厦门凤林红树林湿地自由生活海洋线虫群落的研究

2004年冬季在集美凤林类似底质类型、盐度和潮位的海湾地段4个断面,就不同红树植物林中的小型底栖动物数量和自由生活海洋线虫群落进行了研究。结果表明:海洋线虫是凤林红树林中小型底栖动物中的绝对优势类群,占到小型底栖动物的76.1%~96.3%;从丰度来看,旧区白骨壤(Avicennia marina)林中小型底栖动物的数量较少,有污水流过的光滩数量较大;4个断面共鉴定出海洋线虫37种(分类实体单元),其中新区秋茄(Kandelia candel)林中的生物多样性指数较低,旧区白骨壤林中群落具有较高的物种多样性;从出现的物种来看,新区秋茄林、旧区白骨壤林和光滩上出现的优势种和摄食功能群的类型各不相同。从4个断面13个站位进行的聚类分析和MDS标序分析结果推断自由生活海洋线虫的群落结构与不同的红树植物形成的沉积物有关。     

Benthic responses to organic matter variation in a subtropical coastal area off SE Brazil

Organic matter quality, expressed as the proportion of chlorophyll a (Chl a) to degraded organic material (i.e. phaeopigments), is known to influence the structure of benthic associations and plays an important role in the functioning of the ecosystem. This study investigates the vertical distribution of microbial biomass, meiofauna and macrofauna with respect to organic matter variation in Ubatuba, Brazil, a southeastern, subtropical coastal area. On three occasions, samples were collected in exposed and sheltered stations, at high and low hydrodynamic conditions. We hypothesize that benthic assemblages will have high meio‐ and macrofaunal densities and high microbial biomass at the sediment surface at the sheltered site, and lower and vertically homogeneous microbial biomass and densities of meio‐ and macrofauna are expected at the exposed site. The accumulation of fresh organic matter at the sediment surface was observed at both stations over the three sampling dates, which contributed to the higher densities of meiofauna in the first layers of the sediment column. Macrofauna followed the same trend only at the exposed station, but changes in the number of species, biodiversity and feeding groups were registered for both stations. Microbial biomass increased at the sheltered station over the three sampling dates, whereas at the exposed station, microbial biomass was nearly constant. Physical exposure did not influence organic matter loading at the sites and therefore did not affect overall structure of benthic assemblages, which negates our original hypothesis. Most of the benthic system components reacted to organic matter quality and quantity, but relationships between different‐sized organisms (i.e. competition and/or predation) may explain the unchanged microbial profiles at the exposed site and homogeneous vertical distribution of macrofauna at the sheltered site. In conclusion, the high quality of organic matter was a crucial factor in sustaining and regulating the benthic system, but coupled results showed that interactions between micro‐, meio‐ and macrofauna can be highly complex.     

虾池小型底栖动物的数量研究

提出１９８７年５月至１０月在黄岛养虾池对虾生长周期内对小型底栖动物数量逐月调查。指出：小型底栖动物总平均密度为１０９２．４ｉｎｄｓ·１０ｃｍ－２，自由生活海洋线虫和底栖桡足类是主要类群，其总平均密度分别为４６６．９和４５７．９ｉｎｄｓ·１０ｃｍ－２。８９．７％的小型底栖动物分布在沉积物表层２ｃｍ内。结果指明小型底栖动物被对虾捕食，并提出了捕食模式。     

Distribution of meiofaunal abundance in relation to environmental factors in Beibu Gulf, South China Sea

This study aims to explore the distribution of meiofaunal abundance in relation to environmental factors in the Beibu Gulf,a natural semi-enclosed part of the South China Sea,surrounded by China and Vietnam.Meiofauna and ten benthic environmental factors were determined at 27 sampling stations in the Beibu Gulf in four surveys during 2006-2007.The results show a clear geographical trend in meiofaunal abundance,water depth,salinity and clay content.The meiofaunal abundance and the clay content decreased,whereas the water depth and the salinity increased from the north to the south of the Gulf.The percentage of meiofaunal abundance in the 0-2 cm layer increased,whereas in the 2-5 cm and 5-10 cm layers it decreased from the north to the south of the Gulf.Correlation analysis show significant negative correlations between meiofaunal abundance and water depth,benthic temperature,salinity and pH,but significant positive correlations between meiofaunal abundance and dissolved oxygen,chlorophyll a and clay content.     

The effects of brine disposal on a subtidal meiofauna community

Desalination plants generate notable (>1,000 s m³) quantities of hypersaline brine which potentially affect the biological communities in the receiving area. We assessed whether proximity to a brine discharge point located off Gran Canaria (Canary Islands, eastern Atlantic) altered patterns in the abundance and assemblage structure of subtidal, soft-bottom, meiofauna. Samples were collected twice (May 2008 and January 2009) at 0, 15 and 30 m away from the brine discharge point, corresponding to a change in salinity from 45 to 36. Proximity to the brine discharge point affected overall meiofaunal abundances: lowest abundances were observed at 0 m (64.55 ± 39.86 ind 10 cm⁻², mean ± SD) than at 15 (210.49 ± 121.01 ind 10 cm⁻²) and 30 m (361.88 ± 102.64 ind 10 cm⁻²) away from the brine discharge point. This pattern was particularly notable for the most conspicuous meiofaunal groups: nematodes and copepods, and meiofaunal assemblage structure also differed with varying proximity to the brine discharge point. Although multivariate techniques identified changes in salinity as a relevant driver of patterns in meiofaunal assemblage structure with varying proximity to the brine outfall, a shift in particle size composition between May 2008 and January 2009 also contributed to explain differences in meiofaunal abundances and assemblage structure with varying proximity to the brine discharge point. Hence, meiofauna can be considered a suitable tool to monitor environmental impacts derived from the discharge of hypersaline effluents on subtidal, soft-bottom, assemblages if potential confounding drivers, i.e. here temporal changes in particle size composition, are accounted for to avoid possible confusing interpretations.     

南大西洋洋中脊调查区小型底栖生物丰度和生物量研究

“大洋一号”调查船于2011年5—6月在南大西洋中脊14°S附近进行了7个站位的小型底栖生物采样。共鉴定出小型底栖生物10个类群。小型底栖生物平均丰度为(60.63±54.77) ind/10 cm²,平均干重生物量为(9.42±8.92) μg/10 cm²。线虫是其中的优势类群,丰度为(47.42±47.99)ind/10 cm²,占总丰度的78.21%,另外,肉鞭动物和桡足类分别占总丰度的16.63%和3.91%。生物量前3位的类群依次为桡足类、线虫和肉鞭动物。小型底栖生物密度随沉积物深度增加而减少,约73.55%的生物丰度分布在0～2 cm层内。个体大小方面,有75.32%的小型底栖生物粒径处于32～125 μm范围内。     

双台子河口砂质潮间带小型底栖动物的群落结构及其对环境的响应

潮间带是典型的陆海交互区,其生物群落及其环境具有典型性特征。海洋小型底栖动物具有极高的群落多样性和环境适应性,但是其时空分布特征以及与环境因子的关系研究具有区域局限性。2017年春季(5月)、夏季(8月)和秋季(10月)于我国纬度最高的双台子河口潮间带,布设7个断面,21个站位,进行了小型底栖动物和沉积环境的定量采样与分析。共检获7个小型底栖动物主要类群,总平均丰度和生物量分别为(3530±1474)ind./10cm2和(1836.5±976.3)μgdwt/10cm2,其中海洋线虫为最优势类群,平均丰度和生物量分别占96.6%和72.1%,其次是双壳类和桡足类。丰度/生物量的季节波动小,自陆向海略呈降低趋势(高位≥中位>低位),统计分析表明其与中值粒径和和叶绿素a含量显著相关。小型底栖动物群落受季节和潮位影响显著, Bio-env分析显示相关性最高的环境因子组合为沉积物中值粒径、叶绿素和脱镁叶绿酸含量。海洋线虫与桡足的比值(N/C)评估显示该区域存在有机污染,且研究区西部最严重,与同区有机污染物的环境评价结果较为一致,说明其在生物监测中具有重要意义。     

The influence of geological, geochemical, and biogenic habitat heterogeneity on seep biodiversity

Cold seeps are among the most heterogeneous of all continental margin habitats. Abiotic sources of heterogeneity in these systems include local variability in fluid flow, geochemistry, and substrate type, which give rise to different sets of microbial communities, microbial symbiont-bearing foundation species, and associated heterotrophic species. Biogenic habitats created by microbial mats and the symbiotic species including vesicomyid clams, bathymodiolin mussels, and siboglinid tubeworms add an additional layer of complexity to seep habitats. These forms of habitat heterogeneity result in a variety of macrofaunal and meiofaunal communities that respond to changes in structural complexity, habitat geochemistry, nutrient sources, and interspecific interactions in different ways and at different scales. These responses are predicted by a set of theoretical metacommunity models, the most appropriate of which for seep systems appears to be the 'species sorting' concept, an extension of niche theory. This concept is demonstrated through predictable patterns of community assembly, succession, and beta-level diversity. These processes are described using a newly developed analytical technique examining the change in the slope of the species accumulation curve with the number of habitats examined. The diversity response to heterogeneity has a consistent form, but quantitatively changes at different seep sites around the world as the types of habitats present and the size-classes of fauna analyzed change. The increase in beta diversity across seep habitat types demonstrates that cold seeps and associated biogenic habitats are significant sources of heterogeneity on continental margins globally.     

Ecophysiological response of meiofauna to physicochemical gradients in intertidal sandy sediments

The spatial and ecophysiological preferences of the most abundant meiofaunal taxa inhabiting the sandy intertidal areas of NW Spain are characterised using ecological profiles methodology. Eh and water content are the best variables to explain the spatial distribution of most of the meiofaunal taxa. In general, most of the taxa show good agreement between the spatial and ecophysiological preferences, except for shear strength, mean grain size, carbonate, chlorophyll-a and depth. Eh and water content are the environmental variables that best explain the occurrence and densities of the majority of the meiofaunal taxa.