Seasonal variations and distributions of dissolved free and total carbohydrates at the ?zmir Bay,Aegean Sea

Seasonal variations and distributions of dissolved carbohydrate concentrations at the ?zmir Bay were investigated with salinity, chlorophyll a(Chl a), and dissolved organic carbon(DOC) levels to understand their relationships.Samples were collected from surface, subsurface and bottom depths at seven stations. DOC concentrations ranged from 32.2 to 244.2 μmol/L, and in general, DOC levels increased from winter to summer, then slightly decreased in autumn. Monosaccharide(MCHO), polysaccharide(PCHO) and total dissolved carbohydrate(TDCHO) levels were found between 0.7–8.3, 0.7–19.5, and 2.6–24.6 μmol/L. DOC, MCHO, PCHO and TDCHO levels were found higher in middle-inner bays, under the influence of anthropogenic inputs, compared to outer bay. Seasonal changes of MCHO/DOC, PCHO/DOC and TDCHO/DOC ratios were statistically significant(p0.05)and the ratios showed decrease trends from winter to summer-autumn seasons. Distributions of TDCHO/DOC ratios at wide ranges(2.5%–42.3%) indicated the presence of newly forming and degrading fractions of DOM.According to results of factor analysis, Chl a, MCHO and TDCHO were explained in the same factor groups. In conclusion, the results showed that dissolved carbohydrate levels in the ?zmir Bay might be influenced by biological processes and terrestrial/anthropogenic inputs.     

Seasonal variations and distributions of dissolved free and total carbohydrates at the İzmir Bay, Aegean Sea

Seasonal variations and distributions of dissolved carbohydrate concentrations at the İzmir Bay were investigated with salinity, chlorophyll a (Chl a), and dissolved organic carbon (DOC) levels to understand their relationships. Samples were collected from surface, subsurface and bottom depths at seven stations. DOC concentrations ranged from 32.2 to 244.2 μmol/L, and in general, DOC levels increased from winter to summer, then slightly decreased in autumn. Monosaccharide (MCHO), polysaccharide (PCHO) and total dissolved carbohydrate (TDCHO) levels were found between 0.7-8.3, 0.7-19.5, and 2.6-24.6 μmol/L. DOC, MCHO, PCHO and TDCHO levels were found higher in middle-inner bays, under the influence of anthropogenic inputs, compared to outer bay. Seasonal changes of MCHO/DOC, PCHO/DOC and TDCHO/DOC ratios were statistically significant (p<0.05) and the ratios showed decrease trends from winter to summer-autumn seasons. Distributions of TDCHO/DOC ratios at wide ranges (2.5%-42.3%) indicated the presence of newly forming and degrading fractions of DOM. According to results of factor analysis, Chl a, MCHO and TDCHO were explained in the same factor groups. In conclusion, the results showed that dissolved carbohydrate levels in the İzmir Bay might be influenced by biological processes and terrestrial/anthropogenic inputs.     

The origin of the suspended particulate matter in the seagrass meadow of tropical waters, an evidence of the stable isotope signatures

Suspended particulate matter (SPM) has been known as an important variable in the organic matter flow of coastal ecosystem. Half of burial carbon in seagrass meadows is contributed by allochthonous sources that compose the SPM such as phytoplankton, seagrass detritus, marine snow aggregates and terrestrially derived particles. Each composition of the SPM contributes different roles and is important to be identified, for instance, the exact contribution of seagrass detritus will be useful for determination of carbon export through the detritus form in seagrass meadows. Here, the SPM of seagrass meadows is studied in Bintan Island and the Selayar Archipelago. The aim of this research is to determine the source origin of the SPM using a stable isotope signature. In order to fulfill this aim, the objectives are defined as: (1) to specify the stable isotope signature (δ¹³C and δ¹⁵N) of the SPM, and (2) to determine the proportional distribution of the SPM''s prospectus sources. The result shows that the possibility of the source origin of the SPM includes a seagrass fraction (Enhalus acoroides and Thalassia hemprichii), terrestrial C4 plant, macroalgae, and terrestrial C3 plant. The SPM lies between the marine- and terrigenous-end members. However, it seems that the SPM is more to be terrigenous-end and allochthonous. According to a Bayesian mixing model, the terrestrial C4 has the highest contribution of the SPM at all sites except Barugaia and Pasi Island in Selayar (i.e., the highest contribution of the SPM is from the detritus of E. acoroides). The second contribution has been contributed by either seagrass detritus (E. acoroides or Th. hemprichii) or terrestrial C3 plant. The finding of this study indicates that there is a strong influence of the terrigenous sources in the SPM of the seagrass meadows.     

Carbon distribution and fluxes of 16 rivers discharging into the Bohai Sea in summer

Riverine carbon input is closely related to the inshore aquatic environment,the marine carbon pool and climate change.Samples were synchronously obtained from 16 rivers discharging into the Bohai Sea (China) in 1-5 July 2005.The dissolved organic carbon (DOC) concentrations of the 16 rivers were mainly controlled by anthropogenic activities.The particulate organic carbon (POC) of the Haihe,Luanhe,Ziyaxinhe,Chaobaixinhe,Xiaoqinghe,Xiaolinghe,Duliujianhe,Jiyunhe,and Majiahe Rivers mainly originated from pollu...     

The decomposition rate of the organic carbon content of suspended particulate matter in the tropical seagrass meadows

In terms of downward transport, suspended particulate matter(SPM) from marine or terrigenous sources is an essential contributor to the carbon cycle. Within mesoscale environments such as seagrass ecosystems, SPM flux is an essential part of the total carbon budget that is transported within the ecosystem. By assessing the total SPM transport from water column to sediment, potential carbon burial can be estimated. However, SPM may decompose or reforming aggregate during transport, so estimating the vertical flux without knowing the decomposition rate will lead to over-or underestimation of the total carbon budget. Here this paper presents the potential decomposition rate of the SPM in seagrass ecosystems in an attempt to elucidate the carbon dynamics of SPM. SPM was collected from the seagrass ecosystems located at Sikka and Sorong in Indonesia. In situ experiments using SPM traps were conducted to assess the vertical downward flux and decomposition rate of SPM. The isotopic profile of SPM was measured together with organic carbon and total nitrogen content. The results show that SPM was transported to the bottom of the seagrass ecosystem at a rate of up to(129.45±53.79)mg/(m~2·h)(according to carbon). Considering the whole period of inundation of seagrass meadows, SPM downward flux reached a maximum of 3 096 mg/(m~2·d)(according to carbon). The decomposition rate was estimated at from 5.9 μg/(mg·d)(according to carbon) to 26.6 μg/(mg·d)(according to carbon). Considering the total downward flux of SPM in the study site, the maximum decomposed SPM was estimated 39.9 mg/(m~2·d)(according to carbon) and 82.6 mg/(m~2·d)(according to carbon) for study site at Sorong and Sikka, respectively.The decomposed SPM can be 0.6%–2.7% of the total SPM flux, indicating that it is a small proportion of the total flux. The seagrass ecosystems of Sorong and Sikka SPM show an autochthonous tendency with the primary composition of marine-end materials.     

Chemical properties of colored dissolved organic matter in the sea-surface microlayer and subsurface water of Jiaozhou Bay, China in autumn and winter

The distribution and chemical properties of chromophoric dissolved organic matter (CDOM) in the Jiaozhou Bay, China were examined during four cruises in 2010-2011. The influence of freshwater and industrial and municipal sewage along the eastern coast of the bay was clearly evident as CDOM levels (defined as a 305 ), and dissolved organic carbon (DOC) concentrations were well correlated with salinity during all the cruises. Moreover, DOC concentrations were significantly correlated with chlorophyll a concentrations in the surface microlayer as well as in the subsurface water. The concentrations of DOC and CDOM displayed a gradually decreasing trend from the northwestern and eastern coast to the central bay, and the values and gradients of their concentrations on the eastern coast were generally higher than those on the western coast. In addition, CDOM and DOC levels were generally higher in the surface microlayer than in the subsurface water. In comparison with DOC, CDOM exhibited a greater extent of enrichment in the microlayer in each cruise, with average enrichment factor (E F ) values of 1.38 and 1.84, respectively. Four fluorescent components were identified from the surface microlayer and subsurface water samples and could be distinguished as peak A, peak T, peak B and peak M. For all the cruises, peak A levels were higher in the surface microlayer than in the subsurface water. This pattern of variation might be attributed to the terrestrial input.     

A simple guideline to apply excitation-emission matrix spectroscopy (EEMs) for the characterization of dissolved organic matter (DOM) in anoxic marine sediments

Marine sediments represent a major carbon reservoir on Earth. Dissolved organic matter(DOM) in pore waters accumulates products and intermediates of carbon cycling in sediments. The application of excitation-emission matrix spectroscopy(EEMs) in the analysis of subseafloor DOM samples is largely unexplored due to the redoxsensitive matrix of anoxic pore water. Therefore, this study aims to investigate the interference caused by the matrix on EEMs and propose a guideline to prepare pore water sam...     

The satellite reversion of dissolved organic carbon (DOC) based on the analysis of the mixing behavior of DOC and colored dissolved organic matter: the East China Sea as an example

The retrieval of dissolved organic carbon (DOC) distribution by remote sensing is mainly based on the empirical relationship of DOC concentration and colored dissolved organic matter (CDOM) concentration in many literatures. To investigate the nature of this relationship, the distributions and mixing behaviors of DOC and CDOM are reviewed in the world’s major estuaries and bays. It is found that, generally, the CDOM concentration is well correlated with the salinity in most estuaries, while DOC usually shows a nonconservative behavior which leads to a weak correlation between the DOC concentration and the CDOM concentration. To establish a good satellite reversion of the DOC concentration, the East China Sea(ECS) was taken as an example, and the mixing behavior of DOC and CDOM as well as the influence of biogeochemical processes were analyzed except for the physical mixing process with the data from late autumn (November, 2010) and winter (December, 2009) cruises. In the two ECS cruises, the CDOM concentration was found to be tightly correlated with the salinity, influenced little by the photochemical or biological processes. The data from the winter cruise show that DOC followed a conservative mixing along the salinity gradient, while in the late autumn cruise it was significantly affected by the biological activities, resulting in a poor correlation between the DOC and the CDOM. Accordingly, an improved DOC algorithm (CSDM) was proposed: when the biological influence was significant (Chl a greater than 0.8 μg/dm3 ), DOC was retrieved by the conservative and biological model, and if the conservative mixing was dominant (Chl a less than 0.8 μg/dm3 ), the direct DOC concentration and CDOM concentration relationship was used. Based on the proposed algorithm, a reasonable DOC distribution for the ECS from satellite was obtained in this study, and the proposed method can be applied to the other large river-dominant marginal sea.     

Biodiversity and seasonal variation of benthic macrofauna in Minicoy Island, Lakshadweep, India

From the Indian coast only limited data are available on the benthic fauna of the seagrass communities. In this study, seasonal variation in the distribution of macrobenthos and influence of environmental parameters was explored at four seagrass beds and two mangrove stations along the Minicoy Island, Lakshadweep, India, from September 1999 to August 2001. A total of 160 macrobenthic species from eight major groups represented the macrofauna of the Minicoy Island. Of the identified taxa, molluscs 70（gastropods 41.46%, bivalves 7.5%）, polychaetes 27（16.88%）, crustaceans 30（18.75%）, echinoderms 11（6.88%） and remaining others. Average seasonal abundance of benthic macrofauna ranged from 219 to 711 ind./m2, species diversity varied from 1.45 to 3.64 bits per individual, species richness index ranged from 4.01 to 26.17, evenness 0.69 to 1.66. In general, the higher abundance and species diversity was noticed in southern seagrass stations and northern seagrass stations, but in the mangrove stations comparatively low species diversity was observed. Three-way analysis of variance indicated that all communities resulted as being significantly different between seagrass and mangrove station, mainly when the seasonal interaction was considered. Multivariate analyses were employed to help define benthic characteristic and the relationship between environmental parameters at the six monitoring stations. Results of cluster analyses and multidimensional scale plot suggest that for mangrove region, different physiographic provinces, lower salinity, dissolved oxygen and sediment biotic structure have a higher influence on the species composition and diversity than other oceanographic conditions.     

桑沟湾及附近海域表层沉积物碳氮同位素分析及有机质来源

Naturally existing stable carbon and nitrogen isotopes are important in the study of sedimentary organic matter sources. To identify the sources of sedimentary organic matter in Sanggou Bay and its adjacent areas, which is characterized by high-density shellfish and seaweed aquaculture, the grain size, organic carbon(OC), total nitrogen(TN), carbon and nitrogen isotopic composition(δ13C and δ15N) of organic matter in the surface sediment were determined. The results showed that, in August, sedimentary OC and TN ranged from 0.17% to 0.76% and 0.04% to 0.14%, respectively. In November, OC and TN ranged from 0.23% to 0.87% and 0.05% to 0.14%, respectively. There was a significant positive correlation between OC and TN(R=0.98, P0.0001), indicating that OC and TN were homologous. In August, the δ13C and δ15N of organic matter varied from-23.06‰ to-21.59‰ and 5.10‰ to 6.31‰, respectively. In November, δ13C and δ15N ranged from-22.87‰ to-21.34‰ and 5.13‰ to 7.31‰, respectively. This study found that the major sources of sedimentary organic matter were marine shellfish biodeposition, seaweed farming, and soil organic matter. Using a three-end-member mixed model, we estimated that the dominant source of sedimentary organic matter was shellfish biodeposition, with an average contribution rate of 65.53% in August and 43.00% in November. Thus, shellfish farming had a significant influence on the coastal carbon cycle.     

东印度洋5种缘毛类纤毛虫(钟虫属和聚缩虫)水平分布初次报道

腹壁纤毛虫是一种附着在浮游动物上的原生生物，尤其是附着在桡足类和甲壳类上的。而缘毛虫是可以以自由或寄生的形式在世界各沿海地区和港湾处被发现。本研究首次对东印度洋表层至200 m深海域的缘毛类纤毛虫以及其水平分布展开了研究。根据纤毛虫的形态、纤毛结构和茎的形态等的特征，在2014年4月10日至5月13日东印度洋航次的浮游生物拖网样品中鉴定出了五种富腹纤毛虫，海洋钟形虫Vorticella oceanica、交替聚缩虫Zoothamnium alternans、阿拉聚缩虫Zoothamnium alrasheidi、远洋聚缩虫Zoothamnium pelagicum和海洋聚缩虫Zoothamnium marinum。并通过光显微镜和扫描显微镜拍摄的照片，说明了其形态、尺寸和特征。研究结果表明，海洋钟形虫和远洋聚缩虫的分布与硅藻（如，密聚角毛藻Chaetoceros coarctatus）和桡足类（如，短角长腹剑水蚤Oithona brevicornis）等寄主有关，也包括甲藻（如，三角角藻Ceraitum tripose）周围的一些个体。这些附着纤毛虫的分布在东印度洋海域东南区以海洋钟形虫、远洋聚缩虫和海洋聚缩虫为主，而在孟加拉湾北部则有大量的阿拉聚缩虫。这种分布的变化可能是与寄主的分布有关，如桡足类（短角长腹剑水蚤）和硅藻（密聚角毛藻）的分布影响。     

四种贝类和鱼类外寄生车轮虫的国内新纪录

车轮虫是一类主要寄生于贝类和鱼类体表的缘毛类纤毛虫原生动物。本文对分别寄生于海洋贝类－－虾夷扇贝Mizuhopecten yessoensis，半咸水鱼类－－鲻鱼Mugil cephalus和双色鳗鲡Anguilla bicolor bicolor，以及淡水鱼类－－光唇鱼Acrossocheilus fasciatus鳃表和体表的虾夷扇贝车轮虫Trichodina pectenis，亚卓车轮虫T.jadranica，急尖车轮虫T.acuta和喙状车轮虫T.rostrata，进行了详细的分类学研究。本文第一次报道了虾夷扇贝车轮虫的活体和蛋白银染色后特征，该虫体也是国内新记录种。其它三个车轮虫物种感染的鱼类，均属新纪录宿主。同时，也报道了这四种车轮虫对宿主的感染率和感染强度。     

利用扩增vvhA基因的环介导等温扩增技术快速，特异而敏感地检测创伤弧菌

创伤弧菌是一种可感染人类的河口病原菌。建立快速，特异而敏感的检测方法，有助于创伤弧菌感染的早期疾病诊断和及时治疗。本研究设计了针对vvhA基因的一系列引物（包括两对外部引物和两对内部引物），采用环介导等温扩增技术（LAMP）来检测创伤弧菌。结果显示，本方法的最适扩增温度是63℃，反应仅需35分钟。扩增产物不仅可以用含有DNA ladder的琼脂糖凝胶电泳检出，也可借助钙黄绿素直接肉眼观察。采用45株菌株检测该方法的特异性，其中所有创伤弧菌均被检出而其他菌株检测结果皆为阴性。本方法的敏感性是普通PCR扩增的100倍，同时利用该方法可以准确检测出所有的模拟样品、临床标本及环境样品。与其他已知方法比较，针对vvhA基因的介导等温扩增技术可以快速、简单、敏感及特异地鉴定创伤弧菌。     

Integration of the nuclease protection assay with sandwich hybridization (NPA-SH) for sensitive detection of Heterocapsa triquetra

Microalgae are photosynthetic microorganisms that function as primary producers in aquatic ecosystems. Some species of microalgae undergo rapid growth and cause harmful blooms in marine ecosystems. Heterocapsa triquetra is one of the most common bloom-forming species in estuarine and coastal waters worldwide. Although this species does not produce toxins, unlike some other Heterocapsa species, the high density of its blooms can cause significant ecological damage. We developed a H. triquetra species-specific nuclease protection assay sandwich hybridization (NPA-SH) probe that targets the large subunit of ribosomal RNA (LSU rRNA). We tested probe specificity and sensitivity with five other dinoflagellates that also cause red tides. Our assay detected H. triquetra at a concentration of 1.5×10⁴ cells/mL, more sensitive than required for a red-tide guidance warning by the Korea Ministry of Oceans and Fisheries in 2015 (3.0×10⁴ cells/mL). We also used the NPA-SH assay to monitor H. triquetra in the Tongyeong region of the southern sea area of Korea during 2014. This method could detect H. triquetra cells within 3 h. Our assay is useful for monitoring H. triquetra under field conditions.     

热带西太平洋的小粟虫属的四种有孔虫(原生动物)的形态学研究以及Miliolinella obesa nov. spec. 新种描述

Foraminiferal oozes were sampled from the tropical West Pacific seamount and seabed of deep sea,by a remotely operated vehicle(ROV)in December 2014 and March 2016.Using standard morphological method,four Miliolinella species,including Miliolinella obesa,M.circularis,M.suborbicularis and M.subrotunda were described.Among the four species,M.obesa is a new species.It is a large member(about 500μm in length)of the genus.This species is characterized by having a very stout and transverse broadly circular outline,and its body width is greater than the body length.In addition,its chamber demarcations are obscure from the exterior appearance.Three chambers are unclearly visible on one side and two chambers are visible on the opposite.Finally,we provided very detailed taxonomic microphotographs and the ecological distribution information for each species.     

中国东南沿海小头虫科(环节动物:多毛类)一新种

中蚓虫是小头虫科较为常见的属，中国海区的样品过去常被鉴定为加洲中蚓虫Mediomastus californiensis Hartman。本研究中，来自东南沿海四个不同海区的118条中蚓虫样品被鉴定为一个新的种类，在此给出具体描述。这个新种具有如下特征：（1）第1至9刚节表皮双环型，刚毛束位于体节中间位置，而后的刚节多环型，刚毛束位于体节后半部；（2）后腹区具有疣足突起；（3）前4个胸刚节仅具双羽型翅毛状刚毛，其它体节仅具巾钩刚毛；（4）胸区巾钩刚毛的柄长且直，巾长为宽的3至5倍；（5）腹区巾钩刚毛不同于胸区，较短且具收缩部；（6）甲基绿染色模式独特。这个研究表明了中国海区的中蚓虫可能被误鉴定为加洲中蚓虫，而这个新种M.chinensis sp.nov.在东南沿海广为分布。     

太平洋褶柔鱼冬生群资源丰度变动对ENSO事件的响应研究

太平洋褶柔鱼为大洋性经济鱼种，具有一年生命周期，其资源变动受气候和海洋环境条件的显著影响。本研究根据日本提供的2003-2012年太平洋褶柔鱼冬生群体的渔业统计数据，结合产卵场环境数据以及尼诺指数ONI（定义为Niño 3.4区海表温度距平值），分析不同气候条件下（厄尔尼诺和拉尼娜）太平洋褶柔鱼冬生群体产卵场海表温度（SST）、叶绿素a（Chl-a）浓度以及适宜产卵面积（SSA）的变动情况及对其资源丰度（CPUE）的影响。结果表明，太平洋褶柔鱼冬生群体产卵场SST、Chl-a浓度和SSA具有明显的季节性变化。相关分析表明，各年CPUE与Chl-a浓度以及SSA具有显著的正相关关系（p<0.05），但与SST相关性不显著（p>0.05）。此外，厄尔尼诺和拉尼娜事件通过驱动太平洋褶柔鱼冬生群体产卵场SSA和关键海域（25°-29°N，122.5°-130.5°E）内的Chl-a空间分布和大小变化，从而改变其资源丰度，但影响作用随各异常事件的强度不同而变化，具体表现为：发生弱强度厄尔尼诺事件时，产卵场SSA较高，Chl-a浓度处于较低水平，导致资源补充量处于较低水平，CPUE降低；发生中等强度厄尔尼诺事件时，产卵场SSA较低，但Chl-a浓度处于较高水平，导致资源补充量增加，CPUE处于上升水平；发生中等强度拉尼娜事件时，产卵场SSA和Chl-a浓度均处于较高水平，资源补充量显著增加，CPUE显著升高。研究表明，厄尔尼诺和拉尼娜事件对太平洋褶柔鱼冬生群体产卵场摄食孵化环境和资源丰度变动具有显著影响。     

酸化过程对不同碳酸钙含量的海洋沉积物中总氮及其同位素分析的影响

为节约成本和样品，一些学者同时分析海洋沉积物中的碳、氮及其同位素（TOC、TN、δ¹³C和δ¹⁵N）。分析沉积物中的δ¹³C，需要对样品进行酸化去除无机碳，但是这一酸化过程会使TN和δ¹⁵N的分析结果产生偏差，且偏差范围与沉积物中无机碳含量（CaCO₃）有关。本研究选取了低CaCO₃含量（1-16%）和高CaCO₃含量（20-40%）的海洋沉积物样品，比较了酸化过程对TN和δ¹⁵N的影响。研究结果表明，酸化过程对海洋沉积物中TN和δ¹⁵N的分析结果产生了显著影响。对于低CaCO₃含量的样品，酸化导致样品中TN流失了约0-40%，δ¹⁵N偏移了约0-2‰；而对于高CaCO₃含量的样品，酸化导致样品中TN流失了约10-60%，δ¹⁵N偏移了约1-14‰。表明酸化对TN和δ¹⁵N的影响已经超过了仪器的误差范围0.002%（TN）和0.08‰（δ¹⁵N），将影响TN和δ¹⁵N的环境指示意义。因此，即使海洋沉积物样品中CaCO₃含量很低，也必须用原样分析TN和δ¹⁵N以避免酸化过程的影响。     

发现于我国渤海辽东湾的海洋甲藻新种-渤海异冒藻(Heterocapsa bohaiensis sp. nov.)

A small armed dinoflagellate bloomed in the aquaculture ponds off the coast of Liaodong Bay, Bohai Sea of China,resulting in heavy mortalities of the cultured prawns(Penaeus japonicus) and larvae of Chinese mitten handed crabs(Eriocheir sinensis). The bloom-forming species was successfully isolated, and cellular morphology of the specimen was consequently investigated through light, fluorescent and electron microscopy. The small((14.4±1.6) μm in length) ellipsoid cells show typical Heterocapsa thecal plate arrangement(Po, cp, 5′, 3 a, 7′′, 6 c,5 s, 5′′′, 2′′′′). The episome is evidently bigger than the hyposome. One to three spherical pyrenoids are located above or beside the large elongated nucleus. The body scale is characterized by a triangle basal plate with one central upright and nine peripheral spines. Above all, Heterocapsa bohaiensis could be distinguished from other Heterocapsa species by the combination of the cell size, morphology, cellular structure and body scale. Sequence analyses of both ITS and LSU regions reveal the significant genetic divergence between H. bohaiensis and other established species in this genus, further supporting novelty of this species. Noticeably, different sample treatment methods resulted in morphological variation of the apical pore complex(APC) of H. bohaiensis, which needs to be taken into account in future study.     

西太平洋深海海水中乙醛降解菌多样性及群落结构研究

As a major aldehyde pollutant widely existing in industry and our daily life, acetaldehyde is more and more harmful to human health. As characteristic habitat niche, bacteria from deep sea environments are abundant and distinctive in heredity, physiology and ecological functions. Thus, the development of acetaldehyde-degrading bacteria from deep sea provides a new method to harness acetaldehyde pollutant. Firstly, in this study,acetaldehyde-degrading bacteria in the deep sea water of the West Pacific Ocean were enriched in situ and in the laboratory respectively, and then the diversity of uncultured bacteria was studied by using 16 S r RNA genes. Then acetaldehyde-degrading strains were isolated from two samples, including enrichment in situ and enrichment in laboratory samples of deep sea water from the West Pacific Ocean using acetaldehyde as the sole carbon source,and then the ability of acetaldehyde degradation was detected. Our results showed that the main uncultured bacteria of two samples with different enrichment approaches were similar, including Proteobacteria,Actinobacteria, Firmicutes, Cyanobacteria, but the structure of bacterial community were significant different.Four subgroups, α, γ, δ and ε, were found in Proteobacteria group. The γ-Proteobacteria was dominant(63.5%clones in laboratory enriched sample, 75% clones in situ enriched sample). The species belonged to γ-Proteobacteria and their proportion was nearly identical between the two enrichment samples, and Vibrio was the predominant genus(45% in laboratory enriched sample, 48.5% in situ enriched sample), followed by Halomonas(9% in situ enriched sample) and Streptococcus(6% in laboratory enriched sample). A total of 12 acetaldehyde-degrading strains were isolated from the two samples, which belonged to Vibrio, Halomonas,Pseudoalteromonas, Pseudomonas and Bacillus of γ-Proteobacteria. Strains ACH-L-5, ACH-L-8 and ACH-S-12,belonging to Vibrio and Halomonas, have strong ability of acetaldehyde degradation, which could tolerate 1.5 g/L acetaldehyde and degrade 350 mg/L acetaldehyde within 24 hours. Our results indicated that bacteria of γ-Proteobacteria may play an important role in carbon cycle of deep sea environments, especial the bacteria belonging to Vibrio and Halomonas and these strains was suggested for their potentials in government of aldehyde pollutants.