Comparing the impacts of climate change on the responses and linkages between terrestrial and aquatic ecosystems

Short-term heat waves have long-term consequences for parents and offspring in stickleback

Extreme temperature events, such as heat waves, can have lasting effects on the behavior, physiology, and reproductive success of organisms. Here, we examine the impact of short-term exposure to a simulated heat wave on condition, parental care, and reproductive success in a population of threespine stickleback (Gasterosteus aculeatus), a small fish with exclusive paternal care, currently experiencing regular heat waves. Males were either exposed to a simulated heat wave (23 °C) for 5 d or held at an ideal temperature (18 °C). Following this 5-d treatment, all males were transferred to 18 °C, where they completed a full parenting cycle. Offspring were raised at 18 °C. We found that while mass and body condition were unaffected in males exposed to a heat wave, cortisol responses were dampened across the nesting cycle compared to control males. In addition, heat wave males had longer latency for eggs to hatch, lower hatching success, and showed lower levels of parental care behavior compared to control males. Offspring of heat wave males had lower body condition, affecting swimming performance. Altogether, our results highlight the long-term impact that even short-term events can have on reproductive success, parental behavior, and subsequent generations, providing insight into population responses to rapid environmental change.

In vivo exposure to high temperature compromises quality of the sperm in Colossoma macropomum

Increases in temperature can affect the reproduction of fish by decreasing the quality of gametes for fertilization. Therefore, this study aimed to evaluate the in vivo effect of temperature on the production and sperm quality of Colossoma macropomum, which is an economically relevant species for Brazil, and other countries. Broodstock were exposed for 10 days at temperatures of 29 °C (n = 4) and 35 °C (n = 4). After exposure, semen was collected and sperm quality was evaluated for kinetic, biochemical, morphological parameters, membrane integrity, and oxygen consumption. The sperm quality of males of specimens of C. macropomum exposed in vivo to the higher temperature was compromised and showed a difference in all the analyses (P < 0.05). Sperm showed decreased motility (51.9 ± 11.6 s) compared to the control (61.3 ± 5.5 s); curvilinear (CLV), straight line (SLV), and average path (APV) velocities decreased, and straightness (STR) and beat cross frequency (BCF) increased; oxygen consumption decreased (32.8 ± 3.4 pmol. (s.ml)-1, picomol per second per ml) compared to the control (46.6 ± 3.5 pmol. (s.ml)-1); and the activity of catalase (CAT) and glutathione S-transferase (GST) enzymes increased and decreased, respectively, in sperm from fish exposed to high temperatures. Furthermore, an increase in non-viable sperm with damaged membranes and sperm with altered morphology was observed. The observed alterations indicate that C. macropomum confined in environments with high temperatures possibly produces more sperm that are unviable for the fertilization process.

UV radiation and temperature increase alter the PSII function and defense mechanisms in a bloom-forming cyanobacterium Microcystis aeruginosa

The aim was to determine the response of a bloom-forming Microcystis aeruginosa to climatic changes. Cultures of M. aeruginosa FACHB 905 were grown at two temperatures (25°C, 30°C) and exposed to high photosynthetically active radiation (PAR: 400-700 nm) alone or combined with UVR (PAR + UVR: 295-700 nm) for specified times. It was found that increased temperature enhanced M. aeruginosa sensitivity to both PAR and PAR + UVR as shown by reduced PSII quantum yields (Fv/Fm) in comparison with that at growth temperature (25°C), the presence of UVR significantly exacerbated the photoinhibition. M. aeruginosa cells grown at high temperature exhibited lower PSII repair rate (Krec) and sustained nonphotochemical quenching (NPQs) induction during the radiation exposure, particularly for PAR + UVR. Although high temperature alone or worked with UVR induced higher SOD and CAT activity and promoted the removal rate of PsbA, it seemed not enough to prevent the damage effect from them showing by the increased value of photoinactivation rate constant (Kpi). In addition, the energetic cost of microcystin synthesis at high temperature probably led to reduced materials and energy available for PsbA turnover, thus may partly account for the lower Krec and the declination of photosynthetic activity in cells following PAR and PAR + UVR exposure. Our findings suggest that increased temperature modulates the sensitivity of M. aeruginosa to UVR by affecting the PSII repair and defense capacity, thus influencing competitiveness and abundance in the future water environment.

Use of CMIP6 scenarios as a reference to understand the responses of macrophyte germination and seedling growth to future warming and allelopathy co-stressors

The application of appropriate references such as CMIP6 climate scenarios for benchmarking studies of climate change on ecosystems can promote consistency among different climate change research. However, the use of CMIP6 climate scenarios is not common among experiments on the effects of climate change on freshwater ecosystems. Also, little is known about the impact of ecological factor such as allelopathy of alien species on macrophyte germination and seedling growth under different climate scenarios. In our study, by simulating three annual mean temperature changes at global warming levels of 1.5 °C (low warming scenario), 2 °C (medium warming scenario) and 4 °C (high warming scenario) corresponding to CMIP6 multi-model mean change at the corresponding global warming level, we conducted a mesocosm experiment to investigate their possible effects of different climate scenarios and allelopathy co-stressors on macrophyte germination and seedling growth. Our study showed that three warming scenarios all can facilitate macrophyte propagule germination and seedling growth, but the effect paths vary with CMIP6 warming scenarios and there are more influence pathways under high warming scenarios than under low and medium warming scenarios. Higher aqueous extract concentrations of Eichhornia crassipes can significantly stimulate macrophyte propagule germination and seedling growth. And the medium and high warming scenarios may exacerbate the impacts of allelopathic substances on macrophyte germination and seedling growth, and their effects depend on the combination of the two stressors. These results indicated that medium- and high-temperature scenarios may have greater ecological effects on macrophytes than low-temperature scenarios. Thus, our results highlighted that future climate studies need proper benchmarks such as CMIP6 warming scenarios, because it can provide relatively more accurate and realistic simulations, valid comparative results, comprehensive understanding and supportive coordination among researchers.

Generalized Ulam-Hyers-Rassias stability and novel sustainable techniques for dynamical analysis of global warming impact on ecosystem

Marine structure changes as a result of climate change, with potential biological implications for human societies and marine ecosystems. These changes include changes in temperatures, flow, discrimination, nutritional inputs, oxygen availability, and acidification of the ocean. In this study, a fractional-order model is constructed using the Caputo fractional operator, which singular and nol-local kernel. A model examines the effects of accelerating global warming on aquatic ecosystems while taking into account variables that change over time, such as the environment and organisms. The positively invariant area also demonstrates positive, bounded solutions of the model treated. The equilibrium states for the occurrence and extinction of fish populations are derived for a feasible solution of the system. We also used fixed-point theorems to analyze the existence and uniqueness of the model. The generalized Ulam-Hyers-Rassias function is used to analyze the stability of the system. To study the impact of the fractional operator through computational simulations, results are generated employing a two-step Lagrange polynomial in the generalized version for the power law kernel and also compared the results with an exponential law and Mittag Leffler kernel. We also produce graphs of the model at various fractional derivative orders to illustrate the important influence that the fractional order has on the different classes of the model with the memory effects of the fractional operator. To help with the oversight of fisheries, this research builds mathematical connections between the natural world and aquatic ecosystems.

Impact of climate change and anthropogenic activities on aquatic ecosystem - A review

All living things depend on their natural environment, either directly or indirectly, for their high quality of life, growth, nutrition, and development. Due to the fast emissions of greenhouse gases (GHGs), the Earth's climate system is being negatively impacted by global warming. Stresses caused by climate change, such as rising and hotter seas, increased droughts and floods, and acrid waters, threaten the world's most populated areas and aquatic ecosystems. As a result, the aquatic ecosystems of the globe are quickly reaching hazardous conditions. Marine ecosystems are essential parts of the world's environment and provide several benefits to the human population, such as water for drinking and irrigation, leisure activities, and habitat for commercially significant fisheries. Although local human activities have influenced coastal zones for millennia, it is still unclear how these impacts and stresses from climate change may combine to endanger coastal ecosystems. Recent studies have shown that rising levels of greenhouse gases are causing ocean systems to experience conditions not seen in several million years, which may cause profound and irreversible ecological shifts. Ocean productivity has declined, food web dynamics have changed, habitat-forming species are less common, species ranges have changed, and disease prevalence has increased due to human climate change. We provide an outline of the interaction between global warming and the influence of humans along the coastline. This review aims to demonstrate the significance of long-term monitoring, the creation of ecological indicators, and the applications of understanding how aquatic biodiversity and ecosystem functioning respond to global warming. This review discusses the effects of current climate change on marine biological processes both now and in the future, describes present climate change concerning historical change, and considers the potential roles aquatic systems could play in mitigating the effects of global climate change.

Immune and Reproductive Biomarkers in Female Sea Urchins Paracentrotus lividus under Heat Stress

The functioning of the immune and reproductive systems is crucial for the fitness and survival of species and is strongly influenced by the environment. To evaluate the effects of short-term heat stress (HS) on these systems, confirming and deepening previous studies, female sea urchin Paracentrotus lividus were exposed for 7 days to 17 °C, 23 and 28 °C. Several biomarkers were detected such as the ferric reducing power (FRAP), ABTS-based total antioxidant capacity (TAC-ABTS), nitric oxide metabolites (NOx), total thiol levels (TTL), myeloperoxidase (MPO) and protease (PA) activities in the coelomic fluid (CF) and mitochondrial membrane potential (MMP), H2O2 content and intracellular pH (pHi) in eggs and coelomocytes, in which TAC-ABTS and reactive nitrogen species (RNS) were also analyzed. In the sea urchins exposed to HS, CF analysis showed a decrease in FRAP levels and an increase in TAC-ABTS, TTL, MPO and PA levels; in coelomocytes, RNS, MMP and H2O2 content increased, whereas pHi decreased; in eggs, increases in MMP, H2O2 content and pHi were found. In conclusion, short-term HS leads to changes in five out of the six CF biomarkers analyzed and functional alterations in the cells involved in either reproductive or immune activities.

The response of aquatic ecosystems to the interactive effects of stratospheric ozone depletion, UV radiation, and climate change

Variations in stratospheric ozone and changes in the aquatic environment by climate change and human activity are modifying the exposure of aquatic ecosystems to UV radiation. These shifts in exposure have consequences for the distributions of species, biogeochemical cycles, and services provided by aquatic ecosystems. This Quadrennial Assessment presents the latest knowledge on the multi-faceted interactions between the effects of UV irradiation and climate change, and other anthropogenic activities, and how these conditions are changing aquatic ecosystems. Climate change results in variations in the depth of mixing, the thickness of ice cover, the duration of ice-free conditions and inputs of dissolved organic matter, all of which can either increase or decrease exposure to UV radiation. Anthropogenic activities release oil, UV filters in sunscreens, and microplastics into the aquatic environment that are then modified by UV radiation, frequently amplifying adverse effects on aquatic organisms and their environments. The impacts of these changes in combination with factors such as warming and ocean acidification are considered for aquatic micro-organisms, macroalgae, plants, and animals (floating, swimming, and attached). Minimising the disruptive consequences of these effects on critical services provided by the world's rivers, lakes and oceans (freshwater supply, recreation, transport, and food security) will not only require continued adherence to the Montreal Protocol but also a wider inclusion of solar UV radiation and its effects in studies and/or models of aquatic ecosystems under conditions of the future global climate.

Photodegradation of organic micropollutants in aquatic environment: Importance, factors and processes

Photochemical reactions widely occur in the aquatic environment and play fundamental roles in aquatic ecosystems. In particular, solar-induced photodegradation is efficient for many organic micropollutants (OMPs), especially those that cannot undergo hydrolysis or biodegradation, and thus can mitigate chemical pollution. Recent reports indicate that photodegradation may play a more important role than biodegradation in many OMP transformations in the aquatic environment. Photodegradation can be influenced by the water matrix such as pH, inorganic ions, and dissolved organic matter (DOM). The effect of the water matrix such as DOM on photodegradation is complex, and new insights concerning the disparate effects of DOM have recently been reported. In addition, the photodegradation process is also influenced by physical factors such as latitude, water depth, and temporal variations in sunlight as these factors determine the light conditions. However, it remains challenging to gain an overview of the importance of photodegradation in the aquatic environment because the reactions involved are diverse and complex. Therefore, this review provides a concise summary of the importance of photodegradation and the major processes related to the photodegradation of OMPs, with particular attention given to recent progress on the major reactions of DOM. In addition, major knowledge gaps in this field of environmental photochemistry are highlighted.

Understanding the relative roles of local environmental, geo-climatic and spatial factors for taxonomic, functional and phylogenetic β-diversity of stream fishes in a large basin, Northeast China

The primary objective of this study was to determine the relative roles of local environmental (Local), geo-climatic (Geo), and spatial (Spatial) factors to taxonomic, functional, and phylogenetic β-diversity of stream fish in a large basin in Northeast China. We quantified the current biodiversity patterns of fish communities in the Hun-Tai River using β-diversity. We assessed (i) corresponding contributions of turnover and nestedness within the taxonomic, functional, and phylogenetic β-diversity of fishes; (ii) correlations among β-diversity facets (i.e., taxonomic, functional, and phylogenetic facets); (iii) relative contributions of Local, Geo, and Spatial factors to β-diversity. We collected fish communities from 171 sampling sites. Mantel tests were used to examine the correlation of three facets of β-diversity and their components (i.e., total, nestedness, and turnover). Distance-based redundancy analysis and variation partitioning assess the relative contributions of Local, Geo, and Spatial factors to β-diversity. We found that turnover is the main driving mechanism for β-diversity in fish. Among the facets of β-diversity, taxonomic and phylogenetic facets have strong ecological information association. Spatial factors have a general contribution to various facets of β-diversity and its components. From aspects of fish β-diversity conservation, connectivity and habitat heterogeneity need to be maintained in the entire aquatic environment. In addition, protecting taxonomic β-diversity is helpful for maintaining phylogenetic β-diversity.

Ocean water quality monitoring using remote sensing techniques: A review

Ocean Water Quality (OWQ) monitoring provides insights into the quality of water in marine and near-shore environments. OWQ measurements can contain the physical, chemical, and biological characteristics of oceanic waters, where low OWQ values indicate an unhealthy ecosystem. Many parameters of water can be estimated from Remote Sensing (RS) data. Thus, RS offers significant opportunities for monitoring water quality in estuaries, coastal waterways, and the ocean. This paper reviews various RS systems and techniques for OWQ monitoring. It first introduces the common OWQ parameters, followed by the definition of the parameters and techniques of OWQ monitoring with RS techniques. In this study, the following OWQ parameters were reviewed: chlorophyll-a, colored dissolved organic matter, turbidity or total suspended matter/solid, dissolved organic carbon, Secchi disk depth, suspended sediment concentration, and sea surface temperature. This study presents a systematic analysis of the capabilities and types of spaceborne systems (e.g., optical and thermal sensors, passive microwave radiometers, active microwave scatterometers, and altimeters) which are commonly applied to OWQ assessment. The paper also provides a summary of the opportunities and limitations of RS data for spatial and temporal estimation of OWQ. Overall, it was observed that chlorophyll-a and colored dissolved organic matter are the dominant parameters applied to OWQ monitoring. It was also concluded that the data from optical and passive microwave sensors could effectively be applied to estimate OWQ parameters. From a methodological perspective, semi-empirical algorithms generally outperform the other empirical, analytical, and semi-analytical methods for OWQ monitoring.

Climate, immigration and speciation shape terrestrial and aquatic biodiversity in the European Alps

Quaternary climate fluctuations can affect speciation in regional biodiversity assembly in two non-mutually exclusive ways: a glacial species pump, where isolation in glacial refugia accelerates allopatric speciation, and adaptive radiation in underused adaptive zones during ice-free periods. We detected biogeographic and genetic signatures associated with both mechanisms in the assembly of the biota of the European Alps. Age distributions of endemic and widespread species within aquatic and terrestrial taxa (amphipods, fishes, amphibians, butterflies and flowering plants) revealed that endemic fish evolved only in lakes, are highly sympatric, and mainly of Holocene age, consistent with adaptive radiation. Endemic amphipods are ancient, suggesting preglacial radiation with limited range expansion and local Pleistocene survival, perhaps facilitated by a groundwater-dwelling lifestyle. Terrestrial endemics are mostly of Pleistocene age and are thus more consistent with the glacial species pump. The lack of evidence for Holocene adaptive radiation in the terrestrial biome is consistent with faster recolonization through range expansion of these taxa after glacial retreats. More stable and less seasonal ecological conditions in lakes during the Holocene may also have contributed to Holocene speciation in lakes. The high proportion of young, endemic species makes the Alpine biota vulnerable to climate change, but the mechanisms and consequences of species loss will likely differ between biomes because of their distinct evolutionary histories.

Association between Lake Sediment Nutrients and Climate Change, Human Activities: A Time-Series Analysis

Climate change and human activities are closely linked with the nutrient accumulation in sediments, but the role of influence factors and the driving mechanisms are unclear. Here, by using the generalized additive model (GAM), we investigated the contributions and driving mechanisms of climate change and human activities on TON, TN, and TP accumulation in sediments of typical lakes in the Huai River basin (Nansi Lake and Hongze Lake) from 1988 to 2018. The impacts of factors, such as air temperature (AT), real GDP per capita (GDP), population density (PD), crop sown area (CSA), artificial impervious area (AIA), and domestic sewage discharge (DSD) were considered in this study. The results of the multivariate GAM showed that the sediment variables were significantly affected by climate change in Nansi Lake, but not in Hongze Lake. AT and DSD contributed the most to the variation of sediment TOC in Nansi Lake, while the most critical factors affecting TN and TP were AT, PD and DSD. PD and CSA showed strong ability to explain the change of TOC in Hongze Lake, while CSA and DSD showed strong ability to explain the variations of TN and TP. The results show that the selected optimal multivariate GAM can well quantify the effects of climate change and human activities on nutrient enrichment in lake sediments. Effective recommendations are provided for decision-makers in developing water quality management plans to prevent eutrophication outbreaks in lake waters by targeting and controlling key factors.

Extreme drought scenario shapes different patterns of Chironomid coexistence in reservoirs in a semi-arid region

Semi-arid regions are particularly prone to extreme climate events such as droughts, which result in drastic fluctuations in the water volume of aquatic ecosystems, including artificial ones. As these climate extremes intensify, species must adapt, however, not all species can persist under new climate regimes in such a short period of time. In this study, we evaluated how fluctuations in the water levels of reservoirs, caused by drought, affect Chironomidae diversity patterns in a semi-arid region. We studied six reservoirs (256 sites) in two basins in Northeastern Brazil, exposed to different levels of anthropic impact. Sampling was carried out in 2014, 2015 (both extremely dry years) and 2019. A dead water volume was attained during the extreme drought in 2015, consequently affecting the reservoir and resulting in a low diversity, abundance, and functional redundancy of the Chironomidae assemblages. Despite precipitation increases in 2019, some reservoirs continued to be water deficient. These drastic water fluctuations led to different patterns in Chironomidae taxonomic and functional diversity, which were also influenced by anthropic stressors. Thus, the most impacted basin presented lower diversity, with some species and trait turnover between reservoirs. The opposite trend was observed in the least impacted basin. Overall, taxonomic and functional diversity decreased with decreasing water volume, resulting in a community dominated by small-medium sized individuals with multivoltine cycles and hemoglobin and diapause resistant forms, conferring higher tolerance to water stress. The drought and consequent water volume fluctuations throughout the years seemed to exacerbate the water quality due to pre-existing exposure to anthropic impacts (e.g., domestic discharge, fishing activity, agriculture, livestock). This resulted in biotic homogenization, with an observed loss of taxa and traits. This study reinforced the need to implement habitat conservation and water quality improvement strategies to prevent further ecosystem damage in the face of climate change uncertainty.

Power Generation Analysis of Terrestrial Ultraviolet-Assisted Solid Oxide Electrolyzer Cell

This paper presents a novel system design that considerably improves the entrapment of terrestrial ultraviolet (UV) irradiance in a customized honeycomb structure to produce hydrogen at a standard rate of 7.57 slpm for places with a UV index > 11. Thermolysis of high salinity water is done by employing a solid oxide electrolyzer cell (SOEC), which comprises three customized, novel active optical subsystems to filter, track, and concentrate terrestrial UV solar irradiance by Fresnel lenses. The output of systems is fed to a desalinator, a photovoltaic system to produce electrical energy, and a steam generator with modified surface morphology to generate the required superheated steam for the SOEC. A simulation in COMSOL Multiphysics ver. 5.6 has shown that a customized honeycomb structure, when incorporated on the copper–nickel surface of a steam generator, improves its absorptance coefficient up to 93.43% (48.98%—flat case). This results in generating the required superheated steam of 650 °C with a designed active optical system comprising nine Fresnel lenses (7 m2) that offer the concentration of 36 suns on the honeycomb structure of the steam generator as input. The required 1.27 kW of electrical power is obtained by concentrating the photovoltaic system using In0.33Ga0.67N/Si/InN solar cells. This production of hydrogen is sustainable and cost effective, as the estimated cost over 5 years by the proposed system is 0.51 USD/kg, compared to the commercially available system, which costs 3.18 USD/kg.

Impacts of Warming on Reciprocal Subsidies Between Aquatic and Terrestrial Ecosystems

Cross-ecosystem subsidies are important as their recipients often rely on them to supplement in situ resource availability. Global warming has the potential to alter the quality and quantity of these subsidies, but our knowledge of these effects is currently limited. Here, we quantified the biomass and diversity of the invertebrates exchanged between freshwater streams and terrestrial grasslands in a natural warming experiment in Iceland. We sampled invertebrates emerging from the streams, those landing on the water surface, ground-dwelling invertebrates falling into the streams, and those drifting through the streams. Emerging invertebrate biomass or diversity did not change with increasing temperature, suggesting no effect of warming on aquatic subsidies to the terrestrial environment over the 1-month duration of the study. The biomass and diversity of aerial invertebrates of terrestrial origin landing on the streams increased with temperature, underpinned by increasing abundance and species richness, indicating that the greater productivity of the warmer streams may attract more foraging insects. The biomass of ground-dwelling invertebrates falling into the streams also increased with temperature, underpinned by increasing body mass and species evenness, suggesting that soil warming leads to terrestrial communities dominated by larger, more mobile organisms, and thus more in-fall to the streams. The biomass and diversity of terrestrial invertebrates in the drift decreased with temperature, however, underpinned by decreasing abundance and species richness, reflecting upstream consumption due to the higher energetic demands of aquatic consumers in warmer environments. These results highlight the potential for asynchronous responses to warming for reciprocal subsidies between aquatic and terrestrial environments and the importance of further research on warming impacts at the interface of these interdependent ecosystems.

Increased CO2 Relevant to Future Ocean Acidification Alleviates the Sensitivity of a Red Macroalgae to Solar Ultraviolet Irradiance by Modulating the Synergy Between Photosystems II and I

While intertidal macroalgae are exposed to drastic changes in solar photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) during a diel cycle, and to ocean acidification (OA) associated with increasing CO₂ levels, little is known about their photosynthetic performance under the combined influences of these drivers. In this work, we examined the photoprotective strategies controlling electron flow through photosystems II (PSII) and photosystem I (PSI) in response to solar radiation with or without UVR and an elevated CO₂ concentration in the intertidal, commercially important, red macroalgae Pyropia (previously Porphyra) yezoensis. By using chlorophyll fluorescence techniques, we found that high levels of PAR alone induced photoinhibition of the inter-photosystem electron transport carriers, as evidenced by the increase of chlorophyll fluorescence in both the J- and I-steps of Kautsky curves. In the presence of UVR, photoinduced inhibition was mainly identified in the O₂-evolving complex (OEC) and PSII, as evidenced by a significant increase in the variable fluorescence at the K-step (F _k) of Kautsky curves relative to the amplitude of F _J-F _o (W_k) and a decrease of the maximum quantum yield of PSII (F _v/F _m). Such inhibition appeared to ameliorate the function of downstream electron acceptors, protecting PSI from over-reduction. In turn, the stable PSI activity increased the efficiency of cyclic electron transport (CET) around PSI, dissipating excess energy and supplying ATP for CO₂ assimilation. When the algal thalli were grown under increased CO₂ and OA conditions, the CET activity became further enhanced, which maintained the OEC stability and thus markedly alleviating the UVR-induced photoinhibition. In conclusion, the well-established coordination between PSII and PSI endows P. yezoensis with a highly efficient photochemical performance in response to UVR, especially under the scenario of future increased CO₂ levels and OA.

Effects of elevated temperature on prooxidant-antioxidant homeostasis and redox status in the American oyster: Signaling pathways of cellular apoptosis during heat stress

Increasing seawater temperature affects growth, reproduction, development, and various other physiological processes in aquatic organisms, such as marine invertebrates, which are especially susceptible to high temperatures. In this study, we examined the effects of short-term heat stress (16, 22, 26, and 30 °C for 1-week exposure) on prooxidant-antioxidant homeostasis and redox status in the American oyster (Crassostrea virginica, an edible and commercially cultivated bivalve mollusk) under controlled laboratory conditions. Immunohistochemical and real-time quantitative PCR (qRT-PCR) analyses were performed to examine the expression of heat shock protein-70 (HSP70, a biomarker of heat stress), catalase (CAT, an antioxidant), superoxide dismutase (SOD, an antioxidant), dinitrophenyl protein (DNP, a biomarker of reactive oxygen species, ROS), and 3-nitrotyrosine protein (NTP, an indicator of reactive nitrogen species, RNS), in the gills and digestive glands of oysters. In situ TUNEL assay was performed to detect cellular apoptosis in tissues. Histological analysis showed an increase in mucus secretion in the gills and digestive glands of oysters exposed to higher temperatures (22, 26, and 30 °C) compared to control (16 °C). Immunohistochemical and qRT-PCR analyses showed significant increases in HSP70, DNP and NTP protein, and mRNA expressions in tissues at higher temperatures. Cellular apoptosis was also significantly increased at higher temperatures. Thus, heat-induced oxidative and nitrative stress likely occur due to overproduction of ROS and RNS. Interestingly, expression of CAT and SOD increased in oysters exposed to 22 and 26 °C, but was at or below control levels in the highest temperature exposure (30 °C). Collectively, these results suggest that elevated seawater temperatures cause oxidative/nitrative stress and induce cellular apoptosis through excessive ROS and RNS production, leading to inhibition of the antioxidant defense system in marine mollusks.

How do life-history traits influence the fate of intertidal and subtidal Mytilus galloprovincialis in a changing climate?

Coastal organisms (i.e. intertidal or upper subtidal species) live in between the terrestrial and aquatic realms, making them particularly vulnerable to climate change. In this context, intertidal organisms may suffer from the predicted sea level rise (increasing their submerged time) while subtidal organisms may suffer from anthropically-induced hypoxia and its consequences. Although there is some knowledge on how coastal organisms adapt to environmental changes, the biochemical and physiological consequences of prolonged submergence periods have not yet been well characterized. Thus, the present study aimed to assess the biochemical alterations experienced by intertidal organisms maintained always under tidal exposure (IT); intertidal organisms maintained submersed (IS); subtidal organisms maintained always submersed (SS); subtidal organisms under tidal exposure (ST). For this, Mytilus galloprovincialis specimens from contiguous intertidal and subtidal populations were exposed to the above mentioned conditions for twenty-eight days. Results indicated that both intertidal and subtidal mussels are adapted to the oxidative stress pressure caused by tidal and submerged conditions tested. Intertidal mussels did not seem to be negatively affected by submergence while ST specimens were energetically challenged by tidal exposure. Both IT and ST mussels consumed glycogen to fuel up mechanisms aiming to maintain redox homeostasis. Overall, both intertidal and subtidal populations were capable of coping with tidal exposure, although the strategies employed differed between them. These findings indicate that although IT mussels may not significantly suffer from the longer-term submergence, hypoxic events occurring in the context of global warming and other anthropogenic impacts may have consequences on both IT and ST populations. Altogether, it is important to highlight that tides may act as a confounding factor in experiments concerning coastal organisms, as it causes additional physiological and biochemical perturbations.

Water Quality Monitoring with Arduino Based Sensors

Water is a quintessential element for the survival of mankind. Its variety of uses means that it is always in a constant state of demand. The supply of water most primarily comes from large reservoirs of water such as lakes, streams, and the ocean itself. As such, it is good practice to monitor its quality to ensure it is fit for human consumption. Current water quality monitoring is often carried out in traditional labs but is time consuming and prone to inaccuracies. Therefore, this paper aims to investigate the feasibility of implementing an Arduino-based sensor system for water quality monitoring. A simple prototype consisting of a microcontroller and multiple attached sensors was employed to conduct weekly onsite tests at multiple daily intervals. It was found that the system works reliably but is reliant on human assistance and prone to data inaccuracies. The system however, provides a solid foundation for future expansion works of the same category to elevate the system to being Internet of Things (IoT) friendly.

A baseline assessment of hydrologic alteration degree for the Mexican catchments at gauged rivers (2016)

River regime has been modified in several freshwater bodies around the world. This alteration has led to species loss, water pollution, higher or lesser economic profits, changes in magnitude, timing, duration and rate change of flow, among others. Thus, hydrologic alteration assessment allows evaluating the regime parameters so that stakeholders, decision-makers, and dams managers may take efficient actions to mitigate or rehabilitate riparian ecosystems. In the present study, Hydrologic Alteration Indexes on Rivers (IAHRIS, for its acronym in Spanish) and the Mexican standard approach were considered to evaluate 1150 gauged catchments in Mexico and come up with an alteration baseline for 67.03% of the country surface. The comparison may assist stakeholders to propose potential changes in the Mexican standard approach. Results reveal that 232 analyzed catchments can be considered as non-altered according to IAHRIS. In stark contrast, there are 281 non-altered catchments in Mexico in agreement with the official standard approach. Altered catchments are mainly impacted by minimum flow metrics and connectivity discharge. Additionally, the correlation between alteration indexes and 5 socio-economic variables was checked to identify which variables may greatly impact hydrologic alteration evolution or mitigation. From the five selected variables, the Human Development Index is significatively correlated to extreme minimum metrics (p = 0.94) while the Gross Domestic Product to extreme maximum metrics (p = 0.90).

The combination of warming and copper decreased the uptake of polycyclic aromatic hydrocarbons by spinach and their associated cancer risk

Both climate warming and co-contamination of polycyclic aromatic hydrocarbons (PAHs) and heavy metals are environmental issues of great concern. However, the interactive effects of warming and heavy metals on PAH accumulation in edible plants and the PAH-associated health risk remain unclear. In this study, enclosed soil/water-air-plant microcosm experiments were conducted to explore the effects of copper (Cu), warming (+6 °C), and their combination on the uptake of four deuterated PAH (PAH-d₁₀) by spinach (Spinacia oleracea L.) in aged soil. PAH-associated health risks for soil, plant, and air exposure pathways were also assessed. The results showed that both individual Cu or warming decreased the PAH-d₁₀ concentrations in root and shoot (non-normalized by lipid content) as well as the total PAH-associated cancer risk. Although antagonism existed between warming and Cu, compared to the presence of Cu, warming further reduced the spinach uptake of PAHs-d₁₀ and total PAH-associated cancer risk, and the reductions were stronger at higher Cu levels. The inhibitory effect of the binary combination on PAH-d₁₀ root uptake was attributed to decreased root lipid content and phytoavailable concentrations of PAHs-d₁₀ in soil as a consequence of biodegradation, aging effect and cation-π interaction. The antagonism between warming and Cu on spinach uptake could be explained by their opposite effects on PAH-d₁₀ biodegradation and the inhibition of the cation-π interaction caused by warming. Additionally, the shoot uptake of PAHs-d₁₀ was mainly controlled by their soil to air to shoot partitioning. The findings suggest that the interactive effects of climate warming and co-existing pollutants should be taken into account for the assessment of plant uptake and health risk of PAHs.

Ozone Layer Evolution in the Early 20th Century

The ozone layer is well observed since the 1930s from the ground and, since the 1980s, by satellite-based instruments. The evolution of ozone in the past is important because of its dramatic influence on the biosphere and humans but has not been known for most of the time, except for some measurements of near-surface ozone since the end of the 19th century. This gap can be filled by either modeling or paleo reconstructions. Here, we address ozone layer evolution during the early 20th century. This period was very interesting due to a simultaneous increase in solar and anthropogenic activity, as well as an observed but not explained substantial global warming. For the study, we exploited the chemistry-climate model SOCOL-MPIOM driven by all known anthropogenic and natural forcing agents, as well as their combinations. We obtain a significant global scale increase in the total column ozone by up to 12 Dobson Units and an enhancement of about 20% of the near-surface ozone over the Northern Hemisphere. We conclude that the total column ozone changes during this period were mainly driven by enhanced solar ultra violet (UV) radiation, while near-surface ozone followed the evolution of anthropogenic ozone precursors. This finding can be used to constrain the solar forcing magnitude.

Impacts of Precipitation and Temperature on Changes in the Terrestrial Ecosystem Pattern in the Yangtze River Economic Belt, China

The terrestrial ecosystem plays an important role in maintaining an ecological balance, protecting the ecological environment, and promoting the sustainable development of human beings. The impacts of precipitation, temperature, and other natural factors on terrestrial ecosystem pattern change (TEPC) are the basis for promoting the healthy development of the terrestrial ecosystem. This paper took the Yangtze River Economic Belt (YREB) as the study area, analyzed the temporal and spatial characteristics of TEPC from 1995 to 2015, and used spatial transfer matrix and terrestrial ecosystem pattern dynamic degree models to analyze the area transformation between different terrestrial ecosystem types. A bivariate spatial autocorrelation model and a panel data regression model were used to study the impacts of precipitation and temperature on TEPC. The results show that: (1) The basic pattern of the terrestrial ecosystem developed in a relatively stable manner from 1995 to 2005 in the YREB, and transformations between the farmland ecosystem, forest ecosystem, and grassland ecosystem were more frequent. The temporal and spatial evolution of precipitation and temperature in the YREB showed significant regional differences. (2) There was a significant negative bivariate global spatial autocorrelation effect of precipitation and temperature on the area change of the forest ecosystem, and a positive effect on the area change of the settlement ecosystem. The local spatial correlation between precipitation or temperature and the terrestrial ecosystem showed significant scattered distribution characteristics. (3) The impacts of precipitation and temperature on TEPC showed significant regional characteristics on the provincial scale. The impact utility in the tail region is basically negative, while both positive and negative effects exist in the central and head regions of the YREB. Moreover, the impact showed significant spatial heterogeneity on the city scale. (4) The Chinese government has promulgated policies and measures for strategic planning, ecological environment protection, and economic support, which could effectively promote ecological and sustainable development of the YREB and promote the coordinated development of the ecology, economy, and society in China.

Satellite Remote Sensing of Precipitation and the Terrestrial Water Cycle in a Changing Climate

The water cycle is the most essential supporting physical mechanism ensuring the existence of life on Earth. Its components encompass the atmosphere, land, and oceans. The cycle is composed of evaporation, evapotranspiration, sublimation, water vapor transport, condensation, precipitation, runoff, infiltration and percolation, groundwater flow, and plant uptake. For a correct closure of the global water cycle, observations are needed of all these processes with a global perspective. In particular, precipitation requires continuous monitoring, as it is the most important component of the cycle, especially under changing climatic conditions. Passive and active sensors on board meteorological and environmental satellites now make reasonably complete data available that allow better measurements of precipitation to be made from space, in order to improve our understanding of the cycle’s acceleration/deceleration under current and projected climate conditions. The article aims to draw an up-to-date picture of the current status of observations of precipitation from space, with an outlook to the near future of the satellite constellation, modeling applications, and water resource management.