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1.
Abundance of deep-sea meiobenthos off Sanriku, Northeastern Japan was studied quantitatively using sediment samples collected by box corers or an Okean grab. Sampling stations were established along a line transect which covered areas from off the mouth of Otsuchi Bay to the abyssal plain of the western Pacific crossing over the Japan Trench (water depths from 120 m to 7460 m). Abundance of meiobenthos decreased linearly with water depth down to 1503 m and became constant at stations deeper than 4130 m. Nematodes predominated over the other taxonomic groups at all stations. An equation to estimate meiofaunal abundance from several sediment characteristics, which was previously proposed by the first author based on data from tropical and subtropical regions of the western Pacific, was applied to the present boreal area. At one station where the Okean grab was used, the estimated value was 4.7 times more than the observed one. Except for the station, however, observed values fell within the confident range of estimated values. The estimated values were always higher than the observed ones at boxcorer stations, whereasvice versa at Okean-grab stations. These results suggested that keen attention is necessary in selecting sampling gear for ecological studies of deep-sea meiobenthos.  相似文献   

2.
Mixed populations of free-living marine bacteria were collected at depths from the surface to the bottom (1,960m in Suruga Bay and 1,585 m in the Japan Sea) in the northwest Pacific during deep-sea diving by the submersible,Shinkai 2000. Their abundance in total cell counts and in lipopolysaccharide (LPS) concentration was found to decrease with increasing depth, and the decreasing profiles were shown to be linear on logarithmic scales. The total cell counts and the LPS concentration showed a linear relationship on arithmetic scales, and the LPS content per cell was found to be 1.02×10–14 g.  相似文献   

3.
Environmental concern for the deep-sea ecosystem is increasing as contaminants, originating from anthropogenic activities, have been detected in deep-sea biota. However, little is known on the xenobiotics metabolising capability of deep-sea fauna. In this study, the deep-sea amphipod Eurythenes gryllus was selected as sentinel species to measure the total oxyradical scavenging capacity (TOSC). Individuals of E. gryllus were sampled at 2000 m depth in the Arctic Ocean. The TOSC assay was measured on the cytosolic fraction and the soluble fraction (3 kDa) of the digestive gland and on the cell-free haemolymph toward peroxyl, hydroxyl and peroxynitrite radicals according to the method of Winston et al. [Free Radical Biology and Medicine 24 (3) (1998) 480] and Regoli and Winston [Toxicology and Applied Pharmacology 156 (1999) 96]. These results provide the first baseline data set for total antioxidant capacity in a deep-sea amphipod.  相似文献   

4.
The structure of the assemblages associated with the mussel aggregations of Bathymodiolus azoricus was investigated. The mussel beds were found on the hydrothermal vent fields on the Mid-Atlantic Ridge (the Menez Gwen, Lucky Strike, and Rainbow areas) at the depths of 850–2400 m. The community structure of the mussel bed assemblages varied between the studied areas. Large number of species was unique to Menez Gwen mussel beds; the most observed taxa were not specialized hydrothermal species. All the other, nonunique species were found for the Lucky Strike region. The lowest mussel assemblage structure evenness was observed in the shallowest area, the Menez Gwen area (850 m depth). We assume that two types of mussel assemblages—nematode-dominated and copepod-dominated ones—exist in the Lucky Strike field. The assemblages of B. azoricus differ significantly from the assemblages of B. thermophilus inhabiting the Pacific hydrothermal vents.  相似文献   

5.
The San Clemente cold seep lies within 100–200 km of other reducing habitats in the NE Pacific, offering an opportunity to compare diversity and species overlap among reducing habitats (i.e. whale‐, kelp‐, and wood‐falls) at similar depths within a single region. Video observations from the research submersible Alvin at the San Clemente seep (1800 m depth) indicated clumps (‘thickets’) of vestimentiferans distributed as meter‐scale patches interspersed with vesicomyid clam beds and black sediments. Sediment‐core samples were collected at distances of 0 to 80–200 m along randomly oriented transects radiating outward from vestimentiferan thickets to evaluate changes in macrofaunal community structure from thickets into the background community. Macrofaunal abundance was elevated at distances of 0–1 m compared to 80–200 m (i.e. the ‘background’ community). The tube‐building frenulate worms Siboglinum spp., along with peracarid crustaceans, dominated sediments within 1 m of vestimentiferan thickets. Species diversity was depressed within 1 m of thickets but with high rates of species accumulation, suggesting that seep sites greatly increase sediment heterogeneity and facilitate colonization by non‐background macrofaunal species. Stable isotope data indicate chemosynthetic nutrition for some dominant macrofaunal species within 1 m of tubeworm thickets. The macrofaunal community near vestimentiferan thickets in San Clemente seep contains intermediate levels of species richness and diversity compared to other deep‐sea seep areas in the northeast Pacific. There was low species overlap between the San Clemente seep macrofauna and communities in reducing habitats near wood‐, whale‐, and kelp‐falls at similar depths within the region, suggesting that seeps harbor a distinct infaunal community.  相似文献   

6.
Quantitative samples of sediments and macrobenthos were collected with a spade corer to reveal the relationships between macrobenthos communities and bottom environments. Twenty-five stations were established along a transect in the lower sublittoral and bathyal zones between the depths of 120 m and 2,600 m off Sanriku, the northeastern coast of the Japanese mainland, Northwestern Pacific.These stations were clustered into two groups on the basis of the principal component analysis of environmental factors and topographic features of the study area. The clustering of stations corresponded to that based on polychaete species composition.The biomass of macrobenthos followed two different patterns in two oceanographic environments; the first trend is found from the shelf to the seaward margin of the deep-sea terrace where macrobenthos biomass did not depend on depth, and the second trend on the lower continental slope, where biomass decreased exponentially with depth as Rowe's formula predicted. The density of macrobenthos showed a simple exponential decrease with depth over the two ecological zones. The data of stable carbon isotope ratio of organic matter in the sediments and topographic features suggested that the pattern of the biomass of macrobenthos corresponded with two different modes of food supply to the deep-sea bottom communities,i.e., vertical transport of the surface products and horizontal transport of food materials.  相似文献   

7.
Recent studies of deep-sea faunas considered the influence of mid-domain models in the distribution of species diversity and richness with depth. In this paper, I show that separating local diversity from regional species richness in benthic isopods clarifies mid-domain effects in the distribution of isopods in the Gulf of Mexico. Deviations from the randomised implied species ranges can be informative to understanding general patterns within the Gulf of Mexico. The isopods from the GoMB study contained 135 species, with a total of 156 species including those from an earlier study. More than 60 species may be new to science. Most families of deep-sea isopods (suborder Asellota) were present, although some were extremely rare. The isopod family Desmosomatidae dominated the samples, and one species of Macrostylis (Macrostylidae) was found in many samples. Species richness for samples pooled within sites ranged from 1 to 52 species. Because species in pooled samples were highly correlated with individuals, species diversity was compared across sites using the expected species estimator (n=15 individuals, ES15). Six depth transects had idiosyncratic patterns of ES15, and transects with the greatest short-range variation in topography, such as basins and canyons, had the greatest short-range disparity. Basins on the deep slope did not have a consistent influence (i.e., relatively higher or lower than surrounding areas) on the comparative species diversity. ES15 of all transects together showed a weak mid-domain effect, peaking around 1200–1500 m, with low values at the shallowest and deepest samples (Sigsbee Abyssal Plain); no longitudinal (east–west) pattern was found. The regional species pool was analyzed by summing the implied ranges of all species. The species ranges in aggregate did not have significant patterns across longitudes, and many species had broad depth ranges, suggesting that the isopod fauna of the Gulf of Mexico is well dispersed. The summed ranges, as expected, had strong mid-domain patterns, contrasting with the local species richness estimates. The longitudinal ranges closely matched a randomized pattern (species ranges placed randomly, 1000 iterations), with significant deviations in the east attributable to lower sampling effort. The depth pattern, however, deviated from the mid-domain model, with a bimodal peak displaced nearly 500 m shallower than the mode of the randomized distribution. The deviations from random expectation were significantly positive above 1600 m and negative below 2000 m, with the result that regional species richness peaked between 800 and 1200 m, and decreased rapidly at deeper depths. The highest species richness intervals corresponded to the number of individuals collected. Residuals from a regression of the deviations on individual numbers, however, still deviated from the randomized pattern. In this declining depth-diversity pattern, the Gulf of Mexico resembles other partially enclosed basins, such as the Norwegian Sea, known to have suffered geologically recent extinction events. This displaced diversity pattern and broad depth ranges implicate ongoing re-colonization of the deeper parts of the Gulf of Mexico. The Sigsbee Abyssal Plain sites could be depauperate for historical reasons (e.g., one or more extinction events) rather than ongoing ecological reasons (e.g., low food supply).  相似文献   

8.
Demersal fish data from 9 deep-sea surveys in the North Atlantic were examined to assess (1) the coherence and continuity of zones around the ocean basin, and (2) the persistence of structured communities over more than just a local scale. The 63 cruises took 96,779 specimens and 325 species in 692 benthic trawl hauls between 204 and 5345m depth. Measures of similarity and overlap applied to this faunal data did not produce patterns other than those reflecting the occurrence of two widespread and abundant species - Synaphobranchus kaupi at slope depths and Nematonurus armatus on the rise. Communities defined within a survey area by commonly-used analytical procedures cannot be identified from place to place over broader areas, and the concept along with its implication should be abandoned.  相似文献   

9.
In 1987, the deep manned submersibles Mir-1 and Mir-2 were introduced into the practice of scientific research of the ocean. For 25 years, with their help, a wide range of deepwater operations have been carried out: oceanic scientific research (including the most active areas on the seabed??hydrothermal fields), shooting films and documentaries, which have brought international fame to the vehicles; special operations concerning solving problems of national importance concerning the sunken nuclear submarines Komsomolets and Kursk; live television broadcast from great depths of the ocean via satellite to the earth; diving under the ice at the geographic North Pole; a three-year cycle of scientific research on lake Baikal; etc. During the 25 years of their operation, there have been no unsolvable problems in the deep ocean for the Mir vehicles. They have rightfully taken a leading position in the field of deep-sea research in the world and were named the best vehicles in technical terms in the history of the creation of such technical facilities. Some of the results and details of the above-mentioned deep-sea operations, as well as the technical innovations developed and implemented during the service of the Mir vehicles, are considered in this article.  相似文献   

10.
High-latitude seas are mostly covered by multi-year ice, which impacts processes of primary production and sedimentation of organic matter. Because of the warming effect of West Spitsbergen Current (WSC), the waters off West Spitsbergen have only winter ice cover. That is uncommon for such a high latitude and enables to separate effects of multiyear-ice cover from the latitudinal patterns. Macrofauna was sampled off Kongsfjord (79°N) along the depth gradient from 300 to 3000 m. The density, biomass and diversity at shallow sites situated in a canyon were very variable. Biomass was negatively correlated with depth (R=-0.86, p<0.001), and ranged from 61 g ww m−2 (212 m) to 1 g ww m−2 (2025 m). The biomasses were much higher than in the multiyear-ice covered High Arctic at similar depths, while resembling those from temperate and tropical localities. Species richness (expressed by number of species per sample and species–area accumulation curves) decreased with depth. There was no clear depth-related pattern in diversity measures: Hurbert rarefaction, Shannon–Wiener or Pielou. The classic increase of species richness and diversity with depth was not observed. Species richness and diversity of deep-sea macrofauna were much lower in our study than in comparable studies of temperate North Atlantic localities. That is related to geographic isolation of Greenland–Icelandic–Norwegian (GIN) seas from the Atlantic pool of species.  相似文献   

11.
Dicopia antirrhinum C. Monniot, 1972 is a rare species of deep-sea ascidian belonging to the Family Octacnemidae, reported at depths of 1000–2500 m in European Atlantic waters. Adult individuals have never been reported before in the Mediterranean Sea, where only seven juvenile specimens were found in 1975 at 500 m water depth in the Central basin (Malta). The affinities of these specimens with D. antirrhinum were noted, but lack of some typical characters of the species in juveniles prevented a definite taxonomical identification. No other member of the Octacnemidae has ever been found in the Mediterranean. In this study we describe the sampling of an adult specimen of D. antirrhinum at around 1100 m water depth on the flank of the La Fonera (Palamós) canyon, Northwestern Mediterranean, confirming their presence in the Mediterranean Sea. We also observed 5 individuals of this species on their natural habitat with a Remotely Operated Vehicle (ROV). Our results highlight the potential occurrence of Octacnemidae, the presence of which has been largely overlooked, in several deep-sea canyon areas within the Western Mediterranean basin. These observations are important because they indicate the need for increased sampling effort with new technologies, such as ROVs, in ecologically relevant habitats such as canyons, in order to obtain a more accurate picture of deep-sea biodiversity in the Mediterranean Sea.  相似文献   

12.
Video analysis of a whale-fall discovered in the northeast Pacific Ocean, off Vancouver Island at a depth of 1288 m during ROV diving operations has identified 26 taxa of deep-sea benthic organisms inhabiting the seafloor immediately surrounding remnants of the whale skeleton. A photo-mosaic derived from high-definition video provides a quantitative visual record of the present condition of the site, the species richness, and substrate preference. Only the skull and caudal vertebrae remains of this large whale skeleton are estimated to have been approximately 16.5 m in length. Most organisms identified near the whale-fall are common benthic deep-sea fauna, typical of this water depth and seafloor composition. Much of this species richness comes from sessile suspension feeding cnidarians attached to the numerous glacial dropstones found throughout the area rather than the presence of the whale skeleton. Seep and bone specialists are rare (4 taxa) and may be, in part, a remnant population from a sulphophilic stage of whale-fall decomposition. Evidence of past colonization by Osedax sp. is visible on the remaining bones and we conclude that rapid degradation of the missing bones has occurred at this site as has been observed at whale-falls off central California in Monterey Canyon.  相似文献   

13.
Remotely operated vehicle (ROV) video observations were used to document benthic fauna at a hydrocarbon drilling location, at 2 720 m depth, in the poorly studied deep water off northern Egypt. The decapod Chaceon mediterraneus was the most common organism at the site and the only benthic megafaunal invertebrate observed. Three species of fish, Coryphaenoides mediterraneus, Cataetyx laticeps and Bathypterois mediterraneus, were also encountered. These findings confirmed these three species as the deepest-distributed benthic fish in the eastern Mediterranean, and confirmed that the deep Mediterranean, in particular the eastern basin, is one of the world's poorest deep-sea ecosystems in terms of diversity. The behaviour exhibited by the species observed was consistent with their natatory capacity, deduced from their feeding intensity (gut fullness) and diet (mainly suprabenthic prey were consumed), and conservative life strategies adapted to an extremely low energy environment.  相似文献   

14.
南海深海鱼类的初步报告   总被引：1，自引：0，他引：1  
南海在我国濒临的四个海中面积最大，而其大陆架宽度则较狭窄，水深在200米以上的深海水域相当广阔。我国过去关于南海深海鱼类的研究报道极少，1962年《南海鱼类志》中曾记载过少数深海鱼类，但具有确切深度记录的仅有8种。在国外文献中，Gilbert和Hubbs(1920), Schultz(1938), Abe(1974 , 1975, 1976 )等曾报道过数种。 本文材料是1959-1960年在海南岛以东海域，水深200-1100米进行底栖生物拖网时所获得的标本。鉴定结果，共71种，分隶于37科，12目，其中34种为我国新记录，7种是我国在南海首次记录。 文内凡是我国新记录的种均有形态描述，并附有外形图,有些种作了分类上的讨论；对我国有过记录的种，只记有地理分布和标本采集记录。此外，就现有资料并参考有关深海鱼类文献，对这些种类的地理分布和深度分布也作了初步分析。由于调查范围较小，拖网次数不多，本文仅为南海鱼类区系提供了一些初步资料。丰富的南海深海鱼类区系，随着我国海洋调查事业的发展，还有待进一步深入研究。  相似文献   

15.
This study was carried out as part of a baseline long-term environmental project in the proposed mining areas for an environmental impact assessment of future mining in the Clarion-Clipperton Fracture Zone (CCFZ). The community structure and distributional pattern of meiobenthos were investigated in the deep-sea bottom of the Clarion-Clipperton Fracture Zone of the northeastern Pacific in July 1998, 1999, 2001, 2003 and August 2004, 2005. Twenty one meiobenthic groups were found at the stations in the study area. The most abundant meiobenthos comprised nematodes followed by benthic foraminiferans and harpacticoid copepods. The maximum density of meiobenthos was 306 ind/10 cm2 at the station located at 11°N (water depth, 4833 m), and the minimum density was 6 ind/10 cm2 at the station located at 14°N (water depth, 5037 m). Oligotrophic conditions in the CCFZ seem to directly reflect the lower standing stocks of meiobenthos in the CCFZ compared to other deep-sea plains of similar depth. The latitudinal distribution pattern of meiobenthos in the study area seemed to be related with surface water primary productivity, which was connected to the water circulation pattern of the Pacific Ocean near the Equator, diverging at 8ºN latitude and converging at 5°N. The horizontal distribution of meiobenthic organisms in the study area showed high densities at the stations within 135–136°W. The densities of meiobenthic organismas within the CCFZ were high at stations with few manganese nodules on the sediment surface at low-latitude sites. In 1998, the observed relative high values of meiobenthic abundance were at stations from 5° to 6°N. Other stations from 7° to 10°N showed no significant fluctuations during the interannual sampling periods. It is considered that the inter-annual fluctuation of meiobenthos abundance is intimately related with a regime shift that may have occurred in the north Pacific between 1998 and 1999, the El Niño period. Vertical distribution of meiobenthic organisms showed the highest individual numbers in the surface sediment layers of 0～2 cm depth and a steep decreasing trend as sediment becomes deeper at the stations of high latitude located in 16～17°N. Size distribution analyses showed that organisms that fit into the sieve mesh size of 0.063 mm were abundant.  相似文献   

16.
The depth distributions of the radiolarian fauna in the Chukchi and Beaufort Seas, marginal seas of the western Arctic Ocean, were examined quantitatively in depth-stratified plankton tows from 4 or 5 intervals above 500 m and in surface sediments from various depths between 163 and 2907 m. The radiolarian assemblage from the water column in September 2000 was dominated by Amphimelissa setosa and followed by the Actinomma boreale/leptoderma group, Pseudodictyophimus gracilipes and Spongotrochus glacialis. These species are related to the Arctic Surface Water shallower than 150 m. This assemblage is similar to that in the Greenland Sea relating to the ice edge, but did not contain typical Pacific radiolarians in spite of the flow of water of Pacific origin in this region. The living depth of Ceratocyrtis historicosa was restricted to the relatively warm water between 300 and 500 m corresponding to the upper Arctic Intermediate Water (AIW) originating from the Atlantic Ocean. Radiolarian assemblages in the surface sediments are similar to those in the plankton tows, except for common Cycladophora davisiana in sediment samples below 500 m. C. davisiana is probably a deep-water species adapted to the lower AIW or the Canadian Basin Deep Water ventilated from the shelves.  相似文献   

17.
Abstract. A complex and highly unusual eukaryotic microorganism was discovered to be penetrating and removing the periostracum of deep-sea mussels from the Florida Escarpment brine seeps at a depth of 3266 m. These brine seeps support a chemolithoautotrophic redox community similar to those known from Pacific hydrotherma! vents. This microorganism of unknown taxonomic affinity is filamentous and coenocytic, with a simple plasma membrane and no cell wall. It forms prostrate, radiating systems of branched tunnels, 8–15 u.m in diameter. The surface of the tunnels is sculptured by helically organized, scale-like depressions, which are left as scars in the process of periostracum removal by the organism. Periostracum is removed in discrete pieces (scallops) at the ends of the tunnels. This organism has been found at three Atlantic deep-sea redox communities, but not in similar communities of the Pacific.  相似文献   

18.
通过对东北太平洋胡安·德富卡隆起西翼沉积柱样中的碳酸盐含量和浮游有孔虫氧同位素测试以及浮游有孔虫丰度、溶解指数和粗组分的统计,发现在晚第四纪约65 ka以来碳酸盐含量变化幅度大(0 4%~77 2%),相差非常悬殊,但其变化未呈现出冰期时溶解作用减弱、间冰期时溶解作用强烈这样明显的旋回性。粗组分分析结果显示,地层中有明显的浊流沉积发育。另外,碳酸盐含量和浮游有孔虫丰度分析结果揭露了研究区的 CCD在3 500 m左右。研究认为,在约65 ka来水深浅于3 500 m的区域碳酸盐含量的无规律性变化应与浊流沉积影响有直接的关系,而水深深于3 500 m的区域碳酸盐含量主要受控于深海碳酸盐的溶解作用。  相似文献   

19.
Time-series sediment traps were deployed in the subtropical oligotrophic northwestern Pacific (SONP) at three depths from August to September 2015 to better understand vertical flux of sinking particles. Sinking particles were collected at 5-day intervals over the sediment trap deployment period. The average total mass flux at water depths of 400 m, 690 m, and 1,710 m was 9.1, 4.4, and 4.1 mg m-2day-1, respectively. CaCO3 materials constituted 50 to 70% of sinking particles while in comparison particulate organic carbon (POC) constituted up to 20%. A synchronous variation of total mass flux was observed at the three depths, indicating that calcite-dominated particles sank from 400 to 1,710 m within a 5-day period. POC flux at these water depths was 2.4, 0.38, and 0.31 mg m-2day-1, respectively. Our results indicate low transfer efficiencies of 16% from 400 to 690 m and 13% for the 400 to 1,710 m depth range. The estimated transfer efficiencies were significantly lower than those observed at the K2 station in the northwest Pacific subarctic gyre, presumably because of a prevalence of pico-cyanobacteria in the SONP. Because cyanobacteria have a semi-permeable proteinaceous shell, they are more readily remineralized by bacteria than are siliceous phytoplankton in the northwest Pacific subarctic gyre. Continued surface water warming and expansion of the SONP will likely have a profound impact on ocean acidification in the northwest Pacific, possibly affecting the transfer efficiency of sinking POC to the deep-sea.  相似文献   

20.
通过整理近年来中国科学院海洋研究所采集的深海海参标本,发现了"蛟龙"号载人潜水器在南海珍贝海山水深2463m处采集的1号蝶参科标本,经鉴定为一个新记录属底游参属Benthodytes Théel, 1882的一个新记录种西伯加底游参Benthodytes sibogae Sluiter, 1901。西伯加底游参与底游参属其他物种的显著差异在于其背部有5—6对大疣,沿背部步带区近乎对称的排列为两行。本文对新记录种的外部形态特征进行了详细的描述,与该种的模式标本进行了分类学讨论,提出背部大疣的数量及排列方式为该属物种区分的重要依据。在对骨片进行超微结构研究时发现,该种背部疣足的骨片与背部和腹部体壁骨片在大小、中央突起的高度和分叉部位上有较大差异,此前的报道未对疣足骨片进行过描述,本文对此进行了补充。  相似文献   

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