黔南石炭纪生物礁造礁群落的基本特征   总被引：11，自引：1，他引：10  

巩恩普张永利  关长庆孙宝亮 《地质学报》2007,81(9):1183-1194

黔南紫云猴场扁平村发育有石炭纪全球罕见的大规模典型的后生动物骨架礁,该礁体的主体部分由大型笙状群体四射珊瑚Fomitchevella建造而成,下部发育点礁层,形成了罕见的、独特的石炭纪礁体类型。对该礁体的造礁群落详细研究,尤其是对Fomitchevella造礁群落的研究后发现,造礁群落内生物结构、物理结构决定了群落的整体面貌而造礁群落的营养结构是维持这种面貌持续发展的主要因素,从而这3个方面共同作用来达到复杂的造礁生态体系的平衡。在礁体的整个发展过程中,后生动物造礁群落的存在与发展是至关重要的,它们维持了一个相对复杂的造礁生态体系的平衡发展。群落的整体面貌、生态体系都是由群落内的关键种所决定的,如果将群落内起到核心作用的物种从群落内移走,那么群落的性质,生物的组成和功能都将发生变化。  相似文献   

区域可持续发展中的环境伦理案例分析:不同社会群体责任     

吴绍洪  戴尔阜  郑度  杨勤业 《地理研究》2007,26(6):1109-1116

环境伦理是对人与自然之间道德关系的认知,在区域发展中构建可持续发展的环境伦理观是实现人与环境协调的核心内容。从区域发展的案例入手,从哲学层面分析区域发展中人与环境产生冲突的原因,构建区域可持续发展环境伦理观,明确不同利益主体应承担的环境伦理责任与义务,是实现可持续发展的必要内容。本文对云南省林浆纸一体化工程进行环境伦理探讨,分析了桉树种植的土地资源、生态效应、纸浆生产的环境影响、经济效益、利益流向等一系列问题;从环境伦理角度对林浆纸工程进行分析,提出了可持续发展环境伦理观建立和环境伦理规范,认为在利益冲突的形势下,应该遵循"非人类中心"的环境伦理准则,贯彻人地和谐的自然观,综合考虑生态安全原则、综合效益原则、公平原则、共赢竞争原则,采取综合思维方法,构建可持续发展的环境伦理观;分析不同社会团体在区域可持续发展建设中的环境伦理责任,提出了决策者群体、企业家群体、媒介群体、科学家群体、公众群体等在环境伦理意识、环境伦理责任、环境伦理义务等方面所应起到的作用。  相似文献   

青岛近海春季大型底栖动物群落特征   总被引：1，自引：0，他引：1  

王宗兴  范士亮  徐勤增  王守强  韦钦胜  臧家业 《海洋科学进展》2010,28(1)

分析2007年4月在青岛近海进行的大型底栖动物定量采集样品资料,研究了该海域大型底栖动物群落的优势种组成和物种多样性、生物量、丰度和群落等级聚类分析(CLUSTER)以及群落受污染扰动情况。本次调查中共获得青岛近海大型底栖动物89种,其中多毛类41种,甲壳动物32种,软体动物5种,棘皮动物6种,其它类群动物5种。群落中优势种以日本美人虾(Callianassa japonica)和日本倍棘蛇尾(Amphioplus japonicus)贡献率较高。平均生物量和丰度空间分布高值区均出现在近岸海域。群落结构聚类分析表明,15个取样站的群落结构相似性程度都非常低,为10%~30%,仅有S10站和S13站、S3站和S9站Bray-Curtis相似性系数达到40%。ABC曲线表明,S6,S7,S12,S13站的底栖动物群落已受到中度扰动,其它各站ABC曲线状态正常,表明底栖动物群落基本未受干扰,处于较稳定状态。  相似文献   

Nocturnal fish utilization of a subtropical mangrove‐seagrass ecotone     

Neil Hammerschlag  Joseph E. Serafy 《Marine Ecology》2010,31(2):364-374

Whereas diel fish migration between mangrove and seagrass habitats has been recognized for decades, quantitative studies have focused mainly on diurnal patterns of fish distribution and abundance. In general, previous studies have shown that fish abundances decline with increasing distance from mangroves; however, evidence for such a pattern at night, when many fishes are actively feeding, is scarce. The present study is the first to report nocturnal fish abundances along a continuous distance gradient from mangroves across adjacent seagrass habitat (0–120 m). Here, we used nocturnal seine sampling to test the null hypothesis (based on diurnal studies and limited nocturnal work) that fish abundance would decrease with increasing distance from shoreline. We focused on species and life‐stage‐specific abundance patterns of Lutjanus griseus, Sphyraena barracuda, Archosargus rhomboidalis, and Haemulon sciurus. Results indicated that assemblage composition and structure differed significantly by season, likely influenced by temperature. However, within each season, the fish habitat use pattern at both the assemblage and species‐specific level generally failed to support our working null hypothesis. Species‐specific analyses revealed that, for most species and life‐stages examined, nocturnal abundance either did not change with distance or increased with distance from the mangrove‐seagrass ecotone. Our results suggest that analyses where taxa are grouped to report overall patterns may have the potential to overlook significant species‐ and stage‐specific variation. For fishes known to make nocturnal migrations, we recommend nocturnal sampling to determine habitat utilization patterns, especially when inferring nursery value of multiple habitats or when estimating fish production.  相似文献   

Respiration partitioning in contrasting subtidal sediments: seasonality and response to a spring phytoplankton deposition     

Maria de Assunção Franco  Jan Vanaverbeke  Dick Van Oevelen  Karline Soetaert  Maria José Costa  Magda Vincx  Tom Moens 《Marine Ecology》2010,31(2):276-290

Biomass and respiration rates of bacteria, nematodes and macrobenthos were estimated in relation to the deposition of the spring phytoplankton bloom at two contrasting sites in the Southern North Sea: one with fine‐grained sediment close to the coastline and another with highly permeable sediments. Sediment community oxygen consumption (SCOC) was also measured. Bacterial biomass was relatively similar at both stations, whereas nematode and macrobenthic biomass were higher in fine‐grained sediment. In fine sediments, bacterial biomass increased quickly after deposition of the phytoplankton bloom, whereas the response of nematodes and macrobenthos was delayed. In coarser sediments, nematodes and macrobenthos also showed a fast response in terms of density and biomass. Respiration in permeable sediments was mainly dominated by bacteria at all periods of the year. Hence, nematode and macrobenthic respiration did not contribute strongly to SCOC. This is in contrast to the patterns observed in finer sediments, where both macrofauna and nematodes were important oxygen consumers as well. Macrobenthos contributed more to total SCOC than did nematodes in winter. However, shortly after the arrival of phytodetritus at the sea floor, nematodes and macrobenthos contributed equally to the total SCOC, indicating that all benthic size classes should be taken into account when investigating marine benthic respiration rates.  相似文献   

Seasonal and temporal trends in metrics of fish community for otter-trawl discards in a Mediterranean ecosystem     

Tsagarakis  K.; Machias  A.; Giannoulaki  M.; Somarakis  S.; Karakassis  I. 《ICES Journal of Marine Science》2008,65(4):539-550

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近30年珠江口海域游泳动物经济物种群落结构变化特征          下载免费PDF全文

徐鹏  谢木娇  周卫国  孙英婷  丁德文  索安宁 《应用海洋学学报》2021,40(2):239-250

本研究以1986—2016年珠江口海域游泳动物调查资料为基础,统计分析了近30年珠江口海域游泳动物经济物种群落结构变化特征及主要经济物种渔获率之间的相关性分析.结果表明:2000年以前和2000年以后珠江口海域游泳动物经济物种群落结构差异明显,2000年以前游泳动物经济物种种类数量显著高于2000年以后(F＝6.711...  相似文献   

Colonization and Disappearance ofMytilus galloprovincialisLam. on an Artificial Habitat in the Mediterranean Sea     

G.D. Ardizzone  A. Belluscio  M.F. Gravina  A. Somaschini 《Estuarine, Coastal and Shelf Science》1996,43(6):665-676

AMytilus galloprovincialispopulation, settled on a new artificial habitat at 12 m depth in the Central Tyrrhenian Sea, was investigated for 10 years. The new substratum, located at a depth lower than the preferential range of the species, was colonized temporarily by mussels which reached very high densities and dominated the benthic community from their colonization until the third year. The length-frequency distribution analysis showed a progressively complex population structure with up to three cohorts. The yearly recruitments were observed once a year in spring. The growth curve provided a maximum length higher than that reported for shallow waters. Nevertheless, the gregarious habits of mussels and the reduced water movement caused edaphic modifications of the substratum, which was covered progressively by sediments and biodeposits (pseudofaeces). Consequently, the population structure was affected by a reduction of the newly recruited cohorts, and mussels disappeared after 5 years of colonization. This may be explained by the reduction in the substratum available for the first settlement (hydroid covering), as well as by the modification of the surface required for final settlement.  相似文献   

The invertebrate benthic community of two solar salt ponds in Aveiro,Portugal     

N. Vieira  F. Amat 《International Journal of Salt Lake Research》1996,5(4):281-286

The invertebrate benthic community of two Aveiro salt pond systems was studied in order to evaluate its diversity, density and the influence of organic matter and salt production. Samples were collected monthly at Esmolas and Tanoeiras. Five groups of benthic organisms were found: Nemathelminthes, Annelida (Nereis diversicolor), Crustacea (Sphaeroma serratum andTanais cavolini), Insecta (Chironomidae), Bivalvia Mollusca (Cerastoderma edule, Spisula solida andMya arenaria) and Gasteropoda Mollusca (Hydrobia ulvae, Cingulla cingullus, Cingulla semistriata, Odostomia rissoides, Odostomia unidentata, Scrobicularia alba, Valvata cristata andPaludestrina acuta). The highest density of the benthic community was observed during the non-productive season in all but the crystallizing pond systems. In both salt ponds, salinity acted as limiting factor. The dominant group was Gasteropoda, although high densities of Bivalvia were recorded in some ponds. In the feeder pond and the channels, species diversity was highest in the Tanoeiras salt pond, probably because its physical and chemical characteristics allowed the development of stable communities.  相似文献   

Hispanic Community Types and Assimilation in Mex-America   总被引：1，自引：0，他引：1  

Terrence W. Haverluk 《The Professional geographer》1998,50(4):465-480

I argue that discrepancies among Hispanic assimilation models can be interpreted through three distinct types of Hispanic communities—continuous, discontinuous, and new. Continuous communities were founded by Hispanics and Hispanics have always been the majority population. As a result, Hispanics have not assimilated as predicted by traditional models. Discontinuous communities were originally settled by Hispanics, but eventually were filled by a minority population. Since WWII, many of these communities have experienced a Hispanic demographic resurgence making assimilation more problematic. Hispanics in new communities are recent immigrants to Anglo dominant communities and are more apt to follow the traditional assimilation model.  相似文献