Understanding how organisms cope with global change is a major question in many fields of biology. Mainly, understanding the molecular mechanisms supporting rapid phenotypic changes of organisms in response to stress and linking stress-induced molecular events to adaptive or adverse outcomes at the individual or population levels remain a major challenge in evolutionary biology, ecology or ecotoxicology. In this view, the present study aimed to test (i) whether environmental factors, especially pollutants, can trigger changes in the activity of retrotransposons (RTs) in wild fish and (ii) if changes in RT DNA methylation or transcription levels can be linked to modifications at the individual level. RTs are genetic elements that have the ability to replicate and integrate elsewhere in the genome. Although RTs are mainly quiescent during normal development, they can be experimentally activated under life-threatening conditions, affecting the fitness of their host. Wild eels were collected in four sampling sites presenting differing levels of contamination. The methylation level and the transcriptional activity of two RTs and two genes involved in development and cell differentiation were analyzed in fish liver in addition to the determination of fish contaminants levels and diverse growth and morphometric indices. An up-regulation of RTs associated to lower methylation levels and lower growth indices were observed in highly contaminated fish. Our results suggest that RT activation in fish experiencing stress conditions could have both detrimental and beneficial implications, affecting fish growth but promoting resistance to environmental stressors such as pollutants.

Release of fluoride from Quaternary sediments produces F-contaminated groundwater which threatens the health of millions of people worldwide. Despite the mechanisms of fluoride release from sediments are documented by numerous studies, it remains poorly understood that whether indigenous microbes participate in or not for the formation of F-rich groundwater by releasing fluoride from aquifer sediments. A microcosm-based approach, geochemistry and techniques of microbiology and molecular ecology were conducted together to investigate these mechanisms. Results show that microbes are abundant in high [F] groundwater containing at least 1129 operational taxonomic units (OTUs), and indigenous microbes can have an essential role in the mobilization of fluoride in sediments collected from aquifers in a typical fluorosis area in China. It also shows that for the sediments in this study, fluoride release (ca. 2 mg/L) is coupled with elevated concentrations of Ca (△ = 75 mg/L), Mg (△ = 33 mg/L), Al (△ = 0.2 mg/L) and Mn (△ = 1.4 mg/L). This suggests that the fluoride may source from the dissolution of F-bearing carbonate minerals and/or Al-Mn hydroxides in a local acidic environment. The findings provide additional insights into the biogeochemical circulation of fluoride in natural environment, especially in groundwater system and the development of effective strategies for the management of F-contaminated groundwater worldwide.

Arctic permafrost soils contain large amounts of organic carbon and the pollutant mercury (Hg). Arctic warming and associated changes in hydrology, biogeochemistry and ecology risk mobilizing soil Hg to rivers and to the Arctic Ocean, yet little is known about the quantity, timing and mechanisms involved. Here we investigate seasonal particulate Hg (PHg) and organic carbon (POC) export in 32 small and medium rivers across a 1700 km latitudinal permafrost transect of the western Siberian Lowland. The PHg concentrations in suspended matter increased with decreasing watershed size. This underlines the significance of POC-rich small streams and wetlands in PHg export from watersheds. Maximum PHg concentrations and export fluxes were located in rivers at the beginning of permafrost zone (sporadic permafrost). We suggest this reflects enhanced Hg mobilization at the permafrost boundary, due to maximal depth of the thawed peat layer. Both the thickness of the active (unfrozen) peat layer and PHg run-off progressively move to the north during the summer and fall seasons, thus leading to maximal PHg export at the sporadic to discontinuous permafrost zone. The discharge-weighed PHg:POC ratio in western Siberian rivers (2.7 ± 0.5 μg Hg: g C) extrapolated to the whole Ob River basin yields a PHg flux of 1.5 ± 0.3 Mg y⁻¹, consistent with previous estimates. For current climate warming and permafrost thaw scenarios in western Siberia, we predict that a northward shift of permafrost boundaries and increase of active layer depth may enhance the PHg export by small rivers to the Arctic Ocean by a factor of two over the next 10–50 years.

In recent decades, rapid development of industrialization and urbanization caused adverse impact on the aqueous ecology and environment of the Huaihe River basin, China. In this work, three ²¹⁰Pb-dated sediment cores extracted from the middle reach of Huaihe River in Anhui Province, China were analyzed to elucidate the temporal trends and sources of polybrominated diphenyl ethers (PBDEs). Source diagnostics indicated that commercial Deca-BDE, Penta-BDE and Octa-BDE products and debromination of higher brominated BDE compounds were likely the PBDE sources in the Huaihe River. The prevalence of BDE-47 in the sediment cores was attributed to the extensive use of commercial Bromkal 70-5DE and Bromkal DE-71 in the region. BDE-28 was another congener that was prevalent in all sediment samples, suggesting that reductive debromination occurred in the sediments. Dramatic increase of PBDE concentrations in both three cores since the post-1980s could be attributed to the rapid expansion of production of electronic and telecommunication equipment and household usage in China. PBDE temporal trends in core S1 located at rural area mainly reflected the regional and national inputs deriving from long distance atmospheric transport, and the positive correlations between PBDE concentration in core S1 and gross domestic product (GDP) and household appliances production volumes (HPVs) were observed. PBDE inputs at site S3 mainly include the transport of contaminated water and re-suspended fine sediment particles from the upstream site S2, which was located in the industrial area and adjacent to e-waste recycling area. The government efforts to protect the environment and improve the e-waste management resulted in the progressive decrease trends in PBDE concentrations in cores S2 and S3.

Mangroves are ecosystems located in tropical and subtropical regions of the world and are vital for coastal protection. Their unique characteristics make them hotspots for carbon cycling and biological diversity. Studies on isolated filamentous fungi and environmental and anthropogenic factors that influence sediments offer new understandings on how to preserve mangroves. Here we report on the filamentous fungi isolated from four mangroves. We correlated fungal community composition with sediment texture, polycyclic aromatic hydrocarbons concentration (oil pollution), pH, salinity, organic matter, total and thermotolerant coliforms (sewage pollution). In total we identified 34 genera and 97 species. The most polluted sites had highest species richness whereas the best preserved site showed the lowest species richness. Oil spill and sewage pollution were identified as the drivers of fungal community composition in the most polluted sites. We found very distinct fungal communities with no >5 species shared between any two mangrove sites.

Brownfields have attracted increasing attentions from both researchers and practitioners. However, few studies have attempted to make a comprehensive and quantitative review on this topic. This study conducted a scientometric review on the brownfield research from 1995 to 2017 using CiteSpace. The knowledge structure, hot topics, research trends, and gaps were analyzed based on the co-author, co-word, co-citation, and clusters analysis. Six hundred thirty articles from the Web of Science core collection database were selected as the research samples. Results revealed that the research focus has changed from soil remediation technologies to sustainable regeneration methods. The most vital development in brownfield research occurred in the USA, England, Canada, Germany, and China. “Brownfield,” “heavy metal,” “remediation,” “redevelopment,” and “sustainability” were the most frequently used keywords. Whereas “management” and “biodiversity” received citation bursts in recent years. Existing researches mainly concentrated on subject categories of environmental sciences ecology, environmental sciences, engineering, environmental studies, engineering environmental, and urban studies. Sustainable regeneration, urban brownfields’ regeneration, mental distribution, coal-mine brownfield, and ecosystem service were the identified co-citation clusters and represented the hot topics and emerging trends. The research gaps can serve as a motivation to research on the next generation of brownfields to support the sustainable development. This study provides researchers and practitioners an extensive and intensive understanding of the salient research themes and trends of brownfields’ research worldwide.

Green behavior is an important part of the study of green development. To promote green development, it is necessary to engage in further innovation on the basis of lessons from international advancements in green behavior. To clarify the spatial and temporal distribution characteristics of international researchers in the study of green behavior, the research focus, and the research frontiers, a visual analysis was performed on 22,114 articles cited in the SSCI and SCI-EXPANDED databases from 2000 to 2017. This analysis was based on bibliometrics and mapping knowledge domain (MKD) analysis with CiteSpace 5.3.R4, a scientific and technological text-mining and visualization software. The results show that international green behavior research has the following main characteristics. First, a positive correlation was found between the number of papers and time. Second, research is highly valued by researchers in the natural sciences, such as ecology. The USA is involved in major research efforts and maintains a high level of cooperation with other countries and regions. International cooperation among institutions needs to be strengthened. The co-cited journals are primarily academic journals in the natural sciences. Third, research hotspots mainly focus on the theory of planned behavior (TPB), consumers, attitudes, performance, and environment, all of which evolve according to the phase path of “germination-growth.” Fourth, the research frontier issues are largely related to management science and environmental science, and the research objects and methods will become increasingly complex and interdisciplinary over time.

The effects of patchouli essential oil (PEO) as an alternative to antibiotics on ruminal methanogenesis, feed degradability, and enzyme activities were evaluated. The basal substrate was incubated without additives (control, CTL) and with monensin (MON, 6 μM/g DM) or patchouli essential oil (PEO, 90 μg/g DM) for 24 h. In three different runs, the gas production (GP) was recorded at 2, 4, 8, 12, and 24 h of incubation using a semi-automatic system. The results revealed that MON had decreased (P < 0.05) the net GP and CH₄ production and digestible and metabolizable energy relative to PEO supplementation. The in vitro truly degraded organic matter was not influenced by PEO application, while was reduced (P = 0.027) with MON. Both PEO and MON had similar reducing effect on the activity of carboxymethylcellulase (P = 0.030), in vitro truly degraded neutral detergent fiber (P = 0.010), NH₃-N concentrations (P = 0.012), acetate proportion (C2, P = 0.046), C2 to C3 ratio (P = 0.023), and total protozoal count (P = 0.017). Both additives recorded similar elevating potential on the α-amylase activity (P = 0.012), propionate (C3) proportion (P = 0.011), and microbial protein (P = 0.034) compared with CTL. Effects of MON and PEO on ruminal feed degradability, microbial enzyme activities, and total protozoa counts may be responsible for modifying rumen fermentation ecology. Addition of PEO may act as a desirable alternative rumen modifier for MON in ruminant diets.

River water temperature (RWT) forecasting is important for the management of stream ecology. In this paper, a new method based on coupling of wavelet transformation (WT) and artificial intelligence (AI) techniques, including multilayer perceptron neural network (MLPNN) and adaptive neural-fuzzy inference system (ANFIS) for RWT prediction is proposed. The performances of the hybrid models are compared with regular MLPNN and ANFIS models and multiple linear regression (MLR) models for RWT forecasting in two river stations in the Drava River, Croatia. Model performance was evaluated using the coefficient of correlation (R), the Willmott index of agreement (d), the root mean squared error (RMSE), and the mean absolute error (MAE). Results indicate that the combination of WT and AI models (WTMLPNN and WTANFIS) yield better models than the conventional forecasting models for RWT simulation for both regular periods and heatwave events. The MLPNN and ANFIS models outperform the MLR models for RWT simulation for the studied river stations. RMSE values of WTMLPNN2 and WTANFIS2 models range from 1.127 to 1.286 °C, and 1.216 to 1.491 °C for the Botovo and Donji Miholjac stations respectively. Additionally, modeling results further confirm the importance of the day of year (DOY) on the thermal dynamics of the river. The results of this study indicate the potential of coupling of WT and MLPNN, ANFIS models in forecasting RWT.

Erhai is a famous tectonic rift lake in China. In this study, the distribution of nitrogen and phosphorus species in Erhai sediment cores and their ecology risk were evaluated. The total nitrogen (TN) in the sediment cores ranged from 1583.3 to 8018.5 mg/kg. Nitrogen (N) was still accumulating in the sediment. For depths of 0 to 25 cm, the TN decreased dramatically and for deeper depths the TN got stabilized. The proportions of various N fractions in the sediments of the study areas ranked as follows: the strong oxidation extractable N (SOEF-N) > the weak acid extractable N (WAEF-N) > the strong alkali extractable N (SAEF-N) > the ion-exchangeable N (IEF-N). The total phosphorus (TP) ranged from 814.9 to 1442.3 mg/kg. The vertical distribution of each fraction of phosphorus showed that there were different sources of sediment phosphorus around the Erhai Lake. The results of nitrogen and phosphorus pollution evaluation in sediments by single pollution standard index method showed that the standard index of the TN (STN) ranged from 4.29 to 14.01, and the standard index of the TP (STP) ranged from 1.69 to 2.18. It illustrated that N and P in the sediments were the serious ecological pollution risks in Erhai Lake.