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1.
Most of the Southeast Atlantic Ocean is abyssal, and global bathymetries suggest that only ～3.2% of the areas beyond national jurisdiction (ABNJ; also known as the high seas, as defined in the United Nations Convention on the Law of the Sea [UNCLOS]) are shallower than 2 500 m. This study mapped bathymetry and characterised substrates in selected seamount summit areas, including several that have been or may become fishing areas. The southernmost location, the Schmitt-Ott Seamount, has exposed volcanic bedrock with surrounding flats covered by thin biogenic sediments and/or coral rubble that appears ancient. At Wüst, Vema, Valdivia and Ewing seamounts the basaltic base appears to be overlain by coral caps and other coral substrates (sheets, rubble). Adjacent summit plains have biogenic sediments of varying thickness. Vema has a flat, roughly circular summit, <100 m deep, with the shallowest point being a 22-m-deep summit knoll; the upper slopes have ancient coral framework, but the summit has a mixture of coralline and volcanic rock and coarse sediments, including extensive areas with coralline algae and kelp forests. Valdivia Bank is a 230-m-deep, flat, rocky area (～11 × 5 km), protruding steeply from the extensive multi-summit Valdivia subarea of the Walvis Ridge. The distribution of past fisheries in the Convention Area of the South East Atlantic Fisheries Organisation (SEAFO) was considered in relation to the new information on bathymetry and substrate.  相似文献   

2.
The benthic fauna on reefs around the Glorieuses Islands, a small and protected Indian Ocean archipelago northwest of Madagascar, was surveyed in November 2015, focusing particularly on the orders Alcyonacea (soft corals and gorgonians) and Scleractinia (stony corals). The species richness of both groups was rather low for a protected, relatively pristine environment in the region. Though certain soft ‘fugitive’ alcyonacean species were noticeably abundant, other soft corals were rare. Sediment-tolerant faviid corals were abundant among the scleractinians. The sediment around the reefs was fine-grained and white, and appeared to be derived from abundant green macroalgae Halimeda and coralline seaweeds. The abundance of these, in turn, might have been attributable to nutrient enrichment from guano deposited on one of the islands by migratory seabirds, causing the aforementioned anomalies in coral biodiversity and abundance.  相似文献   

3.
Although continental shelf and slope environments typically exhibit high epifaunal biomass and have been subjected to increasing fishing pressure, ecological information on assemblages of non‐commercial invertebrate species from subtidal and bathyal areas remains limited. Sea stars (Echinodermata: Asteroidea), which are known to influence communities through their feeding habits, have received less attention than structural taxa such as corals and sponges. To better understand the ecological roles of asteroids on continental shelves, we investigated ~30 species and assessed their distributions and co‐occurrence with other benthic invertebrates on the shelf and slope of Eastern Canada. Using fisheries data and in situ video footage, we compiled a large dataset covering ~600,000 km2 that included over 350,000 individual asteroid records (37–2243 m depth). Multivariate analyses revealed geographically distinct asteroid assemblages, with a maximal overall density at 400–500 m and the highest diversity at 500–700 m. The most abundant and densely occurring species was Ctenodiscus crispatus. We found that asteroids associate with corals, sponges, bivalves, and other echinoderms, and that depth and substrate influence these assemblages. We identified species likely to affect coexisting organisms by their burrowing behavior that can disrupt epi‐ and infauna (C. crispatus) and through predation on ecologically important corals (Hippasteria phrygiana). In addition to providing baseline distribution and ecological information for many bathyal asteroid species in the Northwest Atlantic, this work highlights the abundance and diversified roles of asteroids within continental shelf and slope ecosystems.  相似文献   

4.
Chang-Feng  Dai 《Marine Ecology》1993,14(3):185-204
Abstract. The distribution pattern of corals and benthic space partitioning patterns on the fringing reefs of southern Taiwan were studied by the line-transect method. The bathymetric distribution of corals in the study area was basically homogeneous except on the protected reef slopes and the exposed reef fronts and terraces. Corals on protected reef slopes are mainly foliaceous, including Montipora foliosa, Merulina ampliata, Mycedium elephantotus , and Pachyseris speciosa , but the dominant species on a reef slope vary from site to site. The formation of the foliaceous coral community is possibly related to a complex of environmental factors, chance, and biological interactions. The reef fronts and submarine terraces of exposed areas are dominated by alcyonacean corals. The most abundant species are Sarcophyton trocheliophorum, S. crassocaule , and Lobophytum sarcophytoides ; their distributions are relatively homogeneous. The formation of alcyonacean-dominated assemblages can be related to the special adaptive strategies of these corals. In regard to space partitioning patterns, the major space occupiers on those reefs exposed to storm disturbances are alcyonacean soft corals, scleractinian corals, and algae; on reefs protected from storms, scleractinian corals and algae dominate. Two conspicuous features of the study area are the high proportion of space occupied by algae and the abundant unoccupied space. The dense algal cover is possibly caused by sewage pollution and overfishing of the reef area. The unoccupied space is most likely related to the high frequency of typhoon disturbances.  相似文献   

5.
海南岛西北部海域珊瑚礁造礁石珊瑚种类组成与分布   总被引：1，自引：0，他引：1  
调查了海南岛西北部海域造礁石珊瑚种类的多样性及分布.结果表明:共发现50种造礁石珊瑚和1种多孔螅.海南岛西北部造礁石珊瑚优势种为澄黄滨珊瑚(Porites lutea)和丛生盔形珊瑚(Galaxea fascicularis),与历史资料相比优势种发生明显变化;海南岛西北部海域造礁石珊瑚覆盖率急剧下降,是由自然因素和人为活动共同造成;海南岛西北部海域是北部湾、琼州海峡和南海的重要交汇点,可能是造礁石珊瑚幼虫扩散的重要通道,对华南沿岸造礁石珊瑚资源自然恢复起到重要作用.因此,未来的海洋管理应该加强对珊瑚礁的保护力度,开发利用与环境保护并重,这样才能有效保护海南岛西北部海域的珊瑚礁.  相似文献   

6.
Coral reefs of the Turks and Caicos Islands (TCIs) (Caribbean Sea) constitute some of the few pristine coral reef systems in the world and play a crucial role in the islands’ economy because they support rich fisheries catches and tourism development. Ambitious development plans involving increase in fishing and tourism pressures are about to bring changes in coastal zone resources of the TCIs associated with increased sediments and nutrients and reduced predation by herbivorous fish on coral reefs. Understanding change is critical when attempting to protect the resources that these coral reefs support and to adopt proper management strategies. Yet, an environmental assessment program to detect imminent human‐induced changes on the surrounding reefs of the TCIs is lacking. Thus, (i) we obtained baseline data on benthic composition and coral community structure at seven reef sites of representative reefs of the TCIs within the Admiral Cockburn Land and Sea National Park (ACLSNP) of South Caicos Island and (ii) performed a priori statistical power analysis to calculate replication requirements for safely and confidently detecting small (δ = 0.1), medium (δ = 0.3), and large (δ = 0.5) effect sizes for a number of relevant to anticipated changes, univariate, benthic indices and for power β = 0.95. The platforms of the margin reefs studied (9–12 m depth) appeared rather variable regarding benthic composition but quite homogeneous regarding hard coral community structure. Mean percent cover of algal functional groups was 0.1 ± 0.3 (mean ± sd) percent for coralline algae and Halimeda, 0.1 ± 0.6 (mean ± sd) percent for macroalgae, 21.7 ± 33 (mean ± sd) percent for turf algae and 4.8 ± 4.0 (mean ± sd) percent for hard coral cover. The dominant benthic component, however, was carbonate substrate (mean ± sd = 30.4 ± 34.3), thus indicating an accreting reef framework. Mean hard coral density, colony size and recruit density were 5.5 ± 1.8 (mean ± sd) corals per 20‐m line transect, 13.0 ± 2.3 (mean ± sd) cm maximum colony diameter, and 1.3 ± 1.4 (mean ± sd) recruits per square foot, respectively. Due to high natural variance, hard coral colony size and density were practically the most sensitive indices in detecting even small size changes on benthos. Also, the geometric mean of log‐transformed colony size‐frequency distributions of the most abundant hard coral taxa, i.e. Montastrea annularis, Agaricia spp., Siderastrea spp. and Porites asteroides were practically sensitive for the same purpose. We hope that the study will optimize the spatial component of a necessary environmental impact assessment program on coral reefs of the TCIs once the natural spatial variability of the system has been assessed and sensitive, benthic, univariate indices have been identified for representative reference coral reef sites of the TCIs.  相似文献   

7.
Seamounts, knolls, pinnacles and other “seamount-like” features are prominent and widely distributed features of the New Zealand marine environment, and also the focus of important commercial fisheries and some exploratory mineral mining. There is considerable debate about the effects of such activities on the benthic habitat of deep-water seamounts. In 2001 a study was undertaken of eight seamount-features on the Chatham Rise, an area that has been heavily trawled for orange roughy since the early 1990s. Half of the study seamounts were considered unfished and the other half fished. Benthic macro-invertebrate assemblages of each seamount were sampled using epibenthic sleds, whilst the presence of habitat-forming fauna (e.g., live corals), substrate type and indications of trawling (e.g., trawl door marks) were determined using a towed underwater camera. Fisheries catch-effort data were examined to determine the amount and distribution of bottom trawling effort on the seamounts. Analyses of camera data revealed that unfished seamounts possessed a relatively large amount of stony coral habitat comprising live Solenosmilia variabilis and Madrepora oculata (predominantly on the seamount peaks) whereas fished seamounts had relatively little coral habitat. Indications of trawling were observed over six times more frequently on seabed images from fished as opposed to unfished seamounts, and appeared related to the amount of fishing effort on individual seamounts. Multivariate analyses of sled data revealed a significant difference in macro-invertebrate assemblage composition between fished and unfished seamounts. The variability observed in assemblage composition between seamounts can in part be explained by the relative fishing pressure measured by a fishing effects index. The results of the study are discussed with respect to management of seamount habitat, and the need for ongoing monitoring and research to derive conservation practices that allow for sustainable seamount fisheries.  相似文献   

8.
Shallow reefs are among the most diverse ecosystems, and their substrate is densely occupied by sessile organisms that frequently contact physically and interact mutually. Nevertheless, the relative importance of species abundance in shaping physical contacts in these ecosystems remains largely unknown. The aim of this study was to evaluate physical contact interactions, by using tools derived from the complex network theory, between hard corals and other benthic organisms in four areas along the Brazilian coast comprising coral reefs and rocky shores with different physical and biotic structures. It was also investigated whether interactions with corals occurred as expected by the abundance of the benthic organisms in each area, and whether corals belonging to families known as more aggressive interacted less with other organisms. In all areas, the abundance of both corals and contacting organisms directly influenced the abundance of interactions between benthic organisms, regardless of the physical or biological characteristics of the habitat and of the interacting organisms. In addition, coral species interacted more with the most abundant benthic group, the epilithic algal matrix, in all areas. Nevertheless, some evidence was found about biological mechanisms helping to explain the structure of the studied interactions, although to a lesser extent. The obtained networks presented high nestedness and connectance, but low modularity. These patterns indicate the low specificity of the studied interactions and reinforce the role of abundance as an important driver of contacts between sessile organisms in shallow hard bottom ecosystems.  相似文献   

9.
This paper presents the first compilation of information on the spatial distribution of scleractinian cold-water corals in the Gulf of Cádiz based on literature research and own observations (video footage, sediment samples). Scleractinian cold-water corals are widely distributed along the Spanish and Moroccan margins in the Gulf of Cádiz, where they are mainly associated with mud volcanoes, diapiric ridges, steep fault escarpments, and coral mounds. Dendrophyllia cornigera, Dendrophyllia alternata, Eguchipsammia cornucopia, Madrepora oculata and Lophelia pertusa are the most abundant reef-forming species. Today, they are almost solely present as isolated patches of fossil coral and coral rubble. The absence of living scleractinian corals is likely related to a reduced food supply caused by low productivity and diminished tidal effects. In contrast, during the past 48 kyr scleractinian corals were abundant in the Gulf of Cádiz, although their occurrence demonstrates no relationship with main climatic or oceanographic changes. Nevertheless, there exists a conspicuous relationship when the main species are considered separately. Dendrophylliids are associated with periods of relatively stable and warm conditions. The occurrence of L. pertusa mainly clusters within the last glacial when bottom current strength in the Gulf of Cádiz was enhanced and long-term stable conditions existed in terms of temperature. Madrepora oculata shows a higher tolerance to abrupt environmental changes.  相似文献   

10.
Sven Zea 《Marine Ecology》2011,32(2):162-173
The Caribbean sponge Cliona delitrix is among the strongest reef space competitors; it is able to overpower entire coral heads by undermining coral polyps. It has become abundant in reefs exposed to organic pollution, such as San Andrés Island, Colombia, SW Caribbean. Forty‐four sponge‐colonized coral colonies were followed‐up for 13 months to establish the circumstances and the speed at which this sponge advances laterally into live coral tissue and the coral tissue retreats. Cliona delitrix presence and abundance was recorded at seven stations to interpret current reef space and coral species colonization trends. The spread of C. delitrix on a coral colony was preceded by a band of dead coral a few millimeters to several centimeters wide. However, the sponge was directly responsible for coral death only when live coral tissue was within about 2 cm distance; coral death became sponge advance‐independent at greater distances, being indirectly dependent on other conditions that tend to accelerate its retreat. Cliona delitrix advanced fastest into recently killed clean coral calices; however, sponge spread slowed down when these became colonized by algae. The lateral advance of C. delitrix was slower than other Cliona spp. encrusting excavating sponges, probably owing to the greater depth of its excavation into the substratum. Cliona delitrix prefers elevated portions of massive corals, apparently settling on recently dead areas. It currently inhabits 6–9% of colonies in reefs bordering San Andrés. It was found more frequently in Siderastrea siderea (the most abundant local massive coral), which is apparently more susceptible to tissue mortality than other corals. Current massive coral mortality caused by C. delitrix could initially change the relative proportions of coral species and in the long‐term favor foliose and branching corals.  相似文献   

11.
Caribbean reefs have been unevenly surveyed, with many areas lacking baseline data. In this study, the current status of Orbicella reefs, a structurally complex forereef habitat, was quantified in an understudied region, the Eastern Caribbean. During 2011 the same observers surveyed benthic assemblages, coral juvenile density, herbivorous fishes, and invertebrates at 30 Orbicella reefs in four Eastern Caribbean areas: Antigua, Barbados, St Lucia, and St Vincent and the Grenadines (hereafter St Vincent). Not all Orbicella forereefs were functionally the same in the Eastern Caribbean. Benthic communities and herbivorous fishes varied greatly among islands. Hard coral had the highest overall percent cover on most reefs in this study, with an average cover of 22%, and was greater than fleshy macroalgal cover at 83% of the sites. Overall, coral juvenile density was low but was positively associated with higher densities of Diadema antillarum, highlighting the importance of herbivory on the reefs. Nearshore coral reefs in Barbados were in a better state than other areas, exhibiting higher coral cover dominated by spawning corals, higher densities of coral juveniles exhibiting higher coral cover dominated by spawning corals, higher densities of coral juveniles and D. antillarum. Low biomass of herbivorous fishes at a majority of the coral reef sites is of major concern for the functioning of these reefs. Conservation of parrotfishes and other herbivores is necessary given the abundance of algae on most of these reefs and the beneficial effect of their presence on coral juveniles. This is the first comprehensive study that compares the state of Orbicella reefs in the Eastern Caribbean, providing valuable information that will be useful in creating realistic targets for future management and conservation.  相似文献   

12.
Precious corals (Coralliidae) have been a part of numerous aspects of human life and culture for several millennia. They differ from reef-building corals and primarily inhabit deep waters. Their characteristics of a slow renewal rate and high commercial value make them a frangible resource that is easily overexploited. Proposals to manage the main species with high commercial value through trade controls and listing in Appendix II were submitted to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) in 2007 and 2010. Two of the main arguments for the northern Pacific precious coral CITES proposal were the more than 60–80% decline of Corallium secundum and C. sp. nov. in landings since 1980s and lack of proper management. Although both proposals were rejected, they have sparked debates regarding the benefits of managing coral resources through trade controls and fisheries management. In this study, several arguments related to this topic on northern Pacific precious corals are presented, in the following three dimensions: (1) a reconstructed historical landing series from official FAO data and information on the history of coral fishing have scientifically indicated that the substantial decline in landings in the late 1980s was caused by the abandonment of fishing grounds and a shift in the target species; (2) enhanced management plans, which incorporate effective monitoring, control, and surveillance (MCS) measures, have been implemented in the two main countries that fish precious coral; and (3) the influence of socioeconomic factors must be considered when assessing CITES listing applications. Recommendations for achieving sustainable coral resource conservation are also provided.  相似文献   

13.
Studies of the interactions of demersal fishing gear with the benthic environment are needed in order to manage conservation of benthic habitats. There has been limited direct assessment of these interactions through deployment of cameras on commercial fishing gear especially on demersal longlines. A compact, autonomous deep-sea video system was designed and constructed by the Australian Antarctic Division (AAD) for deployment on commercial fishing gear to observe interactions with benthos in the Southern Ocean finfish fisheries (targeting toothfish, Dissostichus spp). The Benthic Impacts Camera System (BICS) is capable of withstanding depths to 2500 m, has been successfully fitted to both longline and demersal trawl fishing gear, and is suitable for routine deployment by non-experts such as fisheries observers or crew. The system is entirely autonomous, robust, compact, easy to operate, and has minimal effect on the performance of the fishing gear it is attached to. To date, the system has successfully captured footage that demonstrates the interactions between demersal fishing gear and the benthos during routine commercial operations. It provides the first footage demonstrating the nature of the interaction between demersal longlines and benthic habitats in the Southern Ocean, as well as showing potential as a tool for rapidly assessing habitat types and presence of mobile biota such as krill (Euphausia superba).  相似文献   

14.
In reply to the United Nations General Assembly Resolutions on sustainable fisheries, Spain, either by itself or in collaboration with other Nations, has been carrying out studies on vulnerable marine ecosystems (VMEs) in the high seas of the Atlantic Ocean (areas beyond national jurisdictions) since 2005. Such studies provide advice to the Spanish Government, the Regional Fisheries Management Organizations and the European Union. This paper presents the multidisciplinary methodology used and summarises the following management results: (i) contribution to identification of cold-water corals and provision of evidence to close part (∼16,000 km2) of the Hatton Bank (NE Atlantic) to bottom fishing; (ii) compilation of an international data base to identify VMEs on the slopes of the Grand Banks of Newfoundland, Flemish Pass, and Flemish Cap (NW Atlantic) and to redefine areas currently closed to fishing; (iii) improvement of knowledge about deepwater ecosystems on Walvis Ridge and adjacent seamounts (SE Atlantic) as a pilot project for implementation in this region; and (iv) identification of VMEs and closure of an area (∼41,300 km2) on the high seas of the SW Atlantic. Also discussed are progress and challenges related to identifying and protecting VMEs.  相似文献   

15.
基于2018年12月在亚龙湾沿岸进行的13个站位的珊瑚礁调查,本文分析了该区域造礁石珊瑚的多样性、分布、覆盖率、死亡率和补充量。结果表明,亚龙湾西岸8个站位共发现造礁石珊瑚12科27属55种和11个未定种,其中蜂巢珊瑚科的种类最多,包括9属25种,其次为鹿角珊瑚科,包括3属17种。亚龙湾西岸各站位造礁石珊瑚种类数为12—33种,平均27种;覆盖率为2.8%—22.9%,平均12.9%;以丛生盔形珊瑚(Galaxea fascicularis)、同双星珊瑚(Diploastrea heliopora)和澄黄滨珊瑚(Poriteslutea)等团块状珊瑚为主要优势种;种类多样性和空间分布异质性都较高。与2010—2011年相比,亚龙湾西岸造礁石珊瑚平均覆盖率显著下降,优势种也有较大的变化,表明该海域的珊瑚礁已大幅衰退,这可能与偏高的悬浮物含量和沉积速率有关。不过,亚龙湾西岸造礁石珊瑚的补充量为1.6ind./m2,与周边海区相比,有相对较高的自然恢复潜力。  相似文献   

16.
肉芝软珊瑚属(Sarcophyton)是珊瑚礁生态系统中常见的软珊瑚,具有极强的药用价值.我国肉芝软珊瑚种类资源十分丰富,但目前国内对此种珊瑚的分类研究处于停滞状态,肉芝软珊瑚外部形态差异较小,难以直接进行种类鉴定.本研究采集海南省三亚市西瑁岛、万宁市甘蔗岛和大洲岛珊瑚礁区的26个肉芝软珊瑚样品,根据骨针形态学初步鉴定,并分析线粒体msh1基因和COI基因序列进行种类鉴定.结果显示:所有采集的26个样品,鉴定为5个种,分别为:Sarcophyton cherbonnieri、Sarcophyton crassum、Sarcophyton trocheliophorum、Sarcophyton glaucum和Sarcophyton ehrenbergi.其中S. cherbonnieri和S. crassum为我国新纪录种.本研究为海南岛附近海域肉芝软珊瑚的鉴定提供参考,并为我国软珊瑚种类鉴定和生物多样性的研究提供基础数据.  相似文献   

17.
珊瑚移植一直被认为是增加退化珊瑚礁上珊瑚数量的重要手段之一。为了调查多种珊瑚移植方法和不同珊瑚种类的移植效果,我们选择了已严重退化并仍面临着人类和自然环境胁迫的三亚鹿回头珊瑚礁作为移植地,对5种珊瑚共902个断枝利用4种方法进行了移植。在移植后的10个月,移植珊瑚的存活率为45.5%。移植方法对于不同珊瑚种类具有不同效果,但没有一种方法能够对所有珊瑚的移植效果产生促进作用。虽然对于叶状蔷薇珊瑚（Montipora foliosa）和风信子鹿角珊瑚（Acropora hyacinthus）来说,适合的移植方法能够减缓其死亡速率,但并不能改变其死亡趋势。叶状蔷薇珊瑚和风信子鹿角珊瑚的移植个体呈现出高死亡率和明显的存活组织面积下降,而扁枝滨珊瑚（Porites andrewsi）和丛生盔形珊瑚（Galaxea fascicularis）死亡率和组织部分死亡率则优于前两者。扁枝滨珊瑚和丛生盔形珊瑚仅在一种移植方法中出现了存活组织面积明显增长。鹿角杯形珊瑚（Pocillopora damicornis）是移植珊瑚中唯一一种在所有移植方法上都呈现珊瑚平均存活面积增长的种类。实验结果说明在受到高度胁迫的海域进行珊瑚移植很难取得满意效果,珊瑚种类的选择对胁迫环境下的珊瑚移植效果具有决定性影响,而移植方法只能在部分程度上改善移植效果,但无法弥补鹿回头环境压力对敏感种类胁迫造成的影响。在鹿回头珊瑚礁需首先治理对珊瑚造成胁迫的因子,再进行珊瑚移植,并应优先考虑移植环境耐受性高的珊瑚种类。  相似文献   

18.
In this study we characterized the deep assemblages dwelling at 200–250 m depth on a large shoal off Capo St. Vito Promontory (Northwestern coast of Sicily, South Tyrrhenian Sea) by means of ROV‐imaging. Two assemblages of suspension feeders, dominated by the gorgonian Callogorgia verticillata and by the black coral Leiopathes glaberrima, together with a tanatocoenosis of the colonial yellow scleractinian coral Dendrophyllia cornigera, were examined. The three main species were significatively distributed into two areas corresponding to different habitat preferences: a more elevated hardground hosting black corals and a gently sloping, silted rocky bottom hosting the other coral species. The study area is subjected to a heavy pressure from the professional fishery, resulting in the mechanical damage of numerous colonies, some of which are then overgrown by various epibionts including a parasitic bioluminescent zoanthid, new for the Mediterranean fauna, and tentatively identified as Isozoanthus primoidus. In the Mediterranean Sea, these deep off‐shore rocky banks are widely known among recreational and professional fishermen due to their rich fish fauna. However, there has been still little effort into quantifying and characterizing the extent of the impact and its consequences on the benthic communities, which may represent, as in this case, only a partial picture of their original structure and extent.  相似文献   

19.
To ensure that destructive bottom fishing activities do not have significant adverse impacts on Vulnerable Marine Ecosystems (VMEs) in high seas areas of the World Ocean, as required by United Nations General Assembly Resolution 61–105, knowledge of the locations of VMEs is required. Quantifying the occurrence and abundance of VME indicator taxa in research bottom-trawl samples, as well as from in situ observations with underwater photography, provides methods for detecting these ecosystems. A case study is presented in which a threshold density of indicator taxa was used as the basis for VME designation. In 2009, high densities of VME indicator taxa were encountered at 11 sites off th`e South Orkney Islands in the Atlantic sector of the Southern Ocean. In most cases, thresholds were exceeded by a limited number of VME indicator taxa, primarily representatives of the class Demospongiae (siliceous sponges), Hexactinellida (glass sponges) and Ascidiacea (tunicates). In situ imagery further showed the importance of bryozoans (lace corals), scleractinians (stony corals) and stylastrids (hydrocorals) in the study region. The approach outlined here, which relies on widely used sampling techniques, could be employed throughout the World Ocean to detect and document the presence of VMEs from existing datasets. To illustrate this point, the method was applied to a separate dataset, collected in 2006, from a research cruise off the northern Antarctic Peninsula, which led to the detection of 17 VMEs. The VMEs from both the 2006 and 2009 data are now registered and influence the management of fisheries in the Southern Ocean.  相似文献   

20.
永兴岛及七连屿造礁石珊瑚近10年变化分析   总被引：2，自引：1，他引：2  
根据2007-2016年珊瑚礁监测数据，永兴岛及七连屿共调查到造礁石珊瑚11科113种，常见种有鹿角杯形珊瑚Pocillopora damicornis、疣状杯形珊瑚Pocillopora Verrucosa、粗野鹿角珊瑚Acropora humilis、澄黄滨珊瑚Porites lutea、丛生盔形珊瑚Galaxea fascicularis、梳状菊花珊瑚Goniastrea pectinata及锯齿刺星珊瑚Cyphastrea serailia等。研究区域内造礁石珊瑚种类近10年（2007-2016年）来下降明显，其中永兴岛从39种下降到18种，下降率为53.85%；北岛从23种下降到17种，下降率为26.09%；赵述岛从46种下降到12种，下降率为73.91%；西沙洲从51种下降到15种，下降率为70.59%。群体形态群落中皮壳状种类数最为稳定，分枝类下降了59.26%；叶片状下降了75.00%；圆盘状下降了87.50%；团块状下降了57.14%。通过对研究区域造礁石珊瑚种类组成及群落形态等方面的变化分析可见，人为活动、长棘海星、珊瑚病害、台风及全球升温等因素逐渐影响到西沙海域的珊瑚礁生态系统。  相似文献   

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