Seeing the ocean through the eyes of seabirds: A new path for marine conservation?

Seeing the ocean through the eyes of seabirds could help meet the challenges of managing common-pool marine resources both in protected and unprotected areas. First, seabirds are top-predators, exposed to all threats affecting the oceans, and this makes them ideal sentinel organisms for monitoring changes within marine ecosystems. Second, seabirds cross both ecological and political boundaries, and following their movements should help making interdependencies within and between marine ecosystems more visible. Third, seabirds are conspicuous and often charismatic animals, which interact differently with different groups of stakeholders and provide the opportunity to acknowledge and discuss each other's values and interests. In this paper, we present these research avenues using a seabirds’ view, for tackling marine conservation and management issues, and we give operational examples of implementation based on our work in the English Channel.     

文蛤早期发育阶段生长性状遗传参数的估计

采用部分因子设计构建了23个全同胞家系,应用单性状及两性状动物模型对文蛤(Meretrix meretrix)早期不同生长发育时期的生长性状进行遗传力和相关性估计。结果表明,文蛤附着变态期以及稚贝期生长性状的遗传力并无显著差别,在0.11~0.41范围内变化,属于中等遗传力。非遗传的共同环境效应随着年龄的增长而呈现上升趋势,由附着变态期的0.02逐渐增加到稚贝期的0.38,且稚贝期的共同环境效应显著大于其附着变态期(P0.01)。壳长与壳高表型相关和遗传相关的分析结果显示,从附着变态期到稚贝期,壳长与壳高之间的表型相关及遗传相关都存在极显著的正相关性,相关系数的范围分别为0.84~0.95、0.93~0.99。早期发育连续时间段生长性状之间的遗传相关均为正相关,但并不显著,且不同时期的遗传相关也不尽相同(0.34~0.71)。     

夏季辽东湾西部海域大型底栖动物群落结构与多样性

为了解夏季辽东湾西部海域大型底栖动物群落结构与多样性,作者于2009年8月对六股河口外海域15个站位进行了大型底栖动物调查。整个研究海域共采到大型底栖动物124种,其总平均丰度为(2824±1537)个/m2,总平均生物量为(22.01±38.58)g/m2。利用相对重要性指数和优势度指数所确定的前三位优势种一致,分别为二齿半尖额涟虫(Hemileucon bidentatus)、深钩毛虫(Sigambra bassi)和独指虫(Aricidea fragilis),其余优势种存在细微差异。各站位香农-维纳多样性指数、Pielou均匀度指数和Margalef丰富度指数均呈现河口和中部海域低,近岸和外围海域高的分布规律。在50%相似度水平上,可将研究海域划分为4个群落。研究结果表明:研究海域底栖环境整体清洁,底层水环境因子对大型底栖动物群落的影响较弱。     

不同饵料种类、投喂方式及环境条件对凡纳滨对虾相对摄食量的影响

为提高对虾养殖过程中的饵料利用率并减少养殖废水的排放,作者以凡纳滨对虾(Litopenaeus vannamei)为实验对象,研究了不同饵料种类、投喂方式、体质量、充气量、光照强度、水温及盐度对其相对摄食量的影响。结果表明:配合饲料组对虾的相对摄食量显著高于冰鲜虾肉组;连续单颗投喂时对虾的相对摄食量较高;相对摄食量随对对虾体重升高而显著(P0.01)下降,而且不同规格的对虾在竞争条件下平均相对摄食量会降低;充气量6 L/min组对虾的相对摄食量明显高于另外两组;弱光环境下对虾的相对摄食量较高;水温和盐度对相对摄食量的影响极显著(P0.01),在32℃时对虾获得最大相对摄食量,在盐度为5时相对摄食量最小,高盐度下组间差异不显著(P0.05)。因此,在实际生产中应采取少量多次的投饵策略,并根据环境条件的变化合理的调整投饵量。     

Protection of marine birds and turtles at St Brandon’s Rock,Indian Ocean,requires conservation of the entire atoll

A survey of seabirds and turtles at St Brandon’s Rock, 400 km north of Mauritius, was undertaken in 2010. We estimated that 1 084 191 seabirds comprising seven breeding species and excluding non-breeders were present at the archipelago and we counted 279 turtle tracks and nesting pits of green turtles Chelonia mydas. Hawksbill turtles Eretmochelys imbricata were also present. Analyses of 30 different islets that make up the atoll showed that the seabird species mostly partitioned their use of islets based on islet size, with four species preferring larger islets and two species preferring smaller islets. Alien species introduced historically are still present and other threats, such as shipwrecks, remain. We propose conservation and other measures that should adequately protect the birds, turtles and coral reef by treating the atoll as a system.     

Back to the future: reflections and directions of South African marine bioinvasion research

Biological invasions continue to increase around the world, with impacts on many coastal marine systems. Here we review the South African marine invasion literature which, despite the field being relatively new, has grown to have significant presence in both the local and international arenas. Of the 79 papers reviewed, 70% focused on the establishment and spread of alien species, with modes of transport and introduction largely overlooked. An emphasis was also apparent towards field studies, in particular survey work, with few experimental studies. The overwhelming majority of papers focused on a single species, the Mediterranean mussel Mytilus galloprovincialis, reflecting the scale of this invasion and the tractable nature of rocky shores as study systems. With the exception of this one species, the impacts of marine alien species have rarely been quantified. We suggest that future research extends the taxonomic coverage of present work and develops a better understanding of the mechanisms of introduction, establishment and spread of marine alien species. Through an experimental approach, the drivers of altered ecological patterns and processes resulting from invasions should be addressed, providing insight into associated impacts. This approach will maintain the local applicability and international relevance of South African marine invasion research.     

温石棉通过活性氧激活线粒体通路诱导A549细胞凋亡的机制研究

探讨活性氧(reactive oxygen species,ROS)在温石棉激活线粒体通路诱导A549凋亡中的作用。采用不同浓度温石棉粉尘染毒人肺上皮细胞(A549)后,MTT法检测细胞存活率,流式细胞术检测ROS抑制剂N-乙酰半胱氨酸(N-acetyl-L-cysteine,NAC)预处理前后的细胞凋亡率、胞内ROS水平及线粒体膜电位,Western Blot法检测各组细胞半胱天冬氨酸蛋白酶3(caspase-3)、p53蛋白表达水平。实验结果显示,温石棉可降低A549细胞存活率,呈现时间-剂量效应关系;NAC可显著减少胞内ROS水平、阻止线粒体膜电位下降,并下调caspase-3、p53蛋白的表达水平,抑制部分细胞凋亡的发生。表明ROS可通过诱导p53蛋白过表达,激活线粒体凋亡通路,诱导A549细胞发生凋亡。     

生物土壤结皮固沙理论与实践

生物土壤结皮是由土壤微生物、藻类、地衣和苔藓等孢子植物类群与土壤颗粒形成的有机复合体,在全球干旱区地表广泛分布,是干旱地表生物覆被层的主要构建者.生物土壤结皮是荒漠植物群落演替的先锋类群,能够提高荒漠地表的稳定性,固定碳和氮等营养元素,增加土壤肥力,并在保持土壤水分方面发挥重要作用,因此在干旱区受损地表的生态修复方面具...     

Measuring species richness on sandy beach transects: extrapolative estimators and their implications for sampling effort

Species richness is a measure that is fundamental to many studies in ecology, and it is particularly important on sandy beaches, where it underlies patterns described by the broadly accepted swash exclusion hypothesis. However, its estimation in practice is problematic. This has led ecologists in other fields to adopt extrapolative estimators of species richness, which project the total number of species present in a habitat by adjusting upward the number of species observed by an amount related to the number of rare species encountered in the samples. In so doing, the species richness can be estimated, with confidence intervals, at any level of sampling effort. Despite the availability and advantages of these methods, beach ecologists have continued to use the observed species richness as a point estimate of biodiversity for beaches. Here, we employ a Monte Carlo resampling approach over a range of routine transect designs used to sample sandy beaches, and evaluate the performance of seven non-parametric extrapolative estimators for species richness relative to that of the more conventionally used observed species richness. We find that the first-order Jackknife estimator (Jack 1) is the least biased, most accurate and most consistent across sites. Employing this estimator would allow accurate estimation of species richness on short (tens of metres) stretches of beach without exceeding the acceptable levels of sampling effort (4–5 m²). Spreading this effort evenly over three across-shore transects, each with a minimum of 13 equally spaced levels seems appropriately efficient. Although a greater number of research studies is required to ascertain the generality of these results beyond the beaches we sampled, we tentatively recommend the application of our results in biodiversity surveys on sandy beaches.     

Analysis on the indicator species and ecological groups of pelagic ostracods in the East China Sea

Ecological adaptation and ecological groups of pelagic ostracods were examined in the East China Sea （23°30′-33°00′N, 118°30′ -128°00′E）, in relation to temperature and salinity. The data were collected in four surveys conducted from 1997 to 2000. The density, yield density, or negative exponent models were used to determine the optimal temperature and salinity of water for the thriving growth of pelagic ostracods. Thereafter, ecological groups and potential distribution patterns of pelagic ostracods were determined based on the predicted parameters such as optimal temperature and salinity, consulting the geographic distribution. The analytical results indicate that, among the numerical dominant pelagic ostracods in the East China Sea （ECS）, Euconchoecia aculeata, E. elongata, E. chierchiae, E. maimai, and Cypridina dentata, etc. are offshore subtropical water species. These species are widely distributed in the area, and they can be brought by the warm current to north offshore during spring and winter. The predicated optimal temperature （OT） and optimal salinity （OS） for Paraconchoecia decipiens, P. echinata, P. spini- fera, P. oblonga, Conchoecia magna and Porroeciaporrecta are all greater than 25℃ and 34 separately. These species are mainly distributed in the waters of the Kuroshio, the Taiwan Warm Current, and the Taiwan Strait, and therefore are designated as ocean- ic tropical water species. On the other hand, Pseudoconchoecia concerttrica is considered as offshore subtropical water species based on its geographical distribution although its OT is 19℃. The other species, though their OSs are approximately 34 and with OTs ranging from 20° to 25℃, are considered as offshore subtropical water species because they were found to be widely distributed from the South China Sea to the East China Sea.