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101.
Monitoring pollution in River Mureş, Romania, part II: metal accumulation and histopathology in fish
Triebskorn R Telcean I Casper H Farkas A Sandu C Stan G Colărescu O Dori T Köhler HR 《Environmental monitoring and assessment》2008,141(1-3):177-188
As a part of an exposure and effect monitoring conducted along the river Mureş, Western Romania in 2004, the health status
of two indigenous fish species, sneep (Chondrostoma nasus) and European chub (Leuciscus cephalus) was investigated upstream and downstream the city of Arad. In fish, histopathology was assessed in liver and gills, and
heavy metals (cadmium, copper, lead and zinc) were analyzed in liver samples. In both fish species, histopathological reactions
in the gills (epithelial lifting, focal proliferation of epithelial cells of primary and secondary lamellae and resulting
fusion of secondary lamellae, hyperplasia and hypertrophy of mucous cells, focal inflammation and necrosis of epithelial cells)
were most severe at the two sampling sites upstream Arad city, which were shown to be polluted by copper, cadmium, faecal
coliforms and streptococci in a parallel study. At these two sites, also histopathology in the liver of L. cephalus was more prominent than at the two downstream sites. In C. nasus, symptoms in the liver (focal inflammation with lymphocytic infiltrations, macrophage aggregates and single cell necrosis)
were also highly pronounced at the sampling site located directly downstream the municipal sewage treatment plant of Arad.
With the exception of copper accumulation in L. cephalus caught at the most upstream sampling site, in both fish species cadmium and copper accumulation were exceptionally high and
did not differ significantly between the four sampling sites. 相似文献
102.
Wang L Brenden T Seelbach P Cooper A Allan D Clark R Wiley M 《Environmental monitoring and assessment》2008,141(1-3):1-17
Identification of reference streams and human disturbance gradients are crucial steps in assessing the effects of human disturbances
on stream health. We describe a process for identifying reference stream reaches and assessing disturbance gradients using
readily available, geo-referenced stream and human disturbance databases. We demonstrate the utility of this process by applying
it to wadeable streams in Michigan, USA, and use it to identify which human disturbances have the greatest impact on streams.
Approximately 38% of cold-water and 16% of warm-water streams in Michigan were identified as being in least-disturbed condition.
Conversely, approximately 3% of cold-water and 4% of warm-water streams were moderately to severely disturbed by landscape
human disturbances. Anthropogenic disturbances that had the greatest impact on moderately to severely disturbed streams were
nutrient loading and percent urban land use within network watersheds. Our process for assessing stream health represents
a significant advantage over other routinely used methods. It uses inter-confluence stream reaches as an assessment unit,
permits the evaluation of stream health across large regions, and yields an overall disturbance index that is a weighted sum
of multiple disturbance factors. The robustness of our approach is linked to the scale of disturbances that affect a stream;
it will be less robust for identifying less degraded or reference streams with localized human disturbances. With improved
availability of high-resolution disturbance datasets, this approach will provide a more complete picture of reference stream
reaches and factors contributing to degradation of stream health. 相似文献
103.
This study evaluated the effects of an industrial wastewater treatment plant (IWTP) and a municipal wastewater treatment plant (MWTP) effluents on a variety of bioindicators ranging from biochemical, organism, and population-level responses in pale chub (Zacco platypus) and fish community structure. The Index of Biotic Integrity (IBI) indicated that the site upstream of these wastewater treatment plant discharges is in fair–good condition and downstream of the plant is in poor condition. The EROD (ethoxyresorufin-O-deethylase) activity, condition factor, and liver somatic index were significantly increased at the downstream site compared to those of the upstream site. The most significant change observed in pale chub population in the downstream site of the Miho Stream, relative to the upstream population, was the total absence of an younger age group. Stressors impacting the downstream site were identified as mostly organic or nutrient enrichment and habitat degradation associated with wastewater treatment plants. The results of causal analysis suggest that the primary causes affecting fish population in the downstream site are through both size-selective mortality caused by ammonia toxicity and recruitment failure caused by habitat degradation and reproduction problem due to an IWTP and MWTP effluents. 相似文献
104.
Angeler DG Sánchez-Carrillo S Rodrigo MA Alvarez-Cobelas M Rojo C 《Environmental monitoring and assessment》2007,125(1-3):9-17
This study evaluates whether the size structure of seston (the sum of living and nonliving particles in the water column)
reflects the effects of fish on wetland water quality. Using enclosures, we measured water quality and zooplankton community
structure in the presence and absence of two fish species with distinct foraging strategies [benthivorous carp (Cyprinus
carpio) and planktivorous mosquitofish (Gambusia
holbrooki)]. Seston collected from the enclosures was counted and sized automatically with a Coulter counter, and the size structure
in the range of 1–60 μm was modelled using the underlying Pareto distribution of particles. Only Cyprinus contributed to a loss of water quality (increased nutrient levels, algal and non-algal turbidity, hypoxia), while both fish
species changed zooplankton community composition compared to fishless controls. However, these changes were not reflected
in parameters [goodness of fit (r
2) and parameter c (slopes)] of Pareto models. Multivariate statistics suggest that seston size structure responded more to environmental gradients
related to water depth but the relationships were also weak. Our overall result contrasts with the regulation of size spectra
constructed from living organisms. Although seston integrates many structural and functional features of the water column,
the lack of strong relationships between Pareto model parameters and water quality suggests that a size-based approach to
characterise seston structure has a limited potential for assessing biota-mediated effects in wetlands in a straightforward
manner. 相似文献
105.
/ Fishes and their habitats were sampled in Harland Creek, Mississippi, for 3 years to compare the relative value of three types of bank treatment in an incised, warmwater stream. Semiannual samples were collected from 10 reaches: 3 reaches protected by each of the three types of protection (longitudinal stone toe, stone spurs, and dormant willow posts) and an unprotected, slowly eroding bend. Protection of concave banks of bends had no measurable effect on the habitat quality of downstream riffles. Although bends and adjacent downstream riffles were faunistically similar at the species level, catostomids and centrarchids were more dominant in pools and smaller cyprinids more dominant in riffles. Reaches with willow posts were slightly deeper than the others, most likely because of geomorphic factors rather than bank treatment. Mean water surface widths in reaches stabilized with stone spurs were 40% to 90% greater than for other treatments, and current velocities were greatest in reaches with stone toe. Patterns of fish abundance and species diversity did not differ significantly among treatments. However, principal components analysis indicated that the fish species distribution associated with the untreated reference site was distinct. Reaches stabilized with stone spurs supported significantly higher densities of large fish and higher levels of fish biomass per unit channel length than reaches with other bank treatments, generally confirming previous research in the region. Initial costs for spurs were comparable to those for stone toe and about three times greater than for willow posts. 相似文献
106.
Undamming Rivers: A Review of the Ecological Impacts of Dam Removal 总被引:26,自引:4,他引:22
Bednarek AT 《Environmental management》2001,27(6):803-814
Dam removal continues to garner attention as a potential river restoration tool. The increasing possibility of dam removal
through the FERC relicensing process, as well as through federal and state agency actions, makes a critical examination of
the ecological benefits and costs essential. This paper reviews the possible ecological impacts of dam removal using various
case studies.
Restoration of an unregulated flow regime has resulted in increased biotic diversity through the enhancement of preferred
spawning grounds or other habitat. By returning riverine conditions and sediment transport to formerly impounded areas, riffle/pool
sequences, gravel, and cobble have reappeared, along with increases in biotic diversity. Fish passage has been another benefit
of dam removal. However, the disappearance of the reservoir may also affect certain publicly desirable fisheries.
Short-term ecological impacts of dam removal include an increased sediment load that may cause suffocation and abrasion to
various biota and habitats. However, several recorded dam removals have suggested that the increased sediment load caused
by removal should be a short-term effect. Preremoval studies for contaminated sediment may be effective at controlling toxic
release problems.
Although monitoring and dam removal studies are limited, a continued examination of the possible ecological impacts is important
for quantifying the resistance and resilience of aquatic ecosystems. Dam removal, although controversial, is an important
alternative for river restoration. 相似文献
107.
Selecting parameters for calibration via sensitivity analysis: An individual-based model of mosquitofish population dynamics 总被引:1,自引:0,他引:1
A stochastic individual-based model (IBM) of mosquitofish population dynamics in experimental ponds was constructed in order to increase, virtually, the number of replicates of control populations in an ecotoxicology trial, and thus to increase the statistical power of the experiments. In this context, great importance had to be paid to model calibration as this conditions the use of the model as a reference for statistical comparisons. Accordingly, model calibration required that both mean behaviour and variability behaviour of the model were in accordance with real data. Currently, identifying parameter values from observed data is still an open issue for IBMs, especially when the parameter space is large. Our model included 41 parameters: 30 driving the model expectancy and 11 driving the model variability. Under these conditions, the use of “Latin hypercube” sampling would most probably have “missed” some important combinations of parameter values. Therefore, complete factorial design was preferred. Unfortunately, due to the constraints of the computational capacity, cost-acceptable “complete designs” were limited to no more than nine parameters, the calibration question becoming a parameter selection question. In this study, successive “complete designs” were conducted with different sets of parameters and different parameter values, in order to progressively narrow the parameter space. For each “complete design”, the selection of a maximum of nine parameters and their respective n values was carefully guided by sensitivity analysis. Sensitivity analysis was decisive in selecting parameters that were both influential and likely to have strong interactions. According to this strategy, the model of mosquitofish population dynamics was calibrated on real data from two different years of experiments, and validated on real data from another independent year. This model includes two categories of agents; fish and their living environment. Fish agents have four main processes: growth, survival, puberty and reproduction. The outputs of the model are the length frequency distribution of the population and the 16 scalar variables describing the fish populations. In this study, the length frequency distribution was parameterized by 10 scalars in order to be able to perform calibration. The recently suggested notion of “probabilistic distribution of the distributions” was also applied to our case study, and was shown to be very promising for comparing length frequency distributions (as such). 相似文献
108.
2012年3月、6月、9月和12月按季度对涪江支流老河沟的14个样点进行了鱼类群落结构调查和分析。共采集鱼类11种,隶属于2目4科;其中,鲤形目鱼类7种,占物种数的63.64%。沿上游源头到下游的纵向梯度方向,老河沟鱼类的种类数和丰度均逐渐增加,具极显著性差异,而鱼类种类数和丰度则无季节差异性。聚类分析(Cluster Analysis)和多维尺度分析(MDS)表明,当Bray-curtis相似度矩阵值为40.77%时,老河沟鱼类群落分成上游、中游和下游3组。利用相似度百分比分析(SIMPER)确定,引起3组差异性的特定鱼类是宽鳍鱲、尖头、似()、齐口裂腹鱼、贝氏高原鳅、红尾荷马条鳅和青石爬鮡。典型相关分析(CCA)表明海拔、底质类型、流速、溶氧、总溶解固体、水温、电导率、河宽、pH值和水深等环境变量是老河沟鱼类群落时空格局差异的影响因子。 相似文献
109.
Abigail Bennett Xavier Basurto John Virdin Xinyan Lin Samantha J. Betances Martin D. Smith Edward H. Allison Barbara A. Best Kelly D. Brownell Lisa M. Campbell Christopher D. Golden Elizabeth Havice Christina C. Hicks Peter J. Jacques Kristin Kleisner Niels Lindquist Rafaella Lobo Grant D. Murray Michelle Nowlin Pawan G. Patil Douglas N. Rader Stephen E. Roady Shakuntala H. Thilsted Sarah Zoubek 《Ambio》2021,50(5):981
The international development community is off-track from meeting targets for alleviating global malnutrition. Meanwhile, there is growing consensus across scientific disciplines that fish plays a crucial role in food and nutrition security. However, this ‘fish as food’ perspective has yet to translate into policy and development funding priorities. We argue that the traditional framing of fish as a natural resource emphasizes economic development and biodiversity conservation objectives, whereas situating fish within a food systems perspective can lead to innovative policies and investments that promote nutrition-sensitive and socially equitable capture fisheries and aquaculture. This paper highlights four pillars of research needs and policy directions toward this end. Ultimately, recognizing and working to enhance the role of fish in alleviating hunger and malnutrition can provide an additional long-term development incentive, beyond revenue generation and biodiversity conservation, for governments, international development organizations, and society more broadly to invest in the sustainability of capture fisheries and aquaculture.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01451-4) contains supplementary material, which is available to authorized users. 相似文献
110.
Kaifeng Rao Li Tang Xin Zhang Heyu Xiang Liang Tang Yong Liu Wei Wang Jie Jiang Mei M Yiping Xu Zijian Wang 《环境科学学报(英文版)》2021,33(12):150-159
Environmental impact of pollutants can be analyzed effectively by acquiring fish behavioral signals in water with biological behavior sensors. However, a variety of factors, such as the complexity of biological organisms themselves, the device error and the environmental noise, may compromise the accuracy and timeliness of model predictions. The current methods lack prior knowledge about the fish behavioral signals corresponding to characteristic pollutants, and in the event of a pollutant invasion, the fish behavioral signals are poorly discriminated. Therefore, we propose a novel method based on Bayesian sequential, which utilizes multi-channel prior knowledge to calculate the outlier sequence based on wavelet feature followed by calculating the anomaly probability of observed values. Furthermore, the relationship between the anomaly probability and toxicity is analyzed in order to achieve forewarning effectively. At last, our algorithm for fish toxicity detection is verified by integrating the data on laboratory acceptance of characteristic pollutants. The results show that only one false positive occurred in the six experiments, the present algorithm is effective in suppressing false positives and negatives, which increases the reliability of toxicity detections, and thereby has certain applicability and universality in engineering applications. 相似文献