三门湾大型底栖动物群落结构及其与环境因子的关系

为了解三门湾大型底栖动物群落的现状和动态变化,分别于2015年11月、2016年2月、5月和8月在三门湾海域用阿氏拖网对大型底栖动物进行调查。结果表明: 经鉴定,大型底栖动物有119种,主要类群为鱼类、甲壳类和软体动物,占种类总数的79%。大型底栖动物全年优势种为细螯虾、长额超刺糠虾和六丝钝尾虾虎鱼,不同季节优势种的变化明显,种类差异性较大。大型底栖动物的年平均生物量和平均栖息密度分别为0.025 g·m^-2和0.07 ind·m^-2。三门湾大型底栖动物各季节的Shannon多样性指数为2.21～3.18,Margalef物种丰富度指数为3.25～3.78,Pielou均匀度指数为0.53～0.79。ABC曲线分析显示,在春季和冬季,群落受到中等程度干扰;而在夏季和秋季,群落受到轻微扰动。典范对应分析结果显示,水深、温度、盐度和pH值是影响大型底栖动物群落的最主要环境因子。     

杭州湾滨海湿地3种草本植物叶片N、P化学计量学的季节变化

动态平衡理论是生态化学计量学的理论基础, 各种有机体是否存在一个固定的化学计量比是生态学研究的热点问题。该文研究了杭州湾滨海湿地3种优势物种海三棱藨草(Scirpus mariqueter)、糙叶薹草(Carex scabrifolia)和芦苇(Phragmites australis)叶片N、P生态化学计量特征的季节变化。结果发现, 3种植物叶片N含量范围分别是7.41-17.12、7.47-13.15和6.03-18.09 mg·g^-1, 平均值(±标准差)分别为(11.69 ± 2.66)、(10.17 ± 1.53)和(11.56 ± 3.19) mg·g^-1; 叶片P范围分别是0.34-2.60、0.41-1.10和0.35-2.04 mg·g^-1, 平均值为(0.93 ± 0.62)、(0.74 ± 0.23)和(0.82 ± 0.53) mg·g^-1; N:P范围分别是7.19-30.63、11.58-16.81和8.62-21.86, 平均值为16.83 ± 8.31、14.53 ± 3.91和16.49 ± 5.51, 可见不同植物其生态化学计量值范围存在一定差异, 但经方差分析发现3种草本植物间生长季节内N、P元素含量差异并不显著(p > 0.05)。各物种叶片N、P含量均表现出在生长初期显著大于其他生长季节(p < 0.05), 生长旺季(6、7月)随着叶片生物量的持续增加, N、P含量逐渐降低并达到最小值, 随后8-9月叶片不再生长而N、P含量逐渐回升, 在10月叶片衰老时N、P含量再次下降; 叶片N:P则在生长初期较小, 在生长旺季先升高后降低, 随后叶片成熟不再生长时又逐渐增加并趋于稳定。     

浙江乐清湾浮游动物空间生态位

基于2016年5月至2017年2月在乐清湾进行的4个航次浮游动物调查数据,计算乐清湾浮游动物优势种的优势度指数(S)、平均拥挤度(X*)、生态位宽度(Bi)及生态位重叠值(Qik).结果表明:乐清湾海域浮游动物优势种(S＞0.02)共17种,生态位宽度值差异较大,优势度指数与生态位宽度值呈极显著正相关.浮游动物的生态位...     

淡水排放对杭州湾湿地浮游动物群落分布的影响

于2010年4月至2011年1月对杭州湾南岸滩涂湿地5个断面(S1-S3为排水区, S4-S5为非排水区)的高潮位和中潮位分别进行浮游动物群落结构的周年调查, 共发现浮游动物38种(轮虫15种, 枝角类4种, 桡足类19种)。排水区浮游动物年平均密度88.89 ind./L, 生物量0.41 mg/L, 非排水区平均密度仅4.21 ind./L, 生物量0.10 mg/L。排水区轮虫和桡足类的第一优势种分别为萼花臂尾轮虫(Brachionus calyciflorus)和汤匙华哲水蚤(Sinocalanus dorrii), 而非排水区第一优势种为中华哲水蚤(Calanus sinicus)。S2-S3断面中潮位的水体营养盐浓度、浮游动物密度和生物量均明显大于高潮位。淡水排放、潮沟径流和潮汐决定了滩涂湿地群落的时空格局, 后两者还解释了排水区中、高潮位间群落结构组成的差异。       

兴化湾浮游动物群落季节变化和水平分布

兴化湾为福建北部最大的海湾,于2006年对该海湾浮游动物群落进行了四季9个站位的调查。共检出浮游动物及幼虫124种,其中春季42种,夏季89种,秋季71种,冬季20种;分属近岸暖温、近岸暖水和广布外海3个生态类群;优势种15种,春季以水母和桡足类占优势,夏季以水母占优势,秋季以水母、桡足类和箭虫占优势,冬季则以桡足类占优势。不同季节兴化湾浮游动物生物量湿重和丰度水平分布特征变化明显,并与温度和盐度呈显著相关。聚类分析显示兴化湾浮游动物群落夏季类群和秋季类群相似度较高;各季节水平分布基本可分为湾口区和湾内区两大类群。与20世纪80年代相比,尽管本次调查浮游动物群落没有表现出显著差异,但随着电厂等大规模工程的投产,兴化湾海域生态系统健康面临着极大威胁,其环境压力需引起持续关注。     

崂山湾人工鱼礁区星康吉鳗摄食生态及食物网结构

根据2015年4月至2017年1月于崂山湾人工鱼礁区地笼网和延绳钓捕获的279尾星康吉鳗样本,从胃含物组成、食性类型、摄食等级、营养生态位和营养级等方面对其摄食生态进行研究,同时结合海区许氏平鲉、大泷六线鱼、斑头鱼、褐菖鲉、花鲈等9种鱼类的胃含物分析结果,构建人工鱼礁区鱼类关键种的简化食物网模型.食性研究结果表明:星康吉鳗共摄食7类30余种饵料,虾类是其最主要的饵料类群,其次为鱼类和头足类,大泷六线鱼、方氏云鳚、鹰爪虾、玉筋鱼和日本鼓虾等是其优势饵料.星康吉鳗的饵料生物组成随肛长和季节发生显著变化.四季均以鱼类和虾类为主,春季胃含物中包括头足类,秋季包括头足类和蟹类,冬季亦有蟹类出现.肛长≤120 mm的星康吉鳗主要摄食鱼卵和鹰爪虾,120~130 mm肛长组主要摄食玉筋鱼和日本鼓虾,肛长>130 mm的星康吉鳗主要摄食大泷六线鱼和方氏云鳚.其摄食强度也随季节和肛长而变化,空胃率的季节性差异显著,平均胃饱满系数的季节性差异不显著,不同肛长组的空胃率和平均胃饱满系数均不存在显著差异.人工鱼礁区简化食物网结构显示:鱼类关键种的营养级均在3级以上,星康吉鳗的营养级为4.636,处于海区食物网的最顶端.虾类、蟹类、端足类和软体动物等是鱼类关键种的主要饵料,甲壳类、方氏云鳚、大泷六线鱼和玉筋鱼是高营养级鱼类花鲈和星康吉鳗的主要饵料.     

Four-million-year-Old hominids from East Lake Turkana,Kenya

A piece of mandible and several isolated teeth are reported from fluviatile sediments older than 4 million years at East Lake Turkana. They most closely resemble hominids from Laetoli, Tanzania and Hadar, Ethiopia which have been assigned to Australopithecus afarensis. © 1994 Wiley-Liss, Inc.     

胍丁胺对大鼠海马 CA1区神经元放电的影响

应用细胞外记录单位放电技术,在大鼠海马脑片上观察了胍丁胺(agmatine,Agm)对CAl区神经元放电的影响。实验结果如下：(1)在47个海马脑片放电单位上灌流Agm(0．1—1．0μmol／L)2min,有38个单位(80．9％)自发放电频率明显降低,且呈剂量依赖性,9个单位(19．1％)无明显的反应;(2)预先用0．2mmol／L的L-谷氨酸(L-glutamate,L-Glu)灌流12个海马脑片放电单位,有9个单位(75％)放电频率明显增加,表现为癫痫样放电,在此基础上灌流Agm(1．0μmol／L)2min,其癫痫样放电被抑制;(3)在7个海马脑片放电单位上给予L型钙通道激动剂Bay K8644(0．1μmoL／L)时,有6个单位(85．7％)放电频率明显增加,另外1个单位(14．3％)无明显变化,再给予Agm(1．0μmol／L)2min,其放电频率被明显抑制;(4)13个CAl放电单位,灌流50μmoL／L一氧化氮合酶(NOS)抑制剂N^G-nitro-L-arginine methyl ester。(L-NAME)5min后其放电频率明显增加,在此基础上再给予Agm(1．0μmol／L)2min,有11个单位(84．6％)的放电频率被抑制,有2个单位(15．4％)的变化不明显。上述结果提示：胍丁胺能抑制海马CAl区神经元自发放电以及由谷氨酸、BayK8644和L-NAME诱发的放电,这一抑制效应可能与胍丁胺阻断CAl区锥体细胞上的NMDA受体,并减少钙离子内流有关。     

Study on coastal wetland habitat quality evaluation in Quanzhou Bay, Fujian, China

Coastal wetland is located in the active interface between land and sea, which is one of the richest biodiversity habitats, while it is seriously disturbed and destroyed by anthropogenic activities in both terrestrial and marine parts. Habitat serves as the basis for organism survival, providing food, shelter, water, space and so on, and habitat degradation and loss caused by intense anthropogenic activities is widely considered as the main reason for biodiversity decline and loss. However, there is still limited study on the evaluating methods of coastal wetland habitats, especially for those in a large scale. In this study, methods for evaluating coastal wetland habitat quality, including selecting indicators, setting value assignment criteria and weights were discussed systematically, a method of coastal wetland habitat quality evaluation was established, and the habitat quality in Quanzhou Bay was also evaluated as a case study. The present study provided a new concept and method to assess quantitatively habitat status, indicate the ecological status and its change, and also reflect and predict indirectly the ecological impact of human activities.
Referring to the habitat evaluation system (HES) developed by United States in the mid 1970s, the evaluation method was established by thorough analysis of the characteristics of coastal wetland. The habitat indicators were selected in terms of three habitat factors as follows: chemical factors, including dissolved oxygen (DO), phosphate in seawater, sulfide in sediment, and regional priority pollutants; physical factors, including landscape naturalness index and coastline artificialization index; biological factors, including invasive species risk and area ratio of invasive alien species. Weights were established by Analytic Hierarchy Process, combined with several-round expert evaluation. Evaluation criteria providing principles for value assignment of each indicator, were established referring to previous standards and related researches. The final result for assessing habitat quality was indicated and stated by the value of Habitat Quality Index (HQI), which is the weighted sum of each indicator. Habitat quality increased with the HQI value, with value ranging from 0 to 100.
The established evaluating method was applied to assess the habitat quality of Quanzhou Bay, located in the southeast coastal zone of Fujian Province, with a total area of 136.4 km², which is an important bay in Fujian. Quanzhou Bay wetland is a typical coastal wetland with diverse wetland habitats, including mangrove, estuary, island, aquaculture ponds, salt pan, shallow sea, mud flat and so on. The Quanzhou Bay is now seriously suffering environmental problems, e.g. eutrophication due to great discharge of domestic, agricultural and industrial wastewater, rapid urbanization and reclamation resulting in decreased wetland area, and the invasion of alien species. The evaluation results showed that the habitat quality index value was 68.13, 57.99 and 51.23 in 1989, 2002 and 2008, respectively, indicating that the habitat degraded gradually. The five major factors that led to decline of HQI value were phosphate in seawater, lead in sediment, landscape naturalness index and coastline artificialization index and area ratio of invasive alien species. Therefore, in order to improve and maintain habitat quality, it is urgent to control pollution, large-scale reclamation and Spartina invasion in Quzhou Bay.