近30年长江口北支演变及其对物种多样性的影响

分汊河口演变特征及其生态效应是当前河口海岸研究的重要热点问题。长江口北支是长江口第一级分汊的重要水道,其演变会对区域生态与环境条件产生深远的影响。本文在已有研究结果基础上,结合遥感影像分析与水域生态现状调研,阐述了近30年来长江口北支河道的演变特征和生态现状,并对河道演变对物种多样性的影响进行了深入的探讨。结果表明,近30年来北支演变的突出特点在于北支中上段束窄明显,而下段河道虽然有一定程度的束窄,但口门仍呈喇叭口形态;大量的圈围工程是导致北支中上段河道束窄的最重要因素;随着河势变化,北支分流比下降,分沙比上升,河道水深、河槽容积的下降,使北支盐水入侵加剧,水、沙、盐倒灌南支的风险增加。北支演变导致水体盐度条件的改变,使得区域生物类群以适应高盐、咸淡水环境的种类为主;而河道水深、水动力条件、水体含沙量等的变化均会对生物类群的组成产生影响。北支目前仍然是大型底栖动物、鱼类等生物类群的重要栖息地和育幼场,且具有较高的生物多样性。因此,北支治理仍需考虑维持北支水域生态系统的结构与功能不被破坏,确保区域的可持续发展。未来北支的演变趋势及其生态效应,需要在有效监测的基础上进行综合分析。     

Anthropogenic threat assessment of marine-associated fauna in Spencer Gulf,South Australia

Assessing the vulnerability of species to [anthropogenic threats is an essential step when developing management strategies for wild populations. With industrial development forecasted to increase in Spencer Gulf, South Australia, it is crucial to assess the ongoing effects of anthropogenic threats to resident and migratory species. Expert elicitation was used to assess 27 threats against 38 threatened, protected, and iconic marine-associated species. Species and threat interactions were assessed individually, and as taxonomic or functional groups. Climate change had the greatest overall exposure (c.f. risk) across species, followed by disturbance, pollution, disease/invasive species, and fishing/aquaculture threats. The largest overall sensitivities (c.f. consequences) were pollution and disease/invasive species, followed by climate change, disturbance and fishing/aquaculture threats. Vulnerability scores (exposure x sensitivity) showed the climate change group posing the greatest overall threat in Spencer Gulf, with individual climatic threats ranking as three of the top four biggest threats to most animal groups. Noise, shipping, and net fishing were considered the greatest region-specific individual threats to marine mammals; as were trawl fishing, line fishing, and coastal activities to fish/cuttlefish; trawl fishing, line fishing, and net fishing to elasmobranchs; and oil spill, disease, and coastal activities to sea/shorebirds. Eighteen of the 20 highest vulnerability scores involved the short-beaked common dolphin, Indo-Pacific bottlenose dolphin, and Australian sea lion, highlighting the particular susceptibility of these species to specific threats. These findings provide a synthesis of key threats and vulnerable species, and give management a basis to direct future monitoring and threat mitigation efforts in the region.     

春季长江口富营养化水域浮游植物群集对冲淡水和上升流的响应

A comprehensive study on the phytoplankton standing stocks, species composition and dominant species in the eutrophic Changjiang(Yangtze River) Estuary(CE) was conducted to reveal the response of phytoplankton assemblage to Changjiang Diluted Water(CDW) and upwelling in the spring. Phytoplankton presented peak standing stocks(13.03 μg/L of chlorophyll a, 984.5×103 cells/L of phytoplankton abundance) along the surface isohaline of 25. Sixty-six species in 41 genera of Bacillariophyta and 33 species in 19 genera of Pyrrophyta were identified, as well as 5 species in Chlorophyta and Chrysophyta. Karenia mikimotoi was the most dominant species, followed by Prorocentrum dentatum, Paralia sulcata, Pseudo-nitzschia delicatissima and Skeletonema costatum. A bloom of K. mikimotoi was observed in the stratified stations, where the water was characterized by low nitrate, low phosphate, low turbidity, and specific ranges of temperature(18–22 °C) and salinity(27–32). K.mikimotoi and P. dentatum accumulated densely in the upper layers along the isohaline of 25. S. costatum was distributed in the west of the isohaline of 20. Benthonic P. sulcata presented high abundance near the bottom,while spread upward at upwelling stations. CDW resulted in overt gradients of salinity, turbidity and nutritional condition, determining the spatial distribution of phytoplankton species. The restricted upwelling resulted in the upward transport of P. sulcata and exclusion of S. costatum, K. mikimotoi and P. dentatum. The results suggested that CDW and upwelling were of importance in regulating the structure and distribution of phytoplankton assemblage in the CE and the East China Sea.     

A comparison of growth patterns between non‐indigenous Halophila nipponica and the native sympatric Zostera marina on the southern coast of the Korean peninsula

The growth dynamics of two co‐occurring seagrass species, Zostera marina and Halophila nipponica, were examined on the southern coast of the Korean peninsula. Zostera marina is a native dominant seagrass species in Korean coastal waters, whereas H. nipponica is a non‐native tropical and subtropical species that has extended its distributional range to the temperate coastal areas of Korea. To examine the differences in the growth dynamics of H. nipponica and Z.  marina, their morphology, density, productivity and biomass, as well as local environmental conditions, were monitored monthly from January 2008 to July 2009. Underwater irradiance at the study site was the highest in April 2009 and the lowest in January 2008. Water temperature ranged from 10.4°C in January 2009 to 24.8°C in September 2008. Significant differences in growth dynamics were observed between the species, due to the effect of water temperature at the study site. Density and areal productivity were the highest in April 2008 and June 2008, respectively, for Z.  marina but the highest in July 2008 for H. nipponica. Leaf size, shoot height and shoot weight were the highest in July 2008 for Z.  marina but the highest in August 2008 or September 2008 for H. nipponica. The productivity of both species was strongly correlated with water temperature at the study site. However, the productivity of these species was not strongly correlated with underwater irradiance or the nutrient availability of either the water column or sediment pore water. Zostera marina exhibited the ecological characteristics of a temperate seagrass, whereas H. nipponica retained the features of a subtropical/tropical seagrass, even after adapting to the temperate coastal waters of Korea.     

Size scaling patterns of species richness and carbon biomass for marine phytoplankton functional groups

Phytoplankton assemblages were clustered into associations according to functional taxonomic (diatoms, dinoflagellates and coccolithophores) and “ataxonomic” unimodal (nanoplankton, microplankton and macroplankton) size‐based criteria. Scaling relations of species richness‐cell size were performed in terms of histogram and log‐transformed data analyses for both taxonomic and ataxonomic groups. Frequency distribution histograms were fitted to a negative power function, which was strongly unimodal and right skewed and invariant across taxonomic and ataxonomic units. Regression analyses of the log‐transformed data were fitted to negative linear curves, which had common patterns and they were independent of taxonomic or ataxonomic affiliation. Species carbon biomass–cell size spectra produced by log transformation of the relevant data yielded positive slopes for both taxonomic and ataxonomic groups. In contrast, comparisons of the relative cell abundance, cell volume and carbon biomass levels showed large differences among these variables across taxonomic and ataxonomic groups. This work demonstrates that phytoplankton taxonomic and ataxonomic functional group relationships should be considered when developing future models of phytoplankton community structure.     

十年间黄海大型底栖动物优势种的变化

本文根据2000年10月、2001年3月、2003年6月、2004年1月、2011年4月和8月黄海大型底栖动物调查资料对十年间大型底栖动物优势种的变化进行研究。研究结果表明:十年间共出现优势种9种(优势度0.02),包括寡鳃齿吻沙蚕Nephtys oligobranchia、背蚓虫Notomastus latericeus、掌鳃索沙蚕Nin?e palmata,角海蛹Ophelina acuminata和蜈蚣欧努菲虫Onuphis geophiliformis等5种多毛纲动物,薄索足蛤Thyasira tokunagai和橄榄胡桃蛤Nucula tenuis等2种软体动物,浅水萨氏真蛇尾Ophiura sarsii vadicola和紫蛇尾Ophiopholis mirabilis等2种棘皮动物。其中,薄索足蛤为2000年10月、2003年6月、2004年1月和2011年4月航次黄海大型底栖动物优势种,浅水萨氏真蛇尾和掌鳃索沙蚕为2011年4月和8月航次黄海大型底栖动物优势种、角海蛹为2004年1月和2011年4月航次黄海大型底栖动物的优势种。背蚓虫则是2011年8月航次的优势种,优势度为0.0859。对2011年2个航次调查区域深度进行划分,结合底层水温度和盐度等环境因子进行指示种分析,结果表明,黄海0—30m水深区域指示种为日本角吻沙蚕Goniada japonica、寡节甘吻沙蚕Glycinde gurjanovae、美人虾Callianassa sp.和双眼钩虾Ampelisca sp.。30m水深以上区域的指示种主要是背蚓虫、奇异指纹蛤Acila mirabilis、掌鳃索沙蚕和浅水萨氏真蛇尾。指示种组成与优势种的组成较一致,表明水深、底层水温度和盐度是影响黄海大型底栖动物优势种分布的主要因素。十年间上黄海近岸水域底栖动物优势种发生了变化,小型的多毛类如背蚓虫和掌鳃索沙蚕等成为近岸海域主要的优势种。冷水团水域优势种较稳定,主要为浅水萨氏真蛇尾和薄索足蛤。     

利用限制性最大似然方法和贝叶斯方法估计大菱鲆生长性状的遗传参数。

Bayesian and restricted maximum likelihood(REML) approaches were used to estimate the genetic parameters in a cultured turbot Scophthalmus maximus stock. The data set consisted of harvest body weight from 2 462progenies(17 months old) from 28 families that were produced through artificial insemination using 39 parent fish. An animal model was applied to partition each weight value into a fixed effect, an additive genetic effect, and a residual effect. The average body weight of each family, which was measured at 110 days post-hatching, was considered as a covariate. For Bayesian analysis, heritability and breeding values were estimated using both the posterior mean and mode from the joint posterior conditional distribution. The results revealed that for additive genetic variance, the posterior mean estimate( δ_a~2=9 320) was highest but with the smallest residual variance,REML estimates( δ_a~2=8 088) came second and the posterior mode estimate( δ_a~2=7 849) was lowest. The corresponding three heritability estimates followed the same trend as additive genetic variance and they were all high. The Pearson correlations between each pair of the three estimates of breeding values were all high,particularly that between the posterior mean and REML estimates(0.996 9). These results reveal that the differences between Bayesian and REML methods in terms of estimation of heritability and breeding values were small. This study provides another feasible method of genetic parameter estimation in selective breeding programs of turbot.     

日照近岸海域浒苔暴发区浮游植物调查研究

2016年5月和8月浒苔暴发前后,分别对日照近岸海域浒苔暴发区进行了两个航次的浮游植物断面调查。两个航次中,硅藻都占据了调查海域浮游植物组成的主导地位,在种类数上和细胞丰度值上都占了较大的比例。8月航次细胞丰度明显高于5月航次,这与调查海域的历次调查结果相一致。应用PRIMER软件中的单变量分析得到群落种数(S)、丰富度(d)、香农-威纳指数(Shannon-Weaner index)(H′)和均匀度(J),从多样性指数分析可以看出,5月航次的生物多样性优于8月航次,5月航次调查海域浮游植物种类数量和空间分布都较均匀。两个航次中出现的优势种存在较大差别。     

内蒙古荒漠-草原过渡带灌木群落特征

荒漠-草原过渡带是草原逐渐被荒漠取代的区域.沿阿拉善左旗-乌拉特后旗调查灌木群落,分析植物群落的结构和物种多样性,以期为生物多样性保育提供理论依据.结果表明:该荒漠-草原过渡带有62种植物,隶属于18科、47属,禾本科、藜科、豆科和菊科的植物较多.植物主要由灌木和多年生草本构成,以旱生植物为主,主要包括红砂(Reaum...     

无居民海岛植被恢复过程中物种多样性及土壤特征初步研究

2016年4月对厦门无居民海岛猴屿开展了植被和土壤调查,采用全岛调查的方法查清全岛植物种类及生长状况,采用样方调查的方法分析比较人工恢复林和次生林物种多样性和土壤肥力特征,以期为无居民海岛生态修复提供借鉴.结果表明,全岛共有乔木5科5属6种,灌木有10科12属13种,草本植物有21科39属40种.由于被海包围、面积狭小、地形简单,物种传播速度慢,猴屿生物多样性较低,猴屿人工恢复林物种多样性与次生林差异不显著.人工恢复林土壤肥力显著低于次生林,植物生长及其产生的凋落物可以促进土壤肥力的改善.海岛普遍风大、缺水,植被恢复应选用适应海岛环境能力强的物种.猴屿植被破坏导致生态位缺失,进而造成马缨丹生物入侵,影响海岛生态系统稳定性.