大亚湾秋季小型底栖生物初步研究

2009年10月对大亚湾海域的小型底栖动物丰度和生物量进行了研究.结果表明,小型底栖动物的平均丰度为(593±265)ind·(10cm)?2,呈湾内向湾外递增趋势;平均生物量和生产量分别为(568.39±294.49)μg·(10cm)?2(干重)和(5115.53±2811.14)μg·(10cm)?2(干重).在分选的17个主要类群中,海洋线虫在丰度上占绝对优势达92.24%,其次是多毛类和桡足类,分别为2.05%和1.98%.在生物量上,海洋线虫(38.47%)和多毛类(29.97%)为绝对优势类群,其次是寡毛类(13.82%)和介形类(9.15%).在垂直分布上,占总量约53.02%的小型底栖动物和51.44%的海洋线虫分布于0—2cm表层.统计分析表明,本海域的小型底栖动物生物量与含水率、中值粒径和黏土+粉砂含量呈显著负相关(P<0.05),多毛类的生物量与小型底栖动物表现的显著相关性相同,桡足类的生物量与中值粒径值呈显著负相关(P<0.05),与沉积物的黏土+粉砂含量呈极显著负相关(P<0.01),而线虫生物量与环境因子无显著相关关系.由海洋线虫与桡足类的数量比(用 N/C 表示)与本海域环境状况的分析表明,该数值可以在一定尺度上为海洋环境检测提供参考.     

黄海夏季沉积物中异养细菌的现存量及分布特点

采用DAPI荧光染色技术, 进行了2007年6月和2008年7月黄海底栖异养细菌的丰度和生物量及分布特点研究。结果表明, 2007年底栖细菌的丰度为(1.13±0.39)×109cells/cm3, 生物量为(49.63±17.26)?gC/cm3; 2008年底栖细菌的现存量较2007年低了约43%。南黄海的底栖细菌现存量较北黄海分别低8%(2007年)和13%(2008年), 而中央冷水团则较其外围区域高约10%和37%, 在南黄海呈现中央冷水区域高于近岸的分布特点, 而在北黄海则正相反。统计分析表明, 2007年北黄海底栖细菌丰度与沉积物叶绿素a含量呈极显著正相关, 南黄海细菌丰度与沉积物有机质含量及底层水盐度呈极显著正相关; 而2008年北黄海细菌丰度与环境因子未见明显的相关性, 在南黄海则与底层水的叶绿素含量呈极显著负相关, 显示浒苔暴发可能对底栖细菌产生了明显抑制。     

厦门筼筜湖潟湖底栖微藻光合色素的时空变化特征及与环境因子的关系

2010年7月至2011年7月,利用高效液相色谱分离分析技术研究了厦门筼筜湖潟湖表层沉积物的底栖微藻生物量(以叶绿素a计)和光合色素组成,探讨了其与环境因子的关系.结果表明,表层沉积物中检出岩藻黄素、别藻黄素、玉米黄素、叶绿素b四种光合色素,对应的微藻类群包括硅藻、隐藻、蓝藻和绿藻.底层(表层沉积物)与水层(水体)微藻叶绿素a生物量呈显著负相关关系(p＜0.05),但底层-水层对应的光合色素不存在显著相关关系,此暗示底层光合色素主要是底栖微藻的贡献,而非来自水层浮游微藻的沉降.底栖微藻生物量随时间变化明显,夏季(6～8月)较低(1.30 mg/m2),冬季(12月至翌年2月)较高(86.16 mg/m2).各测站底栖微藻生物量存在空间差异,随湖区的水深增加而降低,与沉积物表层光辐照度呈显著的正相关关系(p＜0.05).岩藻黄素与降雨量呈显著负相关,别藻黄素与水体无机氮含量呈显著正相关,玉米黄素分布主要受温度影响,除玉米黄素外,其他光合色素含量与光辐照度呈正相关.初步估算表明,底栖微藻占该浅水潟湖生态系统水层-底层微藻叶绿素a生物量和固碳量的27.64％和12.56％.     

南海小型底栖动物生态学的初步研究

2007年10—11月对南海海域(17—21°N,109—112°E)的小型底栖动物的生态特点进行了研究。结果表明,小型底栖动物的丰度平均为(901±913)ind/10cm2,自近岸向外海域呈递减趋势;平均生物量和生产量分别为(798±713)μgdwt/10cm2和(7185±6421)μgdwt/10cm2。研究海域小型动物的平均丰度与莱州湾和南黄海冬季的研究结果较接近,高于东、黄海,低于胶州湾和长江口。在分选的17个主要类群中,海洋线虫在丰度上占绝对优势(92.9%),多毛类(2.5%)和桡足类(1.5%)所占比例均较小。在生物量上,海洋线虫(41.9%)和多毛类(40.1%)为绝对优势类群,其次是介形类(3.6%)和桡足类(3.2%)。在垂直分布上,占总量约53%的小型底栖动物和52%的海洋线虫分布于0—2cm表层,该结果与长江口较为接近,而较渤海和黄海低。统计分析表明,本海域的小型底栖动物和线虫的数量与沉积物中有机质含量呈显著正相关,与水深呈显著负相关。由海洋线虫与桡足类的数量比(N/C)与本海域环境状况的分析表明,该数值在一定尺度上可为海洋环境监测提供参考。     

利用小型底栖动物对沉积物重金属污染的评估

采用Hakanson的生态风险指数法和自由生活海洋线虫与底栖桡足类数量之比(N/C比值)的变动对长江口及其邻近海域沉积环境重金属污染状况进行评估.结果表明,研究海域沉积物受到重金属元素Cr,Cu,Zn和As不同程度的污染,近岸站位受测各污染物均呈现中度污染,离岸站位为轻度污染,其中Zn累积最严重.单个污染物潜在生态危害参数表明,受测污染物对海洋生态系统的潜在生态危害非常轻微,其中As和Cu是最主要的生态风险贡献因子.小型底栖动物群落丰度及分布验证了此结果,对As和Cu累积具有明显的生态响应.N/C比值法对研究海域沉积物重金属的污染评估结果与Hakanson的生态风险指数评估结果基本一致,特别是对Cu和As元素的污染评估.结合生物群落分析,利用小型底栖动物两大类群数量之比(N/C)是一个简易可行的沉积环境监测方法.     

长江口及其邻近海域大型底栖动物生物量、丰度和次级生产力的初步研究

为了解长江口及邻近海域大型底栖动物生物量、丰度和次级生产力的分布情况于2004年2月、5月、8月和11月共4个航次分别在长江口40个观测站采集大型底栖动物定量样品并利用Brey的经验公式对大型底栖动物栖息丰度、生物量、次级生产力和P/B值进行了研究计算.该调查海域共采到大型底栖动物202种,其中多毛类102种,软体动物51种,甲壳类27种,棘皮动物7种,其它动物15种.大型底栖动物年平均丰度为394.7 ind/m2;年平均生物量以去灰分干重计,为2.58 g(AFDW)/m2;年平均次级生产力以去灰分干重计,为3.52 g(AFDW)/(m2*a);P/B值平均为1.53.结果表明,长江口大型底栖动物次级生产力自长江入海口向东呈递增趋势.本文分析了长江口及其邻近海域大型底栖动物优势种的组成,主要生态类群的分布特征和次级生产力分布格局与生态环境的关系.通过比较,发现长江口大型底栖动物优势种发生了较大的变化;次级生产力高于东海而低于渤海和胶州湾;P/B值高于南黄海、胶州湾和渤海,也说明了长江口大型底栖动物群落中个体小、生活史短,代谢快的种类所占的比例高于以上海域.     

胶州湾菲律宾蛤仔养殖水域内外大型底栖动物群落特征的比较研究

为了解胶州湾养殖水域和自然水域的底栖动物生态状况,尤其是水产养殖等人类活动对胶州湾生态系统的影响,在胶州湾菲律宾蛤仔养殖区内外选取六个典型站位,于2011年4月进行了大型底栖动物和环境因子的采样,分析比较了养殖区内外大型底栖动物的丰度、生物量、群落结构和生物多样性等群落特征以及与环境因子的关系。本研究共采到大型底栖动物77种,其平均丰度为1154.44 ind./m~2,平均生物量为369.33 g.wwt/m~2。研究结果表明的养殖区内外大型底栖动物的优势种、丰度、生物量和群落结构差别较大。根据CLUSTER聚类结果,可以将大型底栖动物群落划分为3个站群。与历史数据相比,本研究6个站位中自然水域的站位丰度、生物量降低,而养殖水域内的站位丰度、生物量较高。菲律宾蛤仔养殖活动压力已造成胶州湾养殖区域及其邻近自然海域的大型底栖动物群落特征发生了一定变化。     

东寨港红树林小型底栖动物的密度和生物量研究

2012年2月对海南省东寨港红树林滩涂沉积物小型底栖动物进行研究,结果表明,红树林中有六大类小型底栖动物,包括自由生活线虫、桡足类、涡虫、多毛类、寡毛类、海螨.在种类组成上,自由生活线虫为优势类群,在4个采样站位中,分别占小型底栖动物总数量的95.30％,97.02％,96.45％,90.53％.东寨港红树林小型底栖动物的总栖息密度为(1 082.23±563.76)个/(10 cm2),总生物量为(764.06±511.63)μg/(10 cm2).4个采样站位平均多样性指数H'分别为0.26、0.17、0.20、0.45,平均均匀度指数 J 分别为0.13、0.09、0.10、0.23.最小显著极差法(LSR)进行多重比较分析表明,4个采样点小型底栖动物差异明显.海洋线虫与桡足类的数量之比(N/C)显示东寨港红树林受到了有机质污染.     

广西钦州湾大型底栖动物生态特征及其与沉积物环境的相关性研究

为研究钦州湾大型底栖动物的生态特征,探讨影响大型底栖动物分布的主要因素,于2011年5月在钦州湾进行大型底栖动物调查,并同步采集沉积物样品,进行理化性质分析。使用Surfer软件绘制各群落特征指数的平面分布图,用SPSS软件分析群落特征指数与沉积物环境因子之间的关联性。共采集到大型底栖动物种类55种。平均生物量为105.48 g/m2,平均密度为50ind/m2。香农-维纳指数(H')、种类均匀度指数(J')和丰富度指数(D)的平均值分别为1.44,0.63和0.64。群落特征指数与沉积物环境因子之间的相关性分析结果显示,密度与Cu,Pb,Zn,Cd,Cr,Hg以及有机碳呈显著负相关;种类数与所分析的10项沉积物环境因子之间均呈显著负相关;均匀度指数与Hg和有机碳呈显著负相关;丰富度指数与硫化物呈显著负相关;生物量和香农-威纳指数与沉积物各环境因子之间均没有显著的相关性。     

中国近海秋季小型底栖动物分布及与环境因子的关系研究

2007年秋季搭栽开放航次时黄海、东海、南海3个海域共10个站位的小型底栖动物组成、丰度和生物量,以及环境因子进行了调查研究.3个海域小型底栖动物的平均丰度以黄海最高,为(2 132±946)个/10 cm2,东海次之,为(1 954±2 047)个/10 cm2,而南海仅(156±56)个/10 cm2;平均生物量(干质量)依次为(2 193±1 148)μg/10 cm2、(1 865±1 555)μg/10 cm2和(212±22)μg/10 cm2.3个海区分选出的14个小型底栖动物类群中,丰度上均以自由生线虫占绝对优势,分别占总量的85%、89%、85%.在生物量上,黄海以自由生线虫贡献最多(33%),多毛类居次;东海二者比例相近(约为37%),而南海则以多毛类占绝对优势(56%).在小型底栖动物的垂直分布上,3个海区差异较大:分布于沉积物表层0～2 cm的小型底栖动物在黄海高迭90%,东海仅46%,在南海为63%.统计分析表明,本研究站位小型底栖动物丰度与沉积物中的叶绿素及脱锾叶绿酸含量和底温呈显著正相关,与水深呈显著负相关.该结果与本航次之后在广东湛江和海南以东的南海海域开展的908调查结果形成了鲜明对照,后者的小型底栖动物及线虫丰度与沉积物中有机质含量呈显著正相关,与水深呈显著负相关,表明近海受人类干扰影响较大.     

近百年来大亚湾沉积物有机质的沉积记录及对人为活动的响应

通过对沉积物中粒度组成、总有机碳（TOC）、总氮（TN）、碳氮比（TOC/TN）和碳、氮稳定同位素丰度（δ13C、δ15N）等的分析,结合沉积年代学信息与端元混合模型结果,解析了百年尺度下大亚湾沉积物中不同来源有机质的演变过程及控制因素。结果表明,大亚湾沉积物特性在20世纪70年代末至80年代初发生了显著改变:在此之前,TOC、TN、δ13C和δ15N表现稳定,陆源与海源有机碳的比例维持在3∶7,而自此之后,TOC与TN含量显著升高,TOC/TN持续下降,在1980—2000年和2010年至今都出现了陆源有机碳比例升高,海源有机碳比例降低的现象。上述显著变化表明大亚湾海洋环境自20世纪70年代末至80年代初已经发生了重大变化。近20年来GDP与沉积柱中TN和δ15N呈现出的显著正相关,与TOC/TN呈现出的显著负相关,表明沿岸经济的迅猛增长,水产养殖业的快速发展,周边人口的急速增加等人为活动,是造成大亚湾生态环境变化的重要原因。未来的研究应更密切关注人为活动对海湾生态环境的影响,通过法律法规约束行为,加强海湾生态环境保护与修复治理工作。     

白令海颗粒有机物碳、氮同位素组成及其生物地球化学意义

Stable carbon and nitrogen isotopic composition of particulate organic matter(POM) were measured for samples collected from the Bering Sea in 2010 summer. Particulate organic carbon(POC) and particulate nitrogen(PN) showed high concentrations in the shelf and slope regions and decreased with depth in the slope and basin, indicating that biological processes play an important role on POM distribution. The low C/N ratio and heavy isotopic composition of POM, compared to those from the Alaska River, suggested a predominant contribution of marine biogenic organic matter in the Bering Sea. The fact that δ13C and δ15N generally increased with depth in the Bering Sea basin demonstrated that organic components with light carbon or nitrogen were decomposed preferentially during their transport to deep water. However, the high δ13C and δ15N observed in shelf bottom water were mostly resulted from sediment resuspension.     

不同碳氮比对辽河口湿地总氮去除的影响

于2010年5月～10月采用现场模拟培养法探讨了辽河口芦苇湿地沉积物中的总氮去除效果,并分析了不同梯度C/N比(5∶1、10∶1、15∶1)对沉积物中总氮去除效果的影响。结果表明:在自然状态下,有植被芦苇湿地总氮去除率比无植被湿地高;当施加C/N因素后可以提高沉积物中总氮去除率,C/N比对裸滩湿地中氮的去除效果比芦苇湿地明显;在有植被芦苇湿地中C/N比为10时总氮去除率最高,而在无植被湿地中C/N比值为15时总氮去除率最高;8月份各实验组中总氮去除率最高。影响辽河口湿地沉积物脱氮效果主要环境因子还有温度、盐度、含水率和pH等。     

应用有机碳同位素技术研究湛江湾生态环境的变化过程

随着工业化进程的加快,湛江湾的生态环境承载力受到了极大的考验。为了解湛江湾生态环境的变化过程,文中利用湛江湾表层柱状沉积物样品中总有机碳含量(TOC)及其稳定同位素、总氮含量(TN)和C/N值的测定,结合端元混合模型,分析了湛江湾沉积物中有机质的来源,探讨了沉积物有机碳同位素的主要影响因素。结果表明,湛江湾沉积物中有机质主要来源为自生藻类,同时也受一定程度陆源输入的影响。沉积序列的元素地球化学参数表明,沉积物δ13C值呈现短暂的负偏随后长期正偏的趋势。底部的负偏可能与大气CO2浓度增加有关,随后δ13C主体正偏的趋势主要受控于气候转暖、生产力增加以及富营养化程度增加的共同影响,暗示了人类活动对湛江湾的生态环境的影响逐渐加剧。其中,人类活动相关的工业、农业有机污染物排放可能是不断加剧海水富营养化的主要原因。     

Functional roles of interzonal migrating mesozooplankton in the western subarctic Pacific

Grazing experiments and production estimation based on life-history analysis of Neocalanus copepods (N. cristatus, N. plumchrus and N. flemingeri) were carried out in the Oyashio region to understand the carbon flows associated with the interzonal migrating copepods. These copepods, and also Eucalanus bungii, fed on nano- and micro-sized organisms non-selectively throughout the season. However, diatoms were the dominant food resource until May and organisms, such as ciliates were the major resource after May. Daily growth rate was estimated from the Ikeda–Motoda, Huntley–Lopez and Hirst–Sheader models. Since the growth rates were considered to be overestimates for the Huntley–Lopez model and underestimates for the other two models, we applied the weight-specific growth rates previously reported for these species in the Bering Shelf. Surface biomass of Neocalanus increased rapidly in June during the appearance of C5, and a successive increase of overwintering stock was evident in the deeper layer. The deep biomass decreased gradually from September to May during the dormant and reproduction period. N. cristatus has the largest annual mean biomass (2.3 gC m⁻²), followed by N. plumchrus (1.1) and N. flemingeri (0.4). Daily production rate of Neocalanus varied from 0.4 to 363.4 mgC m⁻² day⁻¹, to which N. cristatus was the largest contributor. Annual production was estimated as 11.5 gC m⁻² year⁻¹ for N. cristatus, 5.7 for N. plumchrus and 2.1 for N. flemingeri, yielding annual P/B ratio of 5 for each species. The annual production of Neocalanus accounted for 13.2% of the primary production in the Oyashio region. Their fecal pellets were estimated to account for 14.9% (0.7 gC m⁻² year⁻¹) of sinking flux of organic carbon at 1000-m depth. Moreover, their export flux by ontogenetic vertical migration, which is not measured by sediment trap observations, is estimated to be 91.5% (4.3 gC m⁻² year⁻¹) of carbon flux of sinking particles at 1000-m depth. These results suggest the important role of interzonal migrating copepods in the export flux of carbon.     

Effect of carbon and nitrogen ratio control on Artemia growth,water quality,biofloc microbial diversity under high salinity and zero-water exchange culture condition

Biofloc technology has been applied successfully in the intensive aquaculture of several fish and shrimp species. The growth of heterotrophic microorganisms can be stimulated through adding extra carbon, which reduces the nitrogen level in the water and provides microbial protein to the animals. However, most of the studies and practical applications have been conducted in freshwater and marine environment. This paper focused on brine shrimp Artemia that lives in high salinity environment together with other halophilic or halotolerant microorganisms. The effect of carbon supplementation on Artemia growth, water quality, and microbial diversity of biofl ocs was studied in the closed culture condition without any water exchange. The salinity of the culture medium was 100. A 24-d culture trial was conducted through supplementing sucrose at carbon/nitrogen (C/N) ratio of 5, 15, and 30 (Su5, Su15, and Su30), respectively. The culture without adding sucrose was used as a control. Artemia was fed formulated feed at a feeding ration of 60% recommended feeding level. The results showed that sucrose supplementation at higher C/N ratio (15 and 30) signifi cantly improved the Artemia survival, growth and water quality ( P <0.05). Addition of sucrose at C/N ratio of 15 and 30 significantly increased biofloc volume (BFV)( P <0.05). The Illumina MiSeq sequencing analysis showed that supplementing carbon at C/N ratio of 15 had a better total bacterial diversity and richness, and shaped the microbial composition at genera level. This study should provide information for studying the mechanism of biofloc technology and its application in high salinity culture conditions.     

台湾以东黑潮沉积物中的生源要素对近千年来气候环境变化的响应

基于台湾以东黑潮主流系沉积物中碳、氮、磷等生源要素指标的变化,在沉积物年代学的基础上,探讨了近千年来气候环境变化在黑潮沉积物中的历史记录。结果表明,近千年来台湾以东、琉球岛弧南侧斜坡的黑潮主流区平均沉积速率可达34.2 cm/ka,据其变化可大致分成的3个沉积阶段,与中世纪暖期、小冰期和现代暖期的划分基本一致。沉积物中碳以无机碳为主,总无机碳（TIC）的含量从1850年开始逐渐增大并伴随剧烈波动,恰好与大气CO₂水平的快速升高相对应;总有机碳（TOC）含量的变化则与东亚夏季风强度的变化关系密切,在夏季风较弱的小冰期其含量明显高于夏季风较强的中世纪暖期和现代暖期,这是由于较弱的夏季风有利于亚洲大陆风尘的产生和向海输送,从而促进了研究海域的初级生产力。1850年以来,沉积物中的C∶N∶P逐渐从低于转变为高于Redfield比,反映了上层水体营养盐结构从氮缺乏到氮充足的转变,这与近现代以来急剧增加的全球氮排放密切相关。总体来说,黑潮主流系沉积物中的生源要素指标,明确记录和响应了近千年来的气候环境变化,尤其是近150多年以来不断加剧的人类活动所造成的气候环境剧变。     

Attempting Consistent Simulations of Stn. ALOHA with a Multi-Element Ecosystem Model

We used a one dimensional, multi-element model to simulate the primary production (PP), recycling and export of organic matter at Stn. ALOHA, near Hawaii. We compared versions of the model with and without the cycling of dissolved organic matter (DOM) via the Microbial Food Web (MFW). We incorporated recently published measurements of high C:N ratios for uptake by diazotrophs. For other phytoplankton we included a formulation for overflow production of dissolved organic carbon (DOC), which occurs under nutrient-limited, light-replete conditions. We were able to match the observed mean DOC profile near the surface with both models, by tuning only the fraction of overflow DOC that is labile. The simulated bulk C:N remineralization ratio from the MFW model agreed well with a data-based estimate for the North Pacific subtropical gyre, but that from the Base model was too low. This is because the MFW model includes bacteria, with their low-C:N biomass. Simulated mean PP was lower than observed by 10% (Base) and 27% (MFW). This is consistent with the expectation that the ¹⁴C-method measures something greater than net production. DOC accounted for approximately half of simulated PP, most of this being overflow DOC. We find that overflow production and the MFW are key processes for reconciling the various data and PP measurements at this oligotrophic site. The impact of bacteria on the C:N remineralization ratio is an important link between ecosystem structure and the cycling of carbon.     

The relationship between bacteria and micro-algae in the sediment of a Bay of Fundy mudflat

Bacterial abundance was studied from April to December 1979 in the sediments of a Bay of Fundy mudflat. Bacterial biomass ranged from 1·6 to 2·8 g C m⁻² in the top 5 cm and bacterial numbers normalized for the amount of organic carbon in the sediment were about 9 × 10¹¹ g⁻¹ C at the surface during most of the year. However, when a bloom of pennate diatoms occurred in the fall, bacterial numbers per gram carbon doubled. There was a correlation of r=0·83 between bacteria g⁻¹ C and chlorophyll a for all sampling dates at the high intertidal station. Sieved size fractions of surface sediment taken during a period of low micro-algal biomass and just after the micro-algal bloom showed a strong correlation (r=0·92) between the increases in bacterial and algal abundance for the fractions > 20 μm. We suggest that the apparent relation between benthic micro-algal and bacterial abundance on both a seasonal and within-sediment basis may be due to the release of extracellular material by the micro-algae.     

Deposit Feeding and Sediment:

Abstract. The feeding of the epibenthic deposit-feeder Holothuria tubulosa GMELIN and its influence on sediment metabolism was investigated from February 1988 to February 1989. Water samples, specimens of H. tubulosa , and samples of freshly egested feces were taken by SCUBA diving in a 5 m deep seagrass bed at the Island of Ischia in the Gulf of Naples (Italy). Particulate organic carbon (POC), particulate organic nitrogen (PON), total particulate carbohydrates (PCHO), and bacterial biomass exhibited higher values in the foregut than in the surrounding sediment. Even the freshly egested feces were richer in the organic components than the sediment. The percentage of growing bacterial cells increased from 4.1 % in the sediment to 12.2 % in the foregut and declined to 11.6 % in the hindgut and 6.2 % in freshly egested feces.
On an annual average, absorption efficiency was highest for bacteria (x = 71%); for PON we calculated a mean absorption efficiency of 20.9%, for PCHO 19.5%. It was estimated that bacterial biomass supplied between 4 and 25 % of the respiratory carbon demand of H. tubulosa. We present evidence that the feeding activity of H. tubulosa stabilizes the bacterial community in the sediment. Furthermore, our data indicate that H. tubulosa reacts quickly to changing conditions, such as sedimented phytoplankton blooms.