjustment factors such as detection probability and carcass persistence. Studies of carcass persistence occurred along sandy beaches and marsh edges in the northern Gulf of Mexico to obtain site-specific inputs for the model. We estimated persistence rates for these habitat types and evaluated the influence on persistence of carcass size, location of the carcass on the beach, dominant vegetation type in the marsh, carcass distance into marsh vegetation, and length of time a carcass was stranded on a shoreline. The length of time stranded had the greatest influence on persistence in both habitat types, with persistence initially relatively low and increasing logarithmically. Carcass size and position were weakly influential on sandy beaches. Carcass size had stronger influences along marsh edges, and marsh habitat type also affected persistence. We found evidence of a positive relationship between distance into the marsh and persistence during the first 24 h after carcass deployment.


Assuntos
Aves , Poluição por Petróleo , Poluentes Químicos da Água , Áreas Alagadas , Animais , Cadáver , Monitoramento Ambiental , Golfo do México
11.
Environ Monit Assess ; 191(Suppl 4): 818, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32185528

RESUMO

Using ship-based surveys, the Natural Resource Damage Assessment (NRDA) Trustees assessed the external oiling of offshore and pelagic marine birds inhabiting the northern Gulf of Mexico (Gulf) in the year following the Deepwater Horizon oil spill (DWH spill). Study objectives were to (1) collect data on pelagic seabirds that were visibly oiled, (2) collect data to estimate abundance of seabirds in offshore and pelagic waters, and 3) document the location and condition of any bird carcasses encountered. Methods employed included strip line transects and station point counts. Surveys were conducted within a study area bound by the Texas-Mexico border and the Dry Tortugas of Florida to the south, and the nearshore coastal waters of the northern Gulf of Mexico. A total of 5665 strip line transects and 386 station point-counts of variable duration were collected during the study. More than 23,000 individual seabirds comprising 45 estuarine, coastal, offshore, and pelagic species were tallied. Average daily abundance of seabirds detected varied from a low of approximately 7 birds/day in November 2010 along regions of the mid- and outer continental shelf to a high of more than 580 birds/day in June 2011 within the near-shore, coastal waters of the northern Gulf.


Assuntos
Aves , Poluição por Petróleo , Petróleo , Poluentes Químicos da Água , Animais , Monitoramento Ambiental , Florida , Golfo do México , Petróleo/toxicidade , Dinâmica Populacional , Texas , Poluentes Químicos da Água/toxicidade
12.
Environ Sci Technol ; 54(6): 3530-3538, 2020 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-32149499

RESUMO

Shipboard measurements of offshore oil and gas facilities were conducted in the Gulf of Mexico in February 2018. Species measured at 1 s include methane, ethane, carbon-13 (13C) and deuterium (D) isotopes of methane, and several combustion tracers. Significant variability in the emission composition is observed between individual sites, with typical ethane/methane ratios around 5.3% and 13C and D methane isotopic compositions around -40 and -240‰, respectively. Offshore plumes were spatially narrower than expectations of the plume width based on terrestrial atmospheric stability classes; a modified Gaussian dispersion methodology using empirically measured horizontal plume widths was used to estimate the emission rates. A total of 103 sites were studied, including shallow and deepwater offshore platforms and drillships. Methane emission rates range from 0 to 190 kg/h with 95% confidence limits estimated at a factor of 10. The observed distribution is skewed with the top two emitters accounting for 20% of the total methane emissions of all sampled sites. Despite the greater throughput of the deepwater facilities, they had moderate emission rates compared to shallow-water sites. Analysis of background ethane enhancements also suggests a source region in shallow waters. A complete 1 s measurement database is published for use in future studies of offshore dispersion.


Assuntos
Poluentes Atmosféricos , Metano , Monitoramento Ambiental , Etano , Golfo do México , Gás Natural
13.
PLoS One ; 15(1): e0228554, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32004358

RESUMO

Concerns on the timing and processes associated with petroleum degradation were raised after the use of Corexit during the Deepwater Horizon oil spill. There is a lack of understanding of the removal of oil associated with flocculate materials to the sediment. Mesocosm studies employing coastal and open-ocean seawater from the Gulf of Mexico were undertaken to examine changes in oil concentration and composition with time. The water accommodated fractions (WAF) and chemically enhanced WAF (CEWAF) produced using Macondo surrogate oil and Corexit were followed over 3-4 days in controlled environmental conditions. Environmental half-lives of estimated oil equivalents (EOE), polycyclic aromatic hydrocarbons (PAH), n-alkanes (C10-C35), isoprenoids pristane and phytane, and total petroleum hydrocarbons (TPH) were determined. EOE and PAH concentrations decreased exponentially following first-order decay rate kinetics. WAF, CEWAF and DCEWAF (a 10X CEWAF dilution) treatments half-lives ranged from 0.9 to 3.2 days for EOE and 0.5 to 3.3 days for PAH, agreeing with estimates from previous mesocosm and field studies. The aliphatic half-lives for CEWAF and DECWAF treatments ranged from 0.8 to 2.0 days, but no half-life for WAF could be calculated as concentrations were below the detection limits. Biodegradation occurred in all treatments based on the temporal decrease of the nC17/pristane and nC18/phytane ratios. The heterogeneity observed in all treatments was likely due to the hydrophobicity of oil and weathering processes occurring at different rates and times. The presence of dispersant did not dramatically change the half-lives of oil. Comparing degradation of oil alone as well as with dispersant present is critical to determine the fate and transport of these materials in the ocean.


Assuntos
Hidrocarbonetos/análise , Poluição por Petróleo/análise , Poluentes Químicos da Água/análise , Biodegradação Ambiental , Golfo do México , Meia-Vida , Interações Hidrofóbicas e Hidrofílicas , Água do Mar/química
14.
Environ Monit Assess ; 192(3): 168, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32034511

RESUMO

Agricultural nonpoint source pollution from the upper areas of the Upper Mississippi, Missouri, and Ohio River basins accounts for the majority of the excess nitrogen that leads to the Gulf of Mexico's hypoxic zone. However, agriculture landscapes across the USA, Europe, and China are undergoing major changes related to the proliferation of confined animal feeding operations (CAFOs) that account for a greater proportion of point source contamination. Mitigating long-term nutrient inputs at a large scale (Mississippi River Basin) requires understanding these microscale changes at the small watershed level (less than 100 km2). To assess the control of land-use and subsurface hydrological processes on nutrient fate and transport, temporal patterns in nutrient concentrations in a mixed land-use karstic watershed were analyzed. To assess the control of differential land-use sources on total inorganic nitrogen (TIN) loads within the watershed, 4 months of weekly water sampling was performed at a spring location and at two underground conduit locations. The observed temporal variations in nutrient concentrations are primarily associated with seasonal changes in land-use associated with corn growth. Data show that land-use sources explain much of the temporal variability of TIN at the spring when weighted against the hydrological factor. End-member-mixing analysis of dissolved organic carbon (DOC) shows a progressive increase in the contribution of DOC-enriched sources and a more labile form of carbon toward the harvest time. Overall, during high flow, nonpoint source infiltration from manure-fertilized croplands in the northern branch (NB) dominate DOC loads. Because conduit-dominated karstic aquifers are more susceptible to contamination from direct and fast (< 7 h) subsurface infiltration during late summer rainfall period (July to August), a slight advance in the timing of manure application could substantially reduce nutrient loads to local groundwater. A combined evaluation of subsurface hydrological processes and land-use factors controlling nutrients at the scale of small watersheds is crucial to developing site-specific nutrient management plans and managing the Gulf of Mexico's hypoxic zone.


Assuntos
Monitoramento Ambiental , Água Subterrânea , Nutrientes , Agricultura , Animais , China , Europa (Continente) , Golfo do México , Nitrogênio , Rios , Estados Unidos
15.
Mar Pollut Bull ; 151: 110794, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32056589

RESUMO

There is an increasing awareness of microplastics within the global problem of marine plastic pollution. In 2018, small plastic pellets or "nurdles" were observed on the beaches of Corpus Christi, Texas. A citizen science project, "Nurdle Patrol," was established by the Mission-Aransas National Estuarine Research Reserve to monitor the presence of nurdles, with volunteer interest enabling this project to expand across the Gulf of Mexico region. This case study describes the sampling methodology, the policy framework, and initial quantitative data from the citizen science project on nurdle distribution along the Gulf coast. A total of 2042 Nurdle Patrol surveys have been conducted by 744 citizen scientists covering shorelines from Mahahual, Mexico to Fort Jefferson, Florida. All 20 of the highest standardized nurdle counts were recorded at sites in Texas. Results can inform decision-maker response across regulatory scales and further research on nurdle pollution.


Assuntos
Monitoramento Ambiental , Plásticos , Resíduos , Poluentes da Água/análise , Política Ambiental , Florida , Golfo do México , Humanos , Texas
16.
PLoS One ; 15(1): e0227665, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31999717

RESUMO

The restoration of mangroves has gained prominence in recent decades. Hydrological rehabilitation has been undertaken to connect impaired mangroves with the sea, lagoons or estuaries. Because mangrove hydrodynamics occurs on the surface and interstitial spaces in the sediment, we propose to determine the hydrological flow paths to restore the hydrological regimes of the impaired mangroves. The hydrological flow paths were determined through a micro basin analysis based on microtopographic data to generate a digital elevation model. Applying this methodological approach, the hydrology of an impaired area on a barrier island in the Gulf of Mexico was restored by excavating, desilting or clearing the channels on the identified hydrological flow paths. This area was compared to one in which impaired mangroves were reconnected to the marine lagoon but disregarding the flow paths. Data collected in both areas were evaluated by flood level analysis, using two methods: (i) a simple linear regression model (SLRM) and (ii) spectral analysis (SA), also known as dominant frequency analysis. The results suggest that restoration based on the hydrological flow paths was more effective than the direct opening to the nearest main water body without accounting for the microtopography. In both areas, soil salinity and sulfides decreased after hydrological reconnection. However, a greater efficiency in the investment of time and human resources was achieved when preferential flow paths were identified and taken into account. The methodological procedures described in this study are of universal application to other mangrove restoration programs.


Assuntos
Conservação dos Recursos Naturais/métodos , Áreas Alagadas , Mudança Climática/estatística & dados numéricos , Conservação dos Recursos Naturais/estatística & dados numéricos , Conservação dos Recursos Hídricos/métodos , Conservação dos Recursos Hídricos/estatística & dados numéricos , Monitoramento Ambiental/estatística & dados numéricos , Estuários , Inundações/prevenção & controle , Inundações/estatística & dados numéricos , Golfo do México , Hidrodinâmica , Ilhas , Modelos Lineares , México , Modelos Teóricos , Salinidade , Solo
17.
PLoS One ; 15(1): e0228254, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978207

RESUMO

Warsaw grouper, Hyporthodus nigritus, is a western Atlantic Ocean species typically found at depths between 55 and 525 m. It is listed as a species of concern by the U.S. National Marine Fisheries Service and as near threatened by the International Union for the Conservation of Nature. However, little information exists on the species' life history in the northern Gulf of Mexico (nGOM) and its stock status in that region is currently unknown. Age of nGOM Warsaw grouper was investigated via opaque zone counts in otolith thin sections (max age = 61 y), and then the bomb 14C chronometer was employed to validate the accuracy of age estimates. Otolith cores (n = 14) were analyzed with accelerator mass spectrometry and resulting Δ14C values overlain on a loess regression computed for a regional coral and known-age red snapper Δ14C time series. Residual analysis between predicted Δ14C values from the loess regression versus Warsaw grouper otolith core Δ14C values indicated no significant difference in the two data series. Therefore, the accuracy of otolith-based aging was validated, which enabled growth and longevity estimates to be made for nGOM Warsaw grouper. Dissolved inorganic carbon (DIC) Δ14C values collected from the nGOM support the inference that juvenile Warsaw grouper occur in shelf waters (<200 m) since DIC Δ14C values in this depth range are enriched in 14C and similar to the Δ14C values from otolith cores. A Bayesian model was fit to fishery-dependent age composition data and produced von Bertalanffy growth function parameters of L∞ = 1,533 mm, k = 0.14 y-1, and t0 = 1.82 y. Fishing mortality also was estimated in the model, which resulted in a ratio of fishing to natural mortality of 5.1:1. Overall, study results indicate Warsaw grouper is a long-lived species that is estimated to have experienced significant overfishing in the nGOM, with the age of most landed fish being <10 y.


Assuntos
Membrana dos Otólitos/química , Perciformes/fisiologia , Datação Radiométrica/métodos , Animais , Teorema de Bayes , Radioisótopos de Carbono/química , Pesqueiros , Golfo do México , Longevidade , Espectrometria de Massas , Perciformes/crescimento & desenvolvimento
18.
Environ Pollut ; 259: 113858, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31927273

RESUMO

Oil spills can result in changes in chemical contaminant concentrations along coastlines. When concentrations are measured along the Gulf of Mexico over time, this information can be used to evaluate oil spill shoreline exposure dates. The objective of this research was to identify more accurate oil exposure dates based on oil spill chemical concentrations changes (CCC) within sediments in coastal zones after oil spills. The results could be used to help improve oil transport models and to improve estimates of oil landings within the nearshore. The CCC method was based on separating the target coastal zone into segments and then documenting the timing of large increases in concentration for specific oil spill chemicals (OSCs) within each segment. The dataset from the Deepwater Horizon (DWH) oil spill was used to illustrate the application of the method. Some differences in exposure dates were observed between the CCC method and between oil spill trajectories. Differences may have been caused by mixing at the freshwater and sea water interface, nearshore circulation features, and the possible influence of submerged oil that is unaccounted for by oil spill trajectories. Overall, this research highlights the benefit of using an integrated approach to confirm the timing of shoreline exposure.


Assuntos
Monitoramento Ambiental , Poluição por Petróleo , Poluentes Químicos da Água , Exposição Ambiental , Monitoramento Ambiental/métodos , Golfo do México , Modelos Teóricos , Poluição por Petróleo/análise , Movimentos da Água , Poluentes Químicos da Água/análise
19.
Mar Pollut Bull ; 150: 110805, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31910531

RESUMO

The dynamics of crude oil and different surface ocean drifters were compared to study the physical processes that govern the transport and landfall of marine oil spills. In a wave-tank experiment, drifters with drogue did not follow oil slicks. However, patches of undrogued drifters and thin bamboo plates did spread at the same rate and in the same direction as the crude oil slicks. Then, the trajectories of the Deepwater Horizon oil spill and 1300 drifters released near the spill source were investigated. Undrogued drifters were transported twice as fast as drogued drifters across the isobaths. 25% of the undrogued drifters landed, versus about 5% of the drogued ones, for the most part, on the same coastline locations where oil was found after Deepwater Horizon. Results highlight the importance of near surface gradients in controlling the cross-shelf transport and landing of surface material on the Gulf of Mexico's northern shores.


Assuntos
Monitoramento Ambiental , Poluição por Petróleo , Petróleo , Golfo do México , Laboratórios
20.
Sci Total Environ ; 703: 135551, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31767300

RESUMO

Ten grouper species grouper (n = 584) were collected throughout the Gulf of Mexico (GoM) from 2011 through 2017 to provide information on hepatobiliary polycyclic aromatic hydrocarbon (PAH) concentrations in the aftermath of the Deepwater Horizon (DWH) oil spill. Liver and bile samples were analyzed for PAHs and their metabolites using triple quadrupole mass spectrometry (GC/MS/MS) and high-performance liquid chromatography with fluorescence detection (HPLC-F), respectively. Data were compared among species and sub-regions of the GoM to understand spatiotemporal exposure dynamics in these economically and ecologically important species. Significant differences in the composition and concentrations of PAHs were detected spatially, over time and by species. The West Florida Shelf, Cuba coast and the Yucatan Shelf had a greater proportion of the pyrogenic PAHs in their livers than the other regions likely due to non-oil industry related sources (e.g., marine vessel traffic) in the regional composition profiles. Mean liver PAH concentrations were highest in the north central region of the GoM where DWH occurred. Biliary PAH concentrations and health indicator biometrics initially decrease during the first three years following the DWH oil spill but significantly increased thereafter. Increased exposures are likely explained by the resuspension of residual DWH oil as well as continued inputs from natural (e.g., seeps) sources and other anthropogenically derived sources (e.g., riverine runoff, other oil spills, and leaking oil and gas infrastructure). The increasing trend in PAH concentrations in the bile and liver of grouper species in the north central region of the GoM post-DWH suggest continued chronic exposures, however the critical stage at which permanent, irreparable damage may occur is unknown. Long-term monitoring of PAH levels and associated fish health biomarkers is necessary to evaluate impacts of chronic exposures, particularly in regions subject to intensive oil extraction activities.


Assuntos
Monitoramento Ambiental , Peixes/fisiologia , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Golfo do México , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Testes de Toxicidade Crônica , Poluentes Químicos da Água/toxicidade
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