Multi-environmental Factors Research Articles

Framework for Seismic Risk Analysis of Engineering Structures Considering the Coupling Damage from Multienvironmental Factors

Framework for Seismic Risk Analysis of Engineering Structures Considering the Coupling Damage from Multienvironmental Factors

Experience of abrocitinib in atopic dermatitis

Atopic dermatitis is an autoinflammatory, genetically determined, itchy disease characterized by a long, relapsing course and a sharp decrease in the patient’s quality of life. Atopic dermatitis is caused by a complex interaction of immune dysregulation, epidermal gene mutations, and multi-environmental factors that affect the skin, causing intense itchy rashes. The disease often occurs among young children and subsequently has age-related clinical features. Currently, the treatment of atopic dermatitis has a wide range of options, including drugs from the group of small molecules recently registered in the Russian Federation. The drugs are intended for patients with moderate to severe atopic dermatitis. Baricitinib, abrocitinib and upadacitinib as Janus kinase inhibitors from the small molecule group have already demonstrated good tolerability, safety and a pronounced clinical effect in the vast majority of patients with atopic dermatitis in available clinical trials. The first clinical experience with the use of abrocitinib in adult patients with atopic dermatitis is presented. The interest of the presented clinical cases lies in the demonstration of high clinical efficacy and safety of mono- and combination therapy with the Janus kinase inhibitor abrocitinib. Despite the short period of treatment and observation (4 weeks), objective severity of atopic dermatitis manifestations (SCORAD index 60 points) and sharp decrease in the patients' quality of life (DLQI index 20 points), a reduction of clinical parameters exceeding 60% was achieved at a dose of 200 mg daily. During the whole observation period no adverse clinical reactions or changes in laboratory parameters were registered against the background of abrocitinib administration. The pilot results of abrocitinib use are encouraging and provide grounds for conducting longer and larger-scale studies to investigate the efficacy of the drug for its inclusion in the combination therapy of patients with moderate to severe atopic dermatitis.

Intensified effect of nitrogen forms on dominant phytoplankton species succession by climate change

Nutrient proportion, light intensity, and temperature affect the succession of dominant phytoplankton species. Despite these insights, this transformation mechanism in highly turbid lakes remains a research gap, especially in response to climate change. To fill this gap, we investigated the mechanism by which multi-environmental factors influence the succession of dominant phytoplankton species in Lake Chagan. This investigation deployed the structural equation model (SEM) and the hydrodynamic-water quality-water ecology mechanism model. Results demonstrated that the dominant phytoplankton species in Lake Chagan transformed from diatom to cyanobacteria during 2012 and 2022. Notably, Microcystis was detected in 2022. SEM revealed the primary environment variables for this succession, including water temperature (Tw), nutrients (total nitrogen (TN), total phosphorus (TP), and ammonia nitrogen (NH4N)), and total suspended solids (TSS). Moreover, this event was not the consequence of zooplankton grazing. An integrated hydrodynamic-water quality-bloom mechanism model was built to explore the mechanism driving phytoplankton succession and its response to climate change. Nutrients determined the phytoplankton biomass and dominant species succession based on various proportions. High NH4N:NO3N ratios favored cyanobacteria and inhibited diatom under high TSS. Additionally, the biomass proportions of diatom (30.77 % vs. 22.28 %) and green (30.56 % vs. 23.30 %) decreased dramatically. In contrast, cyanobacteria abundance remarkably increased (35.78 % to 51.71 %) with the increasing NH4-N:NO3-N ratios. In addition, the proportion of non-nitrogen-fixing cyanobacteria was higher than that of the nitrogen-fixing cyanobacteria counterparts when TN:TP≥20 and NH4N:NO3N ≥ 10. Light-limitation phenotypes also experienced an increase with the rising NH4N:NO3N ratios. Notably, the cyanobacterial biomass reached 3–6 times that in the baseline scenario when the air temperature escalated by 3.0 °C until 2061 under the SSP585 scenario. We highlighted the effect of nitrogen forms on the succession of dominant phytoplankton species. Climate warming will increase nitrogen proportion, providing an insightful reference for controlling cyanobacterial blooms.

Green roof plant physiological water demand for transpiration under extreme heat

Green roofs are a sustainable strategy for improving the eco-environment in urban areas. However, plants on green roofs are increasingly threatened by extreme heat and drought due to climate change. There is a lack of comprehensive understanding of the physiological water demand of green roof vegetation under extreme heat. Therefore, this exploratory study investigated two commonly used Sedum species for urban green roofs (Sedum spectabile Boreau and Sedum alfredii Hance) under extreme heat, considering two treatments: irrigation and non-irrigation. The results indicated that under extreme heat, if without irrigation, the two Sedum species’ mean daily water consumption by transpiration was approximately 4.68 g per Sedum plant. However, under irrigation, the diurnal variation of stomatal conductance of the two Sedum species allowed the stomata to remain open throughout the day, resulting in an over-twentyfold increase in mean daily water consumption through transpiration (120.34 g per Sedum plant) and twofold increase in leaf area index. A random forest model showed that multi-environmental factors explained 67.53 % of the variability in stomatal behavior. Photosynthetically active radiation and soil moisture are the primary environmental factors that directly affect stomatal conductance. The irrigation induces stomatal opening throughout the diurnal cycle, ensuring the continuation of vegetation growth and the maintenance of physiological functions under extreme heat, which then contributes to keeping its eco-environmental functions and providing sustainable services, such as cooling and carbon sequestration. The findings of this study can guide planning and managing green roofs in urban areas that face extreme heat events.

Interactive Effects of Temperature, Water Regime, and [CO2] on Wheats with Different Heat Susceptibilities

Plants’ response to single environmental changes can be highly distinct from the response to multiple changes. The effects of a single environmental factor on wheat growth have been well documented. However, the interactive influences of multiple factors on different wheat genotypes need further investigation. Here, treatments of three important growth factors, namely water regime, temperature, and CO2 concentration ([CO2]), were applied to compare the response of two wheat genotypes with different heat sensitivities. The temperature response curves showed that both genotypes showed more variations at elevated [CO2] (e[CO2]) than ambient [CO2] (a[CO2]) when the plants were treated under different water regimes and temperatures. This corresponded to the results of water use efficiency at the leaf level. At e[CO2], heat-tolerant ‘Gladius’ showed a higher net photosynthetic rate (Pn), while heat-susceptible ‘Paragon’ had a lower Pn at reduced water, as compared with full water availability. The temperature optimum for photosynthesis in wheat was increased when the growth temperature was high, while the leaf carbon/nitrogen was increased via a reduced water regime. Generally, water regime, temperature and [CO2] have significant interactive effects on both wheat genotypes. Two wheat genotypes showed different physiological responses to different combinations of environmental factors. Our investigation concerning the interactions of multi-environmental factors on wheat will benefit the future wheat climate-response study.

Hypoxia and salinity constrain the sediment microbiota-mediated N removal potential in an estuary: A multi-trophic interrelationship perspective

Reactive nitrogen (N) enrichment is a common environmental problem in estuarine ecosystems, while the microbial-mediated N removal process is complicated for other multi-environmental factors. Therefore, A systematic investigation is necessary to understand the multi-trophic microbiota-mediated N removal characteristics under various environmental factors in estuaries. Here, we studied how multiple factors affect the multi-trophic microbiota-mediated N removal potential (denitrification and anammox) and N2O emission along a river-estuary-bay continuum in southeastern China using the environmental DNA (eDNA) approach. Results suggested that hypoxia and salinity were the dominant environmental factors affecting multi-trophic microbiota-mediated N removal in the estuary. The synergistic effect of hypoxia and salinity contributed to the loss of taxonomic (MultiTaxa) and phylogenetic (MultiPhyl) diversity across multi-trophic microbiota and enhanced the interdependence among multi-trophic microbiota in the estuary. The N removal potential calculated as the activities of key N removal enzymes was also significantly constrained in the estuary (0.011), compared with the river (0.257) and bay (0.461). Structural equation modeling illustrated that metazoans were central to all sediment N removal potential regulatory pathways. The top-down forces (predation by metazoans) restrained the growth of heterotrophic bacteria, which may affect microbial N removal processes in the sediment. Furthermore, we found that the hypoxia and salinity exacerbated the N2O emission in the estuary. This study clarifies that hypoxia and salinity constrain estuarine multi-trophic microbiota-mediated N removal potential and highlights the important role of multi-trophic interactions in estuarine N removal, providing a new perspective on mitigating estuarine N accumulation.

Predicting inhabitable areas for locust based on field observation and multi-environmental factors in alpine grassland—A case study in the Qilian Mountain National Park, China

Alpine grassland is one of the most critical grassland types in the world, and it is vulnerable and sensitive to external disturbances. The development and outbreak of locust might result in the irreversible degradation. However, most locust studies have been on the tropical, temperate, and desert areas. Our knowledge of inhabitable areas in alpine grassland still needs to be explored. This study was carried out in the alpine grassland in the Qilian Mountain National Park. Environmental factors (remote sensing vegetation index, meteorology, soil, topography, and grassland types) and their impact on locust density were investigated. Finally, the inhabitable areas of locust in the study area were mapped. The results showed that: (1) six out of 26 factors [including precipitation, solar radiation (average and maximum value), normalized vegetation index (NDVI), soil, and temperature] had great influence on locust density, with a relative contribution (RC) more than 10%. (2) Among all locust density estimation models, those based on average and maximum solar radiation, maximum precipitation, maximum NDVI, average temperature, and clay content in deep soil performed better than others, with R ranging from 0.58 to 0.73 and root mean square error ranging from 21.70 to 25.82 head/m2. (3) The areas most suited for locust growth, development, and frequent outbreak were found in the south of Tianjun County, middle and northwest of Qilian County (account for 27% of the study area), while the inhabitability was weak in south of Gangcha County, northwest of Tianjun County, and most of Delingha City. Thus our study clarified the distribution region and occurrence variation of the locust and provided a scientific basis for locust prevention and control in alpine grassland in the Qilian Mountain National Park.

Degradation of Reinforced Concrete Beams Subjected to Sustained Loading and Multi-Environmental Factors

In the process of service, reinforced concrete structures have to bear both load and multi-environmental factors. The deterioration of reinforced concrete beams is critical to the durability, safety, and sustainability of reinforced concrete structures. The main aim of the present research is to determine the degradation mechanism of reinforced concrete beams subjected to sustained loading and multi-environmental factors. Reinforced concrete beam specimens were prepared, loaded and then exerted multi-environmental factors. At the end of each degradation period, the degradation of concrete (chemical contents of concrete beam surfaces, carbonation depth, compressive strength and maximum cracks) and the corrosion of steel bars (corrosion ratio and tensile strength) were continuously measured. Moreover, degraded reinforced concrete beams were flexural loaded in four-point bending failure tests. The degradation mechanism of reinforced concrete beams subjected to sustained loading and multi-environmental factors was analyzed. Thus, this study can promote a comprehensive understanding of reinforced concrete beams subjected to sustained loading and multi-environmental factors.

Calibration method of multi-parameter compensation for optical dissolved oxygen sensor in seawater based on machine learning algorithm

Measurement accuracy of optical dissolved oxygen sensor in actual seawater field is affected by many environmental factors. Traditional sensor calibration method is carried out by combining laboratory calibration experiment with field environmental factor correction. First, the influence of temperature on the sensor measurement results is added to the laboratory calibration experiment and model research. The measurement results are then corrected according to salinity and depth environmental factors in the field measurement. However, the influence of these environmental factors on the dissolved oxygen measurement results presents a multi-parameter nonlinear coupling characteristic. Nonlinear machine learning method is used in this study to investigate coupling mapping relationship between seawater multi-environmental factors and measured data of the sensor. A calibration device for controlling temperature, salinity, hydrostatic pressure, and dissolved oxygen concentration conditions and a matching multi-parameter calibration experimental process is designed and established. Analysis of the coupling relationship between multi-parameter conditions and their influence on the measurement of dissolved oxygen concentration showed that the established multi-parameter compensation calibration model achieves a calibration error of ±1 μmol L−1. Compared with existing compensation results after independent calibration of multi-parameters, the proposed model demonstrates better accuracy and rationality. The calibration sensor is tested in the laboratory and seawater field to verify the validity of the calibration model. Dissolved oxygen concentration measured by the sensor is basically consistent with reference measurement data and Winkler analysis value. Results showed that the multi-parameter calibration method based on machine learning can meet calibration requirements of the dissolved oxygen sensor in seawater with improved scientific rationality and calibration efficiency. Furthermore, the proposed method can be extended to other in situ measurement sensors in seawater while considering various environmental factor corrections.

Adsorption of CdII by synthetic zeolite under multi-factor using response surface methodology

The remediation of heavy metal contamination was urgent owing to their toxicity and non-biodegradability. In this study, a synthetic zeolite originated from natural low-grade molybdenum ore (NMO) was used to adsorb CdII from wastewater under simulated multi-environmental factors. X-ray diffraction spectroscopy proved that faujasite was successfully synthesized. The specific surface area of the synthetic zeolite was up to 652.3 m2/g, based on the nitrogen adsorption and desorption isotherms. X-ray photoelectron spectroscopy confirmed that ion-exchange was a major mechanism of CdII adsorption. Batch adsorption experiments showed that synthetic zeolite has an excellent adsorption capacity for CdII at pH above 4. The theoretical maximum adsorption capacity was 249.63 mg/kg, as evidenced by the adsorption model fitting. Systematic adsorption experiments showed that the quadratic regression model can be used to predict the CdII adsorption amount of synthetic zeolite (predicted r² = 0.9027) under six environmental factors. The fitted results showed a decreasing influence on adsorption capacity in the following order: CdII concentration > adsorbent dosage > CaII concentration > NaI concentration > pH > Temperature. In all, the synthetic zeolite has a great potential for treating CdII-containing wastewater. Especially the application could be optimized with the predicted adsorption based on the response surface plots.

Classifying diurnal changes of cyanobacterial blooms in Lake Taihu to identify hot patterns, seasons and hotspots based on hourly GOCI observations

Occurrence of cyanobacterial blooms in most lakes has dramatic changes in time and space. However, most current studies only focused on daily or seasonal scales to obtain a relatively coarse resolution result. To explore the possibility of fine changes occurring within a day in Lake Taihu (China), the area coverage of surface cyanobacterial blooms was quantified from the hourly Geostationary Ocean Color Imager (GOCI) data using a GOCI-derived cyanobacterial index. Based on that, diurnal change characteristics were explored at two scales, and the environmental impacts were investigated. For that, an classification method was first designed to identify the types of diurnal change patterns of cyanobacterial blooms automatically. This method classified the patterns into four types, including the decreasing (Type1), decreasing first and then increasing (Type2), increasing (Type3), increasing first and then decreasing (Type4). Based on that, the types of diurnal change patterns of blooms in Lake Taihu (from April 1, 2011 to October 31, 2020) were identified at pixel (500 m) and synoptic scales. Results indicated that Type1 and Type3 were two hot diurnal change patterns of blooms, and lakeshore was the hotspot occurring severe diurnal changes, and autumn was the hot season occurring frequent diurnal changes. Specifically, hotspot of Type1 was lakeshore, while hotspot of Type3 was Central Regions. Environmental impacts were analyzed at two scales. At pixel scale (500 m), diurnal variation of temperature affected the regional occurence of each type ofdiurnal changes patterns of blooms, and the afternoon temperature played the most critical role (p < 0.001, N = 8316). The occurrence frequency of Type1 was positively (R = 0.41) related with the afternoon temperature, and the occurrence frequency of Type3 was negatively (R = -0.37) related with it. Diurnal variation of wind speed was another key factor impacting the occurrence of obvious diurnal blooms changes, and the wind impacts should be distinguished when the wind speed was over or below 3.5 m/s. At synoptic scale, the interaction of multi environmental factors influenced the diurnal change degree of blooms area, and the environmental contributions were 71%.Comparing with the existing manual classifying workat synoptic scale, the designed classification method can identify the types of diurnal change patterns of blooms at a higher spatial resolution (500 m). These explorations on diurnal dynamics of cyanobacterial blooms in Lake Taihu provide a new insight for advanced cyanobacteria dynamics studies and regional water management.

Foliar C:N:P stoichiometric traits of herbaceous synusia and the spatial patterns and drivers in a temperate desert in Central Asia

Herbaceous synusia is an important component of shrub community/ecosystem in the Junggar Desert and contributes a large proportion of net primary productivity in spring and early summer. Soil in the Junggar Desert is seriously deficient in nitrogen (N), but herbaceous plants possess high N concentration and N:P (phosphorous) ratio at the individual and interspecies levels; however, the community-level leaf stoichiometric characteristics of herbaceous synusia, spatial distribution patterns, and the driving factors at the regional scale remain unclear. In this study, 79 sampling plots were set up across the entire Junggar Desert. Foliar samples were collected by whole-plant harvesting method in each sampling plot, and the status of foliar carbon (C), N, and P concentrations, stoichiometric ratios, interrelationships, spatial patterns, and influencing factors were systematically analyzed. Results showed that the average contents of foliar C, N, and P in herbaceous synusia were 331.47, 25.85, and 1.54 mg g−1, respectively, and foliar C:N, C:P, and N:P were 13.76, 225.91, and 17.30, respectively. In contrast to most terrestrial ecosystems and global vegetation, herbaceous synusia was characterized by low C, C:N, and C:P and high N and N:P. Foliar C, N, and P were linearly and allometrically correlated with one another significantly. The foliar N–C, P–C, and N–P scaling exponents were 1.987, 1.770, and 1.122, respectively, thus the order of accumulation rates of foliar C, N, and P was N > P > C. Foliar C, N, C:N, and N:P presented significant differences among different soil habitats and shrub communities. Foliar stoichiometric traits showed obvious and different spatial heterogeneity at the regional scale. Multi-environmental factors jointly influenced foliar stoichiometric traits, and climate and geographical factors presented greater impact than soil. In conclusion, the foliar C:N:P stoichiometric traits might be the unique and inherent property of desert herbaceous species in this study area formed by long-term adaptation to the arid and barren environments in Central Asia, and this finding should be fully considered in regional ecological conservation and management.

The combined effects of light intensity, temperature, and water potential on wall deposition in regulating hypocotyl elongation of Brassica rapa.

Hypocotyl elongation is a critical sign of seed germination and seedling growth, and it is regulated by multi-environmental factors. Light, temperature, and water potential are the major environmental stimuli, and their regulatory mechanism on hypocotyl growth has been extensively studied at molecular level. However, the converged point in signaling process of light, temperature, and water potential on modulating hypocotyl elongation is still unclear. In the present study, we found cell wall was the co-target of the three environmental factors in regulating hypocotyl elongation by analyzing the extension kinetics of hypocotyl and the changes in hypocotyl cell wall of Brassica rapa under the combined effects of light intensity, temperature, and water potential. The three environmental factors regulated hypocotyl cell elongation both in isolation and in combination. Cell walls thickened, maintained, or thinned depending on growth conditions and developmental stages during hypocotyl elongation. Further analysis revealed that the imbalance in wall deposition and hypocotyl elongation led to dynamic changes in wall thickness. Low light repressed wall deposition by influencing the accumulation of cellulose, hemicellulose, and pectin; high temperature and high water potential had significant effects on pectin accumulation overall. It was concluded that wall deposition was tightly controlled during hypocotyl elongation, and low light, high temperature, and high water potential promoted hypocotyl elongation by repressing wall deposition, especially the deposition of pectin.

Unraveling the nexus of multi-environmental factors and benthic macroinvertebrates in typical inflow river of Taihu Lake in China.

The objective of this study is to examine the relationship between benthic macroinvertebrates and various environmental factors (i.e., physicochemical properties of sediment and hydromorphological condition) in the typical inflow river sediments of the Taihu Basin in China. Pearson correlation and redundancy analysis (RDA) were used to investigate associations between environmental factors and benthic macroinvertebrate community structure. The RDA results indicated that the environmental factors account for 58.6% of the spatial differentiation of benthic macroinvertebrate community. High density of Oligochaeta species, which were potential indicators of heavy metal pollution within sediments, was observed as the pollution-tolerant species in the study area, indicating that the benthic community was seriously polluted by heavy metals and nutrients. Moreover, the variation in benthic macroinvertebrate community structure and trait composition were mainly explained by physicochemical properties of sediment (e.g., Pb, temperature, and phosphate), whereas hydrological condition (e.g., turbidity) alterations played a less important role. Thus, the environmental factors are significantly correlated with the abundance and biomass of benthic macroinvertebrate by taking interacts of multi-environmental factors into account. These results provide scientific basis for water environment health management and pollution control in Taihu Basin river network area.

Impact of elevated precipitation, nitrogen deposition and warming on soil respiration in a temperate desert

Abstract. Soil respiration (Rs) is the most important source of carbon dioxide emissions from soil to atmosphere. However, it is unclear what the interactive response of Rs would be to environmental changes such as elevated precipitation, nitrogen (N) deposition and warming, especially in unique temperate desert ecosystems. To investigate this an in situ field experiment was conducted in the Gurbantunggut Desert, northwest China, from September 2014 to October 2016. The results showed that precipitation and N deposition significantly increased Rs, but warming decreased Rs, except in extreme precipitation events, which was mainly through its impact on the variation of soil moisture at 5 cm depth. In addition, the interactive response of Rs to combinations of the factors was much less than that of any single-factor, and the main response was a positive effect, except for the response from the interaction of increased precipitation and high N deposition (60 kg N ha−1 yr−1). Although Rs was found to show a unimodal change pattern with the variation of soil moisture, soil temperature and soil NH4+-N content, and it was significantly positively correlated to soil dissolved organic carbon (DOC) and pH, a structural equation model found that soil temperature was the most important controlling factor. Those results indicated that Rs was mainly interactively controlled by the soil multi-environmental factors and soil nutrients, and was very sensitive to elevated precipitation, N deposition and warming. However, the interactions of multiple factors largely reduced between-year variation of Rs more than any single-factor, suggesting that the carbon cycle in temperate deserts could be profoundly influenced by positive carbon–climate feedback.

Frequency modification of continuous beam bridge based on co-integration analysis considering the effect of temperature and humidity

The variation of the temperature and humidity significantly affects the modal parameters of the structure, and the effect and the quantitative statistics of single environmental factors such as temperature on the frequency of bridge are intensively studied, but the study on the mechanism and the effective model considering the comprehensive effect of multi-environmental factors is relatively rare. The principle and analysis method of co-integration is introduced, and the frequency-modified method based on co-integration is presented. Through the monitoring of a three-span concrete bridge model in the natural environment, the effective monitoring data are analyzed to establish a long-term equilibrium model about “frequency–temperature–humidity” based on co-integration theory. The experimental results indicate that the model has a better fitting ability and accuracy, and it is can be used to predict the variation trend of frequency. Based on the mathematical model of co-integration analysis, the modified frequency model considering multi-environmental factors is proposed, which can eliminate the comprehensive effect of temperature and humidity on frequency, and the variation of dynamic characteristics due to the internal causes of structure is revealed. The extracted sequence can provide effective information for further safety assessment and damage detection of bridge.

Assessing the interplay between multigenic and environmental influences on adolescent to adult pathways of antisocial behaviors

The current investigation utilized a developmental psychopathology approach to test the hypothesis that multigenic (i.e., dopaminergic and serotonergic genes) and multienvironmental factors interactively contribute to developmental pathways of antisocial behavior (ASB). A sample of 8,834 Caucasian individuals from the National Longitudinal Study of Adolescent to Adult Health (Add Health) were used to (a) examine the developmental pathways of ASB from age 13 to 32 using growth mixture modeling, (b) compute weighted multigenic risk scores (Add Health MRS) for ASB from six well-characterized polymorphisms in dopamine and serotonin genes, and (c) test the interaction between the Add Health MRS and a measures of support (incorporating indicators of both positive and negative support from parents and schools). Four pathways of adolescent to adult ASB emerged from the growth mixture models: low, adolescence-peaked, high decline, and persistent. Add Health MRS predicted the persistent ASB pathway, but not other ASB pathways. Males with high Add Health MRS, but not low MRS, had significantly greater odds of being in the adolescence-peaked pathway relative to the low pathway at low levels of school connectedness. Nonfamilial environmental influences during adolescence may have a cumulative impact on the development of ASB, particularly among males with greater underlying genetic risks.

Riverine phytoplankton shifting along a lentic-lotic continuum under hydrological, physiochemical conditions and species dispersal

The importance of phytoplankton-based bio-assessment has been recently recognized in lowland rivers which are affected by multi-environmental factors. However, some basic questions remain unclear to date, such as: (i) spatial and temporal variations of phytoplankton, (ii) the impact of upstream lakes on downstream community, (iii) the main drivers for species composition or (iv) the regional biodiversity along a lentic-lotic continuum. To answer these questions, we collected and analyzed the fluvial phytoplankton communities along a lentic-lotic continuum from a German lowland catchment, where a well-established ecohydrological modeling predicted long-term discharges at each sampling site. Our results revealed very high spatial and temporal variations of phytoplankton community. The changes of a lake on downstream phytoplankton assemblages were significant, especially the nearest reach after the lake. However, these influences varied along with seasons and limited in a relatively short distance to the lake. Redundancy analysis and Mantel tests showed that phytoplankton composition and dissimilarities along the lentic-lotic continuum attributed more to local hydrological and physicochemical variables than species dispersal, which confirmed the suitability of lowland phytoplankton-based bioassessment. In addition, our findings highlighted the importance of flow regime in shaping phytoplankton community composition and regional beta diversities. This study emphasized the necessity to include the hydrological variables and their relationship with phytoplankton community in future bio-monitoring investigations.

Effects of multi-environmental factors on physiological and biochemical responses of large yellow croaker, Larimichthys crocea

Land-based recirculating aquaculture systems (RAS) and cage culture are important methods of Larimichthys crocea production. The effects of environmental factors on physiological and biochemical aspects of L. crocea require clarification. Temperature and salinity are controlled in RAS and directly affect L. crocea growth and survival. To explore optimal parameters, the oxygen consumption rate (RO), ammonium excretion rate (RN), and O/N ratio at different temperatures (8, 14, 20, 26, and 32 °C) and salinities (5, 15, 25, and 35‰) were determined. RO, RN, and O/N first increased and then decreased with elevated temperature and salinity, peaking at 26 °C and 25‰, respectively. This suggests that the metabolism of L. crocea was maximal at 26 °C and 25‰ salinity, which promote its growth and survival. Additionally, hypoxia affects cage culture, and has significant effects on enzymatic activities and stress-inducible gene expression. To accelerate the selective breeding of hypoxia-tolerant L. crocea in cage culture, we measured adenosine triphosphatase (ATPase), lactate dehydrogenase (LDH), and succinate dehydrogenase (SDH) activities, and hypoxia-inducing factor 1 (HIF-1) mRNA expression in the myocardium under hypoxia (2.5, 3.5, and 4.5 mg L−1). ATPase and SDH activities first decreased and then increased under hypoxia, whereas LDH activity and HIF-1α expression first increased and then decreased. Thus, under hypoxia, the myocardial mitochondria switched from being susceptible to being resistant to injury induced by energy metabolism, and respiration in L. crocea likely converted from aerobic to anaerobic during adaptation. Furthermore, the upregulation of HIF-1α mRNA suggests it has an active role in protection against anoxic damage.

Low durability of concrete elements due to steel corrosion – cases wherein the steel reinforcing bars acted as an internal clock bomb

Concrete elements are expected to resist any process of deterioration to remain its original form, quality and serviceability when exposed to its intended service environment. As the concrete deteriorates durability problems progressively develop leading to structural damage, which might put users in a potential danger. Concrete deterioration may be categorized into three categories of causes: physical, chemical, and mechanical, from which major durability issues come from steel corrosion as a result of combined effect of multi environmental factors. This work reports examples wherein the corrosion of the steel reinforcing bars severely affected the concrete element durability. Five examples wherein the steel reinforcing bars got prematurely corroded, acting as an internal clock bomb for concrete element durability, are reported. It is questioned if the steel reinforcing bars were structurally (un)necessary and if (in)appropriate construction practices were used. Alternative solutions for higher durability are proposed.