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1.
《中国海洋湖沼学报》2021,(4)
With the increase in the need for flood prevention and lake resource used by humans,the construction of floodgates and sluices has changed the hydrological connection between rivers and lakes,and between adj acent lake s.In river-disconnected lake s,exploitation and use of lake re sources have resulted in water quality decline and mechanical disturbance intensification to a different degree.Of the large number of river-disconnected lakes in the middle-lower reaches of the Changjiang(Yangtze) River,the Futou Lake,and the Xiliang Lake lie close together and are,historically,directly connected,and so do Liangzi Lake and Baoan Lake.The extent of human disturbance is severe in the Futou Lake and the Baoan Lake,but relatively mild in the Xiliang Lake and Liangzi Lake.The freshwater rosette-forming submerged plant Vallisneria natans is one of the dominant species in the four lakes.Using microsatellite markers,we studied the genetic variation of V.natans subpopulations in lakes with different intensities of human disturbance and historical direct hydrological connections.Our results showed that human disturbance decreased plant density and clonal growth in V.natans,but might increase genetic and clonal diversity at a subpopulation level and enhance gene flow among subpopulations by sexual propagule movement.Under similar climatic conditions,different intensities of disturbance seem to have such a high selective potential to differentiate genetically adjacent lake populations that they outperform the forces of gene flow through historical direct hydrological interconnection,which tends to produce genetic homogeneity.Our findings imply that human disturbance has a profound effect on the evolutionary process of natural populations of submerged plants.Moreover,increased subpopulation genetic diversity can enhance resistance and resilience to environmental disturbances.To a certain degree,we could expect that disturbed populations have the possibility of re storing spontaneously if humans cease to perturb natural ecosystems in the future. 相似文献
2.
Phytoplanktonic desmids community in Donghu Lake, Wuhan,China 总被引：1，自引：0，他引：1
1 INTRODUCTION Donghu Lake (30o33′N, 114o23′E) is a shallow medium sized freshwater lake in Wuhan City, Hubei Province, China and about 5 kilometers away from the Changjiang (Yangtze) River. Before the 1960s, the water surface area was about 27.8 km2. The lake water was clear and the pH ranged from 6 to 7. The shallow area of the lake abounded with macrophytes. The phytoplanktonic and peripheral desmids were very abundant also in this lake. In the late 1960s, Donghu Lake with tota… 相似文献
3.
《中国海洋湖沼学报》2017,(2)
Freshwater shallow lakes typically exhibit two alternative stable states under certain nutrient loadings:macrophyte-dominated and phytoplankton-dominated water regimes.An ecosystem regime shift from macrophytes to phytoplankton blooming typically reduces the number of species of invertebrates and fishes and results in the homogenization of communities in freshwater lakes.We investigated how microbial biodiversity has responded to a shift of the ecosystem regime in Dianchi Lake,which was previously fully covered with submerged macrophytes but currently harbors both ecological states.We observed marked divergence in the diversity and community composition of bacterioplankton between the two regimes.Although species richness,estimated as the number of operational taxonomic units and phylogenetic diversity(PD),was higher in the phytoplankton dominated ecosystem after this shift,the dissimilarity of bacterioplankton community across space decreased.This decrease in beta diversity was accompanied by loss of planktonic bacteria unique to the macrophyte-dominated ecosystem.Mantel tests between bacterioplankton community distances and Euclidian distance of environmental parameters indicated that this reduced bacterial community differentiation primarily reflected the loss of environmental niches,particularly in the macrophyte regime.The loss of this small-scale heterogeneity in bacterial communities should be considered when assessing long-term biodiversity changes in response to ecosystem regime conversions in freshwater lakes. 相似文献
4.
We conducted acoustical surveys with a horizontal beam transducer to detect fish and with a vertical beam transducer to detect depth and macrophytes in two typical shallow lakes along the middle and lower reaches of the Changjiang(Yangtze) River in November 2013. Both lakes are subject to active fish management with annual stocking and removal of large fish. The purpose of the study was to compare hydroacoustic horizontal beam estimates with fish landings. The preliminary results show that the fish distribution patterns dif fered in the two lakes and were af fected by water depth and macrophyte coverage. The hydroacoustically estimated fish biomass matched the commercial catch very well in Niushan Lake, but it was two times higher in Kuilei Lake. However, acoustic estimates included all fish, whereas the catch included only fish 45 cm(smaller ones were released). We were unable to determine the proper regression between acoustic target strength and fish length for the dominant fish species in the two lakes. 相似文献
5.
The Yellow Sea Cold Water Mass(YSCWM) is a distinct hydrographic phenomenon of the Yellow Sea,and the distribution pattern of meio-and macrobentho s diffe rs inside and outside of the YSCWM.However,such a pattern has never been observed in the microbenthic ciliate communities.Therefore,we hypothesized that benthic ciliates followed a similar distribution pattern as meio-and macrobentho s,but this pattern has not been uncovered by morphological methods.We evaluated the diversity and distribution of benthic ciliates at five stations along hydrographic gradients across the YSCWM and adj acent shallow water by using morphology and DNA and complementary DNA(cDNA) high-throughput sequencing of the V4 region of 18 S rRNA gene.Results showed that the diversity of benthic ciliate s detected by DNA(303 OTU s),and the cDNA(611 OTUs) sequencing was much higher than that detected by the morphological method(79 species).Morphological method detected roughly different ciliate communities inside and outside of the YSCWM,but without statistical significance.No clear pattern was obtained by DNA sequencing.In contrast,cDNA sequencing revealed a distinct distribution pattern of benthic ciliate communities like meioand macrobenthos,which coincided well with the results of the environmental parameter analysis.More than half of the total sequences detected by DNA sequencing belonged to planktonic ciliates,most(if not all) of which were recovered from historic DNA originating through the sedimentation of pelagic forms because none of them were observed morphologically.The irrelevant historic DNA greatly influenced the recovery of rare species and thus limited the understanding of the benthic ciliate diversity and distribution.Our research indicates that the methods used have significant effects on the investigation of benthic ciliate communities and highlights that cDNA sequencing has great advantages in estimating the diversity and distribution of benthic ciliates,as well as the potential for benthic environmental assessments. 相似文献
6.
mooUonONEutrophicationhasdri,andwillperhapsbethemostwidespreadtypeofenviron-rnentalpollutionofwaterbodis.MostUrbanorsuburbanshallowwaterbodishaveex-perientaladetalrnan-causedeutrophhationinevitablyresultinginovergroWthofphytoplanktonandotherdramaticlakeeresySteInchangessuchasthedeCineofmacrophytes.TheensuingdeteriorationofwaterqualitycaedseriousenvirorunentalanderenoAncprobbo,bousemostoftheselakes,asidefrombeingwatefbodiesforlargescalecoInmendalfisheryusuallysupplywaterforindustryandagrict… 相似文献
7.
Rotifer community structure was investigated in Yangcheng Lake in 2008. Dominant species and species diversity indices were determined and QB/T was used to assess water quality. The annual average density and biomass of the rotifers in Yangcheng Lake was 2 894 ± 1 006 ind./L and 12.47 ± 10.28 mg/L, respectively. The highest densities were observed in the western portion of the lake in March, but the highest biomass occurred in inflowing creeks in September. Within a year of monitoring in Yangcheng Lake, 93 species were identified and the dominant species were found to be Polyarthra trigla, Brachionus angularis, Keratella cochlearis, Keratella valga, Brachionus calyciflorus, and Filinia major. Of the species recorded, 75 were pollution indicator species. Density and biomass exhibited significant positive correlations with water temperature (R = 0.209, P = 0.003; R = 0.446, P = 0.000), but the peak density showed two lags in response to chl a. According to the Jaccard similarity index (SJ), the greatest similarity among dominant species occurred between creeks and the eastern part of the lake. The annual average Shannon-Wiener diversity index H’, Margalef richness index D and Pielou evenness index J were 1.96 ± 0.34, 1.61 ± 0.50 and 0.77 ± 0.10, respectively. In all four areas of Yangcheng Lake, β- mesosaprobic species comprised the largest share of pollution indicator species. These data suggest that Yangcheng Lake is mesosaprobic. 相似文献
8.
Using multi-mesh gillnets and trawls, the fish communities in Dianshan Lake at 6 stations from Oct. 2009 to Jul. 2010 were investigated seasonally to reveal the biodiversity and its spatial and temporal distribution patterns. The long-term changes in their structural characteristics were then analyzed to identify the main infl uencing factors and several measures for lake restoration were put forward. Thirty six species, belonging to 9 family and 30 genera, were collected, amongst which, the order Cypriniformes accounted for 61.1% of the total species number. In terms of importance value, Cypriniformes was the predominant group, Coilia nasus the dominant species, while Cyprinus carpio and Rhinogobius giurinus were the subdominant taxa. The community types did not differ among stations, but between seasons. There were no significant differences between seasons and among stations in species diversity, but richness differed both spatially and seasonally. Along with the process of eutrophication and the drastic reduction of the area colonized by macrophytes from 1959 to 2009–2010, the fish diversity declined markedly, and species numbers of herbivores and piscivores declined proportionately more than those of invertivores, omnivores, and planktivores. The decline of potamophilus and river-lake migratory fish was more marked than those of sedentary, river-sea migratory, and estuarine fishes. Eutrophication concomitant with sharp reduction of macrophyte area and overfishing may be the main reasons for the decline in fish diversity in Dianshan Lake. 相似文献
9.
Antioxidant systems are vital in life activities of macrophytes. Species with dif ferent life forms need to cope with distinct environments by modifying physiological characters, especially antioxidant systems. In order to find dif ferences among life forms and consequence of lake eutrophication, we studied three antioxidant enzymes activity(superoxide dismutase(SOD), ascorbate oxidase(APX) and catalase(CAT)) and total soluble phenolics(TP) content in leaves of 26 macrophyte species in September 2013 in Lake Erhai, China. We found that antioxidation varied accordingly with life forms. The activities of SOD and APX in emergent macrophytes(EM) and floating-leaved macrophytes(FM) were much lower than those of submerged macrophytes(SM). On the contrary, TP content was much higher in EM and FM species. There was a negative correlation between TP and antioxidant enzyme activities(CAT and APX).The results suggested that EM and FM species rely on phenolics might to adapt to adverse environments(higher herbivores predation pressure and UV radiation intensity), while SM species more rely on antioxidant enzymes possibly due to lower demand for antioxidation and/or lack of light and inorganic C availability for phenolics synthesis. We also found FM species represent highest fitness in term of antioxidant system,which would lead to overgrowth of FM species and littoral zone bogginess during lake eutrophication.Finally, it is necessary to carry out the verification experiment under the control condition in the later stage,especially for the dominant ones in eutrophic lakes, to understand the exact adaptive mechanisms of them. 相似文献
10.
Epiphytic bacterial communities on two common submerged macrophytes in Taihu Lake: diversity and host-specificity 总被引：1，自引：0，他引：1
Leaves of terrestrial and aquatic plants are home to a wide diversity of bacterial species. However, the diversity and variability of epiphytic bacteria on their submerged plant hosts remains poorly understood. We investigated the diversity and composition of epiphytic bacteria from two common submerged macrophytes: Vallisneria natans and Hydrilla verticillata in Taihu Lake, Jiangsu, China, using methods of terminal restriction fragment length polymorphisms (T-RFLP) and clone library analyses targeted at bacterial 16S rRNA genes. The results show that: (1) the libraries of the two waterweeds contain wide phylogenetic distribution of bacteria, and that the sequences of the two libraries can be separated into 93 OTUs (at 97% similar value); (2) Betaproteobacteria, including Burkholderiales, was the most abundant bacterial group on both plants. Cyanobacteria and Gammaproteobacteria were the second largest groups on V. natans and H. verticillata, respectively. Both clone libraries included some sequences related to those of methanotrophs and nitrogen-fixing bacteria; (3) Cluster analysis of the T-RFLP profiles showed two distinct clusters corresponding to the two plant populations. Both ANOSIM of the T-RFLP data and Libshuff analysis of the two clone libraries indicated a significant difference in epiphytic bacterial communities between the two plants. Therefore, the epiphytic bacterial communities on submerged macrophytes appear to be diverse and host-specific, which may aid in understanding the ecological functions of submerged macrophytes in general. 相似文献
11.
研究雷州半岛自然生活条件、养殖条件下的野生贝和全人工养殖条件下的养殖贝主要污损及寄居生物。结果表明:大珠母贝主要污损及寄居生物共46种,其中自然生活条件下野生贝的污损及寄居生物有24种,养殖条件下野生贝的污损与寄居生物42种,养殖贝的污损及寄居生物有31种;根据附着或寄居部位可将大珠母贝污损及寄居生物可分为4种类型:贝壳表面附生型、贝壳层寄居型、贝壳内侧寄居型、外套腔寄居型;海绵、缨鳃虫、龙介沙蚕、长鳃树蛰虫为贝壳表面附生型主要种类,砗磲江珧虾为外套腔寄居型种类,对大珠母贝危害较小;石蛏、开腹蛤、厥目革囊星虫、有盾海扇虫、才女虫、钻穿裂虫为贝壳层寄居型的主要种类;吻蛇稚虫为贝壳内侧寄居型,对大珠母贝危害较大。自然生活条件下野生贝主要危害种类为石蛏、开腹蛤、厥目革囊星虫、才女虫、钻穿裂虫,养殖条件下野生贝主要危害种类有石蛏、开腹蛤、厥目革囊星虫、有盾海扇虫、吻蛇稚虫、才女虫、钻穿裂虫;养殖贝受寄居生物危害较小。 相似文献
12.
The ciliate community in the Bohai Sea (China) was studied from 23 September to 7 October 1998. A hurricane struck the study area between the two grid station investigations, which were six days apart. Six tintinnid species ( Favella panamensis, Leptotintinnus nordqvisti, Tintinnopsis but-schlii, T. karajacensis , T. Radix and Wangiella dicollaria ) were identified. Total cililate abundance in the surface layer ranged from 20 to 770 ind/l. In the first grid investigation, Tintinnopsis karajacensis dominated in the warm, low salinity waters at the Huanghe River mouth. Aloricate ciliate sp. 1 dominated in the cold, high salinity waters in the northwest of the study area and the Bohai Strait. In the second grid investigation, T. Karajacensis almost disappeared. The abundance of aloricate ciliate sp. 1 decreased drastically. The aloricate ciliate sp. 2 dominated at the Bohai Strait. The change of ciliate abundance may be due to the disturbance of hurricane. 相似文献
13.
Freshwater mussels are a major component of the zoobenthos and they therefore play an important role in freshwater ecosystems. The community composition and the standing crop of freshwater mussels in Poyang Lake, the largest freshwater lake in China and one of two lakes connected to the Changjiang (Yangtze) River, were investigated from February 2008 to May 2009. Mussels were sampled in hydrologically and geographically distinct sampling areas. A total of 42 species and 13 genera were identified, of which 32 species were endemic to China. Two species, Unio douglasiae and Lamprotula caveata, dominated all sampling areas. The number of genera and species, and the number of species within each genus, differed significantly among sampling areas. Freshwater mussels were very abundant, with an overall density of 0.28 ± 0.22 ind./m2 and biomass of 4.08 ± 3.96 g/m2. Significant variation observed among sampling areas and among genera was probably due to the variety of habitats among the areas sampled and to the adaptability of different freshwater mussels to environments. This study suggests that Poyang Lake and other freshwater lakes in the region are important sites of freshwater mussel biodiversity and conservation. 相似文献
14.
We assessed the potential of marine ciliate community as an indicator to coastal water quality using water samples collected from four stations in the Yellow Sea in the summer 2000. The four stations were characterized by different levels of pollution. The ciliate communities consisted primarily of tintinnids and aloricate ciliates that were <30 μm. A total of 78 species were classified: 55 species at Station 2, 51 species each at Stations 1 and 4, and 47 species at Station 3. The mean number of species at each site was 29.2±2.0 (Station 1), 28.5±2.9 (Station 2), 27.8±1.7 (Station 3), and 24.5±2.3 (Station 4). The abundance was highly variable: 19 331±11 187 ind./L at Station 1, 7 960±5 639 ind./L at Station 2, 29 015±12 999 ind./L at Station 3, and 8 190±4 658 ind./L at Station 4. Our results suggest that neither the simple chemical analysis (e.g. chemical oxygen demand, dissolved inorganic nitrogen, and phosphate) nor the eutrophication/pollution index adequately described the water quality at the four stations. The same was true of the number of species and their abundance, both of which had no correlation with the chemical indices. In contrast, Margalef’s diversity index values (3.12 at Station 2, 2.89 at Station 1, and 2.64 at Stations 3 and 4) generally discriminated the water quality status of the four stations. The difference in water quality among the stations was strongly supported by the pattern of species richness (i.e. the total number of species) of ciliates at each station. Our evaluation was consistent with the results of long-term water quality monitoring at the four stations. With increasing eutrophication, we observed also a compositional and functional shift in the ciliate assemblages from algivorous oligotrich/choreotrich to nonselective-omnivorous gymnostomatids to bacterivorous-detrivorous scuticociliatids. Thus, ciliates may be used to indicate the coastal water quality status of a given site. 相似文献
15.
基于长时间序列MODIS数据的鄱阳湖湖面面积变化分析 总被引：1，自引：0，他引：1
湖泊是气候、水和生物地球化学循环的关键组分,遥感观测有助于获得湖泊面积变化及对环境的响应信息。本文基于长时间序列遥感观测提出了一种利用像元水淹没/陆地出露比例的湖面变化分析算法,并应用于鄱阳湖的湖面提取及变化分析。首先,用全年遥感数据合成获得当年最大湖面;然后,在此最大湖面范围内,识别出每景数据的水体和陆地状态;最后,统计一定时期内每个像元的水淹没比例,并据此分析湖泊的年际和季节变化特征。该算法的最大优势是克服了云的干扰,以及湖面快速变化造成的年际变化对比分析困难问题。算法应用于2000-2010年MODIS观测,分析结果表明,本算法检测出的湖面面积与鄱阳湖水文站水位观测资料非常一致;算法可以获得鄱阳湖湖面面积的显著季节变化信息;2000-2010年间,鄱阳湖湖面面积在丰水期未发现有规律的变化;在枯水期,2003年后湖面面积急剧减小。 相似文献
16.
The ultrastructure of extrusomes of the hypotrichous ciliate Pseudourostyla nova was observed in scanning and transmission electron microscopy and enzyme-cytochemistry. The results show that the distribution, morphological characteristics, morphogenesis process, and extrusive process of the extrusomes in P. nova are different from the trichocysts in Paramecium, suggesting that the extrusomes of P. nova can respond to environmental stimuli, play an important role in the defense of this species, and cannot be regarded as "trichocysts". The results also suggest that the extrusomes might be originated from the Golgi apparatus and mature in the cytoplasm; after the extrusion of mature extrusomes, the residual substance might be reabsorbed and reused by the ciliate cell via food vacuoles, and take part in material recycling of the cell. 相似文献
17.
Water quality, nutrient budget, and pollutant loads in Chinese mitten crab (Eriocheir sinensis) farms around East Taihu Lake 总被引：2，自引：0，他引：2
To understand the factors causing frequent outbreaks of harmful algae blooms in the Taihu Lake, China, we studied water quality and nutrient budget in Chinese mitten crab (Eriocheir sinensis) farm ponds in the eastern part of the lake from November 2007 to December 2009. We estimated the nitrogen (N), phosphorus (P), and chemical oxygen demand (COD) loads. Materials input and output ponds, water exchange, and applied management practices of 838.5-hm2 crab ponds were surveyed using questionnaires. Water quality of 12 ponds, which were located no more than 2 km from East Taihu Lake, were monitored. The results show that water quality in the crab ponds was better than reference data. Feeds, including corn seed, commercial feed, trash fish, and gastropod, were the major sources of N and P input in the crab ponds, contributing 88.7% and 94.9%, respectively. In total, 60.5% of N and 37.3% of P were sequestered by macrophytes, and only 15.7% and 8.5% of them were discharged as effluent. The net loads of N and P in effluent were 16.43 kg/hm2/cycle and 2.16 kg/hm2/cycle, respectively, while the COD load was -17.88 kg/hm2/cycle. This indicated that crab farming caused minor negative impact on the trophic status of the lake area, which was attenuated by macrophytes. However, wastewater purification is still necessary in crab faming. 相似文献
18.
Ecological studies on macrozoobenthos were conducted in two small plateau lakes in the Yunnan-Guizhou Plateau, Southwest China： Xingyun Lake （XL）, a eutrophic lake whose main source of primary production was phytoplankton （Chl α=99.76±24.01 μg/L）, and Yangzong Lake （YL）, a mesotrophic lake. Sampling was carried out from October 2002 to May 2004. Altogether 23 benthic taxa were identified in XL and 21 taxa in YL. The density of benthos in XL was much lower than that in YL, but the biomass was about equal in the two lakes, being I 423 ind/m^2 and 8.71 g/m^2 in XL and 4 249 ind/m^2 and 8.60 g/m^2 in YL. The dominant species were Limnodrilus hoffmeisteri, Branchiura sowerbyi, Aulodrilus pluriseta and Chironomus sp. in XL and Limnodrilus hoffrneisteri, Aulodrilus pluriseta and Bellamya sp. in YL. Seasonal fluctuation occurred, showing richer species in summer and winter, but the density and biomass varied in different ways in the two lakes. Analyses on functional feeding groups indicate that collector-gatherers were predominant, but the relative abundances of other groups were different. Stepwise multiple regression analysis demonstrated that the water depth, conductivity and chlorophyll a were the key factors affecting macrozoobenthic abundance in the lakes. 相似文献
19.
By using field survey data from the sixth forest inventory of Jiangxi Province in 2003, the biomass and carbon storage for three studied species （Pinus massoniana, Cunninghamia lanceolata, and Pinus elliottii） were estimated in Taihe and Xingguo counties of Boyang Lake Basin, Jiangxi Province, China. The relationship between carbon density and forest age was analyzed by logistic equations. Spatio-temporal dynamics of forest biomass and carbon storage in 1985-2003 were also described. The results show that total stand area of the three forest species was 3.10 × 10^5 ha, total biomass 22.20 Tg, vegetation carbon storage 13.07 Tg C, and average carbon density 42.36 Mg C/ha in the study area in 2003. Carbon storage by forest type in descending order was： P. massoniana, C. lanceolata and P. elliottii. Carbon storage by forest age group in descending order was： middle stand, young stand, near-mature stand and mature stand. Carbon storage by plantation forests was 1.89 times higher than that by natural forests. Carbon density of the three species increased 8.58 Mg C/ha during the study period. The carbon density of Taihe County was higher in the east and west, and lower in the middle. The carbon density of Xingguo County was higher in the northeast and lower in the middle. In general, the carbon density increased with altitude and gradient. Afforestation projects contribute significantly to increasing stand area and carbon storage. Appropriate forest management may improve the carbon sequestration capacity of forest ecosystems. 相似文献
20.
《中国海洋湖沼学报》2018,(6)
In order to identify the effects of seasonal variation on the migration and transformation of antimony species at the sediment-water interface of the Poyang Lake, the largest fresh lake in China, a simulation study was carried out in the laboratory. Antimony species including antimonite Sb(III), antimonate Sb(V) and the fraction of organic forms(Sb-org) in overlying water at different temperatures were regularly measured during the simulation period. Different bound antimony forms in sediments were also determined along with the different antimony species in porewaters after the simulation terminated. The results indicated that temperature change during seasonal alternation plays an important role in the migration and transformation behavior of antimony at the sediment-water interface of the Poyang Lake. Antimony species both in porewaters and overlying water were sensitive to the variation of temperature, especially the Sb-org species. Antimony migrates from porewaters to the overlying water when the temperature decreases, and meanwhile the equilibrium between Sb(III) and Sb(V) in porewaters shifts toward Sb(V) when the temperature increases during seasonal alternation. Although temperature had less influence on the antimony species in sediments than in porewaters or in the overlying water, the average content of each antimony species in sediments increased with the decrease of temperature, suggesting that the decrease of temperature causes enrichment of antimony in the sediment. 相似文献