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151.
Jennifer Vandenhecke Matthieu Waeles Jean-Yves Cabon Cédric Garnier Ricardo D. Riso 《Estuarine, Coastal and Shelf Science》2010
Over this one-year study, the variations of inorganic As species were examined monthly along the salinity gradient of the Penzé estuary (NW France) in relation with different biogeochemical parameters. In most cases, dissolved As exhibited a non-conservative behaviour which resulted from the competition between two major processes. In the upstream section of the estuary, a strong input of both total inorganic As and As(III) occurred. Then, the removal of the same species, under precipitation of iron oxides/oxyhydroxides, was observed in the low-salinity range (S < 10). Using our experimental data, the fluxes of the various As species were estimated for the first time in estuarine waters. Inputs from the river were mainly constituted of particulate As (∼70%). Conversely, dissolved species were predominant in the net fluxes (∼65%) and As(III) accounted for ∼15% of the dissolved net flux. 相似文献
152.
153.
胶州湾中部海域秋、冬季大型无脊椎动物群落结构及多样性研究 总被引:4,自引:1,他引:3
根据2008年9月~2009年2月在胶州湾中部海域进行的逐月定点底拖网调查,对该海域秋、冬季大型无脊椎动物群落结构及多样性变化进行了初步研究.结果表明,胶州湾秋、冬季共捕获大型无脊椎动物60种,其中甲壳动物和软体动物是主要的无脊椎动物类群;优势种组成具有较明显的月间变化,主要为口虾蛄Oratosquilla oratoria、短蛸Octopus ocellatus、脊腹褐虾Crangon affinis等湾内定居性种类及洄游性较小的种类.Margalef种类丰富度指数范围为1.998~4.669,自9月起逐月递减,11月达到最低值,随后又逐月升高,2月达到最高值;Shannon-Wiener多样性指数和Pielou均匀度指数范围分别为1.325~2.500和0.422~0.693,逐月变化趋势与物种丰富度指数基本一致.多样性指数与海域温度、盐度和深度等环境因子均无显著性相关.多元统计分析表明,胶州湾中部海域秋、冬季大型无脊椎动物群落可划分为2个时间组群;组群间群落种类组成结构差异不显著. 相似文献
154.
以额河源流采金后废弃矿区为研究对象,于2011—2015年期间,通过采取不同恢复措施从被破坏矿区草地植物多样性和生物量的角度分析植被恢复效果。结果表明:(1)不同恢复措施促使各植物群落的物种数增加了5%~30%,说明采取恢复措施使得矿区生态环境得到了一定程度的恢复。(2)综合植被群落结构、盖度和地上生物量、物种多样性指数分析,措施A5(推平+圈羊)、A4(推平+补水)、A3(推平+覆土+黑加仑)较其他措施恢复效果更为显著。(3)通过对各样地植被丰富度指数(R)、Shannon Wiener指数(H′)、Simpson指数(D)、Pielou (Jsw)指数与地上生物量分别进行回归分析,发现指数曲线拟合关系最好。表明物种多样性与地上生物量均存在较显著的正相关关系(P <0.05)。本研究可为类似矿区的植被恢复与重建提供参考和借鉴。 相似文献
155.
森林冠层和林窗的结构及其时空变化是理解森林生态系统格局、动态变化过程的重要基础。在当前生物多样性监测倍受关注的契机下,如何以合适的手段准确描述林窗面积、分布等特征,并与森林固定样地监测数据有效地结合,更好地回答群落构建的理论问题,使森林群落物种多样性维持机制得到更全面的认识,是目前亟待解决的问题。以鼎湖山南亚热带常绿阔叶林20hm2固定监测样地为研究对象,基于不同遥感影像提取方法对其林窗和林冠表层数据进行提取分析。结果表明:基于监督分类的提取方法适合RGB波段航片林窗的提取,在林窗分类中,应首先确定林窗高度、边界木与最小面积,不同分类方法差异主要表现在林冠分类中,林窗分类生产者精度和用户精度表现都较为一致。无人机航拍识别率受地形因素影响较大,在地形复杂林地应按坡度分区域进行飞行以降低误差。相对于地面调查,MD4-1000无人机航片的林窗识别率为98.7%;大疆Phantom4无人机航片的林窗识别率为72.3%,影像后期处理数据量小,同样适用于森林林窗定量研究,符合生态学、林业等从业人员对大型样地林窗长期监测的要求。无人机航拍南亚热带森林物种识别难度较大,基于MD4-1000无人机搭载的高分辨率相机,在地势平缓区域优选的4 hm2样地中可识别林冠表层物种数17种,共2 706个个体。搭载高分辨率无人机在降低飞行高度的基础上可进行部分物种识别。应用无人机近地面遥感对森林固定样地进行林冠监测,可为后期群落构建研究提供数据基础,有望从新的研究角度探讨森林群落物种多样性维持机制。 相似文献
156.
高分六号卫星具有覆盖广、多种分辨率、波段多的优势,能为遥感解译提供更丰富的信息。为探究高分六号卫星新增波段在森林树种识别上的应用,本文以覆盖根河市阿龙山林业局的一期高分六号宽幅影像为数据源,基于特征优化空间算法(Feature Space Optimization,FSO)和最大似然分类法,分别利用高分六号的前4个波段和所有波段(8波段)的光谱、纹理等特征进行了森林树种分类,并逐一添加新增波段特征确定了各波段的贡献率排名。结果表明:在加入了优选出的均匀性纹理、均值纹理和角二阶矩纹理3种纹理特征后,前4波段和8波段的分类精度比只基于光谱特征时的精度分别高出13.23%和24.63%;利用8波段信息比只利用前4波段在基于光谱特征上的精度高11.88%,在基于光谱+纹理特征上则高23.24%;基于8波段光谱+纹理特征的树种分类精度最高,达到68.74%,新增4波段的贡献率排名为B6>B5>B8>B7,说明新增红边波段对于本次树种分类试验的贡献率最高,能为北方树种识别提供有效帮助。 相似文献
157.
Alan Warren 《中国海洋大学学报(英文版)》2009,8(4):317-321
The morphology and infraciliature of a new marine colepid ciliate, Apocoleps magnus gen. nov., spec. nov., are described based on living observations and silver impregnations. The new genus Apocoleps is characterized by having 8 (vs. 6 in most other related genera) armour tiers, spines at both ends of the cell, 3 adoral organelles and plates with 4 reniform uni-windows. Apocoleps magnus spec. nov. is defined by the following features: body elongated and slightly curved, about 100–120μm× 35–45 μm in vivo; an... 相似文献
158.
ZHENG Lianming LIN Yuanshao LI Shaojing CAO Wenqing XU Zhenzu HUANG Jiaqi 《海洋学报(英文版)》2009,28(1):109-115
Aequorea taiwanensis, a new hydrozoan species from the Taiwan Strait was described using morphological and molecular characteristics. Both morphological and mitochondrial cytochrome oxidase subunit I (mtCOI) data supported A. taiwanensis n. sp. as a valid species. Sequence divergence and genetic distance of A. taiwanensis n. sp., A. papillata and A. conica were analysed based on the mtCOI gene sequences. The mtCOI sequences from these three species of the genus Aequorea showed high variation frequency, with sequence divergences ranging from 9.10% to 11.9%, and pairwise genetic distances ranging from 0.097 to 0.130. MtCOI sequence analysis provided diagnostic molecular systematic characteristics for accurate identification and discrimination of the species of Aequorea or their populations, and will be used to resolve evolutionary relationships among them.It was suggested that 10%—20% pairwise mtCOI sequence differences indicated the specieslevel divergence among congeneric species in the Hydromedusae. 相似文献
159.
Nine species of Prionospio complex are recorded from China’s waters, including one new species and six newly recorded species. Prionospio (Prionospio) pacifica sp. nov., is characterized by having first and forth pairs of branchiae pinnate, second and third pairs of apinnate, ventral crest on Setiger 9 and dorsal crests on Setigers 10—25. Apoprionospio kirrae (Wilson, 1990), Prionospio (Aquilaspio) convexa Imajima, 1990, Prionospio (Minuspio) multibranchiata Berkeley, 1927, Prionospio (Prionospio) bocki Sderstrm, 1920, Prionospio (Prionospio) dubia Maciolek, 1985 and Prionospio (Prionospio) paradisea Imajima, 1990 are recorded for the first time from China’s waters. 相似文献
160.
Biodiversity patterns of free-living marine nematodes in a tropical bay: Cienfuegos, Caribbean Sea 总被引:2,自引:0,他引:2
M. Armenteros A. Ruiz-Abierno R. Fernndez-Garcs J.A. Prez-García L. Díaz-Asencio M. Vincx W. Decraemer 《Estuarine, Coastal and Shelf Science》2009,85(2):179-189
Spatial and temporal biodiversity patterns of free-living marine nematodes were studied in Cienfuegos Bay, a tropical semi-enclosed basin in the Caribbean Sea. Taxonomic (to species level) and functional (biological trait) approaches were applied for describing the assemblage structure and relating it to abiotic environment based on a sampling scheme in six subtidal stations and three months. Biological trait approach added relevant information to species pattern regarding relationships between diversity patterns and the abiotic environment. The most common morphotypes were deposit feeding nematodes, with colonising abilities of 2–3 (in a scale from 1 to 5), tail conical cylindrical or filiforme and body slender; and their abundance were correlated with depth, organic matter and silt/clay fraction. In spite of a high turnover of species, functional diversity of assemblages did not change notably in space and time. A result probably due to sampling of the habitat pool of species and to low heterogeneity of the studied muddy bottoms. Chemical pollution (organic enrichment and heavy metals) and hydrodynamic regime possibly drove the biodiversity patterns. Spatial distribution of assemblages support the existence of two well differentiated basins inside the bay, the northern basin more polluted than the southern one. The low hydrodynamic regime would determine a poor dispersion of nematodes resulting in high spatial variance in the assemblage structure; and also the associated hypoxic conditions and pollutants in sediments can explain the dominance of tolerant nematode species such as Daptonema oxycerca, Sabatieria pulchra, Terschellingia gourbaultae, and Terschellingia longicaudata. A comparison of spatial–temporal patterns of biodiversity between Cienfuegos Bay and other semi-enclosed bays in temperate regions suggests several similarities: nematode assemblages are strongly influenced by anthropogenic disturbance, temporal trends are weak or overridden by spatial ones, and few cosmopolitan genera/species tolerant to pollution and hypoxic conditions are dominant. 相似文献