围垦对长江口南岸底栖动物群落结构及多样性的影响

通过对长江口南岸围垦潮滩和自然潮滩大型底栖无脊椎动物进行取样调查,研究了围垦潮滩的底栖动物群落结构及其多样性特性,分析了围垦对潮滩底栖动物群落结构及多样性的影响,研究发现,（1）围垦氏栖动物群落种类减少,种类组成发生变化;总趋势是,围垦以后,甲壳动物种类明显减少,由7种减少到1种;随着围垦时间延长,多毛类种类减少,由4种减少到3种,直到最后消失,而软体动物和昆虫幼虫种类所占比例则明显增加,分别从占总种数的29．41％,5．89％增加到50．00％和25．00％;（2）围垦1a且仍受潮水影响的潮滩,底栖动物种类丰度虽有降低,但其密度和生物量却明显增加,分别从132．10个/m^2,35.31g/m^2（湿重）增加到218．32个／m/ 2和79．66g/m^2（湿重）,围垦2a且潮水不能进入的潮滩,底栖动物生物量大大降低,降到3．02g/m^2（湿重）;（3）围垦时间短且仍受潮水影响的潮滩与未围垦的自然潮滩相比,其底栖动物多样性降低不明显,围垦时间长且潮水不能进入的潮滩,底栖动物多样性明显降低,反映了围垦导致潮滩湿地生境退化;（4）围垦对底栖动物群落结构及多样性的影响,是通过改变潮滩湿地生境中的多种环境因子造成的,如潮滩高保,水,动力,沉积物特性,植被演替等,是各种因子综合作用的结果。     

长江口滨岸潮滩底栖动物泥螺受锌污染的急性毒理试验研究

为了评价长江口滨岸潮滩沉积物中重金属锌对底栖动物的影响,进行了底栖动物泥螺的24h急性毒理学试验研究.结果表明:泥螺的半致死剂量为0.133g/L,全致死剂量为1g/L:对泥螺体内重金属累集量的分析表明:泥螺体内Zn的含量随试验组浓度的增高而增多,试验组的Zn浓度和泥螺累积的Zn含量符合Cubic三次函数:Zn的增加对泥螺富集Pb、Cr、Ni的影响是在浓度为1g/L、4g/L时出现两个峰值:Zn含量的增加对泥螺富集Cu的影响是在Zn浓度为0.5g/L、1g/L时泥螺对Cu富集量有所升高.这说明底栖动物对重金属的富集是个动态的过程,底栖动物富集的重金属元素间具有一定的协同作用.     

珠海淇澳岛红树林和芦苇湿地底栖硅藻群落比较

研究了珠海淇澳岛红树林湿地和芦苇湿地2007年3月至2008年1月间底栖硅藻群落的结构及其动态特征.结果表明,两种湿地共有底栖硅藻28属113种(变种),其中红树林中检出23属95种(变种),明显高于芦苇湿地的21属42种(变种).底栖硅藻的丰度为14.3～553.5 celk cm-3,不同样地和采样期的多样性指数和均匀度指数不同,但红树林湿地高于芦苇湿地.两种湿地底栖硅藻群落的属种结构存在显著差异,红树林湿地中多以羽纹藻类,如布纹藻属(Gyrosigma)、斜纹藻属(Pleurosigma)和羽纹藻属(Pinnularia)等占优势,而芦苇湿地主要以中心藻类,如圆筛藻属(Coscinodiscus)和小环藻属(Cyclotella)等占优势.相似性分析显示,样地基质对底栖硅藻群落的影响大于季节变化的影响.     

大型底栖动物对河口沉积物的扰动作用

利用微宇宙示踪技术,定量研究了天津北塘河口地区的天津厚蟹、沙蚕、泥螺和青蛤4种底栖动物对沉积物的扰动作用.结果表明：生物扰动对沉积物的分布具有明显影响.不同底栖动物扰动能力不同,对表层沉积物的扰动强度（扩散系数,10^-3 cm²·d^-1）大小依次为：沙蚕（2.95）> 天津厚蟹（1.00）> 青蛤（0.78）> 泥螺（0.35）> 对照（0.05）;对深层沉积物则是天津厚蟹（3.10）>沙蚕（2.33）>青蛤（0.28）>泥螺（0.15）> 对照（0.05）.这种差异主要与不同底栖动物所属的功能群不同有关.底栖动物体积与表层沉积物扩散系数显著相关（P<0.05）,可采用底栖动物体积预测其对沉积物的扰动强度.     

潮滩底栖微藻生物量垂直变化对其遥感反演模式的影响

遥感信号与潮滩表层沉积物底栖微藻生物量的定量关系, 与定义生物量对应的沉积物深度相关。以叶绿素浓度表征沉积物底栖微藻生物量, 对烟台四十里湾潮滩表层沉积物柱样分别以3 mm 和1 mm 间隔分层, 分析研究其叶绿素垂直分布特征; 模拟、分析以指数衰减曲线斜率表征的叶绿素垂直分布变化对叶绿素浓度遥感反演模式的影响。结果显示, 潮滩表层1 cm 和3 cm 内, 叶绿素浓度均随着深度增加呈指数式衰减; 垂直衰减曲线斜率逐渐变大时, 沉积物表层1 cm 内的叶绿素浓度逐渐降低, 基于叶绿素浓度与光谱指数NDI-MPB 间回归方程的遥感反演模式亦发生变化。     

互花米草入侵对黄河三角洲秋季底栖食物网的影响

为了保滩护岸,互花米草于1990年被引种至黄河三角洲,随后迅速蔓延,给滨海湿地生态系统带来了严重威胁。为了明晰互花米草入侵对黄河三角洲湿地底栖食物网结构的影响,本研究基于稳定同位素技术,于2020年11月对互花米草入侵区域大型底栖动物的潜在食源、营养级和食物网结构进行了采样分析。结果表明: 调查区域潜在食源δ¹³C平均值的变化规律为沉积物(SOM)>互花米草>底栖微藻>悬浮颗粒物(POM)>盐地碱蓬,潜在食源δ¹⁵N值的变化范围为1.24‰～9.03‰,且不同食源间的δ¹⁵N值存在差异。调查区域大型底栖动物的营养级范围为1.73～4.19,其中双壳类的营养级最低;互花米草及其腐败后的碎屑是大型底栖动物的重要食源之一,但对大型底栖动物的营养级结构没有显著影响。互花米草入侵通过上行效应改变了底栖生物的食源组成,进而可能影响黄河三角洲湿地食物网的结构。     

滦河中游干流底栖动物种类及分布

2007年10月对华北地区的重要河流——滦河干流中游段的底栖动物进行了调查。结果表明:河流底栖动物种类较为丰富,共采集到底栖动物37种,其中优势种有5种;底栖动物平均生物量为5.4 g·m^-2,平均密度为1128 个·m^-2;蜉蝣目有1种在各采样点均出现,说明滦河中游干流水质较好;下游段动物多度、生物量及生物多样性指数值都较小,上游段相应均较大,底栖生物分布与具体生境条件密切相关,下游段人为扰动使得生境质量较差,不利于底栖动物生存繁殖。     

海洋大型底栖动物对海岛开发的生态响应——以宁波大榭岛为例

以开发时间长,产业密集的国家海岛开发试点大榭岛为例分析、评价了海岛开发的潮间带和近岸海域大型底栖动物生态响应。通过对大榭岛岩礁相、泥沙相潮间带以及近岸海域大型底栖动物的物种组成、群落结构和数量分布的分析,同时与该岛周围开发程度较弱的几大海岛的类似生境中大型底栖动物状况进行比较。结果发现:(1)大榭岛岩相潮间带断面牡蛎科(Ostre idae)和藤壶科(Balan idae)等科的物种栖息密度较高,生物多样性较低;(2)泥沙相潮间带底栖动物状况与其他海岛差别不显著;(3)大榭岛近岸海域底栖动物种数少于其他海岛近岸海域,且前者不倒翁虫(Sternaspis scutata)和小头虫(Capitellacapitata)等多毛类物种栖息密度较高,生物多样性较低,群落结构与其他区域相差较大;(4)环境质量的生物评价结果显示,大榭岛近岸海域扰动程度高于其他海岛近岸海域。此外,从海岛开发的规划与功能定位、工程设计与施工工艺、相关人员意识形态三方面提出了一些保护和恢复海洋生物多样性的对策。     

漩门湾不同类型湿地大型底栖动物群落特征比较研究

为研究漩门湾围垦后自然滩涂湿地和不同利用方式人工湿地7种生境的大型底栖动物群落结构现状和受扰动情况,2010年10月至2012年7月在两个区域中进行了为期两周年8个季度的大型底栖动物调查,结果表明:两周年共获得大型底栖动物5门8纲41科63种;第一周年为47种,其中自然滩涂湿地41种,人工湿地14种;第二周年为58种,其中自然滩涂湿地50种,人工湿地10种,人工湿地的物种数明显少于自然滩涂湿地。采集到的物种以软体动物和节肢动物为主,分别为32种和23种,各占总物种数的50.00%和37.10%。两周年的年均栖息密度和年均生物量在生境间从高到低依次为,年均栖息密度第一周年HSGTHHRLSCNYSK,第二周年GTHSHHSCNYRLSK;年均生物量第一周为HSRLHHGTNYSKSC,第二周年是HSHHRLGTNYSCSK。3种大型底栖动物的生物多样性指数(Margalef丰富度指数(S)、Shannon-Wiener多样性指数(H')、Pielou均匀度指数(J))分析表明,两周年7种生境3种多样性指数均处在不断的变化之中,人工湿地的Margalef丰富度指数(S)和Shannon-Wiener多样性指数(H')相对于自然滩涂湿地偏低,而Pielou均匀度指数(J)人工湿地大于自然滩涂湿地。聚类和排序的结果表明,围垦使大型底栖动物的群落结构发生明显的变化。ABC曲线分析结果表明,自然滩涂湿地受到的干扰程度较轻,而人工湿地受到的干扰程度较大。围垦改变了潮滩高程、水动力、盐度、沉积物特性,再加上人类活动的影响,这些因素是造成底栖动物群落结构及生物多样性变化的主要原因,围垦结束后的生态修复十分必要。     

上海市潮滩湿地大型底栖动物的空间分布格局

通过对上海市6个典型潮滩湿地（崇明东滩、崇明北滩、九段沙、青草沙、南汇边滩和杭州湾北岸）的调查,共记录到大型底栖动物112种,甲壳动物、软体动物和环节动物分别占总物种数的51．8％、22．3％和18．8％。6个潮滩湿地中大型底栖动物生物量的空间分布呈现一致的规律,即高潮区〉中潮区〉低潮区;在生物量构成中,甲壳动物是最为重要的类群,其总体平均相对贡献率在51％～97％之间,软体动物的总体平均相对贡献率在2％～48％之间。大型底栖动物密度的空间分布在地点间存在较大差异,在崇明东滩、九段沙和杭州湾北岸湿地中,软体动物在数量上占优势;而在崇明北滩、青草沙和南汇边滩,甲壳动物却是优势类群。与20世纪80和90年代的调查资料相比,近20多年来上海市潮滩湿地中大型底栖动物生物量明显增加,但群落结构发生了根本改变,优势类群由个体较小的软体动物转变为平均体重较大的甲壳动物,这主要与人类活动（过度采捕、环境污染和生物促淤等因素）的强度干扰有关,也反映上海市潮滩湿地的环境质量和生态功能正在逐步下降。     

The evolution of the fine sediment regime of the Severn Estuary and Bristol Channel

Fine sediment forms tidal flats along most of the Severn Estuary coastline but subtidal deposits are localized, mainly confined to Newport Deep and Bridgwater Bay. The estuary is experiencing a period of sea level rise which has led to coastal mud erosion in recent centuries. Sediment exchanges with the sea and river inputs are negligible compared to the large-scale exchanges within the estuary itself. Measurements of tidal flat level changes, archaeological finds and anthropogenic chemical concentrations confirm that mud flat erosion is long term and typical of the entire estuary. Sea level rise and coast erosion would normally lead to much of this sediment being redeposited inshore at the landward limit of the alluvium. Other than in narrow salt marsh strips, such deposition is prevented in the Severn by the river walls. In cores of subtidal muddy sediment, the number and thickness of sand layers decreases upwards. The top metre or so is entirely mud and exhibits thousands of layers of varying thickness and origin. Radiochemical analysis confirms that mud is accumulating in the subtidal zone of Newport Deep and the seaward periphery of the Bridgwater Bay mud patch and is increasing in proportion to sand. Circumstantial evidence strongly suggests that for at least the last 600 years the dominant pattern has been one of erosion of fine sediment from the coastal margin and its accumulation in subtidal sinks.     

Benthic fauna in tropical tidal flats – a comparative perspective

Tidal flats extend seaward from mangrove forests along many tropicalcoastlines. This contribution compiles the current knowledge on tropicaltidal flats with regard to species richness, abundance, spatial distributionpatterns and ecological roles taken by major organisms. Tidal flatsencompass a variety of soft-sediment habitats which are inhabited by aspecies-rich fauna. Species numbers are generally higher than in temperatetidal flats, but vary widely between tropical sites where they have not yetbeen fully assessed due to lack of research and taxonomic problems. Theassessment of biodiversity is further complicated by a low species frequency,the small size of macroinfaunal organisms and variations in the occurrence ofspecies between sites. Mean abundance ranges from 1000–2000individuals m^-2, although figures ten times higher have beenrecorded in a mudflat in Costa Rica, and there are great variations in general.Individual densities of small-sized macrofauna are about ten times higher than for larger macrobenthos. A generalized zonation scheme for intertidaldistribution patterns of tropical tidal flat fauna is presented. The comparisonshows that the occurrence of macrofauna and especially of ecosystemengineers varies between sites, which can in turn explain the great variabilityin species abundance patterns recorded in benthic surveys of tidal flatswithin and between regions. This review revealed similarities as well asdifferences between various tropical tidal flats, which underlines the need for further comparative studies to be done, using the same methodology, before generalizations can be made.     

EFFECT OF SUBSURFACE NUTRIENT SUPPLIES ON THE VERTICAL MIGRATION OF EUGLENA PROXIMA (EUGLENOPHYTA)1

Euglena proxima Dangeard inhabits intertidal sand flats and displays a tidal rhythm in vertical migration. During daytime low tides when the sand flat is emersed, millions of cells are visible on the sediment surface, but the population remains below the surface at all other times. An earlier study demonstrated that the extent of downward migration of E. proxima is reinforced by the presence of a subsurface layer of black sediment. The present study was designed to test the hypothesis that the higher availability of inorganic nutrients or organic substrates in or above the black layer is responsible for the enhancement of downward migration in E. proxima. This hypothesis was tested experimentally by manipulating the bottom water in 24 mesocosm containers in a tidal tank. Six replicates of each of the following nutrient treatments were tested: seawater control; deep porewater collected from 70 cm below the sediment surface; seawater enriched with ammonium, nitrate, and phosphate; and seawater enriched with acetate, glucose, and the preceding inorganic nutrients. Multivariate analysis of variance revealed that the chl a biomass and chl a‐weighted mean depth of the population at high tide were significantly greater for replicates receiving inorganic nutrients. There was no difference between those receiving only inorganic nutrients and those enriched with inorganic nutrients, acetate, and glucose. These findings represent the first experimental evidence that subsurface nutrients are an important resource that reinforces the maintenance of vertical migration behavior in benthic microalgae.     

环境因子对河流底栖无脊椎动物群落结构的影响

底栖无脊椎动物是河流生态系统的重要组成部分,在物质循环和能量流动中是不可或缺的重要环节。其群落结构特点与河流环境因子密切相关,能较好地反映河流生态系统健康状况。综述了物理因子(底质、温度、水深、水流、洪水干扰等)、化学因子(溶氧量、p H值、磷、氮等)、生物因子(水生植物、竞争和捕食)、人为干扰(电站建设、城镇化等)和综合因子对河流底栖无脊椎动物群落结构的影响,并根据国内外研究现状指出水流、海拔和洪水干扰等环境因子对河流底栖无脊椎动物群落结构影响的研究较少或不足,对这些环境因子的研究应是今后河流生态学领域需要着力推进重要内容。深入研究和完善环境因子与底栖无脊椎动物群落结构的关系可为保护底栖无脊椎动物群落、流域水生态系统管理和受损河流生态系统修复提供更为全面的科学依据。     

Changes of Soil Particle Size Distribution in Tidal Flats in the Yellow River Delta

Background

The tidal flat is one of the important components of coastal wetland systems in the Yellow River Delta (YRD). It can stabilize shorelines and protect coastal biodiversity. The erosion risk in tidal flats in coastal wetlands was seldom been studied. Characterizing changes of soil particle size distribution (PSD) is an important way to quantity soil erosion in tidal flats.

Method/Principal findings

Based on the fractal scale theory and network analysis, we determined the fractal characterizations (singular fractal dimension and multifractal dimension) soil PSD in a successional series of tidal flats in a coastal wetland in the YRD in eastern China. The results showed that the major soil texture was from silt loam to sandy loam. The values of fractal dimensions, ranging from 2.35 to 2.55, decreased from the low tidal flat to the high tidal flat. We also found that the percent of particles with size ranging between 0.4 and 126 μm was related with fractal dimensions. Tide played a great effort on soil PSD than vegetation by increasing soil organic matter (SOM) content and salinity in the coastal wetland in the YRD.

Conclusions/Significance

Tidal flats in coastal wetlands in the YRD, especially low tidal flats, are facing the risk of soil erosion. This study will be essential to provide a firm basis for the coast erosion control and assessment, as well as wetland ecosystem restoration.     

Benthic microalgae in coral reef sediments of the southern Great Barrier Reef,Australia

The abundance and productivity of benthic microalgae in coral reef sediments are poorly known compared with other, more conspicuous (e.g. coral zooxanthellae, macroalgae) primary producers of coral reef habitats. A survey of the distribution, biomass, and productivity of benthic microalgae on a platform reef flat and in a cross-shelf transect in the southern Great Barrier Reef indicated that benthic microalgae are ubiquitous, abundant (up to 995.0 mg chlorophyll (chl) a m^–2), and productive (up to 110 mg O₂ m^–2 h^–1) components of the reef ecosystem. Concentrations of benthic microalgae, expressed as chlorophyll a per surface area, were approximately 100-fold greater than the integrated water column concentrations of microalgae throughout the region. Benthic microalgal biomass was greater on the shallow water platform reef than in the deeper waters of the cross-shelf transect. In both areas the benthic microalgal communities had a similar composition, dominated by pennate diatoms, dinoflagellates, and cyanobacteria. Benthic microalgal populations were potentially nutrient-limited, based on responses to nitrogen and phosphorus enrichments in short-term (7-day) microcosm experiments. Benthic microalgal productivity, measured by O₂ evolution, indicated productive communities responsive to light and nutrient availability. The benthic microalgal concentrations observed (92–995 mg chl a m^–2) were high relative to other reports, particularly compared with temperate regions. This abundance of productive plants in both reef and shelf sediments in the southern Great Barrier Reef suggests that benthic microalgae are key components of coral reef ecosystems.Communicated by Environmental Editor, B.C. Hatcher     

The microphytobenthos of Königshafen—spatial and seasonal distribution on a sandy tidal flat

A microphytobenthic species composition of a tidal flat in the northern Wadden Sea was analysed regarding cell numbers and biomass (in carbon units). The three sampling sites differed in tidal inundation from 15 cm to about 90 cm water depth at high tide. The sediment was sandy at all three stations. A cluster analysis revealed a separation of the benthic diatoms into three areas: aNereis-Corophium-belt, a seagrass-bed and theArenicola-flat. Small epipsammic diatoms were most abundant and dominated the microalgal biomass. A microphytobenthic “spring bloom” even started beneath the ice cover of the flat in January. Lowest values of cell numbers and biomass of benthic microalgae were found in summer. Highest values were measured in the uppermost area (Nereis-Corophium-belt), and only here was an autumnal increase of benthic microalgae found. Further cluster analysis within each of the three areas revealed seasonal differences although the majority of species were present all year round. Many species were most abundant in spring, and some showed a bimodal distribution (spring-autumn) in the year of investigation.     

Effects of the burrowing mud shrimp,Upogebia yokoyai,on carbon flow and microbial activity on a tidal flat

Mud shrimps, Upogebia spp., are major constituents of macrobenthic communities in tidal flats in Japan. The impact of Upogebia yokoyai on carbon flow on tidal flats was examined by comparing CO₂ emission rates from plots with and without burrows in the Kurose River estuary, Japan. In situ CO₂ emission rates from plots with burrows were significantly higher than from those without. Laboratory measurements using sediment core samples that excluded respiration of macrobenthic organisms showed similar trends. Although there were no significant differences in grain size distribution, water content, or ignition loss between the sediment cores with and without burrows, oxidation–reduction potential was significantly higher in sediment cores with burrows. Analysis of phospholipid fatty acids (PLFA) indicated that microbial biomass and community structure did not differ significantly between cores with and without burrows. However, microbial respiration activity, as indicated by CO₂ emission rates per total PLFA content, was significantly higher in sediment cores with burrows than in those without. Our results indicate that burrows of U. yokoyai change the physicochemical conditions and increase microbial activity in the sediment, significantly affecting carbon flow in the tidal flat.     

长江口互花米草生长区大型底栖动物的群落特征

2005年对长江口潮滩湿地互花米草(Spartina alterniflora)生长区不同季节大型底栖动物群落特征的研究表明:长江口互花米草生长区的大型底栖动物有21种,其中甲壳纲10种、多毛纲5种、腹足纲5种、辨鳃纲1种.主要种类有拟沼螺(Assiminea sp.)、背蚓虫(Notomastus latericeus)、尖锥拟蟹守螺(Cerithidea largillierli)、中国绿螂(Glauconome chinensis)、钩虾(Gammaridae sp.)等.食性功能群均以碎屑食者和植食者为主.大型底栖动物平均栖息密度为(650.5±719.2)个/m2,标准误主要是由于北湖的拟沼螺密度很大.栖息密度从大到小的顺序为沿河口梯度从内到外分布的北湖边滩、崇明东滩、金山卫边滩.大型底栖动物群落分布不均匀,沿河口梯度变化存在明显的空间差异.栖息密度和物种多样性在夏季最高,冬季最低.大型底栖动物平均生物量为(20.8±6.1)g/m2,季相变化为夏季＞秋季＞春季＞冬季.BIO-ENV分析表明沉积物粒径和盐沼高度是大型底栖动物群落特征的主要影响因素.不同研究结果的差异除了时空因素外可能与互花米草的种群动态有关.加强不同时间尺度的研究有助于正确评价互花米草对大型底栖动物的影响.     

深圳福田红树林区底栖大型动物群落的空间分带及灌污的可能影响

本文自１９９１年４月至１９９３年１月对深圳福田红树林中底栖大型动物的空间分带及灌污的可能影响进行了研究。结果表明,该红树林湿地中主要出现的底栖动物为拟沼螺科,黑螺科,汇螺科,沙蟹科,方蟹科和弹涂鱼科种类。红树区内底栖动物从高潮位到低潮位可分为３个群落分布带：亮泽拟沼螺带;拟黑螺－褶痕相手蟹带;弧边招潮－印尼拟蟹守螺－刻纹拟沼螺带。群落的分带可能主要由潮位线,食物适应性及底质结构因素决定。林前泥滩底栖动物种类多样性最大,生物量最高。林内动物群落则表现出低种类多样性,高种群个体数的特点。群落总栖息密度的变化基本上由软体动物所主导。生活污水排灌对红树林中底栖大型动物的影响不明显,仅在排污口端引起少数污水动物种类的出现及群落总生物量轻微的升高。