Ocean acidification (OA) is becoming a potential threat to marine organisms, especially in calcifying marine invertebrates. So far, along the Kenya Coast, there has been little research on the impact ...of OA on cockle (Anadara antiquata), particularly on their physiological impacts induced by exposure to acidified seawater. Hence, this study aimed to investigate the physiological and biochemical responses of Anadara antiquata under present and future predicted seawater pH. In this study, the Anadara antiquata was exposed to three pH treatments (pH 7.90, 7.60, and 7.30) for 8 weeks to mimic future OA and to understand the physiological and biochemical effects on the organisms. Condition index, energy reserves (glycogen and protein), and cellular damage (e.g., lipid peroxidation level) were measured. Condition index (CI) showed no significant difference at different pH treatments (pH 7.90, 7.60, and 7.30), whereas the survival Anadara antiquata was slightly reduced after 8 weeks of exposure to pH 7.30. Glycogen and protein content were not affected at reduced pH (7.60 and 7.30). However, after 8 weeks of exposure to pH 7.60 and 7.30, Anadara antiquata showed a slight decrease in lipid peroxidation, an indication of cellular damage. The physiological and biochemical parameters analyzed (glycogen and protein content; lipid peroxidation levels) showed useful biomarkers to assess ocean acidification impacts in cockle.
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•Low pH induced mortality in cockle (Anadara antiquata).•The condition index of Anadara antiquata was not impacted by elevated pCO2.•Decrease in lipid peroxidation on exposure to reduced pH•Glycogen content and protein content decrease at low pH after 8 weeks of exposure.
Climate changes and metal contamination are pervasive stressors for soil ecosystems. Mercury (Hg), one of the most toxic metals, has been reported to interact with temperature. However, compared to ...aquatic biota, little is known about how temperature affects Hg toxicity and bioaccumulation to soil organisms. Here, toxicity and bioaccumulation experiments were replicated at 15 °C, 20 °C, and 25 °C to understand how sub-optimal temperatures affect the toxicokinetics and toxicodynamics of Hg via soil. Genotoxicity and energy reserves were also assessed to disclose potential trade-offs in life-history traits. Results underpin the complexity of temperature-Hg interactions. Survival was determined mainly by toxicokinetics, but toxicodynamics also played a significant role in defining survival probability during early stages. The processes determining survival probability were faster at 25 °C: General Unified Threshold of Survival (GUTS) model identified an earlier/steeper decline in survival, compared to 20 °C or 15 °C, but it also approached the threshold faster. Despite potentiation of Hg genotoxicity, temperature promoted faster detoxification, either increasing toxicokinetics rates or damage repair mechanisms. This metabolism-driven increase in detoxification led to higher depletion of energy reserves and likely triggered stress response pathways. This work emphasized the need for comprehensive experimental approaches that can integrate the multiple processes involved in temperature-metal interactions.
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•Temperature-related physiological rates were key for survival probability.•Temperature increased Hg genotoxicity but also improved Hg detoxification.•Hg stored as inert form increased with concentration but not with temperature.•GUTS aided the formulation of a mechanistic hypothesis for the interaction.
•Complete assessment of the regional PV forecast accuracy at different horizons.•Construction of two upscaling methods based on data-driven models.•Prediction intervals computed using a model to ...predict the forecast error.•Analysis of the smoothing effect of forecast error due to regional upscaling.
The growing photovoltaic generation results in a stochastic variability of the electric demand that could compromise the stability of the grid, increase the amount of energy reserve and the energy imbalance cost. On regional scale, the estimation of the solar power generation from the real time environmental conditions and the solar power forecast is essential for Distribution System Operators, Transmission System Operator, energy traders, and Aggregators.
In this context, a new upscaling method was developed and used for estimation and forecast of the photovoltaic distributed generation in a small area of Italy with high photovoltaic penetration. It was based on spatial clustering of the PV fleet and neural networks models that input satellite or numerical weather prediction data (centered on cluster centroids) to estimate or predict the regional solar generation. Two different approaches were investigated. The simplest and more accurate approach requires a low computational effort and very few input information should be provided by users. The power estimation model provided a RMSE of 3% of installed capacity. Intra-day forecast (from 1 to 4 h) obtained a RMSE of 5%–7% and a skill score with respect to the smart persistence from −8% to 33.6%. The one and two days ahead forecast achieved a RMSE of 7% and 7.5% and a skill score of 39.2% and 45.7%. The smoothing effect on cluster scale was also studied. It reduces the RMSE of power estimation of 33% and the RMSE of day-ahead forecast of 12% with respect to the mean single cluster value.
Furthermore, a method to estimate the forecast error was also developed. It was based on an ensemble neural network model coupled with a probabilistic correction. It can provide a highly reliable computation of the prediction intervals.
Estuarine systems are critical transition zones influenced by sea, land and freshwater. An array of human activities impacts these areas leading to multiple-stressor interactions. Temperature and ...salinity are among the most relevant drivers in estuaries, shaping species growth, reproduction and distribution. However, few studies provide an overview of cellular rewiring processes under multiple-stressor environments. Here, we tested how salinity could shape the response of ragworms Hediste diversicolor, an important bioindicator and commercial species, to elevated temperature. We exposed polychaetes to three temperatures for a month, simulating control, ocean warming and heatwave conditions (24, 27 and 30 °C, respectively) combined with two salinities (20 and 30). We quantified whole-organism performance (wet weight gain and survival), along with cellular stress response (CSR) and energy reserves of worms after 14 and 28 days of exposure. Significant three-way interactions between temperature, salinity and exposure time show the non-linearity of molecular responses. Worms at a salinity of 20 were more sensitive to warming than worms exposed to a salinity of 30. The combination of high temperature and low salinity can act synergistically to induce oxidative stress and macromolecular damage in worm tissues. This finding was supported by an induction of the CSR, with a concomitant decrease of energy reserves, pointing towards a metabolic compensation strategy. However, under a higher salinity (30), the need for a CSR upon thermal challenge was reduced and energy content increased with temperature, which suggests that environmental conditions were within the optimum range. Heatwaves striking low-salinity areas of estuaries can therefore negatively impact the cellular physiology of H. diversicolor, with greater metabolic costs. However, extreme stress levels were not reached as worms incremented wet weight and survival was high under all conditions tested. Our findings are important for the optimization of ragworm aquaculture and adaptive conservation strategies of estuarine systems.
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•Estuarine systems are subject to multiple-stressor interactions.•Temperature and salinity are crucial factors shaping estuarine communities.•The effect of these factors was tested in Hediste diversicolor (T24, 27, 30 °C; S20, 30).•High temperature and low salinity activate the CSR, with a decrease in energy reserves.•Extreme stress was not reached as survival was high and wet weight increased.
•The cultivation UVA level affects lettuce quality during shelf-life.•Low UVA intensity postpones the decrease of the primary energy reserves.•Low UVA intensity delays the decline of chlorophyll ...content, and decreases PPO activity.•Low UVA intensity reduces the ROS levels, owing to enhanced antioxidant activity.•The high UVA intensity mostly behaves comparably to the control.
Sunlight includes UVA (320–400 nm). Since it is irrelevant for driving photosynthesis, less recognition is given to its usefulness in indoor cultivation. We examined how the cultivation under different UVA levels (0, 10 and 40 μmol m−2 s−1) affects the lettuce postharvest quality by evaluating the temporal dynamics of several underlying aspects, including weight loss, chlorophyll fluorescence, protein content, primary energy reserves (starch, sugars), pigments (chlorophyll, carotenoids), the activity of enzymes related to enzymatic browning phenylalanine ammonia lyase, polyphenol oxidase (PPO), the activity of antioxidant machinery enzymes (superoxide dismutase, catalase), the accumulation of non-enzymatic antioxidants (polyphenols, ascorbic acid) and the accumulation of reactive oxygen species (ROS; H2O2, O2−). Evaluations were conducted (5 d intervals) on dark-stored excised leaves for 15 d (16 ℃, 70 % relative air humidity). Control samples gradually underwent a decrease in both primary energy reserves and protein content. They also suffered from color degradation owing to both a decrease in chlorophyll content and an enhanced PPO activity. Increased electrolyte leakage was also observed as a result of enhanced ROS levels. The low UVA level clearly improved all quality parameters, whereas the application of high UVA intensity caused limited effects in comparison to the control. In the former case, ROS accumulation was counteracted by an enhanced stimulation of the non-enzymatic and enzymatic antioxidant machinery. Overall, the results show that the promotive effect of UVA during cultivation on lettuce nutritional quality and shelf-life is strongly intensity-dependent and is mediated by diverse processes.
The fat body plays major roles in the life of insects. It is a dynamic tissue involved in multiple metabolic functions. One of these functions is to store and release energy in response to the energy ...demands of the insect. Insects store energy reserves in the form of glycogen and triglycerides in the adipocytes, the main fat body cell. Insect adipocytes can store a great amount of lipid reserves as cytoplasmic lipid droplets. Lipid metabolism is essential for growth and reproduction and provides energy needed during extended nonfeeding periods. This review focuses on energy storage and release and summarizes current understanding of the mechanisms underlying these processes in insects.
The coral microbiome plays a key role in host health by being involved in energy metabolism, nutrient cycling, and immune system formation. Inoculating coral with beneficial bacterial consortia may ...enhance the ability of this host to cope with complex and changing marine environments. In this study, the coral Pocillopora damicornis was inoculated with a beneficial microorganisms for corals (BMC) consortium to investigate how the coral host and its associated microbial community would respond.
High-throughput 16S rRNA gene sequencing revealed no significant differences in bacterial community α-diversity. However, the bacterial community structure differed significantly between the BMC and placebo groups at the end of the experiment. Addition of the BMC consortium significantly increased the relative abundance of potentially beneficial bacteria, including the genera Mameliella and Endozoicomonas. Energy reserves and calcification rates of the coral host were also improved by the addition of the BMC consortium. Co-occurrence network analysis indicated that inoculation of coral with the exogenous BMC consortium improved the physiological status of the host by shifting the coral-associated microbial community structure.
Manipulating the coral-associated microbial community may enhance the physiology of coral in normal aquarium conditions (no stress applied), which may hypothetically contribute to resilience and resistance in this host.
Abstract
As billions of nocturnal avian migrants traverse North America, twice a year they must contend with landscape changes driven by natural and anthropogenic forces, including the rapid growth ...of the artificial glow of the night sky. While airspaces facilitate migrant passage, terrestrial landscapes serve as essential areas to restore energy reserves and often act as refugia—making it critical to holistically identify stopover locations and understand drivers of use. Here, we leverage over 10 million remote sensing observations to develop seasonal contiguous United States layers of bird migrant stopover density. In over 70% of our models, we identify skyglow as a highly influential and consistently positive predictor of bird migration stopover density across the United States. This finding points to the potential of an expanding threat to avian migrants: peri-urban illuminated areas may act as ecological traps at macroscales that increase the mortality of birds during migration.
Rising seawater temperature and ocean acidification threaten the survival of coral reefs. The relationship between coral physiology and its microbiome may reveal why some corals are more resilient to ...these global change conditions. Here, we conducted the first experiment to simultaneously investigate changes in the coral microbiome and coral physiology in response to the dual stress of elevated seawater temperature and ocean acidification expected by the end of this century. Two species of corals, Acropora millepora containing the thermally sensitive endosymbiont C21a and Turbinaria reniformis containing the thermally tolerant endosymbiont Symbiodinium trenchi, were exposed to control (26.5°C and pCO2 of 364 μatm) and treatment (29.0°C and pCO2 of 750 μatm) conditions for 24 days, after which we measured the microbial community composition. These microbial findings were interpreted within the context of previously published physiological measurements from the exact same corals in this study (calcification, organic carbon flux, ratio of photosynthesis to respiration, photosystem II maximal efficiency, total lipids, soluble animal protein, soluble animal carbohydrates, soluble algal protein, soluble algal carbohydrate, biomass, endosymbiotic algal density, and chlorophyll a). Overall, dually stressed A. millepora had reduced microbial diversity, experienced large changes in microbial community composition, and experienced dramatic physiological declines in calcification, photosystem II maximal efficiency, and algal carbohydrates. In contrast, the dually stressed coral T. reniformis experienced a stable and more diverse microbiome community with minimal physiological decline, coupled with very high total energy reserves and particulate organic carbon release rates. Thus, the microbiome changed and microbial diversity decreased in the physiologically sensitive coral with the thermally sensitive endosymbiotic algae but not in the physiologically tolerant coral with the thermally tolerant endosymbiont. Our results confirm recent findings that temperature-stress tolerant corals have a more stable microbiome, and demonstrate for the first time that this is also the case under the dual stresses of ocean warming and acidification. We propose that coral with a stable microbiome are also more physiologically resilient and thus more likely to persist in the future, and shape the coral species diversity of future reef ecosystems.
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