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1.
Sci Total Environ ; 695: 133706, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31419677

RESUMO

Sand mining is a human activity that is increasing in inland waters and has profound effects on entire aquatic ecosystems. However, current knowledge of the effects of sand mining on freshwater lake ecosystems remains limited, especially for biotic communities. Here, we investigated the responses of macroinvertebrates to indiscriminate sand mining in a large shallow lake of China. Our results indicated that sand mining significantly increased the content of suspended particulate matter, total nitrogen, total phosphorus and chlorophyll a in the water column both in the sand mining area and the area adjacent to the dredging activities. While there was significantly lower total nitrogen and the total phosphorus content of the sediment were observed in the sand mining area. In terms of benthic animals, there were reductions of the macroinvertebrate density and biomass of 89.80% and 99.54%, respectively, and there was a considerable decline of the majority of macroinvertebrate taxonomic taxa as well as biological traits observed in the sand mining area due to direct dredging-induced substrate deterioration and high turbidity water. Moreover, in the area adjacent to the dredging activities, dredging-induced high turbidity water also resulted in 28% and 79% decreases in macroinvertebrate density and biomass, respectively, with a significant decrease in the densities of Bivalvia and Polychaeta but an increase in the density of Crustacea. In terms of biological traits, species (e.g., Grandidierella sp. and Sphaerium lacustre) characterized by a small body size, short life cycle and dietary sources mainly from sediment were typically associated with the ecological condition of the indirect effects of the dredging activities. Taxa (e.g., Corbicula fluminea) with a larger body size and longer life cycle that are filter feeders should be favored by the ecological conditions of the reference sites. For biomonitoring of sand mining perturbations, a number of taxonomic and biological trait indicators were proposed in our study based on indicator value analysis, and the general applicability of trait-based indicators was highlighted. We also suggest that the biodiversity indices may be less suitable indicators of sand mining effects. Given the limited understanding of the responses of macroinvertebrates to sand mining in inland freshwaters, we believe that our results may provide important information for biomonitoring of sand mining activities and provide scientific management support to governments.


Assuntos
Ecossistema , Monitoramento Ambiental , Invertebrados , Mineração , Animais , Biodiversidade , China , Lagos
2.
Sci Total Environ ; 659: 451-462, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31096375

RESUMO

Current understanding of different facets of beta diversity and their underlying determinants remains limited at broad scales in the freshwater realm. We examined the geographical patterns and spatial congruence of three beta diversity facets of freshwater molluscs across all of China, and evaluated the relative importance of environmental and spatial factors underlying the observed patterns. Taxonomic (ß-TD), functional (ß-FD) and phylogenetic (ß-PD) beta diversity were calculated for 212 drainage basins belonging to 10 hydrographic regions using compiled occurrence data of 313 molluscan species. Geographical patterns of the three diversity facets were visualized on maps and pairwise spatial congruence among them was evaluated using regression on distance matrices. Variation partitioning and multivariate regression trees were used to assess the relative importance of different factors underlying beta diversity patterns. Beta diversity maps revealed that geographical patterns of ß-TD and ß-PD showed strong spatial clustering and were well matched with hydrographic regions' boundaries, while ß-FD showed only moderate spatial aggregation. The three facets were only moderately congruent, with over 60% of the variation in one facet remaining unexplained by any other facet. Remarkably, all diversity facets were best explained by the spatial factors with considerable unique effects. Environmental filtering associated with energy gradients also made a large contribution, while habitat availability only explained minor fractions of the variation in beta diversity. At the national scale, ß-TD and ß-PD were more strongly related to spatial processes, whereas ß-FD was more strongly associated with energy gradients. Our results suggested that, for freshwater organisms with low dispersal capacity, dispersal processes may override environmental filtering in driving geographical diversity patterns. However, different ecological drivers were important for each diversity facet. Importantly, rather weak spatial congruence among the different diversity facets stresses the need to incorporate functional and phylogenetic facets into the development of conservation planning.


Assuntos
Biodiversidade , Água Doce , Moluscos , Animais , China , Meio Ambiente , Geografia
3.
Environ Monit Assess ; 191(4): 201, 2019 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-30826892

RESUMO

Both environmental and geographic factors interact to structure the metacommunities in river networks, but the importance of these factors is difficult to distinguish. We used six aquatic taxonomic groups to test the relationship between environmental and geographic factors and their effect on species turnover patterns in an agriculturally dominated river (Chaohu Lake Basin, China). The relationships between three dissimilarity indices and geographic distance were assessed using the Mantel test while considering the differences in environmental factors between sites. Then, we employed a variation partitioning method to distinguish the isolated and combined effects of environmental and geographic distance on species turnover. There were significant relationships between environmental distance and species turnover in all groups. All organisms except periphytic diatoms were significantly correlated with two geographic (Euclidean and network) distances when the Chao dissimilarity index was considered. The results suggest that the strength of the correlations changed with environmental and geographic distances and with the aquatic community. The communities displayed more complex relationships with the distance measures when different dissimilarity (Jaccard, Chao, and Bray-Curtis dissimilarity) indices were considered. Nevertheless, aquatic communities are strongly influenced by both environmental and geographic distance, and the former has a stronger effect than the latter.


Assuntos
Biodiversidade , Diatomáceas/classificação , Monitoramento Ambiental , Peixes/classificação , Fitoplâncton/classificação , Rotíferos/classificação , Zooplâncton/classificação , Agricultura , Animais , China , Diatomáceas/isolamento & purificação , Geografia , Lagos , Fitoplâncton/isolamento & purificação , Rios , Rotíferos/isolamento & purificação , Zooplâncton/isolamento & purificação
4.
Sci Total Environ ; 660: 245-259, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30640093

RESUMO

Small, seasonal lakes that exist in floodplains are rarely investigated, and yet they play an important role in the protection of biodiversity and are highly susceptible to modification due to human activities. This study presents a first attempt to combine hydrodynamic modeling and statistical methods to investigate hydrological connectivity and its relationship with the water quality of nine seasonal lakes within the floodplains of Poyang Lake (China). The hydrodynamic model reproduced reasonably well the hydrological regime of the lake and surrounding floodplains, based on field measurements and remote sensing data. Floodplain lakes exhibit similar water-level dynamics to the main lake during connected periods of flooding, while they decouple from the main lake during recession periods. Geostatistical results reveal that although the north-south hydrological connectivity extends over a longer pathway than the west-east connectivity, the rapid reduction in the west-east connectivity indicates a more sensitive response. The west-east connectivity tends to play a dominant role in affecting the interactions between the main lake and floodplains, as expected. Statistical methods indicate that surface hydrological connectivity across the floodplain results in an enhanced spatial similarity in the water quality of the floodplain lakes, in terms of a multitude of water quality parameters (TN, TP, NH4+-N, NO3--N, NO2--N, PO43-, CODMn, and Chl a), while surface hydrological isolation was observed to increase the water quality differences between the seasonal lakes. Additionally, enhanced hydrological connectivity may lead to improved water quality of the seasonal lakes from low connectivity to high connectivity condition. Hydrological connectivity may be a key factor controlling the dynamics in water quality between seasonal lakes. The findings of this study support the management of both Poyang Lake and the floodplain wetlands by providing important information on both water resource and water quality, and proposals to better manage the impacts of intensive human activities.

5.
Sci Total Environ ; 662: 481-489, 2019 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-30695748

RESUMO

A decline in wind speed will have a series of effects on a lake ecosystem. Attention should be paid to macroinvertebrates, a critical ecosystem component, but few previous studies have considered these organisms. To study the influence of wind speed on macroinvertebrates, we selected Meiliang Bay and Zhushan Bay in Lake Taihu, which have high spatial homogeneity. The response of the benthic community and dominant species to a decrease in wind speed was studied using eight years of field survey data through NMDS analysis and regression analysis. The results showed that the decrease in wind speed significantly changed the structure of the macroinvertebrate community. Wind speed may affect macroinvertebrates directly or indirectly, mainly through wind-wave disturbance or changes in dissolved oxygen and food resources. The responses of different species and different growth stages to wind speed varied. According to the regression results, among the 8 most dominant species, the abundance of chironomids and malacostracans was positively correlated with wind speed, and that of bivalves and some oligochaetes was negatively correlated with wind speed. However, while the abundance of oligochaetes was negatively correlated with wind speed during the larval period, it was positively correlated with wind speed during the adult period. With future declines in wind speed, corresponding changes in the dominant species in Lake Taihu will have a series of effects on lake ecosystem, and more attention should be paid to these processes in future studies.


Assuntos
Biodiversidade , Monitoramento Ambiental , Invertebrados/fisiologia , Lagos , Vento , Animais , China , Traços de História de Vida
6.
Sci Total Environ ; 658: 395-404, 2019 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-30579197

RESUMO

Our study illustrated the ecological conditions in the rivers of Lake Taihu Basin (LTB) using an index of biotic integrity based on phytoplankton (P-IBI), and its performance was compared with the previously developed water quality index (WQI). Samples were collected seasonally at 96 sites covering the major rivers from September 2014 to January 2016. Three critical ecological indices, i.e., phytoplankton density, chlorophyll a (chl a), and Menhinick, were selected from a pool of 22 candidate indices mainly according to the correlations among indices and environmental parameters. The results indicated that the ecological status of LTB based on P-IBI was significantly different at spatial (especially between Tiaoxi and the other 5 river systems) and seasonal scales. Furthermore, the proposed P-IBI effectively identified the major environmental parameters (total nitrogen, ammonium, total phosphorus, and permanganate index) associated with each level (bad, low, and moderate). Moreover, the P-IBI was closely and positively correlated with the WQI at the spatial scale regardless of season. However, the ecological conditions were significantly worse according to the P-IBI at both the spatial (P < 0.001) and seasonal scales (P values of 0.018 in winter and < 0.001 in other seasons, respectively), and the seasonal distribution pattern differed between the two methods. Our study suggests that the P-IBI provides an essential supplement for the assessment of ecological conditions of rivers and that the selected critical indices (phytoplankton density, chl a, and Menhinick) are suitable for river ecosystems. Additionally, compared with WQI, the water quality condition was generally worse when using P-IBI, and this phenomenon requires further attention during water quality assessments, as well as different seasonal distribution patterns.


Assuntos
Monitoramento Ambiental/métodos , Fitoplâncton/fisiologia , Rios/química , Qualidade da Água , China , Clorofila A/análise , Fitoplâncton/crescimento & desenvolvimento , Densidade Demográfica , Estações do Ano
7.
Environ Pollut ; 259: 113884, 2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31918143

RESUMO

High concentrations of microcystins (MCs) in sediment pose a serious hazard to aquatic and terrestrial organisms. Hence, we investigated the seasonal variation of dominant MCs (MC-LR, MC-RR and MC-YR) in sediments of Lake Taihu over four seasons for the first time. Sediment MCs varied seasonally (p < 0.01) with concentrations highest in August and lowest in February. The MCs were dominated by MC-LR (61.47%) with the content ranging from 0.02 to 2.37 µg/g dry weight in sediment. The three MC congeners and their proportions were significantly correlated with latitude and longitude. Meiliang Bay in the north had the highest MCs of all sites, while the eastern part of the lake had a high level especially in August. Variation of MC-LR and MC-RR concentrations was significantly correlated (p < 0.05) with water temperature, dissolved total organic carbon, cyanobacteria density, total suspended solid particles, and total organic carbon and total nitrogen in sediment, while MC-YR was negatively correlated (p < 0.01) with nutrients in the water column and heavy metals in sediments. An ecological risk assessment suggested the MCs already pose significant adverse effects on Potamopyrgus antipodarum; although the adverse effects on humans were weak, children were at greater risk than adults.

8.
Sci Total Environ ; 645: 1361-1370, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30248859

RESUMO

Surface wind speed has declined significantly globally. However, the response of aquatic systems to decreasing wind speeds has received little attention. We examined the effects of a long-term decrease in wind speed on shallow, eutrophic Lake Taihu, China's third largest lake, by combining high-frequency monitoring, long-term meteorological and water quality data with short-term laboratory sediment nutrient release experiments. The annual mean wind speed showed a significant decreasing trend and the maximum continuous days with wind speed <3 m/s increased significantly from 1996 to 2017. The high-frequency monitoring data showed that bottom water hypoxia occurred occasionally in summer and autumn. The water quality data combined with the experimental results suggest that lower wind speed and longer low wind duration can enhance the release of phosphorus (P) from the sediments and increase nitrogen (N) losses, likely via denitrification, because a longer stability period leads to lower dissolved oxygen concentrations near the lake bottom. The results of Bayesian functional Linear regression with Sparse Step functions (Bliss) indicated that wind speed during spring and summer strongly affected chlorophyll a (Chla) concentrations in the summer by enhancing the release of nutrients from the sediments. The results of the structural equation models indicated that declined wind speed might increase phytoplankton biomass (as Chla) by altering nutrient availability. Increasing water temperatures and decreasing wind speeds synergistically enhance water column stability, which may offset some of the immediate benefits of reductions in external nutrient loading by enhancing internal loading. Given predicted global change, it will become increasingly important to reduce the external nutrient loading for overall improvement of water quality in this and other shallow eutrophic lakes.

9.
Sci Total Environ ; 634: 158-169, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29627538

RESUMO

Reservoirs play more and more important role in providing potable water in many developing countries, including the China. In the present study, pollution characteristics, source and health risk of dissolved heavy metals in 19 representative reservoirs in the hilly area of southern China were investigated. The results presented great spatial heterogeneity in heavy metal concentrations among the studied reservoirs due to the disturbances by different anthropogenic activities. Several reservoirs had significantly higher concentrations of heavy metals compared with others, FengTan (FT) reservoir (0.34µg/L in dry season), Cr in reservoirs of HuangShi (HS) and ZheLin (ZL) with values of 4.16µg/L and 3.45µg/L in dry season respectively, and Al in reservoirs of JiaoKou (JK), GuTian (GT) and DouShui (DS) with values of 1011µg/L, 1036µg/L and 1001µg/L in wet season, respectively. Furthermore, there was a great difference in the seasonal variation of heavy metals, especially for Al and Pb in wet season characterized with relatively high values of 643µg/L and 0.67µg/L, respectively. Accordingly, Al was identified with a great health risk to living beings in view of its mean value in wet season, which greatly exceeded the criteria for drinking water of China, WHO and US EPA. Furthermore, As might be the greatest concern of health risk in this region considering its high carcinogenic risk to the local residents around the reservoirs of OuYangHai (OYH), DS, ZhiXi (ZX) and HS. Multivariate statistical analysis suggested that there was great heterogeneity in the sources of these heavy metals in the hilly area of southern China. Therefore, specific measures, such as controls on point source pollution control and tailings, should be taken for maintaining drinking water safety and aquatic ecosystem health.


Assuntos
Exposição Ambiental/análise , Metais Pesados/análise , Poluentes Químicos da Água/análise , China , Exposição Ambiental/estatística & dados numéricos , Monitoramento Ambiental , Humanos , Medição de Risco , Poluição Química da Água/estatística & dados numéricos
10.
Sci Total Environ ; 627: 57-66, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29426180

RESUMO

Rapid agricultural development has induced severe environmental problems to freshwater ecosystems. In this study, we aimed to examine the structure and environmental determinants of macroinvertebrate assemblages in an agriculture dominated Lake Chaohu Basin, China. A cluster analysis of the macroinvertebrate communities identified four groups of sites that were characterized by significantly different macroinvertebrate species. These four groups of sites had concentric spatial distribution patterns that followed the variation in the environmental conditions from the less anthropogenically disturbed headwaters towards the more anthropogenically disturbed lower reaches of the rivers and the Lake Chaohu. Moreover, taxa richness decreased from the headwaters towards the Lake Chaohu. The increasing practice of agriculture has reduced the abundances and richness of pollution sensitive species while opposite effects on pollution tolerant species. The study identified substrate heterogeneity and nutrient concentrations as the key environmental factors regulating the changes in the macroinvertebrate communities. We propose that particular attentions should be paid to reduce the nutrient enrichment and habitat degradation in the Lake Chaohu Basin and similar agriculture dominated basins.


Assuntos
Organismos Aquáticos/classificação , Ecossistema , Monitoramento Ambiental , Invertebrados/classificação , Lagos/química , Agricultura , Animais , Organismos Aquáticos/crescimento & desenvolvimento , Biodiversidade , China , Invertebrados/crescimento & desenvolvimento , Rios
11.
Sci Total Environ ; 625: 275-284, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29289776

RESUMO

The shape of the productivity-richness relationship (PRR) for phytoplankton has been suggested to be unimodal, that is, the richness peaks at intermediate productivity levels. However, the mechanistic understanding for this pattern is still widely debated. In this study, we observed a unimodal PRR within 71 lakes along the Yangtze River encompassing an altitude range of 0-2700m, and an over 2200km distance from the upper reaches to the lower reaches. At low productivity, the competition for resources and regulatory processes jointly affected phytoplankton richness and composition, and their explanatory power depend on the gradient scale of driving factors. The variation of temperature attributing to altitudinal difference explained the majority of the variations of phytoplankton. If the altitude variation in temperature was eliminated, the explanatory power of temperature decreased from 31.7 to 7.6, and the independent effect of each resource and regulatory variable were limited and not decisive. At high productivity, the negative feedback of increased productivity (light limitation) affected the phytoplankton species richness and composition. The light-sensitive species disappeared, low-light-adapted species was retained and the phytoplankton composition gradually became similar with an increase in productivity. The findings contribute to an increased understanding of the mechanisms resulting in a hump-shaped PRR for phytoplankton.


Assuntos
Altitude , Biodiversidade , Lagos , Fitoplâncton/classificação , Temperatura Ambiente , China , Monitoramento Ambiental
12.
Sci Total Environ ; 612: 914-922, 2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-28886543

RESUMO

Lake Taihu Basin, one of the most developed regions in China, has received considerable attention due to its severe pollution. Our study provides a clear understanding of the water quality in the rivers of Lake Taihu Basin based on basin-scale monitoring and a water quality index (WQI) method. From September 2014 to January 2016, four samplings across four seasons were conducted at 96 sites along main rivers. Fifteen parameters, including water temperature, pH, dissolved oxygen (DO), conductivity, turbidity (tur), permanganate index (CODMn), total nitrogen, total phosphorus, ammonium (NH4-N), nitrite, nitrate (NO3-N), calcium, magnesium, chloride, and sulfate, were measured to calculate the WQI. The average WQI value during our study period was 59.33; consequently, the water quality was considered as generally "moderate". Significant differences in WQI values were detected among the 6 river systems, with better water quality in the Tiaoxi and Nanhe systems. The water quality presented distinct seasonal variation, with the highest WQI values in autumn, followed by spring and summer, and the lowest values in winter. The minimum WQI (WQImin), which was developed based on a stepwise linear regression analysis, consisted of five parameters: NH4-N, CODMn, NO3-N, DO, and tur. The model exhibited excellent performance in representing the water quality in Lake Taihu Basin, especially when weights were fully considered. Our results are beneficial for water quality management and could be used for rapid and low-cost water quality evaluation in Lake Taihu Basin. Additionally, we suggest that weights of environmental parameters should be fully considered in water quality assessments when using the WQImin method.

13.
Sci Total Environ ; 610-611: 101-110, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-28803188

RESUMO

Clay-based phosphorus (P) sorbents have been increasingly used as geoengineering materials for the management sediment-derived internal P loading in eutrophic lakes. However, the long-term behavior of these sorbents has remained elusive along with their response to burial under suspended particulate matter (SPM), and their effect on macroinvertebrate communities occupying dynamic regions at the sediment-water interface of shallow and turbid lakes. In this study, field mesocosm experiments were undertaken in Lake Chaohu, China, to study the effects of the application of lanthanum-modified bentonite (LMB) and thermally-modified calcium-rich attapulgite (TCAP) on sediment internal P loading and to assess their influence on macroinvertebrate community structure. A complementary laboratory core incubation study was also undertaken to investigate the effects of SPM deposition on LMB and TCAP performance. In the field, both LMB and TCAP effectively intercepted P released from sediment for up to five months. A P fractionation analysis indicated that LMB and TCAP application results in a substantial increase in inert P fractions in sediment. Laboratory studies indicated that deposition of SPM may increase in mobile P both in the upper sediment and across the new post-SPM deposition sediment-water interface. Importantly, a comparison of sediment chemical extractions and estimated P fluxes suggests that chemically-defined forms of P in the sediment may be used as a proxy to estimate the net sediment P flux. Significantly, the surficial application of either LMB or TCAP did not cause negative effects on macroinvertebrate communities. This study indicates that to sustain a low P flux across the sediment-water interface in shallow, turbid lakes, repeat dosing of geoengineering materials, temporally aligned to the deposition of fluvial SPM, may be required.

14.
Sci Rep ; 7(1): 17999, 2017 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-29269834

RESUMO

Twenty-four samplings were conducted every 3 months at 15 sites from January 2009 to October 2014 in Lake Poyang, and 20 parameters were analyzed and classified into three groups (toxic metals, easily treated parameters, and others). The assessment results based on water quality index (WQI) showed that the water quality in Lake Poyang was generally "moderate", according to the classification of the surface water quality standard (GB3838-2002) in China, but a deteriorating trend was observed at the interannual scale. Seasonally, the water quality was best in summer and worst in winter. Easily treated parameters generally determined the WQI value in the assessment, especially total nitrogen (TN) and total phosphorus (TP), while toxic metals and other parameters in Lake Poyang were generally at low and safe levels for drinking water. Water level (WL) has a net positive effect on water quality in Lake Poyang through dilution of environmental parameters, which in practice means TN. Consequently, local management agencies should pay more attention to nutrient concentrations during the monitoring schedule, as well as during the low-water periods which manifest a relatively bad water quality state, especially with the prevailing low WL observed recently in Lake Poyang.

15.
Environ Sci Pollut Res Int ; 24(34): 26574-26585, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28952008

RESUMO

A study on the characteristics of heavy metals in surface sediments of typical reservoirs in the hilly area of southern China was carried out. The results showed that contents of heavy metals had great temporal and spatial heterogeneity among studied reservoirs. Zn, Pb, and As presented significant enrichment ratio in reservoirs of Dou Shui (DS) and Feng Tang (FT), as well as Ti in reservoirs of DZ and GT. The content of Cd in reservoir of FT reservoirs was characterized with high health risk with the significantly highest value of 52.43 mg/kg. Furthermore, Pb was identified with high health risk in reservoirs of SFM, Ouyang Hai (OYH), FT, and DS, and As was in OYH and ZX. Multivariate statistical analysis suggested high consistency in the variations of Cr, Ni, and Cu; moreover, Cd, Zn, and Pb were characterized with great homogeneity in their sources. In addition, agricultural activities might exert less effect on variations of heavy metals in studied reservoirs, considered that there was a weak relationship between heavy metals and nutrients. These results could improve our understanding of the spatial variations of heavy metals and their potential sources in reservoirs in this ecologically fragile region.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , China , Análise Multivariada , Medição de Risco
16.
Sci Total Environ ; 601-602: 1702-1711, 2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-28618660

RESUMO

Studies of aquatic metacommunities have so far been focused almost entirely on relatively isolated systems, such as a set of streams, lakes or ponds. Here, we aimed to quantify the relative importance of spatial processes, natural factors and anthropogenic stressors in structuring of a macroinvertebrate metacommunity within a large, highly-connected shallow lake system. The roles of different drivers were evaluated for the entire metacommunity, 10 trait-based deconstructed metacommunities and four common species by incorporating extensive sampling and a large number of abiotic explanatory variables. Contrary to our expectations, we found that variation in community structure among sites was mostly correlated to spatial and wind-wave variables rather than anthropogenic disturbance factors even though the lake presented strong environmental gradients associated with long-term human pressures. In addition, the relative importance of the three groups of drivers varied slightly among the deconstructed trait matrices (i.e. based on dispersal ability, feeding mode and degree of occurrence). Importantly, the distributions of the most common species showed significant and strong spatial autocorrelation, indicating the prominent role of high dispersal rate for their distributions. These findings suggest that the influences of high dispersal rates and natural disturbance may even override the roles of anthropogenic stressors in metacommunity organization in highly-connected aquatic systems. Hence, we strongly encourage that spatial processes and natural drivers are taken into account in the development of bioassessment approaches in highly-connected aquatic systems.


Assuntos
Ecossistema , Monitoramento Ambiental , Invertebrados , Lagos , Distribuição Animal , Animais , Atividades Humanas , Análise Espacial , Movimentos da Água , Vento
17.
Ecotoxicol Environ Saf ; 142: 117-128, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28395204

RESUMO

The residues of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in surface sediments from Taihu Lake basin (THB) and Taihu Lake body (THL) were investigated. Higher concentrations of both PAHs and OCPs were observed for THB than THL. The concentrations of PAHs ranged from 12.1 to 2281.1ngg-1 dw for THB and from 11.4 to 209.9ngg-1 dw for THL, while OCPs ranged from 16.3 to 96.9ngg-1 dw and from 16.8 to 61.9ngg-1 dw for THB and THL, respectively. Spatial distribution of PAHs and OCPs showed a high correspondence with the land use of THB and surrounding anthropogenic activity. Additionally, the Kriging interpolation plots demonstrated that the major upper reaches were more polluted than the lower reaches, indicating the transport of pollutants with the water flow direction. The organic matter contents were responsible for OCP distribution other than PAHs due to the biodegradation capacity difference of chemicals. Similar compositions of pollutants were observed with 3- and 4-ringed PAHs accounting for a total of 78.3% for THB and 85.8% for THL, respectively. HCHs and DDTs were predominant OCPs, which contributed to 31.8% and 21.7% for THB, and 33.6% and 21.9% for THL, respectively. The isomeric and parent substance/metabolite ratios implied fresh inputs of DDTs and chlordanes, while HCHs and endosulfans were mainly from old usage. PAH source identification performed by diagnostic ratios demonstrated the mixed sources of petrogenic and pyrogenic ones dominated by grass, wood and coal combustion. Furthermore, the hazard quotient (HQ) based on the consensus-based sediment quality guidelines (SQGs) was used to evaluate the ecological risks of sediments. Although no frequently adverse effects were observed, potential ecological risks induced by Ant, BaA, γ-HCH, dieldrin, p,p'-DDT and chlordanes should also be paid attention to considering the continuous inputs of such pollutants.


Assuntos
Sedimentos Geológicos/química , Hidrocarbonetos Clorados/análise , Lagos/química , Praguicidas/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Rios/química , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Análise Espacial
18.
Environ Sci Pollut Res Int ; 24(5): 4685-4698, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27975201

RESUMO

This preliminary research was conducted to evaluate the alpine stream health by using water quality as an indicator in Khunjerab National park of the Karakoram ranges located in Pak-China boarder Pakistan having altitude of 3660 m. This study investigated the stream health in the context of the presence or absence of sensitive species, their diversity, and their taxa richness. The water and macroinvertebrate samples were collected from 17 different locations from upstream and downstream of the river by using random sampling method. Macroinvertebrate samples were obtained using kick net (500-µm mesh size) and hand-picking method (NYSDEC). A total of 710 counts including 41 families of macroinvertebrates were recorded comprising of 7 orders including: Ephemeroptera (46%) being the most dominant group, Plecoptera (33%), Trichoptera (5%), Chironomidae (Diptera) (14%), Heteroptera (1%), and Coleoptera (1%). Ephemeroptera, Trichoptera, and Plecoptera (EPT) were found in abundance at the main source, Qarchanai, Dhee, and Tourqeen Nullah, as compared to the other locations of the stream. The most dominant macroinvertebrate was Ephemeroptera whose relative abundance is Pi = 0.49 by using the Shannon index. However, different statistical tools, including principal component analysis (PCA), cluster analysis (CA), ANOVA, and linear regression model, show a strong correlation between water quality and macroinvertebrates. The overall results of the biological indicators showed better ecological health at downstream compared to upstream. This study will provide basic information and understanding about the macroinvertebrates for future researchers, and the data will be helpful for upcoming research programs on alpine streams for the discovery and occurrences of macroinvertebrates and associated fauna.


Assuntos
Qualidade da Água , Animais , Insetos , Paquistão , Parques Recreativos , Rios
19.
Sci Rep ; 6: 31097, 2016 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-27499175

RESUMO

Although there have been numerous studies on microcystin (MC) accumulation in aquatic organisms recently, the bioaccumulation of MCs in relatively small sized organisms, as well as potential influencing factors, has been rarely studied. Thus, in this study, we investigated the bioaccumulation of three MC congeners (-LR, -RR and -YR) in the chironomid larvae of Tanypus chinensis (an excellent food source for certain fishes), the potential sources of these MCs, and potentially relevant environmental parameters over the course of one year in Lake Taihu, China. MC concentrations in T. chinensis varied temporally with highest concentrations during the warmest months (except August 2013) and very low concentrations during the remaining months. Among the three potential MC sources, only intracellular MCs were significantly and positively correlated with MCs in T. chinensis. Although MC concentrations in T. chinensis significantly correlated with a series of physicochemical parameters of water column, cyanobacteria species explained the most variability of MC accumulation, with the rest primarily explained by extraMC-LR. These results indicated that ingestion of MC-producing algae of cyanobacteria accounted for most of the MC that accumulated in T. chinensis. The high MC concentrations in T. chinensis may pose a potential health threat to humans through trophic transfer.


Assuntos
Chironomidae/metabolismo , Microcistinas/metabolismo , Animais , China , Cianobactérias/crescimento & desenvolvimento , Eutrofização , Lagos/química , Lagos/microbiologia , Larva/metabolismo , Estações do Ano , Microbiologia da Água
20.
Ecotoxicol Environ Saf ; 104: 323-31, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24732028

RESUMO

The residual levels, tissue distribution and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in edible fishes, bighead carp (Aristichthys nobilis) and silver carp (Hypophthalmichthys molitrix), from the largest freshwater lake in China, Poyang Lake, were studied. PAH concentrations ranged from 105 to 513ng g(-1)ww and from 53.9 to 401ng g(-1)ww in different tissues of bighead carp and silver carp, respectively. Low molecular weight (LMW) PAHs were the predominant compounds, suggesting the gill-water transfer might be the major exposure route for PAHs in the studied fish species. Tissue distribution indicated that the hepatobiliary system accumulated higher concentrations of PAHs than the extrahepatic tissues with bile being the most predominant tissue for both species. Composition analysis demonstrated that PAHs were from the combined petrogenic and pyrogenic origin, and the gasoline combustion might be the main source. A preliminary evaluation of human health risk using benzo[a]pyrene (BaP) potency equivalent concentration (PEC) as well as the incremental lifetime cancer risk (ILCR) indicated that PAHs in fish would induce potential carcinogenic effects.


Assuntos
Carpas , Monitoramento Ambiental , Contaminação de Alimentos , Lagos/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Animais , Bile/química , China , Brânquias/química , Humanos , Fígado/química , Músculo Esquelético/química , Hidrocarbonetos Policíclicos Aromáticos/química , Medição de Risco , Pele/química
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