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1.
Sci Total Environ ; 856(Pt 1): 159095, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36181815

RESUMO

The seas and oceans of the planet provide a wide range of essential resources. However, marine ecosystems are undergoing severe degradation due to the unsustainable exploitation and consumption patterns of the linear economy. On the other hand, many economic activities linked to the sea generate a large amount of waste, leading to negative impacts, such as the cost of treating or disposing of this waste. A case in point is bivalve mollusc production: a purification process is needed to avoid the risk of diseases through faecal contamination. The present work proposes an innovative procedure to convert this waste, calcium carbonate as calcite and aragonite allotropic types, into by-products. These by-products can be used to manufacture green artificial reefs, partially replacing concrete aggregates with a sustainable alternative to the geological sources of CaCO3. By installing these reefs, marine ecosystems could be created in a sustainable way and an innovative approach based on the circular economy could be taken towards protecting them. To this end, different concrete mixtures with bivalve shells are proposed. Although this study had been carried out for Galicia (NW Spain), the methodology followed could also be valid for other regions. A physicochemical characterisation of the waste from purifying the bivalves, including oysters, mussels, clams and scallops, was performed. Statistical and multi-criteria analyses were done in order to select the best dosage. Both have provided justification for using a mixture of shells with a predominance of calcite (oyster, scallop) instead of shells with a predominance of aragonite. The multi-criteria analysis served to identify the two best alternatives with dosages in which the medium aggregates were substituted with shells mainly from oysters, with a predominance of calcite. Finally, the statistical analysis played a role in estimating the compressive strength and water absorption of each mixture from the design parameter values.


Assuntos
Bivalves , Ecossistema , Animais , Oceanos e Mares , Carbonato de Cálcio/análise , Geologia
2.
Sci Total Environ ; 857(Pt 2): 159491, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36270380

RESUMO

Rising levels of atmospheric carbon dioxide (CO2) are driving ocean warming and acidification, which may negatively affect the nutritional quality and physiological performance of commercially important fish species. Thus, this study aimed to evaluate the effects of ocean acidification (OA; ΔpH = -0.3 units equivalent to ΔpCO2 ~ +600 µatm) and warming (OW; ΔT = +4 °C) (and combined, OAW) on the proximate composition, fitness and energy budget of juvenile Senegalese sole (Solea senegalensis). After an exposure period of 75 days, growth (G), metabolism (R) and excretion (faecal, F and nitrogenous losses, U) were assessed to calculate the energy intake (C). Biometric and viscera weight data were also registered to determine animal fitness. Overall, the proximate composition and gross energy were not significantly affected by acidification and warming (alone or in combination). Weight gain, maximum and standard metabolic rates (MMR and SMR, respectively), aerobic scope (AS) and C were significantly higher in fish subjected to OA, OW and OAW than in CTR conditions. Furthermore, the highest relative growth rates (RGR), specific growth rates in terms of wet weight (SGRw) and protein (SGRp), as well as feed efficiencies (FE) occurred in fish submitted to OW and OAW. On the other hand, fish exposed to CTR conditions had significantly higher feed conversion ratio (FCR) and ammonia excretion rate (AER) than those exposed to simulated stressors. Regarding energy distribution, the highest fraction was generally allocated to growth (48-63 %), followed by excretion through faeces (36-51 %), respiration (approximately 1 %) and ammonia excretion (0.1-0.2 %) in all treatments. Therefore, ocean warming and acidification can trigger physiological responses in juvenile Senegalese sole, particularly in their energy budget, which can affect the energy flow and allocation of its population. However, and in general, this species seems highly resilient to these predicted ocean climate change stressors.


Assuntos
Linguados , Água do Mar , Animais , Água do Mar/química , Concentração de Íons de Hidrogênio , Amônia/toxicidade , Oceanos e Mares , Temperatura
3.
Sci Total Environ ; 857(Pt 2): 159583, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36270369

RESUMO

Terrigenous discharge represents a mass movement from land to oceanic environment. While previous studies characterized terrigenous freshwater via oceanographic (physical and biochemical) data, the persistent fresh water in the far-field ocean via satellite-gravimetric observation has been rarely explored. This paper aims to characterize the spatiotemporal extension of Mekong freshwater and the interchangeable role of runoff and climatic factors in the southwestern South China Sea. Employing wavelet coherence analysis between the in situ runoff and oceanic freshwater variations inferred from satellite gravimetry, the coherence and transport duration were obtained at annual, intra- and inter-annual time scales during 2003-2015. Despite weak relationship at 6-month and 24-month scales in regions away from the estuary, the two time series remained significantly correlated at the 12-month scale with a highly positive coherence over 0.97. Spatial pattern of the annual transport duration further indicated that freshwater firstly flowed alongshore before turning eastward offshore, qualitatively consistent with the northeastward western boundary current and an anticyclonic eddy during the summertime generated from the ocean circulation model. Using partial wavelet coherence, the time-variable relationship at all these three scales was found closely related to the Indian Monsoon and Western North Pacific Monsoon. A series of alternating ENSO events during 2007-2011 were responsible for the inter-annual variations, contributing <5 % to the seasonal freshwater extension. Compared with the averaged transport duration of the isotope method (i.e., 21.5 days) and the geostrophic current computation (i.e., 38.8 days) in the summer of 2007, our method yielded a comparable transport duration of 23.9 days with smaller uncertainties. The wind-driven Ekman transport, however, was primarily responsible for the anticyclonic movement of freshwater transport in the southwestern South China Sea during late summer.


Assuntos
Água Doce , Vento , Oceanos e Mares , Estações do Ano , China
4.
Ambio ; 52(1): 155-170, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36136262

RESUMO

Marine social-ecological systems (SES) have been providing important cultural, social, and economic services for many centuries. They are, however, increasingly threatened by fast changing environmental, ecological, and socio-economic conditions. As historical marine research is increasingly developing into a multidisciplinary endeavour, it offers outstanding points of departure to analyse historic events and the response and adaptation of the respective SES. Such knowledge helps to inform today's fisheries management and promotes successful management of changing ecosystems. Here, we compile and analyse historical data (1890-1950) of the German Western Baltic Sea fishery SES. This period is characterised by a series of strong impacts due to political, technological, economic, and ecological changes, such as two world wars, a global economic crisis, and other economic or ecological disasters. In our opinion, potential negative effects of those events were in the past attenuated by the system's high capacity to adapt. However, most of the fishers´ historic options on how to respond and adapt have recently become no longer available. New threats (e.g. climate change) have emerged instead. We conclude that today's fisheries management needs to integrate options of adaptation by exhausting all present or future opportunities. Adaptive fisheries management should not only focus on environmental change but need to include socio-economic change as well.


Assuntos
Pesqueiros , Mudança Climática , Ecossistema , Pesqueiros/história , Pesqueiros/tendências , Oceanos e Mares , Fatores Socioeconômicos
5.
Semin Cell Dev Biol ; 134: 79-89, 2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-35305902

RESUMO

Diatoms represent one of the most successful groups of marine phytoplankton and are major contributors to ocean biogeochemical cycling. They have colonized marine, freshwater and ice environments and inhabit all regions of the World's oceans, from poles to tropics. Their success is underpinned by a remarkable ability to regulate their growth and metabolism during nutrient limitation and to respond rapidly when nutrients are available. This requires precise regulation of membrane transport and nutrient acquisition mechanisms, integration of nutrient sensing mechanisms and coordination of different transport pathways. This review outlines transport mechanisms involved in acquisition of key nutrients (N, C, P, Si, Fe) by marine diatoms, illustrating their complexity, sophistication and multiple levels of control.


Assuntos
Diatomáceas , Diatomáceas/metabolismo , Fitoplâncton/metabolismo , Oceanos e Mares , Transporte Biológico
6.
Sci Total Environ ; 855: 158887, 2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36150593

RESUMO

Many studies focus on the transport of plastic from rivers to oceans while little attention was paid to the plastic transport in the upper reaches of rivers. Transport process of plastic from upstream to downstream in the whole river basin scale is still poorly understood. In this work, five sections in the upper reaches of the Yangtze River were investigated to characterize the features of plastic transport. Plastic abundance and flux were 293 to 156,667 n/m3 and 1.2 to 34,711 g/s, respectively. Plastic flux peaked at or right after the first flood peak in most sections, but plastic abundance was the highest in the normal or low water period. The first flood peak caused a temporary rise of plastic flux that last a short duration. Transport of plastic was not limited to water surface, and the Three Gorges Dam showed a peak elimination effect on plastic transport. Annual discharge of plastic was 1392 to 9532 tons and 6.2 × 1014 to 175 × 1014 particles at different sections. An increasing trend was observed for both plastic mass and quantity going downstream. Results showed that river plastic flux is highly variable and influenced by the dam, which should be considered in future to develop better monitoring strategies and to further improve the model.


Assuntos
Monitoramento Ambiental , Rios , Monitoramento Ambiental/métodos , Movimentos da Água , Oceanos e Mares , Água , China
7.
J Hazard Mater ; 443(Pt A): 130144, 2023 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-36242956

RESUMO

Although previous research indicated that the Baltic Sea has a strong "memory effect" for trapping pollutants/nutrients, the associated environmental risks are not well understood due to the knowledge gaps in the long-term hydrodynamics-driven exchange of pollutants/nutrients between the North Sea and the Baltic Sea. In this work, we exploited 99Tc and 129I released from the two European nuclear reprocessing plants as oceanic tracers and pollutant proxies, and performed a five-decade hindcast simulation to quantitatively estimate the fluxes and timescales of marine transport of pollutants/nutrients in the North-Baltic Sea. Modeling results underline two potential environmental risks of the Baltic Sea's "memory effect": (1) ∼26 years of environmental half-life for any existing water-soluble pollutants/nutrients in the Baltic Sea driven by its hydrodynamics; (2) the Baltic Sea as a pollutant reservoir continuously exporting 3 % of contaminations per year to the downstream areas after any pollution event. Our findings provide fundamental knowledge for understanding the long-term hydrodynamics-driven pollutant/nutrient transport in the North-Baltic Sea, facilitating the future regional management of the marine environment.


Assuntos
Poluentes Ambientais , Oceanos e Mares , Países Bálticos
8.
Sci Total Environ ; 857(Pt 1): 159325, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36216044

RESUMO

Climate change is one of the most concerning topics in the Anthropocene. Increasing sea water temperature will trigger a series of ecological consequences, altering the various functions and services that marine ecosystems provide for humans. Fisheries, specifically, will likely face the most direct impact. China provides unparalleled catches with enormous and intensive fishing effort, and China Seas are suffering from significantly increasing water temperature. However, uncertainties in the impacts of climate change on fishing species and fisheries in the China Seas present challenges for the formulation of coping and adapting strategies. Here, we employed a climate risk assessment framework to evaluate the climate risks of fishing species and fisheries of various provinces in China in the past decade, aiming to benefit the development and prioritization of appropriate adaptation options to climate change. Results show that considering the water temperature in the 2010s, 20 % of fishing species in the China Seas have one-fourth of their habitats unsuitable, and the situation will become worse with future warming scenarios in the 2050s when nearly half of species will have at least one-fourth of their habitats no longer suitable. Integrating hazard, exposure and vulnerability, climate risks to fisheries feature heterogeneity among provinces. Climate risks to fisheries of northern provinces are characterized by low hazard and high exposure, while the southern counterparts are largely determined by high hazard and low exposure. Climate change is threatening fishing species and remarkably altering fishery patterns in China Seas. Shifting fishing targets, increasing fishing efficiency, raising catch diversity, and updating fishery-related industries would be effective steps to help fisheries adapt to climate change, and adaptation strategies need to be tailored considering local realities.


Assuntos
Ecossistema , Pesqueiros , Humanos , Animais , Caça , Oceanos e Mares , Mudança Climática , Água , Peixes
9.
Sci Total Environ ; 856(Pt 2): 159284, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36209875

RESUMO

To predict the potential impacts of climate change on marine organisms, it is critical to understand how multiple stressors constrain the physiology and distribution of species. We evaluated the effects of seasonal changes in seawater temperature and near-future ocean acidification (OA) on organismal and sub-organismal traits associated with the thermal performance of Eleginops maclovinus, a sub-Antarctic notothenioid species with economic importance to sport and artisanal fisheries in southern South America. Juveniles were exposed to mean winter and summer sea surface temperatures (4 and 10 °C) at present-day and near-future pCO2 levels (~500 and 1800 µatm). After a month, the Critical Thermal maximum and minimum (CTmax, CTmin) of fish were measured using the Critical Thermal Methodology and the aerobic scope of fish was measured based on the difference between their maximal and standard rates determined from intermittent flow respirometry. Lipid peroxidation and the antioxidant capacity were also quantified to estimate the oxidative damage potentially caused to gill and liver tissue. Although CTmax and CTmin were higher in individuals acclimated to summer versus winter temperatures, the increase in CTmax was minimal in juveniles exposed to the near-future compared to present-day pCO2 levels (there was a significant interaction between temperature and pCO2 on CTmax). The reduction in the thermal tolerance range under summer temperatures and near-future OA conditions was associated with a reduction in the aerobic scope observed at the elevated pCO2 level. Moreover, an oxidative stress condition was detected in the gill and liver tissues. Thus, chronic exposure to OA and the current summer temperatures pose limits to the thermal performance of juvenile E. maclovinus at the organismal and sub-organismal levels, making this species vulnerable to projected climate-driven warming.


Assuntos
Peixes , Água do Mar , Animais , Temperatura , Concentração de Íons de Hidrogênio , Estações do Ano , Oceanos e Mares
10.
Sci Total Environ ; 857(Pt 3): 159540, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36270349

RESUMO

Atmospheric deposition is an important source of exogenous Si in the oceans. As a typical crustal element, Si in the atmosphere emitted from anthropogenic sources is ignored. In this study, the atmospheric dry deposition of anthropogenic Si to China adjacent seas was calculated using WRF-CMAQ in January and July 2019 to investigate the contribution of anthropogenic Si to the oceans. Si emitted from 13 anthropogenic sources in China, the Korean Peninsula, Japan, and marine ships was considered. Emissions of anthropogenic Si in January and July 2019 were 30.2 and 22.0 Gg, respectively. The highest Si emissions were concentrated over eastern China, e.g. Beijing-Tianjin-Hebei region, Shandong province, Yangtze river delta area (0.2-21.3 ng m-2 s-1), while the lowest emissions were in northwestern China (< 5.2 ng m-2 s-1). Among the Bohai (BS), Yellow (YS), and East China seas (ECS), dry deposition fluxes over the southern YS were highest (4.6-16.8 µg m-2 d-1), and those over the ECS were lowest (0.2-7.7 µg m-2 d-1). During pollution episodes, the outflow of polluted air masses from the continent caused a 10-fold increase in Si deposition compared with clear days. The relative contribution of continental anthropogenic emissions and ship combustion varied significantly in two seasons. In winter, deposition from continental anthropogenic emissions to total anthropogenic Si deposition was higher than 96 %. While in summer, the contributions from ship combustion increased obviously, accounting for 10-38 %. Deposition flux of dissolved Si from anthropogenic sources over China adjacent seas was about 4-38 % of that of dissolved mineral dust Si. The annual Si depositions from atmospheric anthropogenic sources to the Si fluxes from rivers to the China adjacent seas were 0.03 %-2.8 %. The marine primary productivity in the BS, YS, and ECS caused by atmospheric anthropogenic dissolved Si deposition were 1.3, 1.2, and 0.7 mg C m-2 a-1, respectively.


Assuntos
Poluentes Atmosféricos , Silício , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Oceanos e Mares , Atmosfera , Estações do Ano , China
11.
Sci Total Environ ; 857(Pt 3): 159713, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36302425

RESUMO

Rivers are undoubtedly the main pathway of waste dispersed in the environment that from land reaches oceans and seas increasing the amount of marine litter. Major cities are a great source of riverine litter as large urbanization can originate pressure on the integrated waste management resulting in litter entering the rivers. Within this study, we aim to investigate the dynamic of floating riverine macrolitter (items >2.5 cm) in the city of Rome before it reaches the sea by assessing the composition, amount, and seasonal trends of litter transported from the urban centre to the main river mouth of Tiber River. Visual surveys for a whole year (March 2021-February 2022) were conducted from two bridges, Scienza Bridge (in the city) and Scafa Bridge (at the main river mouth) and followed JRC/RIMMEL protocol for riverine litter monitoring. Overall, similar litter composition was observed from the city centre to the mouth with a prevalence of plastic material, mainly related to fragmentation process (i.e. plastic pieces) and single use items, mainly in food and beverage sectors. An extrapolated annual loading of 4 × 105 items/year was estimated at the main mouth of Tiber River. The litter flux seems to be influenced by the seasonal variability and hydrometeorological parameters. The frequency of size classes decreases with increasing size in both sites, and more than half of the recorded items were below 10 cm. Specific categories belonging to "other plastics" have been reported related to anti-Covid-19 behaviour such as face masks and beverage sector, e.g. bottle lids and rings. The main colour of plastics was white, suggesting weathering process of floating riverine litter. This study contributes to increasing knowledge of the origin, composition and spatiotemporal dynamics of riverine floating litter from the city and entering the sea.


Assuntos
Rios , Resíduos , Resíduos/análise , Cidades , Monitoramento Ambiental/métodos , Plásticos , Oceanos e Mares
12.
J Hazard Mater ; 441: 129965, 2023 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-36122524

RESUMO

Oil spills frequently occur in the ocean, and adsorption is one of the effective ways to deal with oil spills. Compared with other adsorbent materials, biomass aerogel has superior selective adsorption capacity. CNF/SA aerogels with good mechanical properties (340 kPa at 90 % strain) and high adsorption capacity (88.91 g/g) were prepared by mixing cellulose nanofibers (CNF) with sodium alginate (SA) through bidirectional freeze-drying, ionic crosslinking, and surface modification to effectively solve the ocean oil spill problem. The bidirectional freeze-drying technology is a green and efficient technique for preparing layered microstructured composite aerogels. The prepared aerogels have a three-dimensional interpenetrating lamellar structure, low density (24.2 mg/cm3), high porosity (97.85 %), and high hydrophobicity (WCA = 144.5°), can be calibrated and used repeatedly. It has potential applications in water-oil separation and can be used as an absorbent for effectively treating oil spills in the ocean environment.


Assuntos
Incrustação Biológica , Nanofibras , Alginatos , Incrustação Biológica/prevenção & controle , Celulose/química , Géis/química , Interações Hidrofóbicas e Hidrofílicas , Nanofibras/química , Oceanos e Mares , Água/química
13.
Environ Pollut ; 302: 118918, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35227850

RESUMO

To understand how climate change stressors might affect marine organisms and support adequate projections it is important to know how multiple stressors may be modulated by the presence of other species. We evaluated the direct effects of ocean warming (OW) and ocean acidification (OA) together with non-consumptive effects (NCEs) of the predatory crab Acanthocyclus hassleri on early ontogeny fitness-related traits of the commercially important rocky-shore keystone gastropod Concholepas concholepas. We measured the response of nine traits to these stressors at either the organismal level (survival, growth, feeding rates, tenacity, metabolic rate, calcification rate) or sub-organismal level (nutritional status, ATP-supplying capacity, stress condition). C. concholepas survival was not affected by any of the stressors. Feeding rates were not affected by OW or OA; however, they were reduced in the presence of crab NCEs compared with control conditions. Horizontal tenacity was affected by the OA × NCEs interaction; in the presence of NCEs, OA reduced tenacity. The routine metabolic rate, measured by oxygen consumption, increased significantly with OW. Nutritional status assessment determined that carbohydrate content was not affected by any of the stressors. However, protein content was affected by the OA × NCEs interaction; in the absence of NCEs, OA reduced protein levels. ATP-supplying capacity, measured by citrate synthase (CS) activity, and cellular stress condition (HSP70 expression) were reduced by OA, with reduction in CS activity found particularly at the high temperature. Our results indicate C. concholepas traits are affected by OA and OW and the effects are modulated by predator risk (NCEs). We conclude that some C. concholepas traits are resilient to climate stressors (survival, growth, horizontal tenacity and nutritional status) but others are affected by OW (metabolic rate), OA (ATP-supplying capacity, stress condition), and NCEs (feeding rate). The results suggest that these negative effects can adversely affect the associated community.


Assuntos
Gastrópodes , Comportamento Predatório , Animais , Sinais (Psicologia) , Gastrópodes/fisiologia , Concentração de Íons de Hidrogênio , Oceanos e Mares , Comportamento Predatório/fisiologia , Água do Mar
14.
Sci Rep ; 12(1): 18580, 2022 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-36329054

RESUMO

Human use of marinescapes is rapidly increasing, especially in populated nearshore regions where recreational vessel traffic can be dense. Marine animals can have a physiological response to such elevated human activity that can impact individual health and population dynamics. To understand the physiological impacts of vessel traffic on baleen whales, we investigated the adrenal stress response of gray whales (Eschrichtius robustus) to variable vessel traffic levels through an assessment of fecal glucocorticoid metabolite (fGC) concentrations. This analysis was conducted at the individual level, at multiple temporal scales (1-7 days), and accounted for factors that may confound fGC: sex, age, nutritional status, and reproductive state. Data were collected in Oregon, USA, from June to October of 2016-2018. Results indicate significant correlations between fGC, month, and vessel counts from the day prior to fecal sample collection. Furthermore, we show a significant positive correlation between vessel traffic and underwater ambient noise levels, which indicates that noise produced by vessel traffic may be a causal factor for the increased fGC. This study increases knowledge of gray whale physiological response to vessel traffic and may inform management decisions regarding regulations of vessel traffic activities and thresholds near critical whale habitats.


Assuntos
Ruído , Baleias , Animais , Humanos , Baleias/fisiologia , Ruído/efeitos adversos , Glucocorticoides , Ecossistema , Oceanos e Mares
15.
Sci Adv ; 8(44): eabn6005, 2022 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-36332020

RESUMO

Nutrient availability, along with light and temperature, drives marine primary production. The ability to migrate vertically, a critical trait of motile phytoplankton, allows species to optimize nutrient uptake, storage, and growth. However, this traditional view discounts the possibility that migration in nutrient-limited waters may be actively modulated by the emergence of energy-storing organelles. Here, we report that bloom-forming raphidophytes harness energy-storing cytoplasmic lipid droplets (LDs) to biomechanically regulate vertical migration in nutrient-limited settings. LDs grow and translocate directionally within the cytoplasm, steering strain-specific shifts in the speed, trajectory, and stability of swimming cells. Nutrient reincorporation restores their swimming traits, mediated by an active reconfiguration of LD size and coordinates. A mathematical model of cell mechanics establishes the mechanistic coupling between intracellular changes and emergent migratory behavior. Amenable to the associated photophysiology, LD-governed behavioral shift highlights an exquisite microbial strategy toward niche expansion and resource optimization in nutrient-limited oceans.


Assuntos
Gotículas Lipídicas , Fitoplâncton , Fitoplâncton/fisiologia , Oceanos e Mares , Nutrientes , Natação
17.
PLoS Biol ; 20(11): e3001809, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36413526

RESUMO

This Formal Comment uses re-analysis after appropriate corrections to claim that the extreme decline effect reported by Clements et al. is a statistical artefact caused by the way they corrected for zeros in percentage data, exacerbated by errors in data compilation, selective data inclusions and missing studies with strong effects.


Assuntos
Peixes , Água do Mar , Animais , Concentração de Íons de Hidrogênio , Artefatos , Oceanos e Mares
18.
Aquat Toxicol ; 253: 106346, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36327686

RESUMO

Humans have exhaustively combusted fossil fuels, and released pollutants into the environment, at continuously faster rates resulting in global average temperature increase and seawater pH decrease. Climate change is forecasted to exacerbate the effects of pollutants such as the emergent rare earth elements. Therefore, the objective of this study was to assess the combined effects of rising temperature (Δ = + 4 °C) and decreasing pH (Δ = - 0.4 pH units) on the bioaccumulation and elimination of gadolinium (Gd) in the bioindicator bivalve species Spisula solida (Surf clam). We exposed surf clams to 10 µg L-1 of GdCl3 for seven days, under warming, acidification, and their combination, followed by a depuration phase lasting for another 7 days and investigated the Gd bioaccumulation and oxidative stress-related responses after 1, 3 and 7 days of exposure and the elimination phase. Gadolinium accumulated after just one day with values reaching the highest after 7 days. Gadolinium was not eliminated after 7 days, and elimination is further hampered under climate change scenarios. Warming and acidification, and their interaction did not significantly impact Gd concentration. However, there was a significant interaction on clam's biochemical response. The augmented total antioxidant capacity and lipid peroxidation values show that the significant impacts of Gd on the oxidative stress response are enhanced under warming while the increased superoxide dismutase and catalase values demonstrate the combined impact of Gd, warming & acidification. Ultimately, lipid damage was greater in clams exposed to warming & Gd, which emphasizes the enhanced toxic effects of Gd in a changing ocean.


Assuntos
Bivalves , Spisula , Poluentes Químicos da Água , Humanos , Animais , Gadolínio/toxicidade , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/toxicidade , Água do Mar , Mudança Climática , Oceanos e Mares
19.
BMC Ecol Evol ; 22(1): 136, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36401160

RESUMO

BACKGROUND: Climate change is expected to lead to warming in ocean surface temperatures which will have unequal effects on the rates of photosynthesis and heterotrophy. As a result of this changing metabolic landscape, directional phenotypic evolution will occur, with implications that cascade up to the ecosystem level. While mixotrophic phytoplankton, organisms that combine photosynthesis and heterotrophy to meet their energetic and nutritional needs, are expected to become more heterotrophic with warmer temperatures due to heterotrophy increasing at a faster rate than photosynthesis, it is unclear how evolution will influence how these organisms respond to warmer temperatures. In this study, we used adaptive dynamics to model the consequences of temperature-mediated increases in metabolic rates for the evolution of mixotrophic phytoplankton, focusing specifically on phagotrophic mixotrophs. RESULTS: We find that mixotrophs tend to evolve to become more reliant on phagotrophy as temperatures rise, leading to reduced prey abundance through higher grazing rates. However, if prey abundance becomes too low, evolution favors greater reliance on photosynthesis. These responses depend upon the trade-off that mixotrophs experience between investing in photosynthesis and phagotrophy. Mixotrophs with a convex trade-off maintain mixotrophy over the greatest range of temperatures; evolution in these "generalist" mixotrophs was found to exacerbate carbon cycle impacts, with evolving mixotrophs exhibiting increased sensitivity to rising temperature. CONCLUSIONS: Our results show that mixotrophs may respond more strongly to climate change than predicted by phenotypic plasticity alone due to evolutionary shifts in metabolic investment. However, the type of metabolic trade-off experienced by mixotrophs as well as ecological feedback on prey abundance may ultimately limit the extent of evolutionary change along the heterotrophy-phototrophy spectrum.


Assuntos
Ecossistema , Fitoplâncton , Temperatura , Eucariotos/fisiologia , Oceanos e Mares
20.
Proc Natl Acad Sci U S A ; 119(46): e2210481119, 2022 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-36343255

RESUMO

How clouds respond to anthropogenic sulfate aerosols is one of the largest sources of uncertainty in the radiative forcing of climate over the industrial era. This uncertainty limits our ability to predict equilibrium climate sensitivity (ECS)-the equilibrium global warming following a doubling of atmospheric CO2. Here, we use satellite observations to quantify relationships between sulfate aerosols and low-level clouds while carefully controlling for meteorology. We then combine the relationships with estimates of the change in sulfate concentration since about 1850 to constrain the associated radiative forcing. We estimate that the cloud-mediated radiative forcing from anthropogenic sulfate aerosols is [Formula: see text] W m-2 over the global ocean (95% confidence). This constraint implies that ECS is likely between 2.9 and 4.5 K (66% confidence). Our results indicate that aerosol forcing is less uncertain and ECS is probably larger than the ranges proposed by recent climate assessments.


Assuntos
Clima , Meteorologia , Aerossóis , Sulfatos , Oceanos e Mares
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