Assessing potential impacts of multiple stressors on riverine phytoplankton community by integrated models

Increasing pressures from both natural disturbance and anthropogenic activities challenge river ecosystem resilience. A better understanding of the ecological balancing of structure under multiple stressors is thus critical for sustainable future as well as human wellbeing. Phytoplankton are one of the important autotrophs in the river ecosystem. They are sensitively reflecting multiple filters. However, studies on how flow regime, land-use pattern, physicochemical condition and spatial factors overall affect the lotic phytoplankton community are still scarce. This study aims to examine riverine phytoplankton community structure in relation to combined abiotic gradients, and to consider the potential responses under changing status. Study area is located in a lowland catchment Treene, Germany. We establish an integrated modelling framework in combination of hydrological model with ecological models. The investigations show high spatial and temporal variations of phytoplankton community. Benthic diatom is dominant in most of the study area. Euglenophyta show higher existence percentage in the headwaters and exhibit a strong positive correlation to the share of agricultural land-use. Microcystis has found with high abundance downstream of a lake. Higher phosphorous concentration directly causes the increase of Microcystis population. Both species and traits composition more relate to hydrological and local physicochemical heterogeneity than to species dispersal, which confirm the suitability of lowland phytoplankton-based bioassessment in the study area. Due to the importance of flow regime in shaping pelagic algal community, it is necessary to include hydrological variables in biodiversity conservation. The shares of forest land-use area have outstanding explanation to the variation of species richness. Our findings emphasize the significance of preservation of forest area in protecting the aquatic algal biodiversity for maintaining the river ecosystem functioning

Experimental investigation of dielectric barrier impact on breakdown voltage enhancement of copper wire-plane electrode systems

Non-pressurized air is extensively used as basic insulation media in medium / high voltage equipments. An inherent property of air-insulated designs is that the systems tend to become physically large. Application of Dielectric barrier can increase the breakdown voltage and therefore decrease the size of the equipments. In this paper, the impact of dielectric barrier on breakdown voltage enhancement of a copper wire-plane system is investigated. For this purpose, the copper wire is covered with different dielectric materials. Depending on the air gap and dielectric strength of the barrier the breakdown can be initiated in the solid or gas dielectric. Theoretically, free charges are affected by the electric field between the electrodes and accumulated at the dielectric surface, this leads to the reduction of electric field in air gap and enhancement of the ifield in the dielectric layer. Therefore, with appropriate selection of the barrier thickness and material, it is possible to increase the breakdown voltage of the insulation system. The influence of different parameters like inter-electrode spacing, and dielectric material on the break-down voltage is investigated for applied 50 Hz AC and DC voltages. The results indicate that up to 240% increase of the breakdown voltage can be achieved

Research and evaluation of spatiotemporal dynamic of network green innovation efficiency in China—based on meta-Frontier theory

Green innovation has emerged as a crucial driver for advancing green and high-quality development. Exploring the evolutionary patterns of green innovation efficiency is crucial for achieving the “dual carbon” goals and realizing the benefits of both economic growth and environmental sustainability under the framework of new development concepts. This study employs the network SBM-DEA model under meta-Frontier and group-Frontier. Additionally, it considers the GML index and Moran’s I to conduct a comprehensive analysis of the evolving efficiency of green innovation in Chinese provinces from 2008 to 2020, then uses the Tobit regression model to verify the influencing indicators for green innovation efficiency. The examination covers various aspects, including the stage of green innovation, the diversity of technology accumulation, the comparability of pre- and post-development, the spillover effects in geographical space, and the diversity of influencing factors. The research findings indicate the following: 1) The group division exhibit a high level of geographical correlation, and the efficiency of green innovation in the two-stage and network displays heterogeneity across distinct frontiers. The efficiency loss in the Green Achievement Transformation stage is bigger than that in the Green Technology Research and Development stage. 2) There is an overall increase in green innovation efficiency of each type during most years, and the spatial correlation and stability of the two-stage and network green innovation efficiency have improved year by year. Provinces with higher Green Innovation Environment Composite Index have the highest concentration of “high-high” efficiency agglomeration. 3) Environmental regulation intensity, factor endowment, property rights structure, foreign direct investment and energy consumption have varying degrees of constraints on green innovation, and the regional economic development level can significantly improve the efficiency of various green innovations. Finally, this paper provides some suggestions, including stimulating innovation vitality, formulating differentiated policies, strengthening regional innovation collaboration, and mobilizing resources from various stakeholders. These recommendations aim to provide guidance and reference for promoting green innovation and achieving sustainable development in different regions

Hydrological and environmental variables outperform spatial factors in structuring species, trait composition, and beta diversity of pelagic algae

There has been increasing interest in algae-based bioassessment, particularly, trait-based approaches are increasingly suggested. However, the main drivers, especially the contribution of hydrological variables, of species composition, trait composition, and beta diversity of algae communities are less studied. To link species and trait composition to multiple factors (i.e., hydrological variables, local environmental variables, and spatial factors) that potentially control species occurrence/abundance and to determine their relative roles in shaping species composition, trait composition, and beta diversities of pelagic algae communities, samples were collected from a German lowland catchment, where a well-proven ecohydrological modeling enabled to predict long-term discharges at each sampling site. Both trait and species composition showed significant correlations with hydrological, environmental, and spatial variables, and variation partitioning revealed that the hydrological and local environmental variables outperformed spatial variables. A higher variation of trait composition (57.0%) than species composition (37.5%) could be explained by abiotic factors. Mantel tests showed that both species and trait-based beta diversities were mostly related to hydrological and environmental heterogeneity with hydrological contributing more than environmental variables, while purely spatial impact was less important. Our findings revealed the relative importance of hydrological variables in shaping pelagic algae community and their spatial patterns of beta diversities, emphasizing the need to include hydrological variables in long-term biomonitoring campaigns and biodiversity conservation or restoration. A key implication for biodiversity conservation was that maintaining the instream flow regime and keeping various habitats among rivers are of vital importance. However, further investigations at multispatial and temporal scales are greatly needed

Woodland establishment reduces nutrient losses to waterbodies in urban catchments: a review of the evidence

Systematic review of peer-reviewed literature was undertaken to establish benefits of urban forests on reducing nutrient concentrations in adjacent or downstream waterbodies. Following screening, a small number of articles (40) were found relevant, representing studies quantifying non-point source nutrient losses from urban and peri-urban environments. Evidence was split between plot- and catchment-scale. Plot-scale studies often included evaluations of engineered nature-based solutions. At catchment-scale, studies of streamwater quality typically investigated influence of contributory catchment nutrient sources. Wide ranges of beneficial reductions were apparent, and at both scales not all studies identified significant benefits. Summarizing against this backdrop, at plot (micro-) scale woodland reduces mean concentrations in runoff, soil or groundwater by an average of 44.2% for total nitrogen (TN) and 47.0% for total phosphorus (TP). At catchment (meso-) scale, evidence suggests a 20% areal addition of forest at the expense of mixed urban fabric can reduce mean concentrations by 15.7% and 12.6% for TN and TP respectively. Additionally, some articles reveal potential drawbacks reducing benefits provided specifically by street trees and riparian woodland. Leaf litter falling on impervious surfaces can heighten risk of TP leaching to streams, but has little impact on TN. Riparian woodland was found to have complex water quality impacts. Canopy cover suppresses stream channel biological nitrogen uptake, which based on all evidence appears considerable. However, unshaded headwaters can foster accelerated primary productivity with undesirable downstream consequences. Overall, gathering further evidence is encouraged, given current uncertainties, especially to address differences between impervious, permeable and riparian urban woodland settings

Making waves: effluent to estuary: does sunshine or shade reduce downstream footprints of cities?

Riparian tree canopies are key components of river systems, and influence the provision of many essential ecosystem services. Their management provides the potential for substantial control of the downstream persistence of pollutants. The recent advent of new advances in mass spectrometry to detect a large suite of emerging contaminants, high-frequency observations of water quality and gas exchange (e.g., aquatic eddy covariance), and improved spatial resolution in remote sensing (e.g., hyperspectral measurements and high-resolution imagery), presents new opportunities to understand and more comprehensively quantify the role of riparian canopies as Nature-based Solutions. The paper outlines how we may now couple these advances in observational technologies with developments in water quality modelling to integrate simulation of eutrophication impacts with organic matter dynamics and fate of synthetic toxic compounds. In particular regarding solar radiation drivers, this enables us to scale-up new knowledge of canopy-mediated photodegradation processes at a basin level, and integrate it with ongoing improvements in understanding of thermal control, eutrophication, and ecosystem metabolism

Significant improvement in freshwater invertebrate biodiversity in all types of English rivers over the past 30 years

There remains a persistent concern that freshwater biodiversity is in decline and being threatened by pollution. As the UK, and particularly England, is a densely populated nation with rivers of modest dilution capacity, this location is very suitable to examine how freshwater biodiversity has responded to human pressures over the past 30 years. A long-term dataset of 223,325 freshwater macroinvertebrate records from 1989 to 2018 for England was retrieved and examined. A sub-set of approximately 200 sites per English Region (1515 sites in total with 62,514 samples), with the longest and most consistent records were matched with predicted wastewater exposure, upstream land cover and terrain characteristics (latitude, altitude, slope gradient and flow discharge). To understand changes in macroinvertebrate diversity and sensitivity with respect to these parameters, the biotic indices of (i) overall family richness, (ii) Ephemeroptera, Plecoptera, Trichoptera (EPT) family richness, and (iii) the Biological Monitoring Working Party (BMWP) scores of NTAXA (number of scoring taxa) and (iv) ASPT (average score per taxon) were selected. A review of how close the BMWP scores come to those expected at minimally impacted reference sites was included. For all latitudes, altitudes, channel slope, river size, wastewater exposure levels, and differing proportions of upstream woodland, seminatural, arable and urban land cover, all diversity or sensitivity indices examined improved over this period, although this improvement has slowed in some cases post 2003. Mean overall family richness has increased from 15 to 25 family groups, a 66 % improvement. The improvement in mean EPT family richness (3 to 10 families, >300 % improvement), which are considered to be particularly sensitive to pollution, implies macroinvertebrate diversity has benefited from a national improvement in critical components of water quality

Qualitative Impact Assessment of Land Management Interventions on Ecosystem Services (“QEIA”). Report-1: Executive Summary: QEIA Evidence Review & Integrated Assessment

The focus of this project was to provide an expert-led, rapid qualitative assessment of land management interventions on Ecosystem Services (ES) proposed for inclusion in Environmental Land Management (ELM) schemes. This involved a review of the current evidence base for 741 land management actions on 33 Ecosystem Services and 53 Ecosystem Service indicators by ten teams involving 45 experts drawn from the independent research community in a consistent series of Evidence Reviews covering the broad topics of: • Air quality • Greenhouse gas emissions • Soils • Water management • Biodiversity: croplands • Biodiversity: improved grassland • Biodiversity: semi-natural habitats • Biodiversity: integrated systems-based actions • Carbon sequestration • Cultural services (including recreation, geodiversity and regulatory services). It should be noted that this piece of work is just one element of the wider underpinning work Defra has commissioned to support the development of the ELM schemes

Qualitative impact assessment of land management interventions on Ecosystem Services (‘QEIA’). Report-2: Integrated Assessment

The focus of this project was to provide an expert-led, rapid qualitative assessment of land management interventions on Ecosystem Services (ES) proposed for inclusion in Environmental Land Management (ELM) schemes. This involved a review of the current evidence base for 741 land management actions on 33 Ecosystem Services and 53 Ecosystem Service indicators by ten expert teams drawn from the independent research community in a consistent series of ten Evidence Reviews covering the broad topics of; • Air quality • Greenhouse gas emissions • Soils • Water management • Biodiversity: croplands • Biodiversity: improved grassland • Biodiversity: semi-natural habitats • Biodiversity: integrated systems-based actions • Carbon sequestration • Cultural services (including recreation, geodiversity and regulatory services) These reviews were undertaken rapidly at Defra’s request by ten teams involving 45 experts who together captured more than 2,400 individual sources of evidence. This was followed by the Integrated Assessment (IA) reported here to provide a more accessible summary of these evidence reviews with a focus on capturing the actions with the greatest potential magnitude of change for the intended ES, and their potential co-benefits and trade-offs for the other ES