The relation between distribution of zooplankton and salinity in the Changjiang Estuary

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.     

Meso-scale spatial distribution of large tintinnids in early summer in southern Yellow Sea

The spatial distribution of some large tintinnid species （nominally〉76 μm） was investigated according to samples collected by vertical towing in cruises to the southern Yellow Sea in summer 2000-2002 and 2004. Eight species were identified： Codonellopsis mobilis, Leprotintinnus netritus, Tintinnopsis karajacensis, T. japonica, T. kiaochowensis, T. butschlii, T. radix, and Parafavella sp. With maximum abundance of 158.2 ind/L in June 2004, C. mobilis was the dominant species, lasting from May to July 2004. Tintinnid communities were patchy and distributed mainly in shallow waters along the shore.     

2007年夏季南海北部浮游植物的物种组成及丰度分布

2007年8月10-29日对南海北部41个站位进行了浮游植物群落结构的调查.调查结果表明,共发现浮游植物5门80属216种(包括变种、变形、未定种),调查期间南海浮游植物以硅藻为主,占所有物种数的64.81%,占总浮游植物细胞丰度的89.11%:甲藻次之,占所有物种数的30.56%,占总浮游植物细胞丰度的10.62%;蓝藻门的红海束毛藻Trichodesmium erythraeum在许多站位也占有相当的比例.绿藻和一些淡水的蓝藻只在珠江口附近的站位才被检出.主要优势种为海链藻Thalassiosira sp.、菱形海线藻Thalassionema nitzschioides、中肋骨条藻Skeletonema costatum、微小原甲藻Prorocentrum minimum和裸甲藻Gymnodinium sp..从平面分布来看,南海北部在珠江口外围和台湾浅滩海域存在2个浮游植物丰度高值区.表层和次表层浮游植物的平面分布格局差异很大,表层浮游植物的丰度平均为25.21×10<'3>个·L<'-1>,高值区在珠江口附近海域;次表层浮游植物丰度平均为9×10<'3>个·L<'-1>,高值区在台湾浅滩海域.调查区域的浅水站位(<200m)的浮游植物丰度远高于深水站位(>200m).从垂直分布来看,浮游植物的细胞丰度基本上自上而下随水深的增加而逐渐降低,最大丰度在10m水层.深水站位与浅水站位的浮游植物垂直分布结构有很大的差异.硅藻类在浅水站位中基本随深度的增加而减少,但在10m处出现最大值;而在深水站位则存在次表层(75m)最大值的现象.甲藻类在浅水站位中随深度增加显著减少,而在深水站位的75m以上其分布比较均匀.越靠近外海,浮游植物中硅藻所占的比例越小,硅甲藻比率大的海区一般具有高的生产力和较高的浮游植物丰度.调查海区表层和次表层的浮游植物Shannon-Wiener指数的平均分别为2.8和3.0,生物多样性高的区域分别位于珠江口、粤东近海和海南的东部近海,浅水站位的浮游植物多样性指数远高于深水站位.     

三疣梭子蟹乳化病血液生化指标诊断技术的研究

对患乳化病的三疣梭子蟹进行了血液生化指标检测．结果表明：与健康三疣梭子蟹相比，病蟹肌酐、总胆固醇、Na^＋、Cl^-、Mg^2＋、Ca^2＋等含量明显上升，而血糖、总蛋白、白蛋白、谷丙转氨酶、谷草转氨酶、乳酸脱氢酶、碱性磷酸酶等含量却显著下降．通过感染试验的追踪检测，并与对照组相比，感染后24h含量发生明显变化的血液生化指标为血糖、总胆固醇、总蛋白、谷草转氨酶和Mg^2＋，此5种指标可作为三疣梭子蟹乳化病早期诊断的参考指标．     

胶州湾北部软底大型底栖动物 丰度和生物量的研究

1995年3～11月对胶州湾北部软底海域进行了 两月一次的大型底栖动物调查。调查期间,大型底栖动物总平均丰度和总平均生物量分别为 1891.3 inds./m2和41.9 g.w.w/m2。与该海域有关大型底栖动物丰度和生物量的历史 资料相比较,本研究所得到的大型底栖动物丰度值显著增加,生物量值则有较明显的下降, 初步分析了发生这些变化主要原因。丰度和生物量比较曲线表明,所研究海域底栖生物群落 处于中等干扰(即污染的影响 )状态。     

2004～2010年夏季杭州湾鱼类浮游生物种类组成与数量分布

2004～2010年夏季（8月）,在杭州湾设置12～15个采样点,采集鱼类浮游生物样本共93网次.经鉴定分析,共得鱼卵233粒,仔稚鱼29 825尾,仔稚鱼分别隶属8目17科26属34种,其中凤鲚（Coilia mystus）为优势种,数量占总量的91.5%,历年优势度在80.0%～99.1%之间.各年比例较高的种类还有弹涂鱼属一种（Periophthalmus sp.1）、鮻（Liza haematocheila）、鲻鱼（Mugil cephalus）、中颌棱鳀（Thrissa mystax）、康氏小公鱼（Anchoviella commersonii）、棘头梅童鱼（Collichthys lucidus）和七星底灯鱼（Benthosema pterotum）等.滩浒山附近和杭州湾内湾南部海域鱼类浮游生物密度较高,是杭州湾内凤鲚仔稚鱼活动的主要区域.生态类型主要包括半咸水型种类、沿岸型种类和近岸型种类.对鱼类浮游生物密度与主要环境因子进行逐步回归分析,结果显示,鱼类浮游生物密度的自然对数与水体透明度、盐度和水温的相关性显著（p〈0.05）,其中与水体透明度的相关系数最大.     

厌氧氨氧化细菌物种组成对环境因子响应的研究进展

分析海洋水体及沉积物中厌氧氨氧化细菌所处的环境条件,比较海洋与淡水环境中其物种组成的差异,总结了其物种组成、丰度及厌氧氨氧化活性对环境因子的响应规律。认为厌氧氨氧化细菌物种组成受多种环境因子的影响。其中,盐度为影响其物种组成的最显著因素,如Candidatus Brocadia,Candidatus Kuenenia及Candidatus Scalindua分别适应淡水、寡盐和海水环境;同一地区,其物种组成在不同季节表现出明显差异,夏季的多样性高于冬季的;根据陆源厌氧氨氧化细菌多样性及海洋沉积物中浮霉菌门多样性随深度增加而减小的趋势,推断海洋沉积物中厌氧氨氧化细菌多样性与深度成反比。厌氧氨氧化细菌丰度、厌氧氨氧化活性与温度、NO-2及NO-3浓度之间成正相关;丰度与季节的关系,在不同地区的研究结果存在差异。未来厌氧氨氧化细菌研究工作重点应在其对氧浓度的耐受范围、海洋中厌氧氨氧化细菌多样性随深度的变化规律、导致其物种组成、丰度及厌氧氨氧化活性季节性差异的具体环境因子。     

南海北部微微型光合浮游生物的丰度及环境调控

1999年夏季首次在南海北部海域进行了微微型光合浮游生物(photosynthetic picoplankton)的观测研究,发现了聚球藻(Synechococcus,Syn)、原绿球藻(Prochlorococcus,Pro)和真核球藻(Eukaryotes,Euk)3类微微型光合浮游生物存在,并对其丰度与分布及其环境调控机制进行了研究.结果表明,研究海区Syn,Pro和Euk丰度的总平均值分别为(5.0±7.6)×104,(4.6±4.2)×104和(1.8±1.1)×103个/cm3,Syn种群丰度的高值大多出现在营养盐丰富的雷州半岛及海南岛东部海域的河口、沿岸带与陆架,北部湾次之,是陆坡和开阔海的数十分之一;其水层分布主要在跃层以上,跃层以下其值迅速降低,发现Pro存在两个不同种群:表层种群和深层种群,前者分布型式与Syn相似,后者的分布型式迥然不同,其丰度向营养盐贫瘠的外海、陆坡和开阔海显著增高;同时发现Pro水层分布的高值主要出现在真光层的底部,并往往出现在硝酸盐跃层之上,Euk在不同海域的分布差异不如Syn和Pro来得大,但仍以沿岸带与陆架为高,陆坡与开阔海较低,水层分布的高值大多出现在真光层的底部,而且它是对次表层叶绿素a极大值的主要贡献者,这些分布型式的差异,取决于环境的调控和3类生物生态生理适应的差异.研究海区Syn,Pro和Euk 3类微微型光合浮游生物对微微型光合浮游生物生态生理适应的差异.研究海区Syn,Pro和Euk3类微微型光合浮游生物对微微型光合浮游生物群落总丰度的贡献分别为50.996,47.3%和1.8%.     

温度和饵料丰度对海蜇水母体生长的影响

于1989年3月，以伞弧20mm的幼海蜇为材料，在盐度20和投喂卤虫无节幼体条件下，研究温度和饵料丰度对其生长的影响，并于1994年8月做了补充实验。结果表明，幼蜇生长的最适水温为24℃，存活的上限和下限温度分别为34℃和8℃。在24℃中，幼蜇平均日生长率（Y；％）与投饵频次（X；次／d）的关系式为Y=12．89－4．06／X。投饵频次以4－5次／d最佳，投饵间隔时间超过76h则呈负生长。     

Study of indices for drought characterization in KBK districts in Orissa (India)

Drought is a temporary, random and regional climatic phenomenon, originating due to lack of precipitation leading to water deficit and causing economic loss. Success in drought alleviation depends on how well droughts are defined and their severity quantified. A quantitative definition identifies the beginning, end, spatial extent and the severity of drought. Among the available indices, no single index is capable of fully describing all the physical characteristics of drought. Therefore, in most cases it is useful and necessary to consider several indices, examine their sensitivity and accuracy, and investigate for correlation among them. In this study, the geographical information system‐based Spatial and Time Series Information Modeling (SPATSIM) and Daily Water Resources Assessment Modeling (DWRAM) software were used for drought analysis on monthly and daily bases respectively and its spatial distribution in both dry and wet years. SPATSIM utilizes standardized precipitation index (SPI), effective drought index (EDI), deciles index and departure from long‐term mean and median; and DWRAM employs only EDI. The analysis of data from the Kalahandi and Nuapada districts of Orissa (India) revealed that (a) droughts in this region occurred with a frequency of once in every 3 to 4 years, (b) droughts occurred in the year when the ratio of annual rainfall to potential evapotranspiration (Pae/PET) was less than 0·6, (c) EDI better represented the droughts in the area than any other index; (d) all SPI, EDI and annual deviation from the mean showed a similar trend of drought severity. The comparison of all indices and results of analysis led to several useful and pragmatic inferences in understanding the drought attributes of the study area. Copyright © 2007 John Wiley & Sons, Ltd.