舟山近岸海域主要甲壳类的生态位及其与种间联结性   总被引：3，自引：2，他引：1  

刘惠  郭朋军  陈洲杰  水玉跃  俞存根  邓小艳  颜文超  许永久  郑基 《海洋学报》2019,41(4):83-93

本文基于2015年11月（秋季）和2016年5月（春季）在舟山近岸海域开展80个站位的渔业资源调查所获得的甲壳类资料，将调查海域划分为10个区域，并随机分层抽样选取20个站位进行分析。运用生态位测定、典范对应分析（CCA）、方差比率（VR）、卡方检验、联结系数、种对共同出现百分比、点相关系数等方法进行研究。结果表明:研究海域主要甲壳动物共19种，其中优势种3种，重要种6种。通过生态位宽度聚类分析可将主要甲壳类划分成3类，包括广生态位种、中生态位种和狭生态位种。生态位重叠值区间为[0，0.96]，表明物种对资源利用的相似性差异较大，部分甲壳动物存在资源利用性竞争。CCA排序显示，该海域甲壳类受环境因子中盐度、温度以及叶绿素a影响较大。VR值为4.40大于1，统计量W值为87.91超出置信区间（10.85，31.41），得出甲壳类动物群落总体呈显著正相关，卡方检验显示有61个种对的联结性显著（x2 ≥ 3.841），联结系数（AC）、共同出现百分比（PC）以及点相关系数（Ф）表明种间联结性较强，总体趋于正相关。  相似文献   

Occurrence and ingestion of microplastics by zooplankton in Kenya's marine environment: first documented evidence     

C Kosore  L Ojwang  J Maghanga  J Kamau  A Kimeli  J Omukoto 《African Journal of Marine Science》2018,40(3):225-234

Microplastics can be ingested by marine organisms and may lead to negative impacts at the base of marine food chains. This study investigated the occurrence and composition of microplastics in the sea-surface water and sought evidence of ingestion by zooplankton. Surface seawater was collected using a stainless-steel bucket and sieved directly through a stainless-steel sieve (250-µm mesh), while a 500-μm mesh net was towed horizontally to collect zooplankton, at 11 georeferenced stations off the Kenyan coast in February 2017, on board the national research vessel RV Mtafiti. Microplastic particles were sorted and characterised using an Optika dissecting microscope. Polymer types were identified using an ALPHA Platinum attenuated total reflection—Fourier-transform infrared (ATR-FTIR) spectrometer. A total of 149 microplastic particles, with an average abundance of 110 particles m^–3, were found in the surface seawater. A total of 129 particles were found ingested by zooplankton groups, where Chaetognatha, Copepoda, Amphipoda and fish larvae ingested 0.46, 0.33, 0.22 and 0.16 particles ind.^–1, respectively. Filaments dominated both the surface-water microplastics and the ingested microplastics, contributing 76% and 97% to those compositions, respectively. White particles were prevalent in the water (51%), whereas black was the colour found most commonly (42%) across the zooplankton groups. The sizes of particles that were in the water were in the range of 0.25–2.4 mm, and those ingested ranged between 0.01 and 1.6 mm. Polypropylene was predominant in the surface water, whereas low-density polyethylene was the most-ingested polymer type. The results provide the first documented evidence of the occurrence, composition and ingestion of microplastics by zooplankton in Kenya's marine environment, indicating that microplastics have the potential to enter pelagic food webs and cause pollution in the study area.  相似文献   

灵山岛空气微生物含量的测定   总被引：2，自引：0，他引：2  

孙丕喜  陈皓文  黄秀兰 《海岸工程》2008,27(4):37-41

用平皿自然沉降法测定灵山岛空气微生物及肠道致病菌，结果表明该岛处于空气微生物中-轻度污染状态，以轻度污染为主，其中细菌为主要成分，也舍少量肠病菌，空气微生物显出某种时空变化势态，且与气温、人群活动等因素相关，推测谈岛脆弱的生态环境易被外界干扰，应引起关注。  相似文献   

TOPCAT‐NP: a minimum information requirement model for simulation of flow and nutrient transport from agricultural systems     

P. F. Quinn  C. J. M. Hewett  N. D. K. Dayawansa 《水文研究》2008,22(14):2565-2580

Future catchment planning requires a good understanding of the impacts of land use and management, especially with regard to nutrient pollution. A range of readily usable tools, including models, can play a critical role in underpinning robust decision‐making. Modelling tools must articulate our process understanding, make links to a range of catchment characteristics and scales and have the capability to reflect future land‐use management changes. Hence, the model application can play an important part in giving confidence to policy makers that positive outcomes will arise from any proposed land‐use changes. Here, a minimum information requirement (MIR) modelling approach is presented that creates simple, parsimonious models based on more complex physically based models, which makes the model more appropriate to catchment‐scale applications. This paper shows three separate MIR models that represent flow, nitrate losses and phosphorus losses. These models are integrated into a single catchment model (TOPCAT‐NP), which has the advantage that certain model components (such as soil type and flow paths) are shared by all three MIR models. The integrated model can simulate a number of land‐use activities that relate to typical land‐use management practices. The modelling process also gives insight into the seasonal and event nature of nutrient losses exhibited at a range of catchment scales. Three case studies are presented to reflect the range of applicability of the model. The three studies show how different runoff and nutrient loss regimes in different soil/geological and global locations can be simulated using the same model. The first case study models intense agricultural land uses in Denmark (Gjern, 114 km²), the second is an intense agricultural area dominated by high superphosphate applications in Australia (Ellen Brook, 66 km²) and the third is a small research‐scale catchment in the UK (Bollington Hall, 2 km²). Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Agricultural land use and hydrology affect variability of shallow groundwater nitrate concentration in South Florida     

A. Ritter  R. Muñoz‐Carpena  D. D. Bosch  B. Schaffer  T. L. Potter 《水文研究》2007,21(18):2464-2473

South Florida's Miami‐Dade agricultural area is located between two protected natural areas, the Biscayne and Everglades National Parks, subject to the costliest environmental restoration project in history. Agriculture, an important economic activity in the region, competes for land and water resources with the restoration efforts and Miami's urban sprawl. The objective of this study, understanding water quality interactions between agricultural land use and the shallow regional aquifer, is critical to the reduction of agriculture's potentially negative impacts. A study was conducted in a 4‐ha square field containing 0·9 ha of corn surrounded by fallow land. The crop rows were oriented NW–SE along the dominant groundwater flow in the area. A network of 18 monitoring wells was distributed across the field. Shallow groundwater nitrate–nitrogen concentration [N‐NO₃^?] was analyzed on samples collected from the wells biweekly for 3 years. Detailed hydrological (water table elevation [WTE] at each well, groundwater flow direction [GwFD], rainfall) and crop (irrigation, fertilization, calendar) data were also recorded in situ. Flow direction is locally affected by seasonal regional drainage through canal management exercised by the local water authority. The data set was analyzed by dynamic factor analysis (DFA), a specialized time series statistical technique only recently applied in hydrology. In a first step, the observed nitrate variation was successfully described by five common trends representing the unexplained variability. By including the measured hydrological series as explanatory variables the trends were reduced to only three. The analysis yields a quantification of the effects of hydrological factors over local groundwater nitrate concentration. Furthermore, a spatial structure across the field, matching land use, was found in the five remaining common trends whereby the groundwater [N‐NO₃^?] in wells within the corn rows could be generally separated from those in fallow land NW and SE of the crop strip. Fertilization, masked by soil/water/plant‐delayed processes, had no discernible effect on groundwater nitrate levels. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Surface current and vertical thermal structure on the continental slope in Tosa Bay     

Hiroshi Kuroda  Manabu Shimizu  Yuuichi Hirota  Daisuke Ambe  Hideki Akiyama 《Journal of Oceanography》2008,64(1):81-91

In order to specify a vertical thermal structure related to surface current variation on the continental slope in Tosa Bay, Japan, we analyzed monthly regular hydrographic measurements in the years 1991–2004. Subsurface temperature below 200 m on the slope was found to vary synchronously with the vertical displacement of the main thermocline around 200 m. It is shown that the vertical-averaged temperature below 200 m is significantly correlated with an along-isobath/southwestward surface current velocity on the slope. This correlation indicates that when a strong (weak) southwestward surface current is observed, temperature below 200 m decreases (increases) simultaneously, that is, isotherms below the 200 m are displaced upward (downward) together with the main thermocline. Moreover, when the strong southwestward flow is detected, across-isobath isotherms around 200 m slope upward toward the offshore direction. Furthermore, it is suggested that as the Kuroshio axis moves offshore south of the bay, the southwestward flow tends to be weakened by the combined effect of other Kuroshio parameters such as transport and stream width as well as the Kuroshio axis position. As a result, it is inferred that the correlation between the surface current and subsurface temperature can be interpreted in terms of the formation and decay of an anticlockwise circulation interacting with a cold eddy.  相似文献   

Microbial diversity in polluted harbor sediments II: Sulfate-reducing bacterial community assessment using terminal restriction fragment length polymorphism and clone library of dsrAB gene     

Wen Zhang  Lin-sheng Song  Jang-Seu Ki  Chun-Kwan Lau  Xiang-Dong Li  Pei-Yuan Qian 《Estuarine, Coastal and Shelf Science》2008

Sulfate-reducing bacteria (SRB) are important regulators of a variety of processes in coastal marine sediments regarding organic matter turnover, biodegradation of pollutants, and sulfur and carbon cycles. Yet their community compositions have not been investigated in polluted harbor sediments. This study described the diversity and spatial variation of SRB communities in surface sediments in Victoria Harbor, Hong Kong. The spatial variation of SRB communities was described by terminal restriction fragment length polymorphism (T-RFLP). The results showed that the most diversified terminal restriction fragments were found at polluted sites. In addition, cluster analysis indicated that although the SRB communities were different at the two polluted sites, they were still more similar to each other than to the two more distant reference sites. Based on a dsrAB clone library constructed at a polluted site, diversified SRB were found, represented by 30 Operational Taxonomic Units (OTUs). Upon comparisons among the SRB sequences detected from this study and those in the GenBank, five clades of SRB were found. Three clades belonged to the known families Desulfobacteraceae, Desulfobulbaceae, and Syntrophobacteriaceae. The majority of sequenced clones, which distantly related to sequences in the GenBank, constituted the remaining two unclassified groups, suggesting unique SRB members related to the polluted harbor environment. Statistical analyses indicated that estimated SRB richness correlated with environment factors such as sulfur content, acid volatile sulfate, and redox potential.  相似文献   

Source of and potential bio-indicator for the heavy metal pollution in Ny-(A)lesund, Arctic     

Wang Xiaofei  Yuan Linxi  Luo Honghao  Long Nanye  Wang Yuhong  Sun Liguang 《极地研究(英文版)》2007,18(2)

Three kinds of tundra plant samples including Dicranum angnstum(a type of boreal bryophyte) , PuccineUia phryganodes (a type of fringy p/ant),Salix polaris (a type of vascular plant) and surface soil were samples in 200 at Ny-Alesund of the Arctic.The levels of eight heavy metal elements (Hg, Pb, Cd, Cu, Zn, Ni, Fe and Mn) and three metal-like dements (As, Se, Sr) in the plant and soil samples of the areas within previous coal mining activities are significantly higher than those of other areas.The relative accumulation of these elements in these tundra plant samples is consistent with the one in the soft samples, especially in the areas affected by previous coal-mining activities.Thus, the pollution is apparently from local coal mining activity.Dicranum angustum has the highest concentrations among those elements, and it can be a good bio-indicator for heavy metal pollution in Ny(A)lesund.Though Ny(A)lesund is less polluted by heavy metal than nearby Northern European human living areas, but much more than the tundras of the Alaska, Greenland and the Antarctic.  相似文献   

Granulometric selectivity in Liza ramado and potential contamination resulting from heavy metal load in feeding areas     

Sílvia Pedro  Vera Canastreiro  Isabel Caçador  Eduarda Pereira  Armando C. Duarte  Pedro Raposo de Almeida 《Estuarine, Coastal and Shelf Science》2008

The stomach contents of thin-lipped grey mullets Liza ramado were analysed in terms of granulometric composition and compared to the sediment of potential feeding areas in the Tagus estuary. Total organic matter (TOM) content and heavy metal content were determined in the surface sediment of three areas and eight trace elements were quantified: Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn. The three sampled areas did not differ in TOM; and the heavy metal content was below Effects Range-Low level for most elements. The mean observed concentrations were present in the following sequence: Zn > Pb > Cr > Cu ≈ Ni > Co > Cd > Hg. Stomach contents granulometric composition provided information about the feeding selectivity of the mullets. Sediment fractions with particle size between 20 and 50 μm are preferred, independently of the fishes' length. Smaller standard length (SL) fishes have a higher positive selection of fine grained sediments than those with a larger SL. Finer fractions usually have higher concentration of heavy metals, which makes younger specimens of the thin-lipped grey mullet potentially more exposed to heavy metal load in the estuary. Metal concentration was not independent from the sampling point, presenting higher values near the margins and the estuary tidal drainage system. This means that during the first period of each tidal cycle, the mullets will feed first on the most contaminated areas, as a consequence of their movement following the rising tide to feed on previously exposed areas.  相似文献   

Estimation of non-point source pollution loads under uncertain information   总被引：1，自引：0，他引：1  

Ruzhong Li 《中国地理科学(英文版)》2008,18(4):348-355

Many kinds of uncertainties are involved, such as random, fuzzy, grey, unascertained property and so on, in soil erosion process. To exactly predict the non-point source pollution loads, some uncertainties should be taken into consideration. Aiming at the deficiency of present blind number theory being helpless for fuzziness, a novel blind number, i.e. extended-blind number, was introduced by substituting a set of triangular fuzzy numbers （TFNs）, expressed as a-cuts, for interval values in present blind number, and the expected value of extended-blind number was also brought forward by referring to the current blind number theory. On the basis of denoting the parameters of Uni- versal Soil Loss Equation （USLE） as extended-blind parameters, a novel USLE model was established for quantitatively evaluating soil erosion loss and non-point source pollution loads. As a case, the uncertain USLE was employed for predicting the soil erosion loss and non-point source pollution loads of absorbed nitrogen and phosphorus in a dis- trict in the Hangbu-Fengle River basin, in the upstream of Chaohu Lake watershed. The results show that it is feasible in theory to extend blind number into fuzzy environment and reliable on conclusion to apply extended-blind number theory for predicting non-point source pollution loads.  相似文献