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1.
根据2018年南黄海漂浮态浒苔(Ulva prolifera)绿潮规模卫星监测数据以及春、夏季(4月和7月，绿潮前后)水文环境要素和氮营养盐等数据，对2018年绿潮发展规律及不同氮组分在其中的作用进行分析。结果表明:浒苔于4月25日在江苏南通近海首次发现，随后其向北漂移增殖扩展在6月29日达到最大规模，8月中旬消失。绿潮漂移区域集中在122°E以西近海并呈现两个明显的发展阶段:35°N以南江苏近海绿潮快速增殖阶段和35°N以北山东半岛外海域绿潮聚积衰退阶段。各氮营养盐组分受径流输入、冷水团以及生物活动等因素影响，呈现明显的区域和季节特征。不同绿潮阶段受氮营养盐影响不同，绿潮快速增殖阶段，丰富的氮营养盐(总溶解氮(TDN)>20 μmol/L和溶解无机氮(DIN)>20 μmol/L)是浒苔藻快速繁殖生长的物质基础，此阶段为整个绿潮发展提供了主要的氮支撑且以DIN为主要形态。绿潮聚积衰退阶段，较低的可利用氮(DIN<2 μmol/L和尿素(urea-N)<1.5 μmol/L)不利于浒苔藻持续繁殖生长，此阶段内有机氮(如urea-N)在绿潮后期的氮支撑中起到重要作用。 相似文献
2.
黄河口海域有机氮的分布特征 总被引：3，自引：0，他引：3
海水中含氮化合物按其化学存在形式可分为无机和有机两大类,前者主要是 NO_~-、NO_2~-、NH_4~+;后者主要是蛋白质、氨基酸、尿素等。按其存在形态又可分为颗粒态和溶解态含氯化合物。海洋有机分析中,一般是采用能否被GF/C玻璃纤维滤膜截留来区分溶解态和颗粒态。能被截留的为颗粒态有机氮(PON),主要是生物体及其残骸碎屑中的含氮化合物。通过滤膜的为溶解态,包括溶解无机氮(DIN)和溶解有机氮(DON)。 相似文献
3.
根据2017年12月—2019年12月和2018年小浪底水库泄洪期间对黄河下游营养盐的月观测和日观测,系统的分析了黄河下游溶解态营养盐浓度、组成和通量变化.结果表明,除DON(溶解有机氮)、DSi(溶解态硅)和DIP(溶解无机磷)外,其他各溶解态营养盐浓度均呈丰水期低、枯水期高的特点.在观测期间,DSi/DIN(溶解态... 相似文献
4.
234 Th示踪法测定北太平洋西北海域冬季真光层中颗粒态有机碳输出通量 总被引：1，自引：0，他引：1
讨论了1997年冬季在北太平洋西北海域7个站位的表层至200m水深水柱中溶解及颗粒态234Th,颗粒态有机碳(POC)、氮(PON)及叶绿素a浓度的垂直分布剖面.溶解态、颗粒态及总的234Th的放射性在真光层中显著低于母体238U的放射性,总的234Th放射性在水深大于100m时趋于平衡.利用234Th-238U在海洋表层海水中的放射性不平衡推导出了北太平洋西北海域冬季真光层海水中234Th的平均停留时间和输出通量以及颗粒态有机碳和有机氮的输出通量.在亚北极环流区溶解态234Th的停留时间为40~50d,而在黑潮-亲潮共同影响区为20d左右.颗粒态有机碳和有机氮从真光层的输出通量范围分别为3.8~8.2和0.50~0.98mmol/(m2·d),西部海区高于东部海区,南部海区高于北部海区.在黑潮-亲潮共同影响区较高的颗粒态有机碳输出通量表明光照量及陆源营养盐物质的提供是两个决定生产力的主要因素.叶绿素a的水深分布和POC/PON的值同Redfield的比值的一致性表明这个海区的冬季颗粒物主要由浮游植物构成.北太平洋西北海域在冬季的颗粒有机碳输出通量可高于世界大洋一些海区春、夏季的颗粒有机碳输出通量. 相似文献
5.
黄河下游营养盐浓度、入海通量月变化及“人造洪峰”的影响 总被引：9，自引：3，他引：6
于2009年至2011年在黄河下游采集溶解及颗粒态营养盐样品,分析了黄河下游各形态营养盐的浓度变化及营养盐入海通量,结果表明各形态氮的浓度多呈丰水期低、枯水期高,溶解无机氮是溶解态氮的主要存在形式;受黄河高悬浮颗粒物含量的影响,磷以颗粒态占绝对优势,而溶解态磷以溶解无机磷为主要存在形态;生物硅的含量平均约占硅酸盐与生物硅之和的20％,硅的浓度丰水期高于枯水期.颗粒态磷与生物硅的含量与悬浮颗粒物含量呈正相关.营养盐的组成具有高氮磷比、高硅磷比、低硅氮比的特点.近年来黄河下游溶解无机氮浓度显著升高而溶解无机磷变化不大,硅酸盐的浓度有所下降.黄河下游水沙通量、营养盐入海通量有明显的季节变化,丰水期占全年总入海通量的42％～84％.调水调沙期间,各营养盐的浓度和组成均有明显变化,氮的浓度、DIN/PO4-P下降,磷与硅的浓度、SiO3-Si/DIN、SiO3-Si/PO4-P升高,颗粒态营养盐的比例明显增加.短期内大量水沙及营养盐入海通量对黄河口及渤海生态系统产生重要影响. 相似文献
6.
1997年11-12月(枯水期)，1998年8月和10月(丰水期)，对长江从金沙江至河口干流和主要支流、湖泊入江口总氮、总溶解氮、总有机氮等进行调查。结果表明，长江水中各种形态氮的浓度，枯水期明显高于丰水期，支流明显高于干流；长江TN和TDN在枯、丰期具有基本类似的迁移变化过程；DIN是长江水的TDN的主要存在形式，丰水期TDN的迁移变化主要取决于DIN；TDN是长江水中TN的主要存在形式，TN的迁移变化主要取决于TDN或者由DIN和TON共同决定；丰水期各种形态的氮中只有有机氮比较容易为悬浮颗粒物质所吸附；长江干流枯水期TDN浓度与长江径流呈较好的线性正相关关系；枯水期TN、丰水期TN和TDN浓度与长江径流的正相关主要发生在上游，这与长江水中氮主要来自于面源有关。 相似文献
7.
溶解有机氮(DON)作为近海生态系统总溶解态氮(TDN)的重要赋存形态,其生物可利用性对查明绿潮爆发期间氮的供给机制具有重要意义。本文通过2015年在青岛近海浒苔(Ulva prolifera)绿潮爆发期间和消亡后两个航次调查,对比分析了该海域绿潮爆发期和消亡后溶解有机碳(DOC)、TDN、溶解无机氮(DIN)、DON及其中具有高生物可利用性组分尿素、总溶解态氨基酸(TDAA)浓度变化,以TDAA在DOC中碳摩尔比[TDAA(%DOC)]为指标,评价该海域绿潮爆发期和消亡后DON的生物可利用性。绿潮爆发期青岛近海氮浓度受陆源输入影响较绿潮消亡期明显,不同形态氮的浓度高于绿潮消亡期,DON浓度均值为(13.84±6.77)μmol·L~(-1),较绿潮消亡后高44.5%,在TDN中占比均达到(56.8±9.3)%。其中,尿素和TDAA合计占DON的(38.5±6.4)%。受浮游植物分泌和细菌降解等生物作用调控,DON生物可利用性呈现由表层到底层逐步降低的变化特征;而绿潮爆发期浒苔分泌较多新鲜的DON,导致其生物可利用性高于消亡后。DON在微生物作用下快速转化为DIN并为浒苔所吸收是绿潮爆发期间氮供给的主要机制之一。 相似文献
8.
大亚湾海域低营养盐维持高生产力的机制探讨Ⅰ 总被引：20，自引：0，他引：20
利用2000年4月大亚湾海域的现场调查数据，分析水体中各种形态氮的含量，分布、转化及其影响因素，探讨大亚湾海域低营养盐维持高生产力的原因，调查结果表明：大亚湾海域水体仍属贫氮海区，氮，磷比约为12：1，生产力水平依然受氮控制；大亚湾海域氮以溶解态的形式居多，占总氮的74．8％，颗粒态占25．2％，而溶解态中又以有机氮居多，占总氮的62．1％，孵化实验表明：（1）充氧条件下氨氮向硝氮转化，缺氧条件下硝氮向氨氮转化；（2）水体中溶解有机氮在有氧条件下可以降解转化为无机氮，这意味着占绝对优势的溶解有机氮降解转化为无机氮可能是大亚湾海域低营养盐维持高生产力的主要原因之一。 相似文献
9.
东海陆架典型断面颗粒态氨基酸的分布及控制因素分析 总被引：3，自引：1，他引：2
采用高效液相色谱法,通过现场调查对东海典型PN断面(文中为C断面)的颗粒态氨基酸(Particulate Amino Acids,PAA)进行了分析,并结合叶绿素a(Chla)、颗粒有机碳(POC)、颗粒有机氮(PON)及颗粒态氨基酸的构型特征(D和L型)等参数探讨了该区颗粒有机氮的来源和降解情况。结果表明,在长江口最大浑浊带,受咸淡水混合和生物现场生产双重作用影响,POC、PON以及PAA的总浓度均达到了极大值,其中,受再悬浮作用影响,底层水体中的有机物呈现高度降解的状态;近岸水华区域的颗粒态氨基酸则更多来源于现场生产,而且POC/Chla质量比值与降解因子DI值的负相关特征表明冲淡水向海洋输送的过程中,现场生产力对颗粒有机碳的贡献比重逐渐增大,悬浮颗粒物也变得越来越新鲜。值得关注的是,一些D型氨基酸[如D型天冬氨酸(D-Asp),D型丙氨酸(D-Ala)]与细菌生物量之间存在良好的正相关性,暗示颗粒态氨基酸在受到物理水团和生物现场生产作用控制的同时,还受控于微微型浮游生物以及异养细菌。 相似文献
10.
利用陆基实验围隔,采用原位培养法,对比研究5种草鱼(Ctenopharyngodon idellus)混养系统中细菌生产力的状况。结果表明,细菌生产力波动在(85.22±9.68)~(899.24±29.67)μg C·L-1·d-1,平均为(442.33±210.51)μg C·L-1·d-1。总体上,各处理组细菌生产力随时间呈现先升高后降低的趋势,在8月份达到最高值。其中,草鱼、鲢鱼和鲤鱼的三元混养模式中的细菌生产力显著高于其它处理组(P0.05)。细菌生产力总体上与水体初级生产力、溶解有机碳(DOC)和颗粒有机碳(POC)含量及水温均呈显著正相关,与水体磷酸盐含量呈显著负相关。通过主成分分析(PCA)发现,养殖前期水体无机氮(DIN)、DOC和POC含量对细菌生产力的贡献率高达44.058%,养殖中期DOC和POC含量对细菌生产力贡献率降为32.693%,而养殖后期DIN、DOC和POC含量对细菌生产力的贡献率为45.921%。研究表明,在养殖前期,DIN、DOC、POC是细菌生产力的关键因素;DOC、POC的重要作用使得养殖中期细菌生产力处在较高水平,但PO4-P含量成为限制因素;低温限制了浮游植物的初级生产力,使得养殖后期较高的营养元素含量只能维持细菌较低的生产力。 相似文献
11.
根据2008年1月—2008年11月在铁山港海草生态区进行4个季节月综合调查所获取的数据资料,首次对水体中5种形态氮的含量变化特征及其相互关系进行研究。结果表明:不同形态N的含量变化具有海草生态区特点,TN含量明显偏高,DIN含量却显著偏低,依次排列为:TN>DN>DON>PN>DIN;其中TN、PN和DIN均以春夏季明显高于秋冬季出现,ON则呈夏秋季高、冬春季低特征,只有DON表现为夏季高、秋冬季次之、春季最低。相关分析显示:各种形态N之间以TN与PN、DN与DON之间的关系最为密切,多达非常显著(P≤0.01)的正相关水平,但在季节上却以秋季最为突出,所有形态N之间均以非常显著的正相关出现,具有很好的同源性。整个海区不同形态N/P比均较高,年平均值均在24.64～50.68之间,P相对于N呈匮乏状态,与N的补充源较丰富有关,海草枯落物在其中起重大贡献作用。 相似文献
12.
A preliminary methods comparison for measurement of dissolved organic nitrogen in seawater 总被引：2，自引：0，他引：2
Jonathan H. Sharp Kathrine R. Rinker Karen B. Savidge Jeffrey Abell Jean Yves Benaim Deborah Bronk David J. Burdige Gustave Cauwet Wenhao Chen Marylo D. Doval Dennis Hansell Charles Hopkinson Gerhard Kattner Nancy Kaumeyer Karen J. McGlathery Jeffrey Merriam Nick Morley Klaus Nagel Hiroshi Ogawa Carol Pollard Mireille Pujo-Pay Patrick Raimbault Raymond Sambrotto Sybil Seitzinger Georgina Spyres Frank Tirendi Ted W. Walsh C. S. Wong 《Marine Chemistry》2002,78(4)
Routine determination of dissolved organic nitrogen (DON) is performed in numerous laboratories around the world using one of three families of methods: UV oxidation (UV), persulfate oxidation (PO), or high temperature combustion (HTC). Essentially all routine methods measure total dissolved nitrogen (TDN) and calculate DON by subtracting the dissolved inorganic nitrogen (DIN). While there is currently no strong suggestion that any of these methods is inadequate, there are continuing suspicions of slight inaccuracy by UV methods.This is a report of a broad community methods comparison where 29 sets (7 UV, 13 PO, and 9 HTC) of TDN analyses were performed on five samples with varying TDN and DIN concentrations. Analyses were done in a “blind” procedure with results sent to the first author. With editing out one set of extreme outliers (representing 5 out of 145 ampoules analyzed), the community comparability for analyzing the TDN samples was in the 8–28% range (coefficient of variation representing one standard deviation for the five individual samples by 28 analyses). When DIN concentrations were subtracted uniformly (single DIN value for each sample), the comparability was obviously worse (19–46% cv). This comparison represents a larger and more diverse set of analyses, but the overall comparability is only marginally better than that of the Seattle workshop of a decade ago. Grouping methods, little difference was seen other than inconclusive evidence that the UV methods gave TDN values for several of the samples higher than HTC methods. Since there was much scatter for each of the groups of methods and for all analyses when grouped, it is thought that more uniformity in procedures is probably needed. An important unplanned observation is that variability in DIN analyses (used in determining the final analyte in most UV and PO methods) is essentially as large as the variability in the TDN analyses.This exercise should not be viewed as a qualification exercise for the analysts, but should instead be considered a broad preliminary test of the comparison of the families of methods being used in various laboratories around the world. Based on many independent analyses here, none of the routinely used methods appears to be grossly inaccurate, thus, most routine TDN analyses being reported in the literature are apparently accurate. However, it is not reassuring that the ability of the international community to determine DON in deep oceanic waters continues to be poor. It is suggested that as an outgrowth of this paper, analysts using UV and PO methods experiment and look more carefully at the completeness of DIN conversion to the final analyte and also at the accuracy of their analysis of the final analyte. HTC methods appear to be relatively easy and convenient and have potential for routine adoption. Several of the authors of this paper are currently working together on an interlaboratory comparison on HTC methodology. 相似文献
13.
T. Van Engeland K. Soetaert A. Knuijt R.W.P.M. Laane J.J. Middelburg 《Estuarine, Coastal and Shelf Science》2010
Dissolved organic nitrogen (DON) dynamics in the North Sea was explored by means of long-term time series of nitrogen parameters from the Dutch national monitoring program. Generally, the data quality was good with little missing data points. Different imputation methods were used to verify the robustness of the patterns against these missing data. No long-term trends in DON concentrations were found over the sampling period (1995–2005). Inter-annual variability in the different time series showed both common and station-specific behavior. The stations could be divided into two regions, based on absolute concentrations and the dominant times scales of variability. Average DON concentrations were 11 μmol l−1 in the coastal region and 5 μmol l−1 in the open sea. Organic fractions of total dissolved nitrogen (TDN) averaged 38 and 71% in the coastal zone and open sea, respectively, but increased over time due to decreasing dissolved inorganic nitrogen (DIN) concentrations. In both regions intra-annual variability dominated over inter-annual variability, but DON variation in the open sea was markedly shifted towards shorter time scales relative to coastal stations. In the coastal zone a consistent seasonal DON cycle existed with high values in spring–summer and low values in autumn–winter. In the open sea seasonality was weak. A marked shift in the seasonality was found at the Dogger Bank, with DON accumulation towards summer and low values in winter prior to 1999, and accumulation in spring and decline throughout summer after 1999. This study clearly shows that DON is a dynamic actor in the North Sea and should be monitored systematically to enable us to understand fully the functioning of this ecosystem. 相似文献
14.
厦门潘涂虾池及其附近内湾各态氮的季节性变化特征 总被引：9，自引：0，他引：9
1996年6月至1997年2月，对厦门市潘涂垦区两口虾池及附近内湾不同形态氮的含量与动态进行调查。结果显示虾池的可溶性有机氮（DON）含量明显高于邻近内湾，颗粒有机氮（PN）多数时间也高于内湾，而邻近内湾可溶性无机氮（DIN）含量则明显比池内的高。虾池中的氮主要以DON形态存在（59．76％），DIN，PN含量较少（9．37％和20．87％）；邻近内湾则是以DIN为主（59．97％），其次为DON（29．55％），PN所占比例最小（10．48％）。吓池与邻近内湾不同形态氮的季节变化也存在一定差异。 相似文献
15.
对测量海水中总溶解氮(TDN)的两种常用方法——高温燃烧法和过硫酸钾氧化法进行了比较。结果表明,两种方法在空白、精密度和准确度实验中不存在显著差异。对不同化合物的回收率均在92%～107%之间,加标回收实验回归曲线的斜率分别为0.93和0.92。对于现场海水样品的测定结果,两个断面拟合的斜率分别为0.92和0.97。HTC法比PO法对实际海水样品的氧化效率略高,在操作上也更方便、快捷。因此,高温燃烧法更适合海水中总溶解氮(TDN)的测定。 相似文献
16.
IrocrIowThere is a linkage in shallow marine systerns between sea-noor biOgaxhemical pmeessesand water column pnductivity (Bereson et al., l998). Benthic fluxes provide a significantsource of nutrients to the overlying water tO supPOrt primary pnduction and play a role in de-.creasing oxygen concentrations (van et al., l999; Cowan and Boynton, l996; Berelson etal., 1998; Friedl et al., l998; Zabel et al., l998). TherefOre, it is imPOrtant to define theediment di8genetic pathways for the … 相似文献
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18.
Annelie Skoog Ruben Lara Gerhard Kattner 《Deep Sea Research Part I: Oceanographic Research Papers》2001,48(12):217
Dissolved organic nitrogen (DON), dissolved organic carbon (DOC) and inorganic nutrient concentrations were determined in samples from an area encompassing the Northeast Water Polynya from June to August 1993. In June, still ice-covered polynya area surface waters (PySW) had significantly higher (p<0.05) DOC concentrations (110 μM, n=68) than surface water outside the polynya area (96 μM, n=6). Melting ice and ice algae are suggested as DOC sources. DOC concentrations found in this study are consistent with other studies showing higher DOC concentrations in the Arctic than in other ocean areas. As the productive season progressed, DOC concentrations in Polynya surface water (PySW) decreased (p<0.05) from 110 to 105 μM, while DON concentrations increased (p<0.05) from 5.6 to 6.1 μM, causing a significant decrease (p<0.05) in the C : N ratios of DOM from spring (C : N ratio 20) to summer (C : N ratio 17). We found a significant (p<0.05) decrease in the DOM C : N ratio in all water masses within the polynya area as the productive season progressed. DON was the largest fraction of total dissolved nitrogen (TDN) in PySW and surface waters outside the polynya area. TDN was calculated as the sum of DON, nitrate, nitrite and ammonium concentrations. DON increased (p<0.05) from 62% to 73% of TDN in PySW from spring to summer, a result of increasing DON concentrations and decreasing inorganic nitrogen concentrations over the productive season. The seasonal accumulation of DON and the corresponding decrease in nitrate concentrations in waters with primary production indicate that it is important to take the DON pool into account when estimating export production from nitrate concentration decreases in surface waters. PySW TDN concentrations decreased (p<0.05) from 9.1 (n=61) to 8.6 μM (n=60) from spring (May 25 through June 19) to summer (July 1 through July 27). The seasonal decrease in surface water TDN concentrations corresponded to increases in TDN concentrations in deeper water masses within the Polynya. Most of the TDN increase in deep water was in the form of DON. A possible explanation is that PON was dissolved (partially remineralized) in the water column at mid depths, causing increases in the DON concentration. Transfer of N from PySW (with a short residence time in the polynya area) to Polynya Intermediate Water and deep waters of the Norske and Westwind Trough with multi-year residence times keeps N from leaving the polynya area. In spring, nutrients from degradation of OM in PyIW could support primary production. The role of PyIW as an OM trap could be important in supporting primary production in the polynya area. 相似文献
19.
Distributions and seasonal variability of dissolved organic nitrogen in two estuaries in SW England 总被引：4，自引：0，他引：4
Nitrogen loadings to coastal waters have increased over the last century, resulting in deterioration in water quality. In this study we investigated the distributions and seasonality of dissolved organic nitrogen (DON), and its relationship to total dissolved nitrogen (TDN), for two anthropogenically influenced estuarine systems in southwest England. Concentrations of DON in both estuaries were generally < 80 μM. DON showed non-conservative distributions, resulting from external and internal inputs and in situ reactivity. DON contributed 38 ± 22% (range 4–79%, Yealm) and 36 ± 17% (range 4–84%, Plym) to the TDN pool, with lower values generally observed in the fresher samples relative to the more saline samples. DON was a larger fraction of the TDN pool during the summer and autumn relative to winter and spring, indicating the influence of bacterioplankton release on nitrogen cycling in the estuaries. Ammonification and nitrification were observed in the estuaries, processes which were reproduced in incubation experiments using bioreactors. The bioreactor experiments showed that 12% h− 1 of the DON flux from the River Plym may be available to bacteria, indicating significant removal of DON during the residence time of the water in the estuary (a few days). The bioavailable nature of the DON means that this N fraction significantly adds to the eutrophication burden of the receiving coastal waters, and therefore cannot be ignored in environmental assessments. 相似文献
20.
LI Keqiang WANG Xiulin LIANG Shengkang SHI Xiaoyong ZHU Chenjian CHEN Hu 《海洋学报(英文版)》2008,27(5):98-110
A nitrogen and phosphorus dynamic model of mesocosm pelagic ecosystem was established according to the summary and synthesis of the models available, in which seven state variables （DIN, PO4-P, DON, DOP, phytoplankton, zooplankton and detritus） were included. Logically it had five modules--phytoplankton, zooplankton, dissolved inorganic nutrients, dissolved organic nutrients and detritus. The results showed that this model could simulate the variations of DIN, PO4-P, DON, DOP, POC and phytoplankton biomass in pelagic ecosystem in mesocosm properly, based on the site experiment data in the Jiaozhou Bay in the autumn of 1999 and the summer of 2000. Not only the logical structure but also the model parameters were feasible, and about 20 parameters were made to fit for the Jiaozhou Bay during the simulation. All of these are necessary to study the control mechanism of nutrients biogeochemical cycling in the Jiaozhou Bay and other China＇ s coastal waters. 相似文献