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1.
根据珠江口枯水期(2013年11月)和丰水期(2014年8月) 24个站位调查资料,对中小型浮游动物种类组成、丰度分布、群落结构及其主要影响因子进行了研究.结果表明,枯水期和丰水期分别鉴定浮游动物成体91种和70种,以桡足类最为丰富.浮游动物种类从河口上游向外围逐渐增加.浮游动物丰度时空分布差异显著,丰水期平均值高达11 619. 78 ind/m~3,显著高于枯水期的1 707. 13 ind/m~3.桡足类在珠江口中小型浮游动物中占绝对优势,枯水期和丰水期分别占总丰度的80. 3%和93. 0%,对浮游动物的丰度分布起关键作用.强额孔雀哲水蚤(Parvocalanus crassirostris)、中华异水蚤(Acartiella sinensis)和刺尾纺锤水蚤(Acartia spinicauda)在两个水期均为主要优势种,小拟哲水蚤(Paracalanus parvus)和厦门矮隆哲水蚤(Bestiolina amoyensis)则分别在枯水期和丰水期具有较高的优势度.聚类分析的结果显示,枯水期和丰水期该水域浮游动物均可划分为3个群落.相关性分析表明,珠江口中小型浮游动物群落结构受多个环境因子的影响,但盐度是其中最为关键的非生物因子. 相似文献
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Mantha Gopikrishn Al-Sofyani Abdulmohsin A. Ali M Al-Aidaroos Crosby Michael P 《海洋学报(英文版)》2019,38(12):59-72
Zooplankton and zooneuston observations were made at seven stations(four from the Gulf of Aqaba and three from the northern Red Sea), during September and October 2016. The main objective of this study was to assess the variability of nycthemeral fauna in relation to the sampling methods using two different types of nets namely,WP2 net and Neuston net along the two study sites, i.e., the Gulf of Aqaba and the northern Red Sea. Zooplankton was sampled vertically using a standard WP2 net from a depth of 200 m to the surface, whereas zooneuston was made using a standard Neuston net from a depth of 0–10 cm of the water surface. Total zooplankton density was maximum during night time((617.83 ± 201.84) ind./m~3) at the Gulf of Aqaba and total zooneuston was maximum during night at the northern Red Sea((60.94±29.48) ind./m~3), respectively. The most abundant taxa were Copepoda, Gastropoda, Bivalva, Chaetognatha, Tunicata and Ostracoda. The abundance was almost 50% higher at night time at both the Gulf of Aqaba and the northern Red Sea. Overall, 30 taxa covering 10 phyla and 27 taxa covering 8 phyla were recorded in the Gulf of Aqaba and the northern Red Sea. 相似文献
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The macrobenthos is important in benthic remineralization processes; it represents a trophic link and is also often used as a bio-indicator in monitoring programs. Variations of the environmental parameters strongly influence the structure of the macrobenthic communities in the marshes and since macrobenthos is the most important food item for marsh-visiting fish species in the Schelde, the variation in food resources can have a strong effect on the higher trophic level. The present study deals with the variation in macrobenthic communities in different habitats of intertidal marshes along the salinity gradient and the differences between the marsh creeks and the intertidal part of the estuary. The study measured density and species richness together with the biomass, and sampled a large intertidal channel and a smaller creek within five marshes along the salinity gradient of the Schelde estuary every six weeks between May and October in 2000. 相似文献
5.
The IMECOCAL Program began in 1997, with the objective of sampling plankton systematically in the Mexican region of the California Current. We present results of chlorophyll a concentrations and zooplankton displacement volumes for the eight cruises from September 1997 to October 1999. The abundance of 22 zooplankton groups was also analyzed for the first four cruises. The response of plankton to the 1997–1998 El Niño was atypical. From September 1997 to January 1998, chlorophyll a and zooplankton volume were at typical values (median integrated chlorophyll was 27 mg/m2 and zooplankton 100 ml/1000 m3 in 9801/02). After the peak of El Niño, the system shifted to cooler conditions. Integrated chlorophyll gradually increased to a median of 77 mg/m2 in April 1999. In contrast, zooplankton volumes decreased from October 1998 onward, despite favorable phytoplankton availability in 1999. Zooplankton structure was dominated by copepods and chaetognaths through the ENSO cycle, but interannual changes were evident. In the fall of 1997 there was a higher proportion of copepods, chaetognaths, and other minor groups, while the fall of 1998 zooplankton was richer in salps and ostracods. Historical data from previous Baja California CalCOFI cruises indicated that zooplankton volumes measured during the IMECOCAL cruises were above the long-term mean for the period 1951–1984. This suggests a differential response of plankton to the El Niño of 1997–1998 compared to the El Niño of 1957–1959. Regional differences in zooplankton volumes were also found, with central Baja California having 41% higher biomass than northern Baja California. Volumes from both regions were larger than those recorded by CalCOFI off southern California during 1997–1998, but the situation was reversed in 1999. The higher biomasses in the 1997–1998 El Niño can be attributed to high abundance of salps, which showed an affinity with warm, saline water. 相似文献
6.
Zooplankton biomass consisting of large and small-size copepods, copepod nauplii and tintinnids were investigated over a period of one year at two stations in Funka Bay, Japan. The food requirement of zooplankton was also estimated using the method of Ikeda and Motoda. Estimated total carbon requirement of zooplankton in the coastal and central parts of the bay was equivalent to 52 and 38% of the annual primary production, respectively. These corresponded to zooplankton production of 12–13 gC·m–2·yr–1.The total carbon requirement at each station increased to 63 and 74% of the primary production during summer compared with 26 and 3% in spring or 19 and 17% in winter. The microzooplankton (copepod nauplii and tintinnids) accounted for about half of the carbon requirement from April to November.Food requirements reached 161% at the coastal station and 194% at the central station of the daily organic carbon production during September. Zooplankton may also feed on carbon sources other than living phytoplankton. This could account for the observed decrease in particulate organic carbon in a water column.Contribution No. 202 from the Research Institute of North Pacific Fisheries, Faculty of Fisheries, Hokkaido University. 相似文献
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Seasonal and inter-annual variation of mesozooplankton in the coastal upwelling zone off central-southern Chile 总被引：1，自引：0，他引：1
Ruben Escribano Pamela Hidalgo Humberto González Ricardo Giesecke Ramiro Riquelme-Bugueño Karen Manríquez 《Progress in Oceanography》2007,75(3):470-485
Zooplankton sampling at Station 18 off Concepción (36°30′S and 73°07′W), on an average frequency of 30 days (August 2002 to December 2005), allowed the assessment of seasonal and inter-annual variation in zooplankton biomass, its C and N content, and the community structure in relation to upwelling variability. Copepods contributed 79% of the total zooplankton community and were mostly represented by Paracalanus parvus, Oithona similis, Oithona nana, Calanus chilensis, and Rhincalanus nasutus. Other copepod species, euphausiids (mainly Euphausia mucronata), gelatinous zooplankton, and crustacean larvae comprised the rest of the community. Changes in the depth of the upper boundary of the oxygen minimum zone indicated the strongly seasonal upwelling pattern. The bulk of zooplankton biomass and total copepod abundance were both strongly and positively associated with a shallow (<20 m) oxygen minimum zone; these values increased in spring/summer, when upwelling prevailed. Gelatinous zooplankton showed positive abundance anomalies in the spring and winter, whereas euphausiids had no seasonal pattern and a positive anomaly in the fall. The C content and the C/N ratio of zooplankton biomass significantly increased during the spring when chlorophyll-a was high (>5 mg m−3). No major changes in zooplankton biomass and species were found from one year to the next. We concluded that upwelling is the key process modulating variability in zooplankton biomass and its community structure in this zone. The spring/summer increase in zooplankton may be largely the result of the aggregation of dominant copepods within the upwelling region; these may reproduce throughout the year, increasing their C content and C/N ratios given high diatom concentrations. 相似文献
9.
Amanda M. Vieillard Robinson W. Fulweiler Zoe J. Hughes Joanna C. Carey 《Estuarine, Coastal and Shelf Science》2011
Salt marshes are widely studied due to the broad range of ecosystem services they provide including serving as crucial wildlife habitat and as hotspots for biogeochemical cycling. Nutrients such as nitrogen (N), phosphorus (P), and carbon (C) are well studied in these systems. However, salt marshes may also be important environments for the cycling of another key nutrient, silica (Si). Found at the land–sea interface, these systems are silica replete with large stocks in plant biomass, sediments, and porewater, and therefore, have the potential to play a substantial role in the transformation and export of silica to coastal waters. In an effort to better understand this role, we measured the fluxes of dissolved (DSi) and biogenic (BSi) silica into and out of two tidal creeks in a temperate, North American (Rowley, Massachusetts, USA) salt marsh. One of the creeks has been fertilized from May to September for six years allowing us to examine the impacts of nutrient addition on silica dynamics within the marsh. High-resolution sampling in July 2010 showed no significant differences in Si concentrations between the fertilized and reference creeks with dissolved silica ranging from 0.5 to 108 μM and biogenic from 2.0 to 56 μM. Net fluxes indicated that the marsh is a point source of dissolved silica to the estuary in the summer with a net flux of approximately 169 mol h−1, demonstrating that this system exports DSi on the same magnitude as some nearby, mid-sized rivers. If these findings hold true for all salt marshes, then these already valuable regions are contributing yet another ecosystem service that has been previously overlooked; by exporting DSi to coastal receiving waters, salt marshes are actively providing this important nutrient for coastal primary productivity. 相似文献
10.
崇明东滩潮沟浮游动物数量分布与变动 总被引：3，自引：0，他引：3
根据2008年4-12月对上海市崇明岛东滩潮沟进行4个季节的浮游动物调查资料,研究了崇明东滩潮沟浮游动物的数量分布及变动。结果表明,调查区浮游动物总丰度较高,四季变化明显。受潮汐作用的影响,夏、秋、冬三季落潮时丰度大于涨潮时,春季涨潮时丰度则大于落潮时。浮游动物在6条潮沟的平面分布不均匀,春季东旺沙边滩区和北八边滩区的数量明显多于近团结沙边滩区,夏、秋季分别以东旺沙边滩区和北八滧边滩区的数量最多,冬季则以近团结沙边滩区的数量最多。主要优势种细巧华哲水蚤(Sinocalanus tenellus)、中华华哲水蚤(Sinocalanus sinensis)、火腿许水蚤(Schmackeria poplesia)、四刺窄腹剑水蚤(Limnoithona etraspina)和四刺破足猛水蚤(Mesochra quadrispinosa)等数量的季节、潮汐变化及各时期的空间分布格局差异明显,其数量分布情况决定了浮游动物总数量的分布。盐度是影响冬、春季涨潮时浮游动物总丰度分布的主要因子,水温则是影响夏、秋季涨潮时总丰度分布的主要因子。此外,径流及潮流等动力因素对潮沟浮游动物数量的时空分布也产生重要影响。 相似文献
11.
Dissolved inorganic carbon (DIC) and ancillary data were obtained during the dry and rainy seasons in the waters surrounding two 10-year-old forested mangrove sites (Tam Giang and Kiên Vàng) located in the Ca Mau Province (South-West Vietnam). During both seasons, the spatial variations of partial pressure of CO2 (pCO2) were marked, with values ranging from 704 ppm to 11481 ppm during the dry season, and from 1209 ppm to 8136 ppm during the rainy season. During both seasons, DIC, pCO2, total alkalinity (TAlk) and oxygen saturation levels (%O2) were correlated with salinity in the mangrove creeks suggesting that a combination of lower water volume and longer residence time (leading to an increase in salinity due to evaporation) enhanced the enrichment in DIC, pCO2 and TAlk, and an impoverishment in O2. The low O2 and high DIC and pCO2 values suggest that heterotrophic processes in the water column and sediments controlled these variables. The latter processes were meaningful since the high DIC and TAlk values in the creek waters were related to some extent to the influx of pore waters, consistent with previous observations. This was confirmed by the stochiometric relationship between TAlk and DIC that shows that anaerobic processes control these variables, although this approach did not allow identifying unambiguously the dominant diagenetic carbon degradation pathway. During the rainy season, dilution led to significant decreases of salinity, TAlk and DIC in both mangrove creeks and adjacent main channels. In the Kiên Vàng mangrove creeks a distinct increase of pCO2 and decrease of %O2 were observed. The increase of TSM suggested enhanced inputs of organic matter probably from land surrounding the mangrove creeks, that could have led to higher benthic and water column heterotrophy. However, the flushing of water enriched in dissolved CO2 originating from soil respiration and impoverished in O2 could also have explained to some extent the patterns observed during the rainy season. Seasonal variations of pCO2 were more pronounced in the Kiên Vàng mangrove creeks than in the Tam Giang mangrove creeks. The air–water CO2 fluxes were 5 times higher during the rainy season than during the dry season in the Kiên Vàng mangrove creeks. In the Tam Giang mangrove creeks, the air–water CO2 fluxes were similar during both seasons. The air–water CO2 fluxes ranged from 27.1 mmol C m−2 d−1 to 141.5 mmol C m−2 d−1 during the dry season, and from 81.3 mmol m−2 d−1 to 154.7 mmol m−2 d−1 during the rainy season. These values are within the range of values previously reported in other mangrove creeks and confirm that the emission of CO2 from waters surrounding mangrove forests are meaningful for the carbon budgets of mangrove forests. 相似文献
12.
E. Rios-Jara 《Estuarine, Coastal and Shelf Science》1998,46(6):797-809
Nocturnal variations of zooplankton abundance and hydrographic conditions were examined at three locations (centre, north shore and south shore) in Phosphorescent Bay, Puerto Rico, from May 1992 through April 1993. Seven taxa accounted for approximately 96% of the annual mean zooplankton abundance:Oithonaspp. (43·5%),Acartia tonsa(31·5%), copepod nauplii (8·8%),Paracalanusspp.(6·7%), gastropod veligers (2·5%), larvaceans (1·7%) andPseudo-diaptomus cokeri(1·6%). Copepods dominated numerically throughout the year and comprised 94·3% of total zooplankton. Higher abundance of zooplankton (mean±1 SD=252 259±176 797 individuals m−3) was associated with cool water temperatures (24·9–27·4 °C) and dry conditions (0·3–2·9 cm precipitation/month) which prevailed between December and March relative to the period between April and November (warm/wet season) (mean±1 SD=59 773±26 861 individuals m−3), when temperature and precipitation were higher (27·3–30·3 °C, 3·1–20·6 cm month−1). Fluctuations of zooplankton populations, particularly copepods, followed progressive increments in chlorophyllaconcentrations. This abundance pattern was consistent at the three sampling stations. Zooplankton abundance was higher on the north shore of the bay. The taxonomic composition of zooplankton was similar at the sampling stations studied. 相似文献
13.
2007年夏季黄河口及其邻近水域浮游动物的群落特征 总被引：3，自引：0，他引：3
利用2007年夏季在黄河口及其邻近水域以浅水Ⅰ型浮游生物网采集的浮游动物样品,对浮游动物种类组成、丰度分布和群落结构进行分析;同时结合环境参数,初步探讨浮游动物与环境因子的关系.结果显示:夏季共鉴定浮游动物52种(不包括浮游幼体20类),浮游动物平均丰度为4769.6 ind/m3,香农-威纳指数和均匀度指数分别为2.34和0.48.浮游动物优势种类为:柱头幼虫(tornaria larvae)、小拟哲水蚤(Paracalanus parvus)、中华哲水蚤(Calanus sinicus)、强壮箭虫(Sagitta crassa)和双毛纺锤水蚤(Acartia bifilosa).其中体长较小(0.7～1.1mm)的柱头幼虫和小拟哲水蚤是最重要的优势种类.据各站位浮游动物种类组成和丰度,用聚类分析法可将该水域浮游动物划分为3个组群.相关性分析表明,影响黄河口及邻近水域浮游动物群落结构的主要环境因子组合为底温、表盐和水深. 相似文献
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典型河口浮游动物种类数及生物量变化趋势的研究 总被引：8，自引：0，他引：8
依据国家海洋局2004-2006年每年5月和8月的黄河口、长江口和珠江口生态监控区浮游动物的监测结果,对上述河口浮游动物和桡足类种类数及浮游动物生物量分布进行了分析,并将结果与历史资料进行同测区、同季节的对比。结果表明,与全国海洋普查时期相比,2006年黄河口浮游动物种类数下降了50．6％,桡足类种类数下降了53.3％;桡足类在浮游动物中所占比重由1985年的42.4％下降到2006年的32．6％。长江口浮游动物种类数有所上升,但是桡足类种类数由1985年的62种降低到2006年的37种;桡足类在浮游动物中的比重从1958年的54．2％降低到2006年的42．5％。珠江口桡足类在浮游动物中所占的比例由1959年的59．3％下降到54．4％,未发生明显变化。黄河口春季、夏季浮游动物生物量上升趋势不明显,夏季增幅较小;长江口自2000年以后春季浮游动物平均生物量为528．36mg／m^3,是1958年的2．4倍,2005年与2006年夏季浮游动物生物量分别是1958年的2．2和2．7倍,增加趋势十分明显;珠江口春季浮游动物生物量上升趋势最为显著,2004-2006年3年春季浮游动物平均生物量是1959年同期的5．7—8．7倍,1981年、2006年夏季生物量分别比1959年增加了3．1倍和11倍。就这3个河口生物量变化趋势看,珠江口生物量的上升趋势最为明显,长江口次之,黄河口变化幅度较小。 相似文献
15.
Sediment samples were collected in the intertidal zone of the Dagu River Estuary, Jiaozhou Bay, China in April,July and October 2010 and February 2011 for examining seasonal dynamics of meiofaunal distribution and their relationship with environmental variables. A total of ten meiofaunal taxa were identified, including free-living marine nematodes, benthic copepods, polychaetes, oligochaetes, bivalves, ostracods, cnidarians, turbellarians,tardigrades and other animals. Free-living marine nematodes were the most dominant group in both abundance and biomass. The abundances of marine nematodes were higher in winter and spring than those in summer and autumn. Most of the meiofauna distributed in the 0–2 cm sediment layer. The abundance of meiofauna in hightidal zone was lower than those in low-tidal and mid-tidal zones. Results of correlation analysis showed that Chlorophyll a was the most important factor to influence the seasonal dynamics of the abundance, biomass of meiofauna and abundances of nematodes and copepods. CLUSTER analysis divided the meiofaunal assemblages into three groups and BIOENV results indicated that salinity, concentration of organic matter, sediment sorting coefficient and sediment median diameter were the main environmental factors influencing the meiofaunal assemblages. 相似文献
16.
2014年4月、7月、10月和2015年1月分别对硇洲岛大型海藻场附近海域的浮游动物进行了季节调查,分析了浮游动物的种类组成、优势种、群落结构、丰度和生物量的季节变化及影响因素。结果共检出浮游动物91种和浮游幼虫36种,隶属于17大类群。其4个季节的平均丰度和生物量分别为186.5 ind/m3和431.0 mg/m3,高峰期均位于夏季,低谷位于冬季。优势种共有19种（类）。生物多样性分析表明,研究海域浮游动物具有较高的均匀度（0.74）,生物多样性指数较高（3.14）。根据聚类分析结果,可将调查海区的浮游动物在38％相似性水平上划分为4组,浮游动物的群落组成呈较明显的季节变化。组群的组内相似性和组间非相似性均大于50%,对组内相似性及组间非相似性起主要贡献的种类有37种。通过生物-环境匹配（BIOENV）分析,水温、盐度、浮游植物丰度和叶绿素a浓度是影响浮游动物群落结构的环境因子。 相似文献
17.
Grazing by meso- and microzooplankton on phytoplankton in the upper reaches of the Schelde estuary (Belgium/The Netherlands) 总被引：1，自引：1，他引：1
M. Lionard F. Azmar S. Boulêtreau K. Muylaert M. Tackx W. Vyverman 《Estuarine, Coastal and Shelf Science》2005,64(4):764-774
In contrast with the marine reaches of estuaries, few studies have dealt with zooplankton grazing on phytoplankton in the upper estuarine reaches, where freshwater zooplankton species tend to dominate the zooplankton community. In spring and early summer 2003, grazing by micro- and mesozooplankton on phytoplankton was investigated at three sites in the upper Schelde estuary. Grazing by mesozooplankton was evaluated by monitoring growth of phytoplankton in 200 μm filtered water in the presence or absence of mesozooplankton. In different experiments, the grazing impact was tested of the calanoïd copepod Eurytemora affinis, the cyclopoid copepods Acanthocyclops robustus and Cyclops vicinus and the cladocera Chydorus sphaericus, Moina affinis and Daphnia magna/pulex. No significant grazing impact of mesozooplankton in any experiment was found despite the fact that mesozooplankton densities used in the experiments (20 or 40 ind. l−1) were higher than densities in the field (0.1–6.9 ind. l−1). Grazing by microzooplankton was evaluated by comparing growth of phytoplankton in 30 and 200 μm filtered water. Microzooplankton in the 30–200 μm size range included mainly rotifers of the genera Brachionus, Trichocerca and Synchaeta, which were present from 191 to 1777 ind. l−1. Microzooplankton had a significant grazing impact in five out of six experiments. They had a community grazing rate of 0.41–1.83 day−1 and grazed up to 84% of initial phytoplankton standing stock per day. Rotifer clearance rates estimated from microzooplankton community grazing rates and rotifer abundances varied from 8.3 to 41.7 μl ind.−1 h−1. CHEMTAX analysis of accessory pigment data revealed a similar phytoplankton community composition after incubation with and without microzooplankton, indicating non-selective feeding by rotifers on phytoplankton. 相似文献
18.
The abundance and community structure of metazoan meiofauna were studied in deep-sea sediments from the north and south Aegean Sea (Eastern Mediterranean) in summer 1997 and spring 1998. The two areas varied in their surface primary productivity with the northern area being more productive. Meiofaunal densities displayed strong spatial variability while no temporal changes were observed. Total metazoan density ranged from 128 to 1251 ind./10 cm2, with significantly higher values in the north. Meiofaunal biomass ranged from 27 to 391 μgC/10 cm2 with higher values also in the north. At all stations nematodes dominated the community, comprising on average more than 91% of the total abundance. On a broad scale, meiofaunal densities displayed a positive correlation with food availability (sediment-bound chloroplastic pigments, carbohydrates and lipids); carbon mineralization (an indicator of organic matter turnover) was significantly higher in the northern Aegean, providing evidence of high organic-matter input and intense benthic-pelagic coupling. The spatial structure of the nematode community indicated that the two areas were similar in terms of their dominant genera (Halalaimus, Acantholaimus, and Thalassomonhystera). 相似文献
19.
The materials were obtained from the survey conducted in the Kuroshio area of the East China Sea to the Southwest of Kyushu in Japan (29°30'-32°00', 128°00'-130°'00'E) on board the R. V. Yoko Maru of Seikai Regional Fisheries Lab, Fisheries Agency, Japan in June 15~28, 1988 during China-Japan Joint Research on the Kuroshio. Zoo-plankton was collected by means of the North Pacific Net with model TSK flowmeter through vertical haul from 50 -Om. Temperature and salinity were measured with CTD. 134 species (including 4 spp. ) of planktonic copepods were preliminarily identified in the survey area. Most of them belonged to the tropical and subtropical species and a few of them were the warm-temperate species and eurytopic species. The main dominant species vteieOncaea venusta, Oithona plumifera, Clausocalanus furcatus, C. Arcuicornis, Paracaianus dculeatus, Oithona similis, Temara turbinata, Oncaea media, Undinula danvinii, Acartia negligent, Corycaeus speciosus, Scolecithrix danae, etc. The total number 相似文献
20.
Tracing suspended organic nitrogen from the Yangtze River catchment into the East China Sea 总被引：2，自引：0，他引：2
Ying Wu Thorsten Dittmar Kai-Uwe Ludwichowski Gerhard Kattner Jing Zhang Zhuo Y. Zhu Boris P. Koch 《Marine Chemistry》2007
Total suspended matter was collected along the Yangtze River (Changjiang) and in the East China Sea in April to May and in September 2003, respectively, to study origin and fate of particulate organic nitrogen. Concentrations of particulate organic carbon (POC), nitrogen (PN) and hydrolyzable particulate amino acids (PAA; d- and l-enantiomers) were higher in the Yangtze Estuary than in the river and decreased offshore towards the shelf edge. In the coastal area, higher values of PAA were observed in the surface layer than in the bottom water. Stable carbon isotope ratios (δ13C) of POC increased from − 24.4‰ in the river to values around − 21‰ on the East China Sea Shelf. Dominant amino acids were aspartic acid + aspartine (Asx), glutamic acid + glutamine (Glx), glycine, alanine and serine. The proportions of Asx, Glx and isoleucine were higher in the marine than in the riverine samples contrary to the distributions of glycine, alanine, threonine and arginine. The proportions of d-amino acids were highest in the riverine suspended organic matter (6% of PAA) decreasing towards the shelf edge (1.5% of PAA). d-arginine, not reported in natural aquatic samples so far, was the most abundant d-amino acid in the river. The amino acid composition of the particulate organic matter (POM) in the Yangtze River indicates an advanced stage of degradation of POM. Highly degraded organic matter from soils is probably a main source of POM in the Yangtze River, but the relatively high δ13C values and low C/N ratios (7.7 ± 1.6) also indicate contribution from anthropogenic sources. The degraded riverine material was a dominant organic matter source in the estuary, where aquatic primary production had only a small overall contribution. In the East China Sea, gradual settling of riverine organic matter and the addition of fresher phytoplankton impacted the amino acid composition and δ13C values, and on the outer shelf relatively fresh phytoplankton-derived organic matter dominated. 相似文献