首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
Macrobenthic community in the Xiaoqing River Estuary in Laizhou Bay, China   总被引：1，自引：0，他引：1  
The macrobenthic community of the Xiaoqing River Estuary and the adjacent sea waters was investigated in May and November 2008, August 2009, and May and September 2010, respectively. A total of 95 species of macrobenthos were identified in the five cruises and most of them were polychaetes (46.39%), mollusks (28.86%) and crustaceans (20.62%). The Shannon-Wiener index of macrobenthos was lower than 2 in 67% sites. Along the stream channel, estuary and the coastal waters, the species of polychaetes reduced gradually, while the abundance increased at first and then decreased. The abundance was the biggest at regions with salinity of 5–20 in the estuary. The species and abundance of mollusks and crustaceans increased gradually. As for seasonal distribution, the species, abundance and biomass were higher in spring and lower in summer and autumn. Contemporaneously compared with Laizhou Bay and Yellow River Estuary, the species of macrobenthos appeared in the Xiaoqing River Estuary were much less, while the percentage of polychaetes was higher. Abundance and biomass were higher in Xiaoqing River estuary, then consequently followed by Laizhou Bay and Yellow River Estuary. The dominant species in Xiaoqing River Estuary was polychaete, and Layzhou Bay mollusk. The community structure characteristics of macrobenthos in the Xiaoqing River Estuary revealed a significant pollution status in this region.  相似文献   

2.
The characteristics of seasonal variation in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas were discussed based on field investigation data from 1959 to 2009. The field data from 1981 to 2004 showed that the Chlorophyll-a concentration in surface seawater was between 0.4 and 8.5 ktg dm-3. The seasonal changes generally presented a bimodal trend, with the biomass peaks occurring in May and August, and Chlorophyll-a concentration was the lowest in winter. Seasonal biomass changes were mainly controlled by temperature and nutrient levels. From the end of autumn to the next early spring, phytoplankton biomass was mainly influenced by temperature, and in other seasons, nutrient level （including the nutrient supply from the terrestrial runoffs） was the major influence factor. Field investigation data from 1959 to 2009 demonstrated that dia- toms were the main phytoplankton in this area, and Skeletonerna costatum, Pseudo-nitzschia pungens, Coscinodiscus oculus-iridis, Thalassinoema nitzschioides, Paralia sulcata, Chaetoceros lorenzianus, Chaetoceros curvisetus, and Prorocentrum donghaiense Lu were common dominant species. The seasonal variations in major dominant phytoplankton species presented the following trends： 1） Skeletonema （mainly S. costatum） was dominant throughout the year; and 2） seasonal succession trends were Coscinodiscus （spring） →Chaetoceros （summer and autumn） → Coscinodiscus （winter）. The annual dominance of S. costatum was attributed to its environmental eurytopicity and long standing time in surface waters. The seasonal succession of Coscinodiscus and Chaetoceros was associated with the seasonal variation in water stability and nutrient level in this area. On the other hand, long-term field data also indicated obvious interannual variation of phytoplankton biomass and community structure in the Changjiang River Estuary and adjacent seas： average annual phytoplankton biomass and dinoflagellate proportion both presented inc  相似文献   

3.
闽江口湿地遥感时空演变应用分析   总被引：6，自引：0，他引：6  
将闽江口湿地动态变化度、湿地变化转移矩阵和景观生态学的空间格局模型相结合,横、纵向分析了1986- 1994年、1994-2000年两个时期闽江口湿地的动态演变模式。研究表明,在两个时期不同的社会政策和经济发展阶段,人类活动对闽江口湿地的干扰强度与对象不同,造成两个时期不同的湿地演变模式。在1986-1994年间景观类型动态变化,以水田面积的扩张为主导,在1994-2000年间景观类型动态变化突出表现为城乡建筑用地对水田、非湿地农业的占用。在1986-2000年间,湿地景观中,人工水域破碎度增加,破碎化速度提高,形状更加复杂化;水田破碎度和形状复杂度都由增加向减弱转变;天然水域破碎度减小,形状复杂程度由减少变为增加;滩地破碎度由减少变为增加,形状复杂化由增加转向减少。在中、小时间尺度范围内,人类活动是影响闽江口湿地演变的主要原因之一,特别是近10多年来社会经济的高速发展,城镇化进程的加速,人类活动成为影响闽江口湿地的最主要原因。  相似文献   

4.
广西防城沿海鱼类初步调查有115种,隶属于14目63科91属。软骨鱼类有2目3科4属5种,占总数的4.3％。硬骨鱼类有12目60科87属110种,占总数的95.7％,其中鲈形目鱼类占优势,有68种。暧水性鱼类99种,占总数的86％;暧温性鱼类16种,占总数的14％,无冷温性鱼类。  相似文献   

5.
在动态度、马尔柯夫链等数学方法和景观生态学理论指导下,建立了闽江口湿地时空演变模型,应用组件式技术,利用MapObjects在Visual Basic平台上,进行闽江口湿地时空演变信息系统设计和开发,并应用该信息系统对闽江口湿地时空演变进行实例分析。结果表明,该系统能更高效、直观管理闽江口湿地空间信息和属性信息,以形象化的方式对湿地作全局性时空分析,使得闽江口湿地管理和保护更加科学。  相似文献   

6.
Zooplankton was major indicator species of the environment. To explore the effect of marine environment on zooplankton distribution in the coast of China, the zooplankton samples from stations in Guanhe Estuary(GE), Changjiang(Yangtze River) Estuary(CE), Oujiang Estuary(OE), Jiulongjiang Estuary(JE) and Beilun Estuary(BE)(covering 14 latitudes) in spring were surveyed and the variation of zooplankton ecological group was researched. According to the adaptability temperature, the zooplankton was divided into two ecological groups: warm-temperate species and subtropical species. The warm-temperate species was the main dominant species and subtropical species was only dominant species in BE. Calanus sinicus, a warm-temperate species, was the only dominant species in all five estuaries. From north to south, the proportion of warm-temperate species in the five estuaries gradually decreased depends on the number, were 83.33%, 48.39%, 45.00%, 43.75% and 30.43%, respectively. In contrary, the proportion of subtropical species was gradually increased. The warm-temperate species predominated over the total abundance and the percentage was whopping high in the north estuaries, including GE(96.16%), CE(95.57%), OE(97.83%) and JE(95.53%). The abundance percentage of subtropical species have remarkably higher(82.39%) in BE. Five estuaries zooplankton community was subdivided into three zooplankton groups, which were the northern warm temperate zooplankton group, the southern subtropical zooplankton group and the estuarine brackish-water group. The water temperature and coastal current of China Sea are recognized as the main factors determining the distribution and community structure of estuarine zooplankton in spring.  相似文献   

7.
【目的】研究底拖网作业对珠江口香港海域底层鱼类的影响。【方法】根据2007-2009年及2014-2016年在珠江口香港海域进行的定点底拖网调查数据,分析该海域在禁止底拖网捕捞实施前后鱼类种类组成及生物量和生态多样性指数,评估5种典型底层鱼类资源的变化。【结果与结论】该海域捕获鱼类种类数在禁止底拖网作业后明显增加,鱼类种类数量从44种升至73种。种类丰富度指数D变化范围为:2007至2009年,4.937~5.711,2014至2016年,6.559~7.074;多样性指数H'变化范围为:2007至2009年,1.945~2.841,2014至2016年,2.220~2.381;均匀度指数J变化范围为:2007至2009年,0.539~0.776,2014至2016年,0.557~0.600。卵鳎Solea ovata、韦式羊舌鮃Arnoglossus waitei、尖嘴魟Dasyatis zugei这3种底层鱼类禁止底拖网实施后在数量(number)和生物量(biomass)上都增幅明显。不同站位数量和生物量的数值在“禁拖令”实施后也都有所增加,其中以站位2(大屿山以北,较靠近香港国际机场海域)增加最为显著。  相似文献   

8.
This study on the relationships between dissolved Cd, Cu, Pb and nutrients in the Minjiang River Estuaryduring high and low discharges (in June and Oct., 1990) showed that during both high and lowdischarges Cd, Cu and Pb exhibited additive, conservative and removal behaviour, respectively. Cd increaseappeared to be primarily related to Cd regeneration from microplankton and its organic remains. while Pbremoval was dominated by abiotic processes.  相似文献   

9.
Partial pressure of CO2(pCO2) was investigated in the Changjiang(Yangtze River) Estuary,Hangzhou Bay and their adjacent areas during a cruise in August 2004,China.The data show that pCO2 in surface waters of the studied area was higher than that in the atmosphere with only exception of a patch east of Zhoushan Archipelago.The pCO2 varied from 168 to 2 264 μatm,which fell in the low range compared with those of other estuaries in the world.The calculated sea-air CO2 fluxes decreased offshore and varied from -10.0 to 88.1 mmol m-2 d-1 in average of 24.4 ± 16.5 mmol m-2 d-1.Although the area studied was estimated only 2 × 104 km2,it emitted(5.9 ± 4.0) × 103 tons of carbon to the atmosphere every day.The estuaries and their plumes must be further studied for better understanding the role of coastal seas playing in the global oceanic carbon cycle.  相似文献   

10.
The characteristics of seasonal variation in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas were discussed based on field investigation data from 1959 to 2009. The field data from 1981 to 2004 showed that the Chlorophyll-a concentration in surface seawater was between 0.4 and 8.5 μg dm-3. The seasonal changes generally presented a bimodal trend, with the biomass peaks occurring in May and August, and Chlorophyll-a concentration was the lowest in winter. Seasonal biomass changes were mainly controlled by temperature and nutrient levels. From the end of autumn to the next early spring, phytoplankton biomass was mainly influenced by temperature, and in other seasons, nutrient level(including the nutrient supply from the terrestrial runoffs) was the major influence factor. Field investigation data from 1959 to 2009 demonstrated that diatoms were the main phytoplankton in this area, and Skeletonema costatum, Pseudo-nitzschia pungens, Coscinodiscus oculus-iridis, Thalassinoema nitzschioides, Paralia sulcata, Chaetoceros lorenzianus, Chaetoceros curvisetus, and Prorocentrum donghaiense Lu were common dominant species. The seasonal variations in major dominant phytoplankton species presented the following trends: 1) Skeletonema(mainly S. costatum) was dominant throughout the year; and 2) seasonal succession trends were Coscinodiscus(spring) →Chaetoceros(summer and autumn) → Coscinodiscus(winter). The annual dominance of S. costatum was attributed to its environmental eurytopicity and long standing time in surface waters. The seasonal succession of Coscinodiscus and Chaetoceros was associated with the seasonal variation in water stability and nutrient level in this area. On the other hand, long-term field data also indicated obvious interannual variation of phytoplankton biomass and community structure in the Changjiang River Estuary and adjacent seas: average annual phytoplankton biomass and dinoflagellate proportion both presented increased trends during the 1950 s-2000 s.  相似文献   

11.
There are 3048 species offish occurring in the China Seas (CS), of which at least 2321 species are found in the South China Sea (SCS), belonging to 35 orders, 236 families and 822 genera. The fish species diversity is analyzed in this paper based on biogeography, biostatisties, fishing methods, etc. It is found that the regional environment, especially biological factors, plays an important role in the distribution of faunas, and there are two fish faunas in the SCS, one in the north and another in the center and south. This regional division is of value for sustainable fishery production and efficient management of fishery resources.  相似文献   

12.
In this paper, we assessed the ecological and biodiversity status in the Bohai Sea through a quantitative survey on mac-rofaunal community at 25 stations in Laizhou Bay and adjacent waters in the autumn of 2006.We tested the robustness and effectiveness of taxonomic distinctness as an ecological indictor by analyzing its correlation with species richness and natural environmental variables and by analyzing other ecological indicators (Shannon-Wiener H' and W statistics from Abundance Biomass Comparison curve).Results so obtained indicated that the benthic environment of the study waters in general is not under major impact of anthropogenic disturbance, but some stations in Laizhou Bay and along the coast of the Shandong Peninsula and even in the central Bohai Sea might be moderately disturbed and showed signs of ecological degradation.The taxonomic distinctness measures △+ and Λ+ were independent of sampling effort and natural environment factors and were compliant to other ecological indicators.Further application of the taxonomic distinctness indicator to assess marine biodiversity and ecosystem health on a larger regional scale with historical data seems promising.  相似文献   

13.
We collected fish abundance data in the Changjiang(Yangtze River) estuary and adjacent waters in November 1998,May 1999,November 2000,and May 2001.Using the data,we evaluated the characteristics of the fish assemblages at each site and investigated the effect of several environmental factors.We used a multivariate analysis,including community ordination methods such as detrended correspondence analysis(DCA) and canonical correspondence analysis(CCA),and two-way indicator species analysis(TWINSPAN).We analyz...  相似文献   

14.
Fish assemblage structure in the hypoxic zone in the Changjiang (Yangtze River) estuary and its adjacent waters were analyzed based on data from bottom trawl surveys conducted on the R/V Beidou in June, August and October 2006. Four fish assemblages were identified in each survey using two-way indicator species analysis (TWIA). High fish biomass was found in the northern part, central part and coastal waters of the survey area; in contrast, high fish diversity was found in the southern part of the survey area and the Changjiang estuary outer waters. Therefore, it is difficult to maintain high fishery production when high fish diversity is evenly distributed in the fish community. Fish became smaller and fish size spectra tended to be narrower because of fish species variations and differences in growth characteristics. Fish diversity increased, the age to maturity was reduced and some migrant species were not collected in the surveys. Fish with low economic value, small size, simple age structure and low tropic level were predominant in fish assemblages in the Changjiang estuary and its adjacent waters. The lowest hypoxic value decreased in the Changjiang estuary and its adjacent waters.  相似文献   

15.
报道了越南沿海的双壳纲软体动物 32 0种 ,隶属 3亚纲、6目、2 6总科、4 1科、1 4 8属。从种类的组成中 ,帘蛤科有 5 7种 ,蚶科 32种 ,樱蛤科 2 9种 ,贻贝科 2 5种 ,鸟蛤科 1 6种 ,牡蛎科 1 4种 ,蛤蜊科 1 3种 ,珍珠贝科和扇贝科各 1 2种 ,紫云蛤科 1 1种 ,竹蛏科 1 0种 ,其他各科的种类均在 7种以内。按种的性质而论 ,越南沿海主要是由热带种和亚热带种类组成 ,还有与珊瑚礁紧密联系的热带种。就越南沿海双壳纲软体动物分类区系而论 ,应属印度—西太平洋区的印尼—马来亚区。  相似文献   

16.
【目的】调查了解镇江豚类保护区鱼类资源状况,丰富鱼类资源本底数据。【方法】于2013、2016和2019年,分别开展3次渔业资源调查,对该区域鱼类种类组成、优势种、体型大小及群落多样性进行统计分析。【结果】共记录鱼类68种属于7目13科47属;鲤形目(Cypriniformes)鱼类种类占比较为稳定,鲇形目(Siluriformes)鱼类资源量有下降趋势,鲈形目(Siluriformes)鱼类种类占比上升明显;不同年份优势种替代较为明显;2016年的物种丰富度指数和多样性指数最高,分别为6.528、3.026。【结论】保护区鱼类资源较为丰富,但不同年份鱼类群落变化较为明显,渔业资源面临小型化趋势。  相似文献   

17.
The distinctive estuary hydrodynamics and nutrient input make the estuary ecosystem play a key role in lake ecosystems. The Nanfei River and Zhaohe River are two main inlets of Chaohu Lake, Anhui, East China. We selected estuaries of the two rivers as representative areas to study temporal and spatial changes of bacterial communities. In August (summer) and November (autumn) 2016 and February (winter) and May (spring) 2017, 16 water and sediment samples were collected from the estuaries. Physicochemical characteristics indicate significant differences in the nutritional status and eutrophication index of the estuaries due mainly to organic input. Examination of the number of operational taxonomic units, the diversity index, the community composition, and redundancy analysis revealed the following. First, the existence of varying degrees of seasonal differences in the distribution of almost all bacteria. In addition, the species diversity in the sediment samples was higher than that in the water samples, and the dominant species differed also among these samples. Second, a large number of unknown genera were detected, especially in the sediment samples, such as unclassified Xanthomonadales incertae sedis, unclassified Anaerolineaceae, and unclassified Alcaligenaceae. Last, TP, TN, and TOC were the main influential factors that affected the bacterial community structure.  相似文献   

18.
【目的】研究湛江港海域的游泳动物资源结构及多样性特征。【方法】根据2016—2017年湛江港海域4个季度的底拖网渔业资源调查数据,采用相对重要性指数(index of relative importance,IRI)、Margalef丰富度指数(D)、Shannon-Wiener多样性指数(H')、Pielou均匀度指数(J)和ABC曲线(abundance-biomass comparison curve)分析该海域游泳动物的种类组成、优势种和多样性水平等群落结构特征。【结果】该海域共发现游泳动物173种,隶属于16目68科116属;其中鱼类种类数最多(98种,占总种类数的56.7%),以底层鱼类和暖水性鱼类为主;其次是甲壳类(66种,占38.2%),头足类最少(9种,占5.2%)。4个季节的优势种累计有11种(鱼类6种、甲壳类5种),其中条纹叫姑鱼(Johnius fasciatus)是春、夏、秋3个季节的共同优势种。从时间维度上看,秋季的H'、D均为最高,而春季的J最高;从空间维度上看,湛江港口门处S6站位多样性水平相对较高。ABC曲线结果显示,湛江港海域游泳动物群落在冬季受干扰程度高于其它3个季节。【结论】湛江港海域游泳动物种类丰富,其中鱼类是主要的游泳动物类群。  相似文献   

19.
Seasonal netzplankton samples from stations in the Changjiang (Yangtze River) Estuary were collected from May, 2004 to February, 2005. The dominant species and their contribution to the total zooplankton abundance were determined. Moreover, the relationship between the salinity and abundance was studied with stepwise linear regression. During the whole year, the salinity was positively correlated with the abundance, while the temperature, negatively. Linear regression analysis showed also a high positive correlation with salinity for total abundance in August and November, while in February and May, no obvious relations were found. The most abundant community was composed of neritic and brackish-water species. The North Passage (NP) (salinity <5) was greatly diluted by freshwater while the North Branch (NB) was brackish water with salinity range of 12–28. Consequently, clear decline in abundance of zooplankton was along the estuarine haloclines from the maximum in the area of high salinity to the minimum in the limnetic zone. Total zooplankton abundance and biomass were lower in NP than the NB in all seasons. In short, the salinity influenced the abundance of each species of zooplankton, and ultimately determined the total abundance of zooplankton. Furthermore, a winter peak in the abundance existed, which might be caused by the flourishing of Sinocalanus sinensis, a widely distributed species in the Changjiang Estuary.  相似文献   

20.
The species richness of benthic harpacticoid copepod fauna in Jiaozhou Bay,Qingdao,on the southern coast of Shandong Peninsula,has not been comprehensively studied.We present a preliminary inventory of species for this region based on material found in nine sediment samples collected from 2011to 2012.Our list includes 15 species belonging to 15 genera in 9 families,the most speciose family was the Miraciidae Dana,1846(seven species);all other families were represented by single species only.Sediment characteristics and depth are determined to be important environmental determinants of harpacticoid distribution in this region.We briefl y detail the known distributions of species and provide a key to facilitate their identifi cation.Both harpacticoid species richness and the species/genus ratio in Jiaozhou Bay are lower than in Bohai Gulf and Gwangyang Bay.The poor knowledge of the distribution of benthic harpacticoids,in addition to low sampling ef fort in Jiaozhou Bay,likely contribute to low species richness.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号