福建海坛海峡潮间带大型底栖动物群落结构及次级生产力

为了解海坛海峡潮间带大型底栖生物现状,我们于2005年10月、2006年4月在位于台湾海峡北端的海坛海峡设置6条断面,依据<海洋监测规范第7部分:近海污染生态调查和生物监测>(GB17378.7-1998),进行潮间带大型底栖动物采样.共采获潮间带大型底栖动物228种,其中多毛类77种、软体动物75种、甲壳动物52种、棘皮动物7种、鱼类5种、其它类群动物12种.年平均生物量(湿重)为12.14 g/m2,年平均密度为571.5 ind./m2 .在数量组成中,软体动物占优势(314.2 ind./m2, 5.38 g/m2),其次是多毛类(20 4.7 ind./m2, 3.35 g/m2).Shannon-Weiner多样性指数3.419, Margalef物种丰富度指数3.271, Pielou均匀度指数0.780, 群落特征表明海坛海峡潮间带生态环境属正常状况.年平均去灰干重2.19 g(AFDW)/m2,依据Brey(1990)的公式计算,潮间带大型底栖动物次级生产力3.72 g(AFDW)/ (m2·a),年平均P/B值为1.74 a-1,表明海坛海峡潮间带大型底栖动物中,个体小、生命周期短、繁殖力高、栖息密度大的种类对潮间带大型底栖动物次级生产力的贡献较大[动物学报 54(3):428-435,2008].     

Temporal patterns of benthic community development in an Arctic fjord (Kongsfjorden, Svalbard): results of a 24-year manipulation study

We investigated temporal patterns of recolonisation and disturbance in a benthic hard bottom community in high-arctic Kongsfjorden from 1980 to 2003 through annual photographic surveys. A manipulative sampling design was applied, where half of the study area (treatment areas) was cleared at the beginning of the study. Twenty-three different taxa and groups of benthic epifauna were found in the photographs. The benthic community structures of treatments and controls converged within the first decade, but significant differences prevailed until ≤13 years after the start of the study. We could distinguish between three different time intervals with increased inter-annual changes. While the observed differences during the first two intervals could be attributed to recolonisation and succession, the changes in interval 3 were mostly due to increased external forcing and characterised by low inter-group and high inter-annual differences. During this interval, brown algae (mainly Desmarestia) and the sea urchin Strongylocentrotus droebachiensis emerged in high densities, while sea anemone populations declined. Different recolonisation patterns for individual species were related to life span, rate of maturity, predators and larval settlement. We could not find a climax stage in the succession for the benthic community at Kvadehuken, presumably due to the constant level of disturbances at the site.     

Effects of the exotic invader Musculista senhousia on benthic communities of two Mediterranean lagoons

The impact that the alien mussel Musculista senhousia has on benthic biodiversity and community structure was investigated in two Italian transitional environments, where the species was particularly abundant: the Sacca di Goro (Adriatic Sea), and the Rio Padrongiano Deltaic area (Sardinia, Tyrrhenian Sea). Sampling campaigns were conducted by sampling mussel beds from each of two different patch size classes (small: <1.0 m², and large: >10.0 m²), and the surrounding bare sediments. At both study sites, mussel density varied greatly with time within and between patches. Despite the huge difference in benthic species complement at Goro and Padrongiano (33 and 115 taxa, respectively), at both sites the presence of mussel patches had a gross positive effect on the benthic community. At Goro, many trophic guilds showed a positive relationship with mussel abundance. At Padrongiano, a continuous and directional process of patches colonization (both large and small) through time seemed evident, while at Goro the process was interrupted by high-summer mortalities. At both study sites, M. senhousia played a double role: (1) as secondary substratum, enhancing the environmental structural complexity, and (2) as densely aggregated, living organisms, thus giving rise to a number of possible interactions with other invertebrates. The outcome, however, was strictly dependent by the level of anthropogenic stress, in this case water oxygen deficiency, which was different at the two study sites. Guest editors: A. Razinkovas, Z. R. Gasiūnaitė, J. M. Zaldivar & P. Viaroli European Lagoons and their Watersheds: Function and Biodiversity     

西沙赵述岛潮滩星虫形态特征及其环境适应性

基于2018年夏季赵述岛潮滩现场调查数据,研究西沙赵述岛潮滩内星虫物种组成,并结合沉积物和组织切片分析星虫对环境的适应性特征。在潮滩上设置3个取样站进行定性和定量研究,并对星虫肠道内沙粒组成和摄食消化结构进行测定与观察。结果显示,西沙赵述岛潮滩现存罗岛管体星虫(Siphonosoma rotumanum)、库岛管体星虫(S. cumanense)和富岛管体星虫(S. funafuti),组成比例为4︰2︰1,三种管体星虫生长环境相同,栖息层次均为10～15 cm。管体星虫肠道内均充满沙粒,去除沙粒后可观察到小型颗粒碎屑(10μm,占90%)、硅藻类、桡足类(300μm)和植物纤维碎片等。下行肠(前肠)内大颗粒(粒径0.25mm)沙粒比例(77.65%)高于上行肠(后肠)(62.67%),下行肠内小颗粒(粒径≤0.25mm)沙粒(22.34%)低于上行肠(37.33%),表明管体星虫对珊瑚礁砂砾具有细化作用。管体星虫(体重为8.5 g)吻部和躯干部角质层厚度分别为59.08μm和231.92μm,收吻肌由9 000～9 500个肌纤维组成,表明发达的角质层是对珊瑚礁粗糙底质的适应,收吻肌可以保证完成摄食过程。下行肠内的褶皱、肌纤维明显少于上行肠和直肠,表明管体星虫的消化过程主要发生在后段,这可能与珊瑚礁底质中的有机质含量低有一定关系。     

The effects of bioturbation on particle redistribution in Mediterranean coastal sediment. Preliminary results

In order to quantify bioturbation processes in a coastal Mediterranean ecosystem, experiments were performed to determine sediment mixing rates resulting from macrobenthos activity. Particle flux was measured in situ for 22 days using luminophores, which are colored sediment particles with sizes ranging from 10 to 200 µm.In sediment depths from 0–5 cm, particle mixing was intensive due to high macrobenthos abundance. A small quantity of luminophores was transported down to a depth of 14 ± 2 cm, where the macrofauna was represented principally by Polychetes. In a control experimental structure — without benthic fauna — no transfer of luminophores into the sediment was recorded.Sediment particle mixing measured in the ecosystem studied is intensive, and is the result of high macrobenthos activity. Different mixing modes occur with scales and rates depending on the organisms present. The luminophore profile resulting from bioturbation processes is explained by an intensive bioadvection sediment mixing added to a biodiffusive mixing with an order of magnitude of 10^–6 cm² s^–1. Tracer accumulations between 1 and 2 ± 1 cm and between 4 and 5 ± 1 cm are attributed to bioadvection activity of two or more distinct populations. Studies over a larger time scale have been undertaken to monitor developments in the observed subsurface maxima.     

南沙群岛渚碧礁大型底栖动物群落特征

利用2002年5月12日至5月21日在南沙群岛渚碧礁用轻潜水(SCUBA)方法于该礁盘不同位置设立的4个定量取样站采集的调查资料,采用IRI指数、ABC曲线方法和大型多元统计分析软件PRIMER对渚碧礁大型底栖动物进行等级聚类分析(CLUSTER)和非度量MDS标序,研究群落结构格局以及用Shannon-Wiener指数、物种丰富度指数和物种均匀度指数分析物种多样性和群落种类组成的相似程度,对渚碧礁大型底栖动物的群落结构进行了初步研究。结果表明:调查获得渚碧礁调查站大型底栖动物总种数314种,平均栖息密度为357.94个/m2,平均生物量为64.85g/m2;群落中主要的重要种或优势种为粗糙毛壳蟹(Pilodius scabriculus)和鼓虾(Alpheus spp.),但IRI指数相对较低;群落结构聚类分析和MDS标序表明,4个取样站的群落结构非常相似,Bray-Curtis相似性系数达到80%以上。     

Assessment of the spatial variability of intertidal benthic communities by axial tomodensitometry: importance of fine-scale heterogeneity

At the water-sediment interface of aquatic ecosystems, the presence of biogenic structures produced by benthic invertebrates strongly affects biogeochemical processes. The quantification of these structures and the assessment of the vertical distribution of fauna are essential for determining the impact of communities in sediments. In the present study, computer axial tomodensitometry (CAT-scan) was used to measure the space occupied by an intertidal community of the St. Lawrence estuary. Three cores were sampled at a site that was considered homogeneous according to surface sediments. The vertical distribution of biogenic structures and gravel were measured in the three cores using CAT-scan; the vertical distribution of fauna was also analysed for each core. The biogenic structures were highest at the water-sediment interface and decreased with depth in the three cores. The number of invertebrates also decreased with depth. We observed similar distributions of biogenic structures in cores 1 and 2. However, fewer biogenic structures were observed below 90 mm in core 3. This result was correlated with a high quantity of gravel from 90 to 140 mm in core 3 whereas the other cores had lower quantities of coarse material. We found relationships among the distributions of biogenic structures, fauna, and sediment characteristics (gravel quantity) that can affect species distribution. The vertical distributions of Macoma balthica, Mya arenaria, Nereis virens, and small-sized gallery-producing species (nematodes and oligochaetes) could also be recorded with the CAT-scan method. Thus, CAT-scan is an excellent tool to determine the fine-scale heterogeneity in the space occupied by benthic invertebrates in sediments.     

Abundance and germination capability of resting cysts of Alexandrium spp. (Dinophyceae) from faecal pellets of macrobenthic organisms

The Alexandrium spp. resting cysts were found abundantly in faecal pellets collected from the bottom sediments at two stations in Hiroshima Bay. It is considered that these faecal pellets were excreted by the macrobenthos, such as polychaeta and mollusca, based on their size and morphology. Polychaeta was the most dominant macrobenthos, and mollusca was the second most dominant group in Hiroshima Bay. The resting cysts of Alexandrium spp. in the bottom sediments at the two stations were counted in both the faecal pellets of macrobenthos and in the surrounding sediment. As a result, the number of cysts in the faecal pellets accounted for 28.9-35.2% of total cysts. In addition, cysts isolated from faecal pellets had almost the same germination ability as those in the sediment. Thus, Alexandrium cysts are tolerant to the predation and digestive processes of macrobenthic organisms.     

Seasonal variations in macrobenthic taxonomic diversity and the application of taxonomic distinctness indices in Bohai Bay,northern China

Taxonomic diversity indices have a number of desirable properties as indicators in the assessment of environmental quality, and have become an important measure in biodiversity studies. Macrobenthic taxonomic variations were studied in Bohai Bay, northern China, an area under threat from rapid human development. Four seasonal cruise datasets were collected between 2006 and 2007. Environmental conditions exhibited large fluctuations due to human development; nitrogen and phosphorus were the main environmental stressors. A total of 97 macrofauna taxa were identified belonging to 88 genera, 72 families, 36 orders, 14 classes, and nine phyla. Analysis of similarity indicated that there were significant assemblage differences across sampling stations as well as seasons. Four taxonomic indices, taxonomic diversity (Δ), taxonomic distinctness (Δ*), average taxonomic distinctness (Δ⁺), and variation in taxonomic distinctness (Λ⁺) were calculated using abundance data. Among the stations and seasons, there were greater variations in both Δ and Λ⁺ than in Δ* and Δ⁺. The funnel plot of Δ⁺ could identify disturbed stations to some extent, but was not always a strong indicator of disturbance. The Δ⁺ performance was better in autumn than in spring, but could not identify a disturbed station in autumn due to a low number of species. The efficiency of taxonomic distinctness may depend on taxa or the pollution indicators. Taxonomic distinctness indices can be effective at assessing environmental degradation when correctly applied; however, they are unsuitable for directly assessing environmental quality in a new area prior to efficiency testing.     

Effect of ecological group classification schemes on performance of the AMBI benthic index in US coastal waters

The AZTI Marine Biotic Index (AMBI) requires less geographically-specific calibration than other benthic indices, but has not performed as well in US coastal waters as it has in the European waters for which it was originally developed. Here we examine the extent of improvement in index performance when the Ecological Group (EG) classifications on which AMBI is based are derived using local expertise. Twenty-three US benthic experts developed EG scores for each of three regions in the United States, as well as for the US as a whole. Index performance was then compared using: (1) EG scores specific to a region, (2) national EG scores, (3) national EG scores supplemented with standard international EG scores for taxa that the US experts were not able to make assignments, and (4) standard international EG scores. Performance of each scheme was evaluated by diagnosis of condition at pre-defined good/bad sites, concordance with existing local benthic indices, and independence from natural environmental gradients. The AMBI performed best when using the national EG assignments augmented with standard international EG values. The AMBI using this hybrid EG scheme performed well in differentiating apriori good and bad sites (>80% correct classification rate) and AMBI scores were both concordant and correlated (r_s = 0.4–0.7) with those of existing local indices. Nearly all of the results suggest that assigning the EG values in the framework of local biogeographic conditions produced a better-performing version of AMBI. The improved index performance, however, was tempered with apparent biases in score distribution. The AMBI, regardless of EG scheme, tended to compress ratings away from the extremes and toward the moderate condition and there was a bias with salinity, where high quality sites received increasingly poorer condition scores with decreasing salinity.