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1.
The impacts of fine sediment on riverine fish 总被引：2，自引：0，他引：2
Elevated fine sediment input from terrestrial and aquatic sources as a result of anthropogenic activity is widely recognized to impact negatively on aquatic ecosystems. In rivers, freshwater fish are exposed to a range of impacts resulting from fine sediment pressures. To date, research on the effects of fine sediments on fish has been concentrated within relatively few families, notably the salmonidae. This paper reviews the literature describing indirect and direct impacts of fine sediment on freshwater fish as a contribution towards enhancing the understanding of the impacts of anthropogenic activities on freshwater ecosystems. We identify the causal mechanisms that underpin the observed negative response exhibited by fish populations to enhanced fine sediment loads, and the variability across different fish species. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
2.
Janine Rüegg Courtney M. Currier Dominic T. Chaloner Scott D. Tiegs Gary A. Lamberti 《Aquatic Sciences - Research Across Boundaries》2014,76(4):623-632
Decomposition incorporates organic material delivered by Pacific salmon (Oncorhynchus spp.) into aquatic and terrestrial ecosystems of streams where salmon spawn. We hypothesized that salmon tissue decomposition would be faster, and macroinvertebrate abundance and biomass higher, in terrestrial compared to aquatic habitats, and this would be reflected in the nutritional quality of the tissue. Salmon tissue in coarse-mesh bags was placed in four habitats [terrestrial: riparian (RIP), gravel bars (GRA); aquatic: stream sediment surface (STR), buried in sediments (BUR)] in four southeast Alaska watersheds. After 2 (RIP, GRA) or 4 (STR, BUR) weeks of decomposition, tissue dry mass, macronutrient content, and macroinvertebrate colonizer abundance and biomass were determined. Overall, tissue decomposition was rapid (mean k = 0.088 day?1), while nutritional quality remained high based on elemental ratios (mean C:N = 4.9; C:P = 140; N:P = 30), and differed among habitats (Linear-mixed effects model p < 0.05). Macroinvertebrate assemblages colonizing carcasses were unique to each habitat, although Diptera generally dominated. In terrestrial habitats, the dominant macroinvertebrates were Sphaeroceridae (96 % of invertebrate abundance in RIP habitat) and Calliphoridae larvae (98 % in GRA habitat). In aquatic habitats, the dominant macroinvertebrates were Chironomidae (48 % in STR habitat) and Chloroperlidae (72 % in BUR habitat). Macroinvertebrate colonizer abundance and biomass were higher in RIP (mean 286 individuals and 22 mg g?1) than in other habitats (mean 4 individuals and 3 mg g?1) (Friedman p < 0.05). Rapid decomposition rates and high invertebrate biomass, combined with the high nutritional quality of tissue, suggest rapid incorporation of critical salmon nutrients and energy into both aquatic and terrestrial ecosystems. 相似文献
3.
NANCY B. GRIMM ARTURO CHAC
N CLIFFORD N. DAHM STEVEN W. HOSTETLER OWEN T. LIND PETER L. STARKWEATHER WAYNE W. WURTSBAUGH 《水文研究》1997,11(8):1023-1041
Variability and unpredictability are characteristics of the aquatic ecosystems, hydrological patterns and climate of the largely dryland region that encompasses the Basin and Range, American Southwest and western Mexico. Neither hydrological nor climatological models for the region are sufficiently developed to describe the magnitude or direction of change in response to increased carbon dioxide; thus, an attempt to predict specific responses of aquatic ecosystems is premature. Instead, we focus on the sensitivity of rivers, streams, springs, wetlands, reservoirs, and lakes of the region to potential changes in climate, especially those inducing a change in hydrological patterns such as amount, timing and predictability of stream flow. The major sensitivities of aquatic ecosystems are their permanence and even existence in the face of potential reduced net basin supply of water, stability of geomorphological structure and riparian ecotones with alterations in disturbance regimes, and water quality changes resulting from a modified water balance. In all of these respects, aquatic ecosystems of the region are also sensitive to the extensive modifications imposed by human use of water resources, which underscores the difficulty of separating this type of anthropogenic change from climate change. We advocate a focus in future research on reconstruction and analysis of past climates and associated ecosystem characteristics, long-term studies to discriminate directional change vs. year to year variability (including evidence of aquatic ecosystem responses or sensitivity to extremes), and studies of ecosystems affected by human activity. © 1997 John Wiley & Sons, Ltd. 相似文献
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5.
Assessment of the flow regime alterations in the middle reach of the Yangtze River associated with dam construction: potential ecological implications 
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下载免费PDF全文 Hydrological regimes strongly influence the biotic diversity of river ecosystems by structuring physical habitat within river channels and on floodplains. Modification of hydrological regimes by dam construction can have important consequences for river ecosystems. This study examines the impacts of the construction of two dams, the Gezhouba Dam and the Three Gorges Dam, on the hydrological regime of the Yangtze River in China. Analysis of hydrological change before and after dam construction is investigated by evaluating changes in the medians and ranges of variability of 33 hydrological parameters. Results show that the hydrological impact of the Gezhouba Dam is relatively small, affecting mainly the medians and variability of low flows, the rate of rise, and the number of hydrological reversals. The closure of the Three Gorges Dam has substantially altered the downstream flow regime, affecting the seasonal distribution of flows, the variability of flows, the magnitude of minimum flows, low‐flow pulses, the rate of rise, and hydrological reversals. These changes in flow regime have greatly influenced the aquatic biodiversity and fish community structure within the Yangtze River. In particular, populations of migratory fish have been negatively impacted. The results help to identify the magnitudes of hydrological alteration associated with the construction of dams on this important large river and also provide useful information to guide strategies aimed at restoration of the river's ecosystems. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
6.
杂食性鱼类对浅水水体底栖—浮游生境耦合作用的影响:微综述 总被引：1，自引：0，他引：1
浅水水体存在着强烈的底栖-浮游生境耦合作用,耦合的结果决定着水生态系统关键特征.在缺少大型水生植物的浅水系统中,底栖藻类和浮游藻类对光照和营养盐的竞争是底栖-浮游生境耦合最为重要的生态过程之一,但该过程受到杂食性鱼类的影响.本文以浅水水体的底栖-浮游生境耦合作用为切入点,综述了杂食性鱼类对浅水水体底栖-浮游生境耦合作用的影响过程及机理.一般而言,杂食性鱼类有利于提高水层营养盐浓度,促进浮游藻类生长,降低水体透明度,不利于底栖藻类竞争,从而加速水体富营养化.但不同种类的杂食性鱼类(如底栖杂食性鱼类、偏植物性饵料的杂食性鱼类、偏动物性饵料的杂食性鱼类以及小型杂食性鱼类)因食性差异,对底栖-浮游生境耦合的影响机理不同,产生的生态环境效应各异;即便同一种杂食性鱼类也可因发育阶段不同对底栖-浮游生境耦合产生不同的影响.在人类活动、全球变暖以及富营养化等多重因子胁迫下杂食性鱼类在鱼类群落结构中的比例上升,因此,杂食性鱼类对水生态环境产生的影响深远、复杂,值得持续关注. 相似文献
7.
Waterborne carbon (C) export from terrestrial ecosystems is a potentially important flux for the net catchment C balance and links the biogeochemical C cycling of terrestrial ecosystems to their downstream aquatic ecosystems. We have monitored hydrology and stream chemistry over 3 years in ten nested catchments (0.6–15.1 km2) with variable peatland cover (0%–22%) and groundwater influence in subarctic Sweden. Total waterborne C export, including dissolved and particulate organic carbon (DOC and POC) and dissolved inorganic carbon (DIC), ranged between 2.8 and 7.3 g m–2 year–1, representing ~10%–30% of catchment net ecosystem exchange of CO2. Several characteristics of catchment waterborne C export were affected by interacting effects of peatland cover and groundwater influence, including magnitude and timing, partitioning into DOC, POC, and DIC and chemical composition of the exported DOC. Waterborne C export was greater during the wetter years, equivalent to an average change in export of ~2 g m–2 year–1 per 100 mm of precipitation. Wetter years led to a greater relative increase in DIC export than DOC export due to an inferred relative shift in dominance from shallow organic flow pathways to groundwater sources. Indices of DOC composition (SUVA254 and a250/a365) indicated that DOC aromaticity and average molecular weight increased with catchment peatland cover and decreased with increased groundwater influence. Our results provide examples on how waterborne C export and DOC composition might be affected by climate change. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
8.
放养河蚌,提高水体透明度以促进沉水植物生长,是湖泊生态修复中的常用手段之一.而小型杂食性鱼类鳑鲏依赖河蚌繁殖,河蚌放养可能会促进鳑鲏种群的发展;而鳑鲏与河蚌交互作用对水生态系统的影响仍研究较少.于2018年11 12月通过原位受控实验,设置对照组、河蚌组、鳑鲏组和河蚌+鳑鲏组,研究了鳑鲏(大鳍鱊Acheilognathus macropterus)与河蚌(背角无齿蚌Sinanodonta woodiana)对水质、浮游生物和底栖生物的影响.结果表明:鳑鲏显著增加了上覆水总氮、总磷、悬浮质和叶绿素a(Chl.a)浓度;但并未显著影响无机悬浮质的浓度,说明鳑鲏对沉积物的扰动作用较弱.此外,鳑鲏显著增加了浮游植物生物量和蓝藻的比例.浮游动物总生物量并未受鳑鲏的影响,但显著增加了浮游动物的丰度,其中以轮虫为主.鳑鲏组的底栖动物总丰度(主要为水丝蚓)显著高于对照组,说明鳑鲏对水丝蚓的摄食压力较低.鳑鲏与河蚌交互作用对总磷、Chl.a、浮游植物和浮游动物丰度具有显著影响:具体表现为河蚌虽然抵消了部分鳑鲏对水质(如氮、磷和悬浮质浓度,以及Chl.a浓度和浮游植物生物量等)的负面影响,但其对浮游动物和水丝蚓生物量的影响不显著.在湖泊生态修复和管理中,需要关注和重视鳑鲏等此类小型杂食性鱼类对水生态系统可能产生的负面影响,通过物理(网簖等)或生物(放养肉食性鱼类)等方式将其控制在较低密度水平,从而降低这些鱼类对水质、浮游生物和底栖生物群落可能产生的负面影响,维持生态修复效果的长效与稳定运行. 相似文献
9.
Changsheng Qu Bing Li Haisuo Wu Shui Wang Fengying Li 《Stochastic Environmental Research and Risk Assessment (SERRA)》2016,30(1):271-282
An overall and comparative ecological risk assessment of heavy metals (including Cd, Cr, Cu, Pb, Zn, Hg and As) in surface sediments from China’s eight major aquatic bodies was conducted to better understand their potential risks on a national scale. By applying the joint approach of Hakanson risk index (RI) and Monte Carlo simulation, ecological risk in this work is expressed as probability distribution of RI values instead of single point calculations to reflect the uncertainties in risk assessment process. The results show that the highest ecological risks posed by heavy metals existed in Xiangjiang River and Dianchi Lake. Although only a slim margin of high risk (651.88/600 = 1.08 and 700.61/600 = 1.17) was identified based on average RI values, the probabilities of high risk level derived from Monte Carlo simulation reached as high as 56.7 and 52.9 % in these two aquatic bodies, respectively. And the probability of low risk level was less than 1.6 %. Furthermore, the risk was mainly contributed by Hg and Cd, discharged through local intensive mining and industrial activities. The findings indicate that rigid control and effective management measures to prevent heavy metal pollution are urgently needed in China, especially for the high-risk aquatic bodies. This study shows that the joint approach can be used to identify the high risk water bodies and the major metal pollutants. It may avoid overestimating or underestimating the ecological risk and provide more decision-making support for risk alleviation in the polluted aquatic bodies. 相似文献
10.
Richard K. Johnson David G. Angeler S. Jannicke Moe Daniel Hering 《Aquatic Sciences - Research Across Boundaries》2014,76(1):51-60
Few studies have compared the response of different taxonomic groups to environmental stress across aquatic ecosystems. We regressed assemblage structure of fish, invertebrates, macrophytes, phytoplankton and benthic diatoms to total phosphorus concentration, after removing the effect of ecosystem size (stream order, lake surface area), using data from 66 streams and 45 lakes across Europe. In streams, the structure of benthic diatom assemblages, measured by nonmetric multidimensional scaling, showed the strongest correlation to elevated nutrient concentrations (adj. R2 = 0.495), followed by benthic invertebrates (0.376), fish (0.181) and macrophytes (0.153). For lakes, the patterns were less clear: fish (0.155), macrophytes (0.146) and phytoplankton (0.132). Cross-system comparison showed that stream assemblages were responding more strongly to nutrient concentrations than lake assemblages. Moreover, our results lend some support to the conjecture that response signatures are related to trophic level, with primary producers (benthic diatoms) responding more strongly than consumers (invertebrates, fish). Knowledge of differences in responses among taxonomic groups and between habitats to disturbance can be used to design more cost-effective monitoring programs. 相似文献
11.
了解湖泊生态系统基准环境和历史演变规律是进行湖泊生态环境保护和管理的关键.本文研究江汉湖群32个浅水湖泊现代环境和基准环境下的摇蚊组合特征,分析摇蚊组合变化的趋势和影响因素,并探讨了江汉湖群生态和营养参考值.研究发现Paratanytarsus penicillatus-type、Microchironomus tener-type、Cricotopus sylvestris-type、Polypedilum nubifertype、Dicrotendipes nervosus-type、Procladius等为基准环境下的摇蚊优势种.现代环境中Chironomus plumosus-type、Microchironomus tabarui-type、Procladius、Tanypus、Propsilocerus akamusi-type等富营养种明显增多.摇蚊组合CONISS聚类分析结果表明,32个湖泊主要分为3类,其中21个湖泊(第Ⅰ、Ⅱ类)的摇蚊属种与基准环境相比发生了显著变化,主要原因是流域营养盐输入和水生植被的破坏.本研究介绍了摇蚊古生态研究在重建湖泊基准环境方面的应用,并为湖泊管理和生态修复提供参考数据. 相似文献
12.
1960年以来太湖水生植被演变 总被引：9，自引：5，他引：4
太湖的富营养化污染日益严重,针对太湖水生植被的研究工作非常重要,然而全面的太湖水生植被调查已经有将近二十年未见报道.基于2014年夏季全湖水生植被调查结果,结合历史资料,比较分析1960年以来太湖水生植被演变情况.结果表明,1960年以来,共有23种水生植物从太湖消失,其中1981、1997和2014年分别消失7、4和12种.从分布区面积来看,1960年以来太湖水生植被总体呈北部湖区水生植被消失,东北部、东部及南部湖区水生植被分布区面积持续扩张的态势,1981年全湖水生植被分布区面积占8%,到2014年已经有33.82%的水面有水生植被分布.从生物量组成来看,太湖水生植被先升后降,从1960年的10×104 t,持续上升到1988年的44.72×104 t,1997年下降到36×104 t,2014年进一步下降到29.09×104 t.但挺水植被以外的水生植被,尤其是浮叶植被的生物量一直保持上升态势.总生物量的下降与东太湖挺水植被大面积消失有关,到2014年全湖挺水植被生物量比重仅占5.15%,东太湖沼泽化问题已不复存在.从群落组成变化情况来看,苦草（Vallisneria natans）群落分布区面积锐减,马来眼子菜（Potamogeton malaianus）和荇菜（Nymphoides peltatum）分布区持续扩张.目前太湖水生植被管理面临的主要问题是北部湖区水生植被恢复和东部湖区水生植被过量生长. 相似文献
13.
Rooted aquatic macrophytes affect abiotic conditions in low-gradient rivers by altering channel hydraulics, consuming biologically available nutrients, controlling sediment transport and deposition, and shading the water surface. Due to seasonal macrophyte growth and senescence, the magnitude of these effects may vary temporally. Seasonal changes in aquatic macrophyte biomass, channel roughness and flow velocity, were quantified and trends were related to spatiotemporal patterns in water temperature in a low-gradient, spring-fed river downstream from high-volume, constant-temperature groundwater springs. Between spring and summer, a nearly threefold increase in macrophyte biomass was positively correlated with channel roughness and inversely related to flow velocity. On average, flow velocity declined by 34% during the study period, and channel roughness increased 63% (from 0.064 to 0.104). During the spring and fall period, the location of a minimum water temperature variability “node” migrated upstream more than 4 km, whereas daily maximum water temperature cooled by 2–3°C. Water temperature modelling shows that the longitudinal extent of cold-water habitat was shortened due to increased channel roughness independent of seasonal surface water diversions. These results suggest that macrophyte growth mediates spatiotemporal patterns of water temperature, constraining available cold-water habitat while simultaneously improving its quality. Understanding complex spatial and temporal dynamics between macrophyte growth and water temperature is critical to developing regulatory standards reflective of naturally occurring variability and has important implications for the management and conservation of cold-water biota. 相似文献
14.
We conducted an analysis of heavy metals content, including As, Cd, Cr, Cu, Hg, Pb, and Zn in sediments from aquatic ecosystems in China measured in recent publications. Then, we evaluated the extent of heavy metal pollution in these ecosystems in seven different industrial districts in China (Dongbei, Huabei, Huazhong, Huanan, Huaxik, Xibei, and Huadong) with the potential ecological risk index. We found that Cd was the most concentrated pollutant, followed by Hg and As, while Cr, Cu, Pb, Zn were found in low concentrations in sediments from all types of aquatic ecosystem in China. Sediments collected from all seven industrial districts were heavily polluted, and the sequence, from most to least polluted was Dongbei>Huabei>Huazhong>Huanan>Huaxi>Xibei>Huadong. All four types of aquatic ecosystem were found to be seriously polluted and the sequence, from most to least polluted was: river>sea>lake>wetland. Specifically, Cd and Hg were the most serious pollutants in all four aquatic ecosystems, and As was also a serious pollutant in rivers. For the seven industrial districts studied the sea was the most polluted ecosystem in Dongbei, the river was the most polluted ecosystem in Huabei, Huanan, Huazhong, and the lake was the most polluted in Huadong, Huaxi, and Xibei. 相似文献
15.
K. L. Hondula M. L. Pace J. J. Cole R. D. Batt 《Aquatic Sciences - Research Across Boundaries》2014,76(2):217-229
Large differences in δ 2H of primary producers between aquatic and terrestrial ecosystems are used to identify subsidies, discriminate organic matter sources, and reduce uncertainty in food web studies. Previous investigations of hydrogen isotope ratios suggest there may be predictable differences between the δ 2H of water and organic matter for different types of primary producers. We define the difference in the net isotopic discrimination between water and bulk organic matter (om) as: ΔH = (δ 2Hom ? δ 2Hwater) ÷ (1 + δ 2Hwater ÷ 1,000). We summarized ΔH values from published literature and we measured the δ 2H of water and primary producers in order to compare ΔH among aquatic and terrestrial primary producers. Measurements were made from three water body types (lake, river, coastal lagoon) and their associated watersheds. Although we predicted a large and equivalent net isotopic discrimination for aquatic primary producers, we found considerable variability among groups of aquatic producers. Macroalgae, benthic microalgae, and phytoplankton had more negative ΔH values (i.e. greater isotopic discrimination) than both aquatic macrophytes and terrestrial vegetation. The more positive δ 2Hom and hence lower ΔH of terrestrial vegetation was expected due to relative increases in the heavier isotope, deuterium, during transpiration. However, the more positive values of δ 2Hom and relatively low ΔH in aquatic macrophytes, even submerged species, was unexpected. Marine macroalgae had high variability in δ 2Hom as a group, but low variability within distinct species. Variability among types of primary producers in δ 2Hom and in ΔH should be assessed when hydrogen is used in isotopic studies of food webs. 相似文献
16.
《Marine pollution bulletin》2014,78(1-2):235-245
The major aim of this study was to investigate heavy metal content of edible fish in the PRD. Eleven species of fish (consisting of 711 individuals) [catfish (Clarias fuscus), tilapia (Oreochromis mossambicus), grass carp (Ctenopharyngodon idellus), bighead carp (Aristichthys nobilis), mandarin fish (Siniperca kneri), snakehead (Channa asiatiea), black bass (Micropterus salmoides), mangrove snapper (Lutjanus griseus), star snapper (Lutjanu stellatus), snubnose pompano (Trachinotus blochii) and orange-spotted grouper (Epinephelus coioides)] were collected for the analyses of heavy metals. Overall concentrations (mg/kg, ww) in the fish muscles were: As (0.03–1.53), Pb (0.03–8.62), Cd (0.02–0.06), Ni (0.44–9.75), Zn (15.7–29.5), Cr (0.22–0.65), Cu (0.79–2.26), Mn (0.82–6.91). Significant level of Pb were found in tilapia at all locations. It is recommended that heavy metal concentrations in different fish species must be determined on a regular basis in the future so as to reduce human health risks from acute and chronic food intoxication. 相似文献
17.
热带浅水湖泊后生浮游动物群落结构对生态修复的响应 总被引：5，自引：4，他引：1
热带浅水湖泊后生浮游动物群落以轮虫和小型枝角类为主,往往缺乏大型浮游动物,其影响因子还存在争议,因此通过减少鱼类,提高大型后生浮游动物密度,从而增强对浮游植物的下行控制、修复热带富营养化湖泊的方法受到质疑.暨大南湖位于广州暨南大学校园内,是热带富营养化浅水湖泊,于2014年1—2月实施以鱼类去除和水生植被重建为主的生态系统修复工程,以期改善水质.通过对南湖修复前后水质、后生浮游动物以及修复后鱼类群落的调查分析,研究了后生浮游动物群落对修复的响应.结果表明:与修复前相比,总氮、总磷和叶绿素a浓度显著降低,透明度显著上升.枝角类丰度和生物量显著增加,修复后初期出现较高密度的大型枝角类蚤状溞(Daphnia pulex),桡足类丰度和生物量没有显著变化,轮虫丰度下降而生物量上升;后生浮游动物体长和生物多样性显著增加.随着鱼类密度的增加,蚤状溞丰度快速降低,后期鱼类减少后蚤状溞丰度又有所升高.因此,本研究显示鱼类是控制热带浅水湖泊大型浮游动物种群的主要因素,由于控制鱼类密度以维持较高大型浮游动物密度较为困难,因此单纯生物操纵在热带浅水湖泊修复中难以取得显著效果. 相似文献
18.
Francesc Ordines Gabriel JordàAntoni Quetglas Mar FlexasJoan Moranta Enric Massutí 《Continental Shelf Research》2011,31(17):1835-1844
Linking the abiotic and biotic traits of ecosystems is a critical step towards understanding their structure and functioning. Here we attempt to determine the connections between the hydrodynamics, benthic landscape and the associated fish communities on the coastal continental shelf off the Balearic Islands (western Mediterranean). Specifically we investigate the role the hydrodynamics play in shaping the benthic landscape, and whether the hydrodynamics affect the composition and structure of demersal fish communities. A realistic numerical model was used to establish the hydrodynamic characteristics of the area. The study area showed high hydrodynamic variability on a medium spatial scale (tens of km) in terms of mean water velocity (ū). Principal component analysis was used to determine the main gradients of macro-epibenthic variability. Redundancy analysis (RDA) was used to model the effect of the hydrodynamics on macro-epibenthic species. RDA was also used to model the effect of the hydrodynamics and macro-epibenthos on the abundance of the associated fish fauna, and on its biomass at a community level using biomass spectra classes. The results showed that the hydrodynamics had a significant influence on the distribution of both macro-epibenthic species and the associated fish species. The latter was also influenced by the macro-epibenthos. Fish size appeared to be a key attribute for the distribution of species across gradients of ū and macro-epibenthic change. Our findings can be applied in ecosystem-based fisheries management, as they show that it is necessary to take into account both the biotic and abiotic traits of the habitats when the habitat use and requirements of the associated species are defined. 相似文献
19.
The acceleration of the industrialization process in China has increased the demand for electricity and triggered a power-plant building boom, especially along China’s eastern coast, where the economy gets off early and enjoys a fast development. The thermal plumes, residual chlorine, nuclides and other pollutions produced by the thermal and nuclear power plants have exerted an impact on the coastal eco-environment. To monitor the thermal pollution from the power plants at Yueqing Bay on the eastern coast, in this research, the distribution of sea surface temperature (SST) surrounding the power plants is obtained by using the SST retrieval methods developed for Landsat Enhanced Thematic Mapper Plus (ETM+), HJ-1B infrared sensor (IRS) and Terra moderate resolution imaging spectroradiometer (MODIS) data. The comparison of the SST retrieval results before and after the operation of power plants indicates that the total area of sea waters that is impacted by the thermal discharge from the two power plants at Yueqing Bay is approximately 17.95 km2, with the highest SST rise of 4.5 °C appearing over the waters around the outlet of the Huaneng Yuhuan power plant on the eastern shore, whereas the highest SST rise around the Zheneng Yueqing power plant on the western shore reaches 3.8 °C. The intensity and scope of influence of the thermal discharge mainly depend on the installed capacity of power plants, coastal terrain, and tide. Although the area where the SST rise is more than 3 °C is not large, thermal discharge still has an impact on bay ecosystems due to the relatively closed nature of the bay environment. Due to the influence of rising water temperatures on the reproduction and individual evolution of fish, shrimp, crabs, shellfish and other aquatic creatures, in the long term, the thermal pollution from coastal power plants will affect the volume of natural fishery and biological resources throughout the waters. The quantitative retrieval results also suggest that relative to MODIS data, Landsat ETM+ and HJ-1B IRS data with a high spatial resolution are more applicable to the estimation of small-scale SST, and IRS data with a high temporal resolution are more helpful in the study of spatio-temporal variability of thermal plumes from coastal power plants. 相似文献
20.
Soil denitrification in reservoir shoreline wetlands is an important process for removing excess inorganic nitrogen from upland runoff and controlling eutrophication in aquatic ecosystems. As yet, little is known about the influence of vegetation characteristics on the soil denitrification potential in reservoir shoreline wetlands, although vegetation can affect both denitrifying bacteria and soil properties. In this study, we measured the spatial variability of denitrification enzyme activity (DEA) using acetylene block method in shoreline wetlands of the Danjiangkou Reservoir, a water source of the South‐to‐North Water Transfer Project in China. Results indicated that DEA ranged from 0.001 to 2.449 µg N (N2O) g?1 h?1, with a mean of 0.384 µg N (N2O) g?1 h?1. DEA varied significantly among five representative plant communities and the highest DEA (0.248–2.449 µg N (N2O) g?1 h?1) was observed in the Polygonum hydropiper community. Plant biomass and vegetation cover were significantly and positively related to DEA and together explained 44.2% of the total variance. These results suggest that vegetation characteristics should also be considered in assessing soil denitrification capacity and restoring shoreline wetlands for nitrogen pollution removal in the Danjiangkou Reservoir after dam heightening. 相似文献