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1.
The seasonal variability in fouling community recruitment on submerged artificial substratum was studied in Kudankulam coastal water, Gulf of Mannar, East coast of India for a period of two years, from May 2003 to April 2005. The results indicated that the fouling community recruitment occurred throughout the year with varying intensities. Barnacles, ascidians, polychaetes, bivalves and seaweeds were the major fouling groups observed from the test panels. Maximum fouling biomass of 9.17 g dm−2 was observed during August 2004 and a minimum value of 0.233 g dm−2 in February 2004. The biomass build-up on test panels was relatively high during the premonsoon season and low during the postmonsoon months. The number of barnacles settled on the panels varied from 1 to 4460 no. dm−2. The maximum percentage of the ascidian coverage (72%) on test panels was observed during March 2005. In general, July–December was the period of intense recruitment for barnacles and March–May was the period for ascidians.  相似文献   

2.
Mandovi estuary is a tropical estuary strongly influenced by the southwest monsoon. In order to understand, sources and fate of particulate organic nitrogen, suspended particulate matter (SPM) collected from various locations, was analyzed for particulate organic carbon (POC) and particulate organic nitrogen (PON), δ13CPOC, total hydrolysable amino acid enantiomers (l- and d- amino acids) concentration and composition. δ13CPOC values were depleted (−32 to −25‰) during the monsoon and enriched (−29.6 to −21‰) in the pre-monsoon season implying that OM was derived from terrestrial and marine sources during the former and latter season, respectively. The biological indicators such as C/N ratio, d-amino acids, THAA yields and degradation indices (DI) indicate that the particulate organic matter (POM) was relatively more degraded during the monsoon season. Conversely, during the pre-monsoon, the biological indicators indicated the presence of relatively fresh and labile POM derived from autochthonous sources. Amino acids such as alanine, aspartic acid, leucine, serine, arginine, and threonine in monsoon and glutamic acid, glycine, valine, lysine, and isoleucine in pre-monsoon were relatively abundant. Presence of bacterial biomarker, d-amino acids in the SPM of the estuary during both the seasons signifies important contribution of bacteria to the estuarine detrital ON pool. Based on d-amino acid yields, bacterial OM accounted for 16-34% (23.0 ± 6.7%) of POC and 29-75% (47.9 ± 18.7%) of PON in monsoon, and 30-78% (50.0 ± 15%) of POC and 34-79% (51.2 ± 13.3%) of the PON in pre-monsoon in the estuary. Substantial contribution of bacterial-N to PON indicates nitrogen (N) enrichment on terrestrial POM during the monsoon season. Transport of terrestrial POM enriched with bacterial OM to the coastal waters is expected to influence coastal productivity and ecosystem functioning during the monsoon season.  相似文献   

3.
Rare earth elements (REEs) in the suspended particulate matter (SPM) of the Mandovi estuary indicated that the mean total-REEs (∑REE) and light REE to heavy REE ratios are lower than that of the average suspended sediment in World Rivers and Post-Archean average Australian shale. High ∑REE were associated with high SPM/low salinity and also with high SPM/high salinity. Although the ∑REE broadly agree with SPM levels at each station, their seasonal distributions along transect are different. SPM increased seaward in the estuary both during the monsoon and pre-monsoon, but consistently low at all stations during the post-monsoon. The mean ∑REE decreased marginally seaward and was <25% at sea-end station than at river-end station. Spatial variations in ∑REE are maximum (64%) during the pre-monsoon. Strong to moderate correlation of ∑REE with Al, Fe and Mn in all seasons indicates adsorption and co-precipitation of REEs with aluminosilicate phases and Fe, Mn-oxyhydroxides. The ratio of mean ∑REE in sediment/SPM is low during the monsoon (1.27), followed by pre-monsoon (1.5) and post-monsoon (1.62). The middle REE- and heavy REE-enriched patterns with positive Ce and Eu anomalies are characteristic at every station and season, both in SPM and sediment. They also exhibit tetrad effect with distinct third and fourth tetrads. Fe-Mn ore dust is the most dominant source for REEs. However, the seasonal changes in the supply of detrital silicates, Fe-Mn ore dust and particulates resuspended from bottom sediments diluted the overall effect of salinity on fractionation and distribution of REEs in the estuary.  相似文献   

4.
Interactions between microfouling components influence the biofilm community and the cascading events, thus playing an important role in the biofouling process. Bacteria and diatoms are among the dominant forms reported in biofilms. Experiments were carried out with natural marine biofilms from a tropical monsoon‐influenced environment to evaluate the interactions between bacteria and diatoms through application of antibiotics (streptomycin and chloramphenicol). Overall, chloramphenicol inhibited diatom communities, whereas streptomycin did not. These antibiotic‐mediated changes in the fouling diatom community were consistent across the seasons. However, the rates at which the fouling communities changed depended on the initial species composition. It was also observed that elevated nutrient concentrations overrode the inhibitory effect of chloramphenicol. Maximum Vibrio enhancement was observed in the enriched conditions during the pre‐monsoon and unenriched conditions during the monsoon (with naturally elevated background nutrient concentrations), highlighting the relevance of nutrient concentrations for Vibrio spp. This has interesting implications for antibiotic‐mediated interactions between fouling diatom and bacterial communities under differing nutrient regimes. Although this study indicates the relevance of ‘cross‐talk’ at the microfouling level, understanding the effects of additional microbial products (e.g. bacteriocins and peptidoglycan) on these community‐level interactions will represent a step forward.  相似文献   

5.
烟台市龙口港污损生物生态研究   总被引：1，自引：0，他引：1  
于2007年03月22日至2008年03月21日在山东省烟台市龙口港附近海域,进行了为期1年的挂板试验,本次调查共记录该海域污损生物32种,优势种为内枝多管藻(Polysiphonia morrowii)、软丝藻(Ulothrix flacca.)、肠浒苔(Entermorpha intestinalis)、中胚花筒螅(Tubularia mesembryanthemum)等.该海域全年均有污损生物附着,月板平均生物量为525.18 g/m2,5-11月的生物附着量较高,最高值出现在7月;季板平均生物量为1569.39 g/m2,生物群落的种类组成和生物量变化明显,其中秋季板生物量最高,龙口海域污损生物的附着种类受季节性水温变化的影响比较明显,藻类开始附着的温度低于动物.4个季度污损生物的种群多样性指数(H忆)春季最高,均匀度指数(J)和种群丰富度指数(M)则夏季最高.统计分析表明,龙口港海域污损生物群落可大致划分为 4个组群,秋季附着的污损生物代表了试验海域的主要特征,同时揭示出污损生物附着季节、演替时间长短等是影响群落种类组成的重要因素  相似文献   

6.
The diversity, abundance and biomass of microzooplankton in Cochin backwaters were studied for the first time during pre-summer monsoon to peak of summer monsoon (April–July 2003) to understand the impact of large freshwater influx. Microzooplankton abundance and biomass were highest during pre-summer monsoon (av. 3817 ind. L−1 and 146 μg C L−1) that declined with the onset (av. 2052 ind. L−1 and 45 μg C L−1) and peak (av. 409 ind. L−1 and 10 μg C L−1) summer monsoon. Species diversity, richness and evenness of microzooplankton also showed similar trends as that of abundance and biomass. Grazing experiment showed that microzooplankton consumes 43 ± 1% of the daily phytoplankton standing stock during the high saline condition (27.5). Low abundance of microzooplankton during summer monsoon period (1/8 of the pre-summer monsoon value) along with the concomitant occurrence of low mesozooplankton (1/8 times of pre-summer monsoon value) suggests that there could be a general lack of planktonic grazers. This would result in a weak transfer of primary and bacterial carbon to higher trophic levels, eventually leaving behind much unconsumed basic food in the estuary during summer monsoon. Thus a major portion of the primary carbon either settles down or gets transported to the coastal regions during monsoon. High flushing of Cochin backwaters also facilitates faster removal of primary producers to the coastal regions during monsoon.  相似文献   

7.
东山湾污损生物生态研究   总被引：7，自引：4，他引：3  
2008年9月-2009年8月在东山湾海域进行了污损生物周年挂板试验,共记录污损生物102种,以近岸暖水种为主,其中网纹藤壶(Amphibalanus reticulates)是该海域最具代表性的优势种,其他优势种还有裂片石莼(Ulva fasciata)、双列笔螅(Pennaria disticha)、纵条肌海葵(Haliplanella luciae)、僧帽牡蛎(Saccostrea cucullata)、变化短齿蛤(Brachidontes variabilis)、巴西地钩虾(Podocerus brasiliensis)、梳肢片钩虾(Elasmopus pecteniclus)、强壮板钩虾(Stenothoe valida)、长鳃麦秆虫(Caprella equilibra)和厦门华藻苔虫(Sinoflustra amoyensis)等。该海区污损生物全年均可附着,附着盛期在4-10月,月板的平均附着量(湿重)为979.43 g/m2,夏季可高达11 799.00 g/m2。污损生物群落多样性以夏季最高,冬季最低;随着试板浸海时间的延长,其上污损生物群落的多样性明显增加,且结构也趋于稳定。  相似文献   

8.
The changes in dinoflagellate community structure in both – the water column and sediment in a mesotrophic, tropical port environment were investigated in this study. Since the South West Monsoon (SWM) is the main source of climatic variation, observations were made during two consecutive post-monsoon periods (2001 and 2002) and the intervening pre-monsoon period (2002). The pre-monsoon period supported a more diverse dinoflagellate community in the water column compared to both post-monsoon periods. Heterotrophic dinoflagellates were abundant in the water column as well as sediment. A seasonal cycling between vegetative and resting cysts of autotrophic and heterotrophic dinoflagellates governed by the environmental characteristics of the study area was observed. Temperature, salinity and suspended particulate matter were the main factors affecting dinoflagellate community structure in both the water column and sediment. The dominant dinoflagellates in the water column differed during both post-monsoon periods that followed two dissimilar monsoon events. Prorocentroids and gonyaulacoids dominated the water column subsequent to the 2001 SWM, whereas dinophysoids and unidentified tiny dinoflagellates dominated during the next post-monsoon period. The 2001 SWM started in May, peaked during June–July and reduced gradually to end in October. The 2002 SWM was erratic; it started late (in June) and ended earlier (in September). These observations highlight the potential of the SWM to influence the community structure of dinoflagellates in tropical waters and points to the importance of long-term studies to discern robust variations in dinoflagellate communities in response to fluctuating monsoon regimes.  相似文献   

9.
Suspended particulate matter (SPM) collected at regular stations from the Mandovi and Zuari estuaries indicates that the peaks of high SPM coincide with peaks of high rainfall and low salinity and also with peaks of moderate/low rainfall coupled with high salinity during the monsoon. The estuarine turbidity maximum (ETM) is a characteristic feature, it occurs in the channel accompanying spring tide during the monsoon and pre-monsoon, and shifts to the bay on neap tide during post-monsoon. ETM remains at the same position in the Mandovi River, both during the monsoon and pre-monsoon, whereas in Zuari it stretched upstream during monsoon and migrates seaward of the channel during pre-monsoon. The ETM coincides with the freshwater–seawater interface during the monsoon and is formed by the interaction between tidal currents and river flows. The ETM during pre-monsoon is associated with high salinities and is generated by tidal and wind-induced currents. The turbidity maximum on neap tide during post-monsoon may be due to the erosion and resuspension of sediments from the emergent tidal flats and transport of these turbid waters into the bay. Funneling effect of the narrowing bay in the Zuari estuary and associated physical processes effectively enhance the magnitude of the currents and transports sediments to the channel. SPM retention percentage indicates that the estuarine channel is prone to siltation.  相似文献   

10.
Zooplankton communities, studied in the surface mixed layer on a 1600 m transect across the Arabian Sea, were found to differ in their temporal and spatial response to seasonal forcing. The transect studied, spanned seasonally eutrophic upwelling, mesotrophic downwelling and aseasonal oligotrophic waters. The nano- and microzooplankton communities constituted a relatively constant compartment in the tropical monsoon ecosystem, whilst the mesozooplankton showed a clear response to both upwelling and season. The heterotrophic nanoflagellates were concentrated in the surface mixed layer, except in the eutrophic upwelling waters of the SW monsoon. They reached maximum cell concentrations of 855 ml-1 during the SW monsoon and a maximum biomass of 8.4 mg C m-3 during the intermonsoon. Nanozooplankton standing stocks, in the surface mixed layer, ranged between 7 and 333 mg C m-2, with highest stocks found during the intermonsoon. The microzooplankton community was dominated by Protozoa, particularly aloricate ciliates and heterotrophic dinoflagellates, which accounted for up to 99% in terms of numbers and up to 71% of the biomass. Sarcodines and metazoan nauplii were recorded in lower numbers (<400 l-1). The microzooplankton were also concentrated in the surface mixed layer during both periods, except in the eutrophic coastal waters during the SW monsoon, when relatively high biomass values were found below the mixed layer depth. Their standing stocks, in the surface mixed layer, ranged between 50 and 182 mg C m-2, with the highest concentration found in the mesotrophic offshore waters during the late monsoon period. Total mesozooplankton standing stocks, in the surface 100 m, decreased with distance from the coastal to offshore waters and between seasons, decreasing from 1248 to 238 mg C m-2 during the late SW monsoon and 656–89 mg C m-2 during the following intermonsoon. The largest size class, of 1000–2000 μm sized organisms, dominated throughout except at the oligotrophic station during the intermonsoon period, when the smallest class, of 200–500 μm, were more important. The shift in size structure from large to small zooplankton occurred in response to a shift in dominance from large to small phytoplankton cells both spatially, along a eutrophic–oligotrophic gradient, and seasonally. These responses are a result of the physical forcing associated with the monsoon seasons in the Arabian Sea.  相似文献   

11.
广西白龙半岛邻近海域污损生物群落结构分析   总被引：1，自引：1，他引：0  
田伟  徐兆礼 《海洋学报》2015,37(6):120-127
2011年12月-2012年11月,在广西白龙半岛邻近海域进行周年污损生物挂板试验,共记录到污损生物60种,以亚热带暖水种为主,其中优势种类有河蜾蠃蜚Corophium acherusicum、钩虾Gammarus sp.、网纹藤壶Amphibalanus reticulatus、翡翠贻贝Perna viridis、华美盘管虫Hydroides elegans、太平洋侧花海葵Anthopleura nigrescens、冠瘤海鞘Styela canopus、凸壳肌蛤Musculus senhousia和多齿围沙蚕Perinereis nuntia。全年均有生物附着,四季平均附着密度和附着湿质量分别为45 136个/m2和4 246.03g/m2,其中以秋季附着密度最高,达到153 514个/m2,春季附着湿质量最大,为9 418.42g/m2。污损生物群落Shannon-Wiener多样性指数(H′)、Pielou均匀度指数(J)和Margalef物种丰富度指数(d)均以夏季最高,冬季最低。丰度/生物量比较法结果表明,冬季、秋季、下半年和周年板上的污损生物群落结构不够稳定。  相似文献   

12.
In order to gain insight into the formation dynamics of mudbanks off the Kerala coast of India, extensive surveying of the nearshore bathymetry along with sediment characterization was undertaken. The textural and geotechnical properties of the surficial sediments of a mudbank were determined during pre-monsoon, monsoon, and post-monsoon periods. The mudbank sediments were clayey silts with high water and organic carbon contents, high Atterberg limits, and low bulk density, and therefore very susceptible to entrainment. During the monsoon, the mudbank regime was characterised by enhanced turbidity and a benthic fluff layer, triggered by the increasing swell of the early monsoon period. Re-suspension exposed a more consolidated, previously sub-bottom, layer which exhibited lower water content and greater shear strength than the pre-monsoon seabed. Texturally, the monsoon seabed was similar to the pre-monsoon seabed, with the same modal grain size, but the proportions of sand and coarse silt increased nearshore, while the proportions of fine and very fine silt increased offshore. There was a seaward-fining textural gradient at all times, but this became pronounced during the monsoon period. Paradoxically, the monsoonal seabed displayed greatly reduced wet bulk density. It is hypothesized that this was due to the presence of gas, probably methane, in the sediments (while the pre-monsoon sediments were fully saturated, the monsoon sediments were only 83% saturated). We speculate that the gas was forced into the surficial sediments either by wave pumping (at the onset of the monsoon) or by seaward-flowing subbottom freshwater (derived from monsoonal rains). With the waning of the monsoon, the benthic fluid mud layer rapidly disappeared and the seabed returned to its pre-monsoon state as suspended sediments were redeposited. The mudbank regime is therefore essentially an in situ phenomenon. It is suggested that the mudbanks are palimpsest, marshy, lagoonal deposits, rich in organic matter and derived gas, that were submerged after a marine transgression. The surficial sediment is annually entrained during the monsoon, but erosion is limited by the formation of the benthic fluid mud layer, which attenuates wave generated turbulence. Although some fine sediment disperses alongshore and offshore, most is returned to the seabed as the monsoon declines.  相似文献   

13.
海南岛东部海域生物污损研究   总被引：17，自引：0，他引：17  
于１９８９年１０月－１９９０年６月,在位于海南岛东部海域的琼 东和琼东南海区,分别布设Ｗ１和Ｊ２两个浮标站,进行生物污损的挂板试验。  相似文献   

14.
浙江北关港污损生物的群落结构及其主要影响因子   总被引：1，自引：1，他引：0  
于2016年3月至2017年2月在浙江北关港附近海域进行污损生物周年挂板试验，全年共记录大型污损生物9门44科53属59种，种类组成以近岸暖水种为主，属于典型的亚热带内湾型污损生物群落。固着生活类型的悬浮物食者是该海域污损生物群落的优势群体，群落最主要的优势种是网纹藤壶（Amphibalanus reticulates），其次为长鳃麦秆虫（Caprella equilibra）、中胚花筒螅（Ectopleura crocea）、太平洋侧花海葵（Anthopleura nigrescens）、廉形叶钩虾（Jassa falcata）和强壮藻钩虾（Stenothoe valida）等种类。该海域污损生物全年各月均有附着，6-10月板的覆盖面积均达100%，附着盛期为6-8月，月板、季板、半年板和年板的平均附着密度和生物量分别为（21 371±8 722） ind/m2和（1 667.5±506.0） g/m2，（31 605±17 671） ind/m2和（5 879.1±2 576.5） g/m2，（31 188±10 834） ind/m2和（13 989.6±4 755.4） g/m2，（18 425±5 757） ind/m2和（6 581.9±2 175.9） g/m2，其中夏季附着强度最高。污损生物群落个体间因栖息空间和食物竞争而存在着相互依存或互相制约的关系，又依照对环境的适应性而存在着一定的时空分布规律。分析表明，温度是决定污损生物地理分布的最主要环境因素；另外，盐度、水体透明度以及光照等自然环境也是影响污损生物附着的重要影响因素。  相似文献   

15.
洋山港海域大型污损生物生态特点   总被引：4，自引：2，他引：2  
洋山港是上海国际航运中心的枢纽港。为了解该海域污损生物的群落结构及演变趋势,2009年3月至2010年3月在洋山港海域进行了周年污损生物挂板调查研究。洋山港海域污损生物种类较少,共记录污损生物19种,隶属于5个类群,优势种为僧帽牡蛎(Ostrea cucullata)、网纹纹藤壶(Balanus reliculatus) 、大室膜孔苔虫(Membranipora grandicella)、厦门华藻苔虫(Sinoflustra amoyensis)、双钩楯琥珀苔虫(Aspidelectra bihamata)、中胚花筒螅(Tubularia mesembryanthemum)、曲膝薮枝螅(Obelia geniculata)和亚洲帚毛虫(Sabellaria ishikawai),种类组成以广布种为主,同时部分具有河口低盐种的特征;污损生物的附着高峰期是6—10月份,除冬季月份外,其余月份均有生物附着;受盐度、水流及泥沙含量的影响,洋山港污损生物的生物量变化较大,月板、季板及年板的平均附着生物量分别为9.20,127.20和774.04 g/m2。另外,通过对洋山港海域污损生物周年的物种组成和群落结构变化分析,发现该海域污损生物群落受季节变化和盐度的升高影响较大,群落结构不稳定,物种演替明显。  相似文献   

16.
Data on temporal variations of total dimethylsulfoniopropionate (DMSPt) and the environmental factors that influence DMSPt concentrations are important in understanding the biogeochemical cycling of organic sulfur compounds. Annual and diurnal variations of DMSPt were investigated in relation to environmental variables at a fixed station in Dona Paula bay (west coast of India). DMSP concentrations were high in the day and low at night and ranged from 3.69 to 84 nM with a maximum at 17.00 h. The high concentrations of DMSPt during daytime closely followed that of Chl a concentrations. The DMSP utilizers averaged 0.8 ± 0.3 × 103 cells l?1 during night and 0.4 ± 0.1 × 103 cells l?1 during the day. The diel variation of DMSPt was influenced more by biological variables than hydrographic parameters. In the year-round study, the concentrations ranged from 0.69 to 15.8 nM. It was fourfold higher during the southwest monsoon season (13.4 ± 2 nM) and threefold higher during the post-monsoon season (9.96 ± 5 nM) compared to the pre-monsoon season (3.1 ± 1 nM). DMSPt concentrations showed temporal variability, both during diurnal and annual studies. Diatoms were identified as producers of DMSP in Dona Paula bay. Dinoflagellates also contributed during the non-monsoon seasons. Another factor involved in the variability of DMSPt was DMSP utilizing bacteria, which ranged from 1 to 10% of the total heterotrophic count.  相似文献   

17.
泉州湾污损生物生态研究   总被引：5，自引：4，他引：1  
2001年12月—2002年11月在泉州湾海域进行了污损生物周年挂板试验,共记录污损生物112种,以近岸暖水种为主,其中长鳃麦秆虫(Caprella equilibra)和网纹藤壶(Amphibalanus reticulates)是该海域最具代表性的优势种,其次为裂片石莼(Ulva fasciata)、中胚花筒螅(Tubularia mesembryanthemum)、薮枝螅(Obeliasp.)、纵条矶海葵(Haliplanella luciae)、外伪角涡虫(Pseudoceros exoplatus)、柄涡虫(Stylochus sp.)、僧帽囊牡蛎(Saccostrea cucullata)、翡翠贻贝(Perna viridis)、巴西地钩虾(Podocerus brasiliensis)、强壮板钩虾(Stenothoe valida)、镰形叶钩虾(Jassa falcata)和角突麦秆虫(Caprella scaura)等种类。该海区污损生物全年均可附着,种类丰富且附着强度大,附着盛期在4—11月,月板、季板、半年板和周年板的平均附着生物量分别为2 624g/m2、5 309g/m2、6 210g/m2和8 247g/m2,夏季可达11 295g/m2。随着试板浸海时间的延长,试板上污损生物群落的多样性明显增加,且结构也趋于稳定。  相似文献   

18.
1986年5月—1988年4月在海南岛西南部莺歌海水域布设4个浮标调查站，以了解该海区生物污着状况。结果表明，该海区污着生物群落的厚度及生物量主要取决于双壳类软体动物和无柄蔓足类等硬性污着生物，而海藻、水螅、苔藓虫及有柄蔓足类则是生物污着的重要种类。此外，随着离岸距离的增加，污着生物群落的种类组成及数量也发生相应变化。  相似文献   

19.
Wood destruction in test panels ofShorea leprosulawas related to the percentage of fouling, types of wood borers and the number of wood borers. The natural durability ofShorea leprosulapanels was estimated to be 4–5 months in Malaysian marine waters. A higher fouling cover resulted in lower rates of wooden panel deterioration. Larger numbers of wood borers brought about greater panel deterioration. Primary wood destruction was caused by bivalve wood borers, mainlyMartesia striata, Lyrodus pedicellatus, Bankia campanellata, Teredo furciferaandTeredo bartschi. Martesia striatawas the important wood destroying agent in the intertidal zone and, together with the shipworms, was also responsible for panel destruction in the subtidal zone.  相似文献   

20.
1986年6月至1987年6月,在北部湾东北部离岸分别为40和3．6nmile处布设了BZ,B3两个浮标调查站,以了解该海区的污着生物生态特点。调查结果表明,该水域的污着生物主要为热带、亚热带海域沿岸常见种类,其中无柄蔓足类在近岸的B3站处于绝对优势的地位;至于远岸的BZ站;不仅珍珠贝和牡蛎等双壳类软体动物的生物附着量（湿重）高于B3站,而且还有少量的茗荷Lepasanatifera、鹅茗荷L．anserdera等外海性种类出现。  相似文献   

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