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1.
PLoS One ; 15(9): e0238550, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32976502

RESUMO

Knowledge of community resilience aids the development of strategies to mitigate the impacts of a disturbance. An extreme low-seawater temperature event in late January and February 2008 resulted in high fish mortality in the coastal waters of the Penghu Islands, Taiwan. In this study, we used underwater diving visual censuses to analyze fish communities at eight sampling stations along the coast of the Penghu Islands for seven years after the 2008 event. We evaluated community metrics, including species richness, abundance-weighted diversity, average thermal affinity, and average trophic level, and described the temporal variation in select dominant species abundances. Species richness and diversity of the communities required 53 months to reach a steady-state at the sampling stations following the cold water intrusion. The cold event initially reduced community thermal affinity, which then increased throughout the study period, reflecting the recovery of the community to baseline thermal conditions. The increased average trophic level after the cold event implied that the temperature shock decreased the proportion of lower trophic-level fishes. Average trophic level declined as the communities recovered from the disturbance, reflecting the recovery of the community to baseline species composition in terms of feeding habit. Our results suggest that functional diversity may require longer to recover than taxonomic diversity for communities in the Penghu Islands.


Assuntos
Biodiversidade , Peixes , Animais , Clima , Temperatura Baixa , Ecossistema , Peixes/fisiologia , Água do Mar/análise , Taiwan
2.
PLoS One ; 15(9): e0238432, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32881918

RESUMO

The carbonate system in two contrasting fjords, Rivers Inlet and Bute Inlet, on the coast of British Columbia, Canada, was evaluated to characterize the mechanisms driving carbonate chemistry dynamics and assess the impact of anthropogenic carbon. Differences in the character of deep water exchange between these fjords were inferred from their degree of exposure to continental shelf water and their salinity relationships with total alkalinity and total dissolved inorganic carbon, which determined seawater buffering capacity. Seawater buffering capacity differed between fjords and resulted in distinct carbonate system characteristics with implications on calcium carbonate saturation states and sensitivity to increasing anthropogenic carbon inputs. Saturation states of both aragonite and calcite mineral phases of calcium carbonate were seasonally at or below saturation throughout the entire water column in Bute Inlet, while only aragonite was seasonally under-saturated in portions of the water column in Rivers Inlet. The mean annual saturation states of aragonite in Rivers Inlet and calcite in Bute Inlet deep water layers have declined to below saturation within the last several decades due to anthropogenic carbon accumulation, and similar declines to undersaturation are projected in their surface layers as anthropogenic carbon continues to accumulate. This study demonstrates that the degree of fjord water exposure to open shelf water influences the uptake and sensitivity to anthropogenic carbon through processes affecting seawater buffering capacity, and that reduced uptake but greater sensitivity occurs where distance to ocean source waters and freshwater dilution are greater.


Assuntos
Carbonatos/análise , Monitoramento Ambiental/métodos , Água do Mar/química , Colúmbia Britânica , Carbonato de Cálcio/química , Carbono/química , Dióxido de Carbono/análise , Ecossistema , Estuários , Concentração de Íons de Hidrogênio , Salinidade , Água do Mar/análise
3.
Nature ; 584(7821): 393-397, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32814886

RESUMO

The rate of global-mean sea-level rise since 1900 has varied over time, but the contributing factors are still poorly understood1. Previous assessments found that the summed contributions of ice-mass loss, terrestrial water storage and thermal expansion of the ocean could not be reconciled with observed changes in global-mean sea level, implying that changes in sea level or some contributions to those changes were poorly constrained2,3. Recent improvements to observational data, our understanding of the main contributing processes to sea-level change and methods for estimating the individual contributions, mean another attempt at reconciliation is warranted. Here we present a probabilistic framework to reconstruct sea level since 1900 using independent observations and their inherent uncertainties. The sum of the contributions to sea-level change from thermal expansion of the ocean, ice-mass loss and changes in terrestrial water storage is consistent with the trends and multidecadal variability in observed sea level on both global and basin scales, which we reconstruct from tide-gauge records. Ice-mass loss-predominantly from glaciers-has caused twice as much sea-level rise since 1900 as has thermal expansion. Mass loss from glaciers and the Greenland Ice Sheet explains the high rates of global sea-level rise during the 1940s, while a sharp increase in water impoundment by artificial reservoirs is the main cause of the lower-than-average rates during the 1970s. The acceleration in sea-level rise since the 1970s is caused by the combination of thermal expansion of the ocean and increased ice-mass loss from Greenland. Our results reconcile the magnitude of observed global-mean sea-level rise since 1900 with estimates based on the underlying processes, implying that no additional processes are required to explain the observed changes in sea level since 1900.


Assuntos
Temperatura Alta , Camada de Gelo/química , Água do Mar/análise , Água do Mar/química , Monitoramento Ambiental , Aquecimento Global/estatística & dados numéricos , Groenlândia , História do Século XX , História do Século XXI , Probabilidade , Incerteza
4.
Nature ; 584(7819): 82-86, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32760046

RESUMO

Marine heatwaves (MHWs)-discrete but prolonged periods of anomalously warm ocean temperatures-can drastically alter ocean ecosystems, with profound ecological and socioeconomic impacts1-8. Considerable effort has been directed at understanding the patterns, drivers and trends of MHWs globally9-11. Typically, MHWs are characterized on the basis of their intensity and persistence at a given location-an approach that is particularly relevant for corals and other sessile organisms that must endure increased temperatures. However, many ecologically and commercially important marine species respond to environmental disruptions by relocating to favourable habitats, and dramatic range shifts of mobile marine species are among the conspicuous impacts of MHWs1,4,12,13. Whereas spatial temperature shifts have been studied extensively in the context of long-term warming trends14-18, they are unaccounted for in existing global MHW analyses. Here we introduce thermal displacement as a metric that characterizes MHWs by the spatial shifts of surface temperature contours, instead of by local temperature anomalies, and use an observation-based global sea surface temperature dataset to calculate thermal displacements for all MHWs from 1982 to 2019. We show that thermal displacements during MHWs vary from tens to thousands of kilometres across the world's oceans and do not correlate spatially with MHW intensity. Furthermore, short-term thermal displacements during MHWs are of comparable magnitude to century-scale shifts inferred from warming trends18, although their global spatial patterns are very different. These results expand our understanding of MHWs and their potential impacts on marine species, revealing which regions are most susceptible to thermal displacement, and how such shifts may change under projected ocean warming. The findings also highlight the need for marine resource management to account for MHW-driven spatial shifts, which are of comparable scale to those associated with long-term climate change and are already happening.


Assuntos
Migração Animal , Organismos Aquáticos , Ecossistema , Calor Extremo , Aquecimento Global , Água do Mar/análise , Animais , Calor Extremo/efeitos adversos , Aquecimento Global/estatística & dados numéricos , História do Século XX , História do Século XXI , Modelos Teóricos , Oceanos e Mares
5.
Nature ; 584(7820): 227-233, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32788734

RESUMO

Anthropogenic global surface warming is proportional to cumulative carbon emissions1-3; this relationship is partly determined by the uptake and storage of heat and carbon by the ocean4. The rates and patterns of ocean heat and carbon storage are influenced by ocean transport, such as mixing and large-scale circulation5-10. However, existing climate models do not accurately capture the observed patterns of ocean warming, with a large spread in their projections of ocean circulation and ocean heat uptake8,11. Additionally, assessing the influence of ocean circulation changes (specifically, the redistribution of heat by resolved advection) on patterns of observed and simulated ocean warming remains a challenge. Here we establish a linear relationship between the heat and carbon uptake of the ocean in response to anthropogenic emissions. This relationship is determined mainly by intrinsic parameters of the Earth system-namely, the ocean carbon buffer capacity, the radiative forcing of carbon dioxide and the carbon inventory of the ocean. We use this relationship to reveal the effect of changes in ocean circulation from carbon dioxide forcing on patterns of ocean warming in both observations and global Earth system models from the Fifth Coupled Model Intercomparison Project (CMIP5). We show that historical patterns of ocean warming are shaped by ocean heat redistribution, which CMIP5 models simulate poorly. However, we find that projected patterns of heat storage are primarily dictated by the pre-industrial ocean circulation (and small changes in unresolved ocean processes)-that is, by the patterns of added heat owing to ocean uptake of excess atmospheric heat rather than ocean warming by circulation changes. Climate models show more skill in simulating ocean heat storage by the pre-industrial circulation compared to heat redistribution, indicating that warming patterns of the ocean may become more predictable as the climate warms.


Assuntos
Dióxido de Carbono/análise , Aquecimento Global , Temperatura Alta , Oceanos e Mares , Água do Mar/análise , Água do Mar/química , Movimentos da Água , Atmosfera/química , Atividades Humanas
6.
PLoS One ; 15(7): e0235817, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32678858

RESUMO

Whether marine fish will grow differently in future high pCO2 environments remains surprisingly uncertain. Long-term and whole-life cycle effects are particularly unknown, because such experiments are logistically challenging, space demanding, exclude long-lived species, and require controlled, restricted feeding regimes-otherwise increased consumption could mask potential growth effects. Here, we report on repeated, long-term, food-controlled experiments to rear large populations (>4,000 individuals total) of the experimental model and ecologically important forage fish Menidia menidia (Atlantic silverside) under contrasting temperature (17°, 24°, and 28°C) and pCO2 conditions (450 vs. ~2,200 µatm) from fertilization to ~ a third of this annual species' life span. Quantile analyses of trait distributions showed mostly negative effects of high pCO2 on long-term growth. At 17°C and 28°C, but not at 24°C, high pCO2 fish were significantly shorter [17°C: -5 to -9%; 28°C: -3%] and weighed less [17°C: -6 to -18%; 28°C: -8%] compared to ambient pCO2 fish. Reductions in fish weight were smaller than in length, which is why high pCO2 fish at 17°C consistently exhibited a higher Fulton's k (weight/length ratio). Notably, it took more than 100 days of rearing for statistically significant length differences to emerge between treatment populations, showing that cumulative, long-term CO2 effects could exist elsewhere but are easily missed by short experiments. Long-term rearing had another benefit: it allowed sexing the surviving fish, thereby enabling rare sex-specific analyses of trait distributions under contrasting CO2 environments. We found that female silversides grew faster than males, but there was no interaction between CO2 and sex, indicating that males and females were similarly affected by high pCO2. Because Atlantic silversides are known to exhibit temperature-dependent sex determination, we also analyzed sex ratios, revealing no evidence for CO2-dependent sex determination in this species.


Assuntos
Dióxido de Carbono/análise , Peixes/crescimento & desenvolvimento , Animais , Dióxido de Carbono/metabolismo , Mudança Climática , Feminino , Masculino , Água do Mar/análise , Processos de Determinação Sexual , Diferenciação Sexual , Temperatura
7.
PLoS One ; 15(6): e0235235, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32598345

RESUMO

Mobile Bay, the fourth largest estuary in the USA located in the northern Gulf of Mexico, is known for extreme hypoxia in the water column during dry season caused by NH4+-rich and anoxic submarine groundwater discharge (SGD). Nutrient dynamics in the coastal ecosystem point to potentially elevated microbial activities; however, little is known about microbial community composition and their functional roles in this area. In this study, we investigated microbial community composition, distribution, and metabolic prediction along the coastal hydrological compartment of Mobile Bay using 16S rRNA gene sequencing. We collected microbial samples from surface (river and bay water) and subsurface water (groundwater and coastal pore water from two SGD sites with peat and sandy lithology, respectively). Salinity was identified as the primary factor affecting the distribution of microbial communities across surface water samples, while DON and PO43- were the major predictor of community shift within subsurface water samples. Higher microbial diversity was found in coastal pore water in comparison to surface water samples. Gammaproteobacteria, Bacteroidia, and Oxyphotobacteria dominated the bacterial community. Among the archaea, methanogens were prevalent in the peat-dominated SGD site, while the sandy SGD site was characterized by a higher proportion of ammonia-oxidizing archaea. Cyanobium PCC-6307 and unclassified Thermodesulfovibrionia were identified as dominant taxa strongly associated with trends in environmental parameters in surface and subsurface samples, respectively. Microbial communities found in the groundwater and peat layer consisted of taxa known for denitrification and dissimilatory nitrate reduction to ammonium (DNRA). This finding suggested that microbial communities might also play a significant role in mediating nitrogen transformation in the SGD flow path and in affecting the chemical composition of SGD discharging to the water column. Given the ecological importance of microorganisms, further studies at higher taxonomic and functional resolution are needed to accurately predict chemical biotransformation processes along the coastal hydrological continuum, which influence water quality and environmental condition in Mobile Bay.


Assuntos
Monitoramento Ambiental/métodos , Água Subterrânea/análise , Água Subterrânea/microbiologia , Microbiota , Água do Mar/análise , Água do Mar/microbiologia , Golfo do México , Hidrologia , RNA Ribossômico 16S/análise , Movimentos da Água
8.
Chemosphere ; 258: 127307, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32554007

RESUMO

This study presents a new approach for the investigation of tributyltin (TBT) behaviour and fate in the marine environment. The approach is based on a simultaneous analysis of butyltins (BuTs) and total Sn in sediments, thus enabling an assessment of long-term persistence and historical input of TBT. The study also presents first evaluation of the extent to which the TBT-antifouling paints contribute to the contamination of coastal environments with inorganic Sn; it was demonstrated that the inorganic Sn in the investigated areas primarily originates from TBT degradation. The study was conducted by analyzing BuTs and total Sn in sediments from 34 locations along the Croatian Adriatic coast. The results revealed that 85% of the locations were contaminated with both BuTs and inorganic Sn. The share of Æ©BuTs/total Sn was low (<10%) even in sediments with low TBT degradation efficiency (TBT/Æ©BuTs >40%), demonstrating that only small portion of TBT introduced into the water column reached the sediment before being degraded. This means that recent TBT input into the marine environment may be at least 10 times higher than the amount estimated if only BuTs levels in sediments are considered. It was also demonstrated that TBT concentration in sediments with TOC <1% is not a good indicator of the overall pollution level, even if TBT/TOC approach is used in pollution assessment. Finally, in situ investigation showed that resuspension of contaminated sediments leads to significant release of MBT and DBT into the water column, whereas TBT mainly remains in sediment.


Assuntos
Monitoramento Ambiental , Compostos Orgânicos de Estanho/análise , Poluentes Químicos da Água/análise , Sedimentos Geológicos/análise , Pintura , Água do Mar/análise , Estanho/análise , Compostos de Trialquitina
9.
PLoS One ; 15(5): e0232065, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32374730

RESUMO

Thermal discharge from a nuclear power plant (NPP) provides an opportunity to foresee changes in faunal communities that may be induced by ocean warming. I assessed these changes by identifying characteristics of the fish community near the thermal discharge from a NPP and by recording temporal changes that occurred after the suspension of the NPP. Underwater visual censuses were conducted near Takahama NPP in the Sea of Japan, and fish assemblages were compared to those in two other sites: a site with discharge from a coal-fired power plant and a control site. During the surveyed period (8 years) when the NPP was in operation, the sea water temperature at the site near the NPP was warmer, had a significantly higher fish abundance, and a higher species richness, including tropical fishes, than the other two sites. However, once the NPP was suspended, tropical fishes dramatically decreased near the NPP. This abrupt change in fish assemblage may be due to the lowest lethal temperatures of tropical fishes being only slightly higher than the winter temperature in this area. Relatively poor ecosystem structure in the local warming area may also have contributed to low resilience of tropical fish species to this temperature change.


Assuntos
Biodiversidade , Mudança Climática , Peixes , Centrais Nucleares , Animais , Ecossistema , Meio Ambiente , Peixes/classificação , Peixes/fisiologia , Japão/epidemiologia , Centrais Nucleares/organização & administração , Oceanos e Mares , Dinâmica Populacional , Estações do Ano , Água do Mar/análise , Temperatura , Clima Tropical
10.
Chemosphere ; 257: 127151, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32470539

RESUMO

Spatial distributions of bromocarbons, including bromoform (CHBr3), dibromochloromethane (CHBr2Cl), and dibromomethane (CH2Br2), and influential oceanographic parameters that determine their concentrations were measured in the marine atmosphere and seawater of the East China Sea (ECS) and western Pacific Ocean during two cruises from 14 to 24 September, 2017 and from 5 October to 3 December, 2018. The atmospheric concentrations of CHBr3, CHBr2Cl, and CH2Br2 were 0.33-3.02, 0.16-1.96, and 0.85-1.75 pptv over the western Pacific Ocean and 2.23-4.92, 0.26-1.52, and 0.24-7.47 pptv over the ECS, respectively. There was significant spatial variability in atmospheric bromocarbon concentrations in the study region, with higher concentration over the ECS. The atmospheric mixing ratios of bromocarbons were significantly correlated to the surface seawater bromocarbon concentrations and wind speed. In the ECS, input from terrestrial sources also significantly influenced the distributions of bromocarbons in air. PCA analysis revealed that seawater bromocarbon concentrations were correlated with both water mass and chlorophyll a. Generally lower CH2Br2/CHBr3 ratios were observed in the ECS, which was indicative of mixing and/or dilution in coastal areas. The estimated average sea-to-air fluxes of CHBr2Cl, CH2Br2, and CHBr3 were 46.86, -3.77, and -6.71 nmol m-2 d-1 in the western Pacific Ocean and 111.49, 0.89, and 321.74 nmol m-2 d-1 in the ECS, respectively. These results of the net sea-to-air fluxes indicated oceanic net uptake of CH2Br2 and CHBr3 for the western Pacific Ocean and oceanic emission of bromocarbons for the ECS.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Hidrocarbonetos Bromados/análise , Atmosfera/análise , China , Clorofila A , Oceanos e Mares , Oceano Pacífico , Água do Mar/análise , Trialometanos/análise
11.
PLoS One ; 15(4): e0231718, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32310994

RESUMO

Water sampling and filtration of environmental DNA (eDNA) analysis have been performed by several different methods, and each method may yield a different species composition or eDNA concentration. Here, we investigated the eDNA of seawater samples directly collected by SCUBA to compare two widely used filtration methods: open filtration with a glass filter (GF/F) and enclosed filtration (Sterivex). We referred to biomass based on visual observation data collected simultaneously to clarify the difference between organism groups. Water samples were collected at two points in the Sea of Japan in May, September and December 2018. The respective samples were filtered through GF/F and Sterivex for eDNA extraction. We quantified the eDNA concentration of five fish and two cnidarian species by quantitative polymerase chain reaction (qPCR) using species-specific primers/probe sets. A strong correlation of eDNA concentration was obtained between GF/F and Sterivex; the intercepts and slopes of the linear regression lines were slightly different in fish and jellyfish. The amount of eDNA detected using the GF/F filtration method was higher than that detected using Sterivex when the eDNA concentration was high; the opposite trend was observed when the eDNA concentration was relatively low. The concentration of eDNA correlated with visually estimated biomass; eDNA concentration per biomass in jellyfish was approximately 700 times greater than that in fish. We conclude that GF/F provides an advantage in collecting a large amount of eDNA, whereas Sterivex offers superior eDNA sensitivity. Both filtration methods are effective in estimating the spatiotemporal biomass size of target marine species.


Assuntos
Cnidários/genética , DNA Ambiental/genética , Filtração/instrumentação , Peixes/genética , Água do Mar/análise , Animais , DNA Ambiental/análise , DNA Ambiental/isolamento & purificação , Desenho de Equipamento , Cifozoários/genética
12.
PLoS One ; 15(4): e0231104, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32255794

RESUMO

Over the last three decades corals have declined precipitously in the Florida Keys. Their population decline has prompted restoration effort. Yet, little effort has been invested in understanding the contemporary niche spaces of coral species, which could assist in prioritizing conservation habitats. We sought to predict the probability of occurrence of 23 coral species, including the critically endangered Acropora cervicornis, using observations at 985 sites from 2011-2015. We ran boosted regression trees to evaluate the relationship between the presence of these corals and eight potential environmental predictors: (i) bathymetry (m), (ii) mean of daily sea surface temperature (SST) (°C), (iii) variance of SST (°C), (iv) range of SST (°C), (v) chlorophyll-a concentration (mg m3), (vi) turbidity (m-1), (vii) wave energy (kJ m-2), and (viii) distance from coast (km). The Marquesas and the lower and upper Florida Keys were predicted to support the most suitable habitats for the 23 coral species examined. A. cervicornis had one of the smallest areas of suitable habitat, which was limited to the lower and upper Florida Keys, the Dry Tortugas, and nearshore Broward-Miami reefs. The best environmental predictors of site occupancy of A. cervicornis were SST range (4-5°C) and turbidity (K490 between 0.15-0.25 m-1). Historically A. cervicornis was reported in clear oligotrophic waters, although the present results find the coral species surviving in nearshore turbid conditions. Nearshore, turbid reefs may shade corals during high-temperature events, and therefore nearshore reefs in south Florida may become important refuges for corals as the ocean temperatures continue to increase.


Assuntos
Distribuição Animal , Antozoários/fisiologia , Recifes de Corais , Espécies em Perigo de Extinção/estatística & dados numéricos , Recuperação e Remediação Ambiental , Animais , Clorofila A/análise , Espécies em Perigo de Extinção/tendências , Monitoramento Ambiental/estatística & dados numéricos , Florida , Temperatura Alta/efeitos adversos , Água do Mar/análise , Água do Mar/química
14.
Nat Commun ; 11(1): 1534, 2020 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-32210225

RESUMO

Changes in ocean circulation and the biological carbon pump have been implicated as the drivers behind the rise in atmospheric CO2 across the last deglaciation; however, the processes involved remain uncertain. Previous records have hinted at a partitioning of deep ocean ventilation across the two major intervals of atmospheric CO2 rise, but the consequences of differential ventilation on the Si cycle has not been explored. Here we present three new records of silicon isotopes in diatoms and sponges from the Southern Ocean that together show increased Si supply from deep mixing during the deglaciation with a maximum during the Younger Dryas (YD). We suggest Antarctic sea ice and Atlantic overturning conditions favoured abyssal ocean ventilation at the YD and marked an interval of Si cycle reorganisation. By regulating the strength of the biological pump, the glacial-interglacial shift in the Si cycle may present an important control on Pleistocene CO2 concentrations.


Assuntos
Atmosfera/química , Camada de Gelo/química , Isótopos/metabolismo , Água do Mar/química , Silício/metabolismo , Movimentos da Água , Regiões Antárticas , Oceano Atlântico , Dióxido de Carbono/metabolismo , História Antiga , Isótopos/análise , Oceanografia/métodos , Paleontologia/métodos , Água do Mar/análise , Silício/análise , Temperatura
15.
PLoS One ; 15(2): e0228873, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32040527

RESUMO

The manila clam Ruditapes philippinarum is widely distributed in the sandy mud sediments of tidal flats and plays a role in seawater purification by filtering suspended organic matter. This study was designed to evaluate differences in seawater purification based on the filtration rate of the manila clam in terms of particulate organic matter (POM) between two tidal flats with different hydrographic regimes. In situ experiments were carried out at Geunso and Sihwa tidal flats, along the west coast of Korea. The amount of POM removed from the water column by the feeding activity of the clam was measured in the field using a closed circulation chamber. The filtration rate of clams for POM at Sihwa tidal flat (2.86 for POC, 2.29 for PON and 5.46 L h-1 gDW-1 for Chl a) was higher than that at Geunso tidal flat (0.61 for POC, 0.89 for PON and 2.54 L h-1 gDW-1 for Chl a) which resulted from differences in the hydrographic regime, including tide characteristics, current speed and submergence time, and food quantity and quality. The current speed was much greater at Geunso tidal flat than at Sihwa tidal flat, but the submergence time by tide was longer at the latter site than the former, resulting in different feeding times for clams. The food quantity in terms of chlorophyll a was higher at Sihwa tidal flat than at Geunso tidal flat, and the food quality based on the C/N ratio of POM was better at the former site than the latter, with values of 12.8 and 15.6, respectively. These findings suggest that hydrographic regime could be important in understanding in situ filtration rates of R. philippinarum.


Assuntos
Bivalves/fisiologia , Animais , Clorofila A/análise , Comportamento Alimentar/fisiologia , Cadeia Alimentar , Sedimentos Geológicos/análise , Hidrodinâmica , Material Particulado/análise , República da Coreia , Água do Mar/análise , Poluentes Químicos da Água/análise , Purificação da Água
16.
Artigo em Inglês | MEDLINE | ID: mdl-32019251

RESUMO

Concentrations of phase-partitioning 13 polycyclic aromatic hydrocarbons (PAHs) in seawater were investigated in the Tsukumo Bay, Noto Peninsula, Japan, during 2014-2018, to improve the understanding of the environmental behavior of PAHs in the coastal areas of the Japan Sea. Total PAH (particulate plus dissolved) concentrations in surface seawater were in the range 0.24-2.20 ng L-1 (mean 0.89 ng L-1), an order of magnitude lower than the mean values observed in the Japan Sea in 2008 and 2010. Although the PAH contamination levels during 2014-2018 were significantly lower than those in the East China Sea, the levels increased from 2014 to 2017 and were maintained at the higher level during 2017-2018. The main sources of particulate and dissolved PAHs during 2014-2018 were combustion products, of which the former were more influenced by liquid fossil-fuel combustion and the latter by biomass or coal combustion. The increase in particulate PAH concentrations in October-December during 2014-2018 was due to the impact of PAH-rich airmasses transported from the East Asian landmass in the northwesterly winter monsoon winds. The increase in dissolved PAH levels during July-September in 2014, 2016, 2017, and 2018 indicates that the Tsukumo Bay is possibly impacted by the PAH-rich summer continental shelf water transported by the Coastal Branch of the Tsushima Warm Current, which flows into the Japan Sea from the East China Sea.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos/análise , Água do Mar/análise , Poluentes Químicos da Água/análise , Baías , Monitoramento Ambiental , Japão , Estações do Ano
17.
Nature ; 577(7792): 660-664, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31996820

RESUMO

Sea-level histories during the two most recent deglacial-interglacial intervals show substantial differences1-3 despite both periods undergoing similar changes in global mean temperature4,5 and forcing from greenhouse gases6. Although the last interglaciation (LIG) experienced stronger boreal summer insolation forcing than the present interglaciation7, understanding why LIG global mean sea level may have been six to nine metres higher than today has proven particularly challenging2. Extensive areas of polar ice sheets were grounded below sea level during both glacial and interglacial periods, with grounding lines and fringing ice shelves extending onto continental shelves8. This suggests that oceanic forcing by subsurface warming may also have contributed to ice-sheet loss9-12 analogous to ongoing changes in the Antarctic13,14 and Greenland15 ice sheets. Such forcing would have been especially effective during glacial periods, when the Atlantic Meridional Overturning Circulation (AMOC) experienced large variations on millennial timescales16, with a reduction of the AMOC causing subsurface warming throughout much of the Atlantic basin9,12,17. Here we show that greater subsurface warming induced by the longer period of reduced AMOC during the penultimate deglaciation can explain the more-rapid sea-level rise compared with the last deglaciation. This greater forcing also contributed to excess loss from the Greenland and Antarctic ice sheets during the LIG, causing global mean sea level to rise at least four metres above modern levels. When accounting for the combined influences of penultimate and LIG deglaciation on glacial isostatic adjustment, this excess loss of polar ice during the LIG can explain much of the relative sea level recorded by fossil coral reefs and speleothems at intermediate- and far-field sites.


Assuntos
Camada de Gelo , Elevação do Nível do Mar/história , Água do Mar/análise , Animais , Regiões Antárticas , Antozoários , Recifes de Corais , Foraminíferos , Fósseis , Groenlândia , História Antiga , Camada de Gelo/química , Modelos Teóricos , Temperatura
18.
Int J Mol Med ; 45(2): 658-668, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31894254

RESUMO

Mineral­balanced deep sea water (MBDSW), an unlimited natural sea source, has been demonstrated to minimize the risk of developing cardiovascular diseases, such as obesity, hypertension, inflammation and hyperlipidemia. This study investigated the effects of MBDSW [magnesium (Mg):calcium (Ca) ratio, 3:1] on platelet activation. MBDSW significantly inhibited the collagen­ and thrombin­induced platelet aggregation of human platelets. In collagen­induced platelets, MBDSW inhibited intracellular calcium mobilization, granule secretion [serotonin, adenosine triphosphate (ATP) and P­selectin expression] and thromboxane A2 (TXA2) production. Moreover, MBDSW markedly inhibited Akt and extracellular signal­regulated kinase (ERK) phosphorylation, but not that of c­Jun N­terminal kinase (JNK) and p38. Moreover, MBDSW phosphorylated inositol 1,4,5­triphosphate receptor (IP3R) and vasodilator­stimulated phosphoprotein (VASP), and it increased the cyclic adenosine monophosphate (cAMP) level in collagen­induced human platelets. Dipyridamole, a phosphodiesterase (PDE) inhibitor, significantly increased the cAMP level and regulated the Akt, ERK and VASP (Ser157) levels in a manner similar to that of MBDSW. In addition, LY294002, an Akt inhibitor, inhibited the phosphorylation of ERK, and U0126, an ERK inhibitor, inhibited the phosphorylation of Akt. Taken together, the results of the present investigation suggest that the inhibitory effects of MBDSW on platelet aggregation may be associated with the cross­inhibition of Akt and ERK phosphorylation. These results strongly indicate that MBDSW may have preventive or therapeutic potential for platelet aggregation­mediated diseases, such as thrombosis, atherosclerosis and myocardial infarction.


Assuntos
Águas Minerais , Inibidores da Agregação de Plaquetas/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Água do Mar , Plaquetas/citologia , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Águas Minerais/análise , Inibidores da Agregação de Plaquetas/análise , Proteínas Proto-Oncogênicas c-akt/metabolismo , Água do Mar/análise , Transdução de Sinais/efeitos dos fármacos
19.
Environ Pollut ; 258: 113743, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31838396

RESUMO

The extensive use of melamine and its three derivatives (i.e., ammeline, ammelide, and cyanuric acid) resulted in their widespread occurrence in the environment. Nevertheless, limited information is available on their distribution in the aquatic environment. In this study, concentrations and profiles of melamine and its derivatives were determined in 223 water samples, comprising river water, lake water, seawater, tap water, bottled water, rain water, wastewater, and swimming pool water, collected from New York State, USA. The sum concentrations of melamine and its derivatives (∑4MELs) decreased in the following order: swimming pool water (median: 1.5 × 107 ng/L) ≫ wastewater (1240) > precipitation (739) > tap water (512) > river water (370) > lake water (347) > seawater (186) > bottled water (98). Cyanuric acid was the major compound, accounting for 60-100% of ∑4MELs concentrations in swimming pool water, wastewater, precipitation, tap water, seawater, and bottled water, whereas melamine dominated in river and lake water (54-64% of ∑4MELs). Significant positive correlations (0.499 < R < 0.703, p < 0.002) were found between the concentrations of melamine and atrazine (a triazine herbicide) in surface waters. The geographic distribution in the concentrations of ∑4MELs in river, lake, and tap water corresponded with the degree of urbanization, suggesting that human activities contribute to the sources melamine and cyanuric acid in the aquatic environments. A preliminary hazard assessment of melamine and cyanuric acid in waters suggested that their ecological or human health risks were minimal. This is the first study to document the occurrence and spatial distribution of melamine and its derivatives in waters from the United States.


Assuntos
Água Potável/análise , Monitoramento Ambiental , Chuva , Piscinas , Triazinas/análise , Águas Residuárias/análise , Água Doce/análise , New York , Água do Mar/análise
20.
J Environ Sci Health B ; 55(3): 220-229, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31680622

RESUMO

Although the prevalence and concentrations of antibiotic resistance genes (ARGs) in aquaculture is receiving increasing scientific interest, there is little understanding of the direct sources and dissemination pathways of ARGs in marine aquaculture-reared organisms. This study investigated the dynamics of ARGs and the bacterial community throughout the rearing period in a typical marine aquaculture farm in South China. The results demonstrated that sul1 and qnrD were predominant in the sediment, and qnrD and qnrA were predominant in the intestinal tracts of shrimps. Network analysis showed that the chemical oxygen demand, total organic carbon, dissolved organic carbon, suspended solids, and total phosphorus were positively correlated with the predominant ARGs. The results of the network and source tracking analyses indicate that environmental factors and the bacterial community may drive the dissemination of ARGs dissemination in the environment and in shrimp reared by marine aquaculture, and sediment is the most direct and important medium in this dissemination. These results aid in improving our understanding of the sources, level, and dissemination of ARGs in marine aquaculture.


Assuntos
Aquicultura , Resistência Microbiana a Medicamentos/genética , Genes Bacterianos , Sedimentos Geológicos/microbiologia , Penaeidae/microbiologia , Animais , Análise da Demanda Biológica de Oxigênio , Carbono/análise , China , Intestinos/microbiologia , Consórcios Microbianos/genética , Fósforo/análise , Tanques , Água do Mar/análise , Água do Mar/microbiologia , Microbiologia da Água
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