Combination Of High Temperature Research Articles

Breeding success of eurasian cranes (<i>grus grus</i>, gruiformes, aves) in the conditions of a changing environment: the impact of climatic and hydrometeorological trends

Theoretical predictions usually assume that changes in conditions caused by climate warming would render negative effects on the population dynamics of many bird species, but evidence is only rarely presented. Changes in phenology, nesting timing, and the physical condition of breeders have been published for a wide range of species in most regions of the Northern Hemisphere; however, data are still insufficient for a better understanding of the consequences for changes in productivity, reproductive success and offspring recruitment. Long-term monitoring (1994–2023) the numbers and age structure of premigratory gatherings of Eurasian cranes in the northern Moscow Region, Central Russia, reveals that, despite the climate warming in the region, the proportion of offspring has not changed over the 30-year long period of observation. The number of young birds is positively related to the temperature of the breeding season; in warmer years, the productivity of Eurasian cranes was higher. In seasons with high precipitation rates, the proportion of chicks was decreased. The reproduction efficiency of cranes on Central Russia is controlled by two parameters: the amount of precipitation and the average temperature during the breeding season.More chicks rise in years with a combination of higher temperatures and low precipitation amounts. Increased precipitations and decreased temperatures lead to reduced proportions of chicks in the premigratory gatherings. The most unfavorable situation for common cranes was low temperatures combined with high precipitations, the proportion of chicks being the minimum in such years.

Effects of Temperature and Salinity on Perfluorooctane Sulfonate (PFOS) Toxicity in Larval Estuarine Organisms.

Perfluorooctane sulfonate (PFOS) is a persistent contaminant that has been found globally within the environment. Key data gaps exist in the toxicity of PFOS to marine organisms, especially estuarine species that are crucial to the food web: fish, shrimp, and mollusks. This study developed toxicity thresholds for larval estuarine species, including grass shrimp (Palaemon pugio), sheepshead minnows (Cyprinodon variegatus), mysids (Americamysis bahia), and Eastern mud snails (Tritia obsoleta). Multiple abiotic stressors (salinity and temperature) were included as variables in testing the toxicity of PFOS. Acute 96 h toxicity testing under standard test conditions of 25 °C and 20 ppt seawater yielded LC50 values of 0.919 mg/L for C. variegatus, 1.375 mg/L for A. bahia, 1.559 mg/L for T. obsoleta, and 2.011 mg/L for P. pugio. The effects of increased temperature (32 °C) and decreased salinity (10 ppt) varied with test species. PFOS toxicity for the sheepshead minnows increased with temperature but was not altered by decreased salinity. For grass shrimp and mud snails, PFOS toxicity was greater under lower salinity. The combination of higher temperature and lower salinity was observed to lower the toxicity thresholds for all species. These data demonstrate that expanding toxicity testing to include a wider range of parameters will improve the environmental risk assessment of chemical contaminants, especially for species inhabiting dynamic estuarine ecosystems.

The vulnerability of World Heritage seagrass habitats to climate change.

Seagrass is an important natural attribute of 28 World Heritage (WH) properties. These WH seagrass habitats provide a wide range of services to adjacent ecosystems and human communities, and are one of the largest natural carbon sinks on the planet. Climate change is considered the greatest and fastest-growing threat to natural WH properties and evidence of climate-related impacts on seagrass habitats has been growing. The main objective of this study was to assess the vulnerability of WH seagrass habitats to location-specific key climate stressors. Quantitative surveys of seagrass experts and site managers were used to assess exposure, sensitivity and adaptive capacity of WH seagrass habitats to climate stressors, following the Climate Vulnerability Index approach. Over half of WH seagrass habitats have high vulnerability to climate change, mainly from the long-term increase in sea-surface temperature and short-term marine heatwaves. Potential impacts from climate change and certainty scores associated with them were higher than reported by a similar survey-based study from 10 years prior, indicating a shift in stakeholder perspectives during the past decade. Additionally, seagrass experts' opinions on the cumulative impacts of climate and direct-anthropogenic stressors revealed that high temperature in combination with high suspended sediments, eutrophication and hypoxia is likely to provoke a synergistic cumulative (negative) impact (p < .05). A key component contributing to the high vulnerability assessments was the low adaptive capacity; however, discrepancies between adaptive capacity scores and qualitative responses suggest that managers of WH seagrass habitats might not be adequately equipped to respond to climate change impacts. This thematic assessment provides valuable information to help prioritize conservation actions, monitoring activities and research in WH seagrass habitats. It also demonstrates the utility of a systematic framework to evaluate the vulnerability of thematic groups of protected areas that share a specific attribute.

Stress Relieving Heat Treatment of 316L Stainless Steel Made by Additive Manufacturing Process.

Residual stress occurs in the materials after different methods of processing due to the application of pressure and/or thermal gradient. The occurrence of residual stresses can be observed in both subtractive and additive-manufactured (AM) materials and objects. However, pressure residual stresses are considered, in some cases, to have a positive effect; there are applications where the neutral stress state is required. As there is a lack of standards describing the heat treatment of AM materials, there is a need for experimental research in this field. The objective of this article is to determine the heat treatment thermal regime to achieve close to zero stress state in the subsurface layer of additively manufactured AM316L stainless steel. The presented objective leads to the long-term goal of neutral etalons for eddy current residual stress testing preparation. A semi-product intended for the experiment was prepared using the Selective Laser Melting (SLM) process and subsequently cut, using Abrasive Water Jet (AWJ) technology, into experimental specimens, which were consequently heat-treated in combination with four temperatures and three holding times. Residual stresses were measured using X-ray diffraction (XRD), and microstructure variations were observed and examined. A combination of higher temperature and longer duration of heat treatment caused more significant stress relaxation, and the original stress state of the material influenced a degree of this relaxation. The microstructure formed of cellular grains changed slightly in the form of grain growth with randomly occurring unmolten powder particles, porosity, and inclusion precipitation.

Significant efficiency improvement of conventional tempering by a novel flash tempering technique

A flash tempering process has been demonstrated for low-carbon low-alloy lath martensite, which includes heating the sample to 750 °C (Ac1: 752 °C), dwelling at 750 °C for 2 s, and quenching directly to room temperature. The high temperature accelerated the spread of the supersaturated carbon atoms in the lath martensite, activated the dislocation migrations and thus their combining and annihilation, and promoted the mass recrystallisation. The reduced dwelling time inhibited the coarsening of the martensitic laths and suppressed the growth of the recrystallized structures. The combination of higher temperature and the shorter dwelling period, so-called flash tempering, gives rise to the same microstructure and mechanical properties as those obtained by the conventional tempering process (i.e., dwelling at 600 °C for 1 h). The high efficient flash tempering, possessing significantly reduced energy and time consumptions, may have important consequence in industrialization of tempering process.

Influence of temperature on the biomarker responses of bullfrog tadpoles (Lithobates catesbeianus) to 2-hydroxyatrazine exposure

The influence of temperature (25 and 32 °C) on the biomarker responses of bullfrog tadpoles (Lithobates catesbeianus) to different concentrations of the atrazine metabolite 2-hydroxyatrazine (2-HA, 0, 10, 50 and 200 ng.L−1, 16 days), was evaluated. Temperature affected the activities of superoxide dismutase, glutathione S-transferase and acetylcholinesterase. The activities of catalase, glutathione peroxidase, glucose-6-phosphate dehydrogenase and carboxylesterase presented no alterations. Frequencies of micronuclei and nuclear abnormalities were also not altered. 2-HA decreased SOD activity at 25 °C and caused histopathological changes in the liver and the kidney at both temperatures, with the kidney being more affected by the combination of higher temperature and 2-HA exposure, presenting glomerular shrinkage and an increase in Bowman's space. Our results indicate that at environmentally relevant concentrations, 2-HA can cause changes in biomarker responses as well as in the morphology of liver and kidney in L. catesbeianus tadpoles. Temperature has an important influence on biomarker response and histopathological alterations.

Phase stability of stress-sensitive Ag2CO3 silver carbonate at high pressures and temperatures

Silver carbonate (Ag2CO3) is a material currently used for artificial carbon storage. In this work, we report synchrotron X-ray powder diffraction (XRD) experiments under high pressure and high temperature in combination with density-functional theory (DFT) calculations on silver carbonate up to 13.3 GPa. Two pressure-induced phase transitions were observed at room temperature: at 2.9 GPa to a high-pressure (HP1) phase and at 10.5 GPa to a second high-pressure phase (HP2). The facts that a) the HP2 phase can be indexed with the initial P21/m structure, b) our DFT calculations predict the initial structure is stable in the entire pressure range, and c) the HP2 phase is stable under decompression suggest that the intermediate HP1 phase is a product of the appearance of non-hydrostatic stresses in the sample. The observed structural transformations are associated to a high sensitivity of this compound to non-hydrostatic conditions. The compressibility of Ag2CO3 has also been determined, showing the c axis is the most compressible and that the bulk modulus increases quickly with applied pressure. We attribute both observations to the weak nature of the closed-shell Ag–Ag interactions in this material. The behavior of Ag2CO3 under heating at approximately 3 GPa was also studied. No temperature-induced phase transitions were found at this pressure, and the thermal expansion was determined to be relatively high for a carbonate.

Effect of temperature and loading rate on the mode I fracture energy of structural acrylic adhesives

Understanding the changes in the adhesive properties with the temperature and loading rate is important, particularly for designing adhesively bonded joints in structural applications. The viscoelastic behavior of adhesives is widely known to be based on the time–temperature superposition principle. In the case of the elastoplastic behavior, the stress–strain relationship is significantly affected by the external conditions, particularly for ductile adhesives. Similarly, the fracture behavior is expected to exhibit a temperature–loading rate dependence; however, few studies have focused on them, especially for structural acrylic adhesives.In this study, the impact of the temperature and test speed on the fracture energy of structural acrylic adhesives was investigated. Bulk tensile tests and double cantilever beam (DCB) tests were performed at different temperatures and test speeds. Bulk behavior showed an increase in the maximum stress and a decrease in the elongation at lower temperatures and higher loading rates. Conversely, the fracture toughness increased with a combination of higher temperatures and loading rates when the crack stably propagated. The mode I fracture energies of the test speed of 500 mm/min at 60°C increased by approximately 1.5–2 times that of 0.05 mm/min at room temperature. In addition, stick-slip crack propagation was observed at lower temperatures or higher loading rates.

Effect of processing conditions on electromagnetic shielding and electrical resistivity of injection‐molded polybutylene terephthalate compounds

AbstractThis research introduces an analysis of the anisotropic electrical resistivity (ER) and its relation to the electromagnetic shielding effectiveness (EMSE) for two injection‐molded carbon‐fiber‐reinforced polybutylene terephthalates (PBTs). The properties were measured for 2‐mm thick injection moldings considering the effect of melt temperature, injection velocity, and flow distance. The results for one compound showed an EMSE in the range of 30–40 dB, while EMSE for a compound with lower filler content is in the range of 45–75 dB. A combination of higher temperature and higher velocity leads to an increase of EMSE for both compounds in the range of 3%–8.5%. However, the increase in flow path reduced the EMSE for both compounds up to 10%. A novel experimental apparatus was used to measure the anisotropic ER in the three directions, that is, parallel, perpendicular, and transversal to flow. It is evident that injection molding induced high anisotropy for both compound specimens, and, depending on the processing conditions, produced similar longitudinal resistivity (0.2–4 Ω.cm) but higher transversal resistivity (8–22 Ω.cm). ER properties were compared with EMSE, evidencing an inverse relation as expected. Furthermore, it was found that the longitudinal resistivity is the main contributor to the specimens shielding.

Modification of the effects of nitrogen dioxide and sulfur dioxide on congenital limb defects by meteorological conditions.

Can meteorological conditions modify the associations between NO2 and SO2 exposure and congenital limb defects (CLDs) during the first trimester of pregnancy? Increases in NO2 and SO2 exposure were consistently associated with higher risks of CLDs during the first trimester of pregnancy; both low- and high-temperature exposure and high air humidity act synergistically with the two air pollutants on CLDs. Animal studies have indicated air pollutants are associated with CLDs, but corresponding epidemiological studies are limited with equivocal conclusions. Meteorological conditions are closely connected to the generation, diffusion, distribution and even chemical toxicity of air pollutants. This case-control study included 972 cases of CLDs and 9720 controls in Changsha, China during 2015-2018. Cases from the hospital based monitoring system for birth defects (including polydactyly, syndactyly, limb shortening, and clubfoot) and healthy controls from the electronic medical records system were studied. Complete data on daily average NO2 and SO2 concentrations and meteorological variables were obtained from local monitoring stations to estimate monthly individual exposures during the first trimester of pregnancy, using the nearest monitoring station approach for NO2 and SO2 concentrations, and the city-wide average approach for temperature and relative humidity, respectively. The 25th and 75th percentiles of daily mean temperature, as well as the 50th percentile of daily mean relative humidity during the study period were used to classify high- and low-temperature exposure, and high humidity exposure based on existing evidence and local climate characteristics. Multivariate logistic regression models were used to estimate the independent effects per 10 μg/m3 increase in NO2 and SO2 on CLDs, and the attribute proportions of interaction (API) were used to quantify the additive joint effects of air pollutants with meteorological conditions after including a cross product interaction term in the regression models. NO2 and SO2 exposures during the first trimester of pregnancy were consistently and positively associated with overall CLDs and subtypes, with adjusted odd ratios (aORs) ranging from 1.13 to 1.27 for NO2, and from 1.37 to 2.49 for SO2. The effect estimates were generally observed to be the strongest in the first month and then attenuated in the second and third months of pregnancy. Synergistic effects of both low and high temperature in combination with NO2 (with APIs ranging from 0.07 to 0.38) and SO2 (with APIs ranging from 0.18 to 0.51) appeared in the first trimester of pregnancy. Several significant modifying effects by high humidity were also observed, especially for SO2 (with APIs ranging from 0.13 to 0.38). Neither NO2 nor SO2 showed an interactive effect with season of conception. The methods used to estimate individual exposure levels of air pollutants and meteorological factors may lead to the misclassification bias because of the lack of information on maternal activity patterns and residential mobility during pregnancy. Moreover, we were unable to consider several potentially confounding factors, including socioeconomic status, maternal nutrient levels, alcohol use and smoking during early pregnancy due to unavailable data, although previous studies have suggested limited change to the results after when including these factors in the analysis. The findings are helpful for understanding the combined effects of air pollution and meteorological conditions on birth defects. Environmental policies and practices should be formulated and implemented to decrease air pollutant emissions and improve meteorological conditions to reduce their harmful effects on pregnancy. Additionally, pregnant women should be suggested to reduce outdoor time when the air quality is poor, especially when ambient temperature is higher or lower than what is comfortable, or when it is excessively humid. The study is funded by Major Scientific and Technological Projects for Collaborative Prevention and Control of Birth Defects in Hunan Province (2019SK1012), Major Research and Development Projects in Hunan Province (2018SK2060) and Scientific and Technological Department Projects in Hunan Province (2017SK50802). There are no competing interests. N/A.

A Review of Chenopodium quinoa (Willd.) Diseases-An Updated Perspective.

The journey of the Andean crop quinoa (Chenopodium quinoa Willd.) to unfamiliar environments and the combination of higher temperatures, sudden changes in weather, intense precipitation, and reduced water in the soil has increased the risk of observing new and emerging diseases associated with this crop. Several diseases of quinoa have been reported in the last decade. These include Ascochyta caulina, Cercospora cf. chenopodii, Colletotrichum nigrum, C. truncatum, and Pseudomonas syringae. The taxonomy of other diseases remains unclear or is characterized primarily at the genus level. Symptoms, microscopy, and pathogenicity, supported by molecular tools, constitute accurate plant disease diagnostics in the 21st century. Scientists and farmers will benefit from an update on the phytopathological research regarding a crop that has been neglected for many years. This review aims to compile the existing information and make accurate associations between specific symptoms and causal agents of disease. In addition, we place an emphasis on downy mildew and its phenotyping, as it continues to be the most economically important and studied disease affecting quinoa worldwide. The information herein will allow for the appropriate execution of breeding programs and control measures.

Sustainable Large-Scale Aquaculture of the Northern Hemisphere Sea Lettuce, Ulva fenestrata, in an Off-Shore Seafarm

The growing world population demands an increase in sustainable resources for biorefining. The opening of new farm grounds and the cultivation of extractive species, such as marine seaweeds, increases worldwide, aiming to provide renewable biomass for food and non-food applications. The potential for European large-scale open ocean farming of the commercial green seaweed crop Ulva is not yet fully realized. Here we conducted manipulative cultivation experiments in order to investigate the effects of hatchery temperature (10 and 15 °C), nutrient addition (PES and 3xPES) and swarmer density (500 and 10,000 swarmers ml−1) on the biomass yield and biochemical composition (fatty acid, protein, carbohydrate, pigment and phenolic content) of off-shore cultivated Ulva fenestrata in a Swedish seafarm. High seedling densities were optimal for the growth of this northern hemisphere crop strain and significantly increased the mean biomass yield by ~84% compared to low seedling densities. Variations of nutrients or changes in temperature levels during the hatchery phase were not necessary to increase the subsequent growth in an open-water seafarm, however effects of the factors on the thallus habitus (thallus length/width) were observed. We found no significant effect of the environmental factors applied in the hatchery on the total fatty acid or crude protein content in the off-shore cultivated Ulva. However, low seedling density and low temperature increased the total carbohydrate content and furthermore, high temperature in combination with high nutrient levels decreased the pigment content (chlorophyll a, b, carotenoids). Low temperature in combination with high nutrient levels increased the phenolic content. Our study confirms the successful and sustainable potential for large-scale off-shore cultivation of the Scandinavian crop U. fenestrata. We conclude that high seedling density in the hatchery is most important for increasing the total biomass yield of sea-farmed U. fenestrata, and that changing temperature or addition of nutrients overall does not have a large effect on the biochemical composition. To summarize, our study contributes novel insights into the large-scale off-shore cultivation potential of northern hemisphere U. fenestrata and underpins suitable pre-treatments during the hatchery phase of seedlings to facilitate a successful and cost-efficient large-scale rope cultivation.

On the effects of varying coflow oxygen on soot and precursor nanoparticles in ethylene laminar diffusion flames

This paper reports an experimental investigation of the effects of varying the oxygen concentration in the oxidizer stream on the formation and evolution of soot and precursor nanoparticles in an axisymmetric ethylene laminar coflow diffusion flame. The optical diagnostics employ temporally and spectrally resolved point-measurements of 266 nm excited scattering and laser-induced fluorescence, combined with 1064 nm excited laser-induced incandescence. Previous studies have indicated that oxygen enhancement changes soot volume fraction in sooting flames. However, the effects of coflow oxygen concentration on soot precursors are not well understood, and this aspect is addressed explicitly here. A set of eight flames is studied where the oxygen concentration in the coflow stream is varied from 19 to 40%, by volume, while the chemical composition of the jet stream is kept constant at 60% C2H4 / 40% N2. Oxygen enhancement in the coflow leads to a change in flame temperatures, luminosity, and flame length. It is found that the concentration of precursor nanoparticles increases with coflow oxygen. A combination of higher temperatures, red-shifting, and increased decay-times suggest structural growth in precursor nanoparticles with increasing coflow oxygen. In all flames, a similarity of particle evolution is noted with axial location, and this includes the presence of an intermediate stage during the transformation of precursors to soot. Moreover, the structural transformation from aliphatic to aromatic features is shifted towards the beginning of the precursor region when coflow oxygen is increased. It is found that structural growth starts at a similar temperature, regardless of coflow oxygen concentration. Soot volume fraction and primary soot particle diameter increase with coflow oxygen enrichment up to a threshold oxygen volume fraction, after which both the soot volume fraction and diameter decrease with further oxygen enrichment.

A case study of rangeland vegetation changes from 1979 to 2016 in the Middle Atlas Mountains of Morocco

This case study assessed changes in vegetation composition of a 0.8 ha rangeland site over the past four decades, in relation to changes in temperature and to an increase in grazing pressure. The frequency and standing crop (biomass) of species and functional groups were sampled in the spring of 1979 and 2016. Mean annual temperature increased, whereas changes in frequency varied between species and functional groups. Species that decreased included perennial plants, whereas species that increased were comprised mostly of annuals and unpalatable herbaceous plants. An NMDS ordination showed significant differences in species composition between 1979 and 2016. Total biomass, as well as the biomass of annual and perennial grasses and forbs did not differ between 1979 and 2016. Shrub biomass, however, decreased by 60% between years. Biomass of the ‘graminoids’ (e.g. Carex divisa), on the other hand, increased fourfold between 1979 and 2016. Species richness and the Shannon–Weaver diversity index H′ declined in 2016. This, together with a decline in the frequency of palatable species and a shift in species composition, could signal a decline in resilience over the long term. Changes in vegetation were most likely driven by a combination of higher temperatures and increased grazing pressure.

Agronomic and environmental performance of dairy farms in a warmer, wetter climate

The northeast United States has experienced higher temperatures, more annual precipitation, and more frequent heavy rain events in recent decades. These trends appear likely to continue, and they may depress crop yields and exacerbate environmental problems associated with the region’s dairy farms. To investigate these possibilities, we used the Agricultural Policy/Environmental eXtender (APEX) model to simulate runoff, erosion, nutrient losses, and crop yields on two Vermont farms in a small set of possible future climates. Raising temperatures by 2°C, combined with increasing total precipitation or changing the seasonality of precipitation, had relatively modest effects on any outcome (less than 10% change in median values). However, a combination of higher temperatures and more intense precipitation led to increased runoff volumes and larger soil and nutrient losses. Median values of runoff, sediment, and nutrient losses increased by 2% to 15% at one site and by 36% to 58% at the other (although the changes at the latter site were relative to very low baseline values), while the 95th percentile rose by 6% to 19% and 53% to 65%. This suggests that management practices adapted to reducing runoff etc. in extreme precipitation events will be increasingly valuable in the coming years. Corn (<i>Zea mays</i> L.) silage yields changed by less than 10% in all simulations, and in some cases increased slightly. However, modeling that includes many additional factors that can reduce yields (such as new pests, or delays to farm operations in wet conditions) is needed for a more complete understanding of how climate change may affect the viability of forage production on dairy farms in this region.

Effect of temperature, nitrate concentration, pH and bicarbonate addition on biomass and lipid accumulation in the sporulating green alga PW95

The mixed effects of temperature (20 °C, 25 °C and 30 °C), nitrate concentration (0.5 mM and 2.0 mM), pH buffer, and bicarbonate addition (trigger) on biomass growth and lipid accumulation were investigated in the environmental alga PW95 during batch experiments in standardized growth medium. PW95 was isolated from coal-bed methane production water and classified as a Chlamydomonas-like species by morphological characterization and phylogenetic analysis (18S, ITS, rbcL). A factorial experimental design tested the mixed effects on PW95 before and after nitrate depletion to determine a low cost, high efficiency combination of treatments for biomass growth and lipid accumulation. Results showed buffer addition affected growth for most of the treatments and bicarbonate trigger had no statistically significant effect on growth and lipid accumulation. PW95 displayed the highest growth rate and chlorophyll content at 30 °C and 2.0 mM nitrate and there was an inverse relation between biomass accumulation and lipid accumulation at the extremes of nitrate concentration and temperature. The combination of higher temperature (30 °C) and lower nitrate level (0.5 mM) without the use of a buffer or bicarbonate addition resulted in maximal daily biomass accumulation (5.30 × 106 cells/mL), high biofuel potential before and after nitrate depletion (27% and 20%), higher biofuel productivity (16 and 15 mg/L/d, respectively), and desirable fatty acid profiles (saturated and unsaturated C16 and C18 chains). Our results indicate an important interaction between low nitrate levels, temperature, and elevated pH for trade-offs between biomass and lipid production in PW95. This work serves as a model to approach and advance the study of physiological responses of novel microalgae to diverse culture conditions that mimic environmental changes for outdoor biofuel production. The most promising conditions for growth and biofuel production were identified for PW95 and this approach can be implemented for other microalgal production systems.

The effect of temperature changes and K supply on the reproduction and growth of Bolboschoenus planiculmis

Abstract Aims Climate warming and agricultural non-point source pollution both resulting from anthropogenic activities have been projected to affect plant reproduction and growth in wetlands worldwide. In order to predict and mitigate impacts of these anthropogenic activities, it is important to investigate how marsh plants respond to such environmental changes. Methods In this study, Bolboschoenus planiculmis, a tuberous sedge with a wide distribution range in Eurasia, was selected to examine the effect of air temperature changes (15, 20 and 25 °C over 24 h; 20/10 and 30/15 °C, day/night) and K supply (0, 1, 3, 9 and 18 mmol/L) on its reproductive and growth traits in climate chambers. Important Findings We found that high constant temperatures (20 and 25 °C) were more beneficial for tuberization of B. planiculmis than high alternating temperatures (30/15 °C), whereas aboveground biomass and shoot height were generally largest at high temperatures (30/15 and 25 °C). Both reproductive and growth traits of B. planiculmis showed hump-shaped relationships with K supply, with an optimum K concentration of around 1–3 mmol/L. The combination of high constant temperatures and optimal K concentrations promoted reproductive traits the most, whereas the combination of higher temperatures (30/15 and 25 °C) and K concentrations up to 9 mmol/L increased growth traits only. We therefore conclude that population abundance of B. planiculmis might benefit from global warming and the additional K supply.

Comparison of respiration rate and electron transport system (ETS) enzyme-mediated reduction assay of the invasive copepod Eurytemora carolleeae Alekseev &amp; Souissi, 2011 (Calanoida, Temoridae) in Green Bay, WI, U.S.A.

Abstract Anthropogenic activities can cause important changes in aquatic ecosystems, such as warming due to climate change, nutrient loading from agricultural runoff and urban areas, and decreased concentrations of oxygen in bottom waters. These changes may lead to impacts on both organism performance and ecosystem functionality. Studying planktonic species that form an aquatic ecosystem’s foundation is an important step towards understanding the entire food web and predicting how it may respond to a changing environment. One important planktonic species in the Laurentian Great Lakes is the invasive calanoid copepod Eurytemora carolleeae (formerly considered part of the Eurytemora affinis species complex). This study analyzes the metabolic activity of E. carolleeae from Green Bay, Lake Michigan, U.S.A. using two different methods, over a range of temperatures from 9 to 26°C. Total oxygen consumption was measured directly using a micropulse oxygen probe system, and the activity of aerobic metabolic enzymes in the electron transport system (ETS) was quantified using in vitro reduction of iodonitrotetrazolium chloride (INT). Respiration rate of E. carolleeae increases approximately linearly from 9 to 26°C. Measurements of ETS activity indicate that the copepod’s metabolic enzymes have an Arrhenius activation energy of 46.5 ± 15.6 kJ/mol with a thermal maximum between 22 and 26°C. Overall, E. carolleeae ETS rates increased by approximately 7% per °C over the range 9 to 22°C. This thermal limit has implications for future performance of this species, as the combination of higher temperatures and disappearance of oxygenated colder-water refuges may limit E. carolleeae’s success in the Green Bay system following warmer climate and increased nutrient conditions.

The Application of Nanofiltration for Separating Aluminium and Lithium from Lepidolite Leaching Solution

AbstractThis paper concerns the feasibility of separating Al3+ and Li+ by nanofiltration, and a new method for separating and recovering lithium from lepidolite leaching solution was proposed. Factors like salinity, mass ratio of Al3+/Li+, operating pressure, temperature and proportion of SO42− were investigated under single‐stage cycle mode. Multiple linear regression was used to further study the mixed effect of pressure and temperature on separation efficiency and membrane flux. The results suggest that the combination of charge effect and steric hindrance effect plays a decisive role in the separation of lithium and aluminum. When the salinity of the feed solution is 45 g/L and the mass ratio of Al/Li is 6, a combination of higher temperature and pressure within the range that the membrane can withstand is beneficial to improve separation efficiency. And a proper amount of SO42− is beneficial for the separation of aluminum and lithium. Overall, it is found that nanofiltration has a relatively good separation efficiency of lithium and aluminum and provided a novel vision for future separation from lepidolite leaching solution.

Ocean warming alters the responses to eutrophication in a commercially farmed seaweed, Gracilariopsis lemaneiformis

The economically important marine red macroalga Gracilariopsis lemaneiformis was cultured for 2 weeks at two different temperatures, ambient and elevated CO2 levels, and two fertilizer levels. After the experimental period, growth, photosynthesis, and biochemical components were determined. Higher pCO2 significantly increased relative growth rates and nitrate reductase activity with the combination of higher temperature (HT) and/or N enrichment, whereas photosynthetic rates were rapidly reduced at the same condition. Both Q10 values for photosynthetic- (Pm) and respiratory (Rd) rates were higher in algae grown at 24 than at 20°C. This enhancement of Pm rate by HT was much more pronounced than that of the Rd rate. As a result, soluble carbohydrates produced by photosynthesis accumulated to higher levels at the higher temperature. Most of fluorescence variables and antioxidant enzyme activities (super oxide dismutase, catalase, peroxidase, malondialdehyde) did not differ among treatments. Additionally, higher pCO2 reduced chlorophyll a, carotenoids, phycoerythrin, and phycocyanin contents by 48.6, 41.7, 24.7, and 47.8% under LTLN condition, respectively, compared with the control treatment. We propose that high pCO2 would depress the carbon acquisition but increase N assimilation with higher temperature and/or coastal eutrophication, thereby exerting a positive effect on algal growth.