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1.
2021年3月对长江口及其邻近海域9个断面溶解氨基酸(THAA)、溶解有机碳(DOC)和溶解有机氮(DON)的分布和组成进行了调查研究。结果表明:THAA的浓度范围为1.24~4.71μmol/L,平均浓度为(2.61±0.85)μmol/L;DOC的浓度范围为118.17~450.58μmol/L,平均浓度为(149.73±33.34)μmol/L;DON的浓度范围为10.48~24.45μmol/L,平均浓度为(13.80±1.81)μmol/L。THAA、DOC和DON的水平分布表现出近岸高于远岸的特点,表明陆源输入对调查区域的THAA等分布有重要影响。而THAA与D-天门冬氨酸、D-谷氨酸、D-丝氨酸和D-丙氨酸的D/L比均呈显著负相关,与天门冬氨酸/β-丙氨酸(Asp/β-Ala)呈正相关,表明细菌活动是影响THAA浓度变化的重要因素。长江口及邻近海域的优势氨基酸为L型氨基酸,D型氨基酸和非蛋白型氨基酸的占比仅为7.34%。基于C/N比值分析,长江口及其邻近海域溶解有机物(DOM)的来源受到长江冲淡水和台湾暖流的共同影响。THAA-C%、THAA-N%、降解因子和反应活性指数表明:水平方向上盐度接近于0的淡水区域和盐度高于34的远海区域降解程度较高;垂直方向上随着深度的增加,有机物的降解程度逐渐升高。调查区域有机物的降解程度主要受到陆源输入和细菌活动的影响。 相似文献
2.
根据2018年4月(春季,绿潮前期)和7月(夏季,绿潮后期) 南黄海营养盐、温度、盐度等水文参数及每日绿潮卫星监测数据,深入分析2018年绿潮的发展规律与营养盐结构特征之间的关系。结果表明：4月25在江苏南通外海首次发现浒苔绿潮,8月中旬在山东半岛近海消亡,其发展区域集中在122°E以西近海,且快速增殖阶段处在35°N以南江苏近海。各组分的营养盐浓度受沿岸径流、冷水团及生物作用等因素影响,均呈现江苏近海高外海以及北部低的特征。对比绿潮发展和营养盐分布呈现3个明显的绿潮−营养盐特征区域：高营养盐−绿潮快速发展区域(35°N以南,122°E 以西,江苏近海);低营养盐−绿潮消亡区域(35°N以北,122°E 以西,山东半岛外海域)及122°E以东外海无绿潮区域。不同特征区营养盐变化表明,江苏近岸较高的营养盐含量(${\rm{NO}}_3^- $-N>6.5 μmol/L, ${\rm{PO}}_4^{3-} $-P>0.27 μmol/L)和丰富来源是浒苔萌发和绿潮快速发展的重要物质基础,为绿潮发展提供了主要的氮、磷生源要素。北部山东半岛南外海较低的营养盐水平(7月,DIN<2 μmol/L, ${\rm{PO}}_4^{3-} $-P<0.03 μmol/L)是限制绿潮继续发展的重要因素。 相似文献
3.
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
4.
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
5.
本文对2012年秋季中国东海31个站位的海水样品中溶解态氨基酸（THAA）和颗粒态氨基酸（PAA）的分布与组成进行了研究。结果表明：表层海水中溶解游离氨基酸(DFAA)的平均浓度为0.12±0.04 μmol/L (0.06~0.19 μmol/L),溶解结合氨基酸(DCAA)的平均浓度为0.61±0.51 μmol/L (0.15~1.79 μmol/L),PAA的平均浓度为0.11±0.06 μmol/L (0.02~0.27 μmol/L)。THAA的水平分布特点大致为近岸高、远岸低;PAA的水平分布特点是近岸海域向远海海域分布呈现逐渐减小的趋势。THAA的垂直分布特点是由表层向底层逐渐降低。DCAA、PAA与Chl-a有很好的相关性,而DFAA与Chl-a的相关性不明显。东海表层海水中THAA的主要组分是天门冬氨酸、谷氨酸、丝氨酸、甘氨酸、苏氨酸及丙氨酸,PAA的主要组分是天门冬氨酸、谷氨酸、丝氨酸、甘氨酸、丙氨酸及亮氨酸。在表层海水中氨基酸是作为一个整体而对海洋生物地球化学过程产生影响的。 相似文献
6.
为探讨浒苔绿潮消亡腐败过程中的营养盐释放规律以及浒苔绿潮聚积腐烂对海水水质的影响,在室外模拟近岸浒苔绿潮聚积腐烂过程,并于2018年6月在浒苔绿潮靠岸前开始对主要浒苔绿潮聚积地(鳌山湾、鳌山湾口的海参池、石老人海域)进行观测,实时记录浒苔腐烂状况及对周边环境的影响。模拟实验结果表明:各形态氮、磷营养盐在浒苔腐烂分解过程中升高明显,且以溶解有机态、颗粒态为主。其中生物量为5 g/L实验组溶解有机氮(Dissolved Organic Nitrogen,DON)、颗粒态氮(Particulate Nitrogen,PN)、溶解有机磷(Dissolved Organic Phosphorus,DOP)、颗粒态磷(Particulate Phosphorus,PP)的浓度在浒苔腐烂分解过程中达本底浓度的5～10倍以上。现场调查结果显示,随着浒苔绿潮在青岛近岸聚积,各调查站点的溶解无机氮(Dissolved Inorganic Nitrogen,DIN)、DON、DOP受浒苔绿潮吸收影响均降至最低值,后随着浒苔绿潮腐烂逐渐上升,水质恶化。其中鳌山湾受浒苔绿潮腐烂影响最为严重,在调查期间水体甚至劣于二类水质。PN、PP为调查区内营养盐的主要赋存形式,其中鳌山湾海域PP变化最为明显,随着浒苔绿潮聚积腐烂达到最高值(2.02 μmol/L)。相比于鳌山湾,石老人海域海水交换能力强且在浒苔绿潮靠岸后进行了及时拦截打捞,受浒苔绿潮消亡腐烂影响较小。浒苔绿潮靠岸聚积腐烂,使海域内营养盐含量与结构明显变化,影响海域浮游植物群落结构的稳定,可能引发赤潮等次生生态灾害。因此需要及时清理聚积在青岛近岸的浒苔,避免其腐烂对周边环境造成影响。 相似文献
7.
本文以2022年南黄海(119 °E~122.5 °E, 34.5°N~37°N)表层海水浮游生物为对象, 利用高通量测序技术分析绿潮期间浮游生物群落结构特征,同时对环境要素进行调查,综合分析环境与浮游生物分布之间的潜在关联, 为掌握南黄海绿潮的生态效应提供依据。结果表明, 2022年7月上旬调查期间南黄海绿潮浒苔生物量湿重估计值为7.24×104吨, 分布特征为以山东近岸以及海州湾附近为主要堆积处, 浒苔生物量、浮游植物以及浮游动物与溶解性无机磷酸盐均有着显著的正相关性。浒苔覆盖区域中, 浮游植物和浮游动物都有着较高的丰富度, 甲藻和桡足类为主要优势种, 属水平下包括: 新角藻、未分类到属的共甲藻、薮枝螅水母、尖头溞等。与无浒苔覆盖的区域相比, 该区域优势种相对单一, 导致次生灾害发生的可能性大。浮游细菌群落调查中发现脱硫单胞菌纲和优势种γ-变形菌纲都与浒苔生物量有着紧密的联系, 其中脱硫单胞菌与浒苔生物量呈显著性正相关, γ-变形菌纲与浒苔生物量呈显著性负相关。相关性分析表明, 浮游细菌多样性与环境中总溶解性氮、磷以及溶解性有机氮呈显著性相关, 结合浒苔与环境因子相关性分析, 浒苔绿潮的发生可以为某些浮游细菌提供生长所需的营养物质。共线性网络分析表明, 在绿潮发生的浒苔覆盖区域, 浮游生物丰富度高且关系紧密复杂, 因此浒苔绿潮对浮游生物的群落结构以及丰富度有潜在的影响。 相似文献
8.
自2007年以来,浒苔绿潮已经连续15年在南黄海暴发。浒苔(Ulva prolifera)作为主要肇事藻种,在暴发过程中向海水释放大量的溶解有机碳(DOC)。然而,这些藻源DOC能否长期保存在海洋中,主要取决于它们的生物可利用性,目前关于此方面的研究甚少。本研究在浒苔绿潮大规模暴发时期(2019年6月),分别在浒苔暴发海区和无浒苔海区各选择3个站位富集表层海水,在实验室进行长期(300 d)的DOC降解实验。结果发现,在60 d内,不同站位富集海水中的DOC浓度随着微生物的利用快速下降,微生物丰度也在第60天达到峰值,表明这些被消耗的DOC是生物可利用性高的活性DOC(LDOC)。60 d后,剩余的DOC可抵抗微生物的降解,在60～300 d内保持稳定,表明这些DOC是具有强稳定性的惰性DOC(RDOC)。最终发现,浒苔暴发海水的RDOC占富集DOC的46%,明显高于无浒苔海水的(36%)。并且,荧光溶解有机物(FDOM)中活性的类蛋白组分随着微生物的利用被快速消耗,惰性的类腐殖质组分逐渐积累,暗示了在降解过程中LDOC逐渐向RDOC转化。可见,浒苔绿潮暴发除了在短时间内增加海水中的D... 相似文献
9.
南海北部海水中氨基酸的分布及其对溶解有机物降解行为的指示研究 总被引：2，自引：0，他引：2
于2015年6月对南海北部海区5个断面共26个站位海水中溶解态氨基酸（THAA）、溶解有机碳（DOC）和叶绿素a（Chl a）的浓度进行了科学调查。结果表明:夏季南海北部海水中THAA的浓度范围为0.40~1.95 μmol/L,平均值为（0.80±0.40） μmol/L,THAA的水平分布总体上体现出近岸高、远海低的特点,表明陆源输入对南海北部海域表层THAA分布有重要影响。THAA在断面上的垂直分布呈现出由近岸至远岸、由表层至底层逐渐降低的趋势。THAA浓度与两种D型氨基酸（D-谷氨酸:D-Glu和D-丙氨酸:D-Ala）含量之间存在显著负相关性,与天门冬氨酸/β-丙氨酸（Asp/β-Ala）和谷氨酸/γ-氨基丁酸（Glu/γ-Aba）比值之间存在显著正相关性,表明细菌的消耗是影响南海海水中THAA浓度的重要因素。D-Ala作为细菌肽聚糖中相对稳定的氨基酸,根据其占DOC的含量估算南海海水中的细菌源有机碳对DOC的贡献率为（29.32±14.32）%,其水平分布显示出近岸低、远岸高的特点;而其垂直分布则呈现出从表层至底层逐渐增加的趋势。THAA占DOC百分比（THAA-C%）的变化范围为1.02%~5.49%,平均值为（2.97±1.38）%。THAA-C%、活性因子和降解因子的高值均出现在珠江口外围区域。随着海水深度增加3种降解因子的数值均显著降低,这表明底层海水中有机物比表层海水中的有机物降解程度更大。 相似文献
10.
江苏－山东沿岸大型绿藻微观繁殖体时空分布特征研究 总被引：1，自引：0，他引：1
为研究暴发浒苔绿潮的黄海近岸水体中大型绿藻微观繁殖体时空分布和种群演替,以及绿潮对海域繁殖体群落结构的影响,本研究在江苏－山东沿岸设置4个站位,开展周年取样调查研究。通过室内培养和分子检测结合的方法,共鉴定出6种大型绿藻:缘管浒苔(Ulva linza)、浒苔(U. prolifera)、扁浒苔(U. compressa)、孔石莼(U. pertusa)、未命名种(Ulva sp.) 和盘苔(Blidingia sp.)。定量研究结果表明,各站位微观繁殖体丰度和种类组成具有明显时空变化特征,苏北浅滩与青岛近岸周年绿藻微观繁殖体丰度明显高于连云港燕尾港和日照岚山港站位;各站位丰度呈双峰型波动,春季到初夏达最高,秋季为次高峰,其他季节丰度较低。群落结构组成研究表明,苏北浅滩周年存在较高丰度的浒苔微观繁殖体(平均为77株/L),其中造成黄海大规模绿潮的“漂浮生态型”浒苔占绝对优势,年均占浒苔微观繁殖体总数的75.7%;青岛近岸微观繁殖体种类组成波动显著,在夏季大规模浒苔绿潮到达时,优势种从缘管浒苔转变成浒苔,其中,“漂浮生态型”浒苔微观繁殖体数量急剧上升,并在绿潮消退时快速消失。对比研究显示,苏北浅滩海域是浒苔微观繁殖体“栖息地”,对维持浒苔种群、造成绿潮连年暴发具有重要作用;青岛近岸微观繁殖体群落受到大规模漂浮浒苔的季节性扰动,其组成结构在绿潮暴发期发生显著变化。 相似文献
11.
《Marine Chemistry》2002,77(1):23-41
Chromophoric dissolved organic matter (CDOM) is the light absorbing fraction of dissolved organic carbon (DOC). The optical properties of CDOM potentially permit remote sensing of DOC and CDOM, and correction for CDOM absorption is essential for remote sensing of chlorophyll a (chl a) in coastal and estuarine waters. To provide data for this purpose, we report the distributions of CDOM, DOC, and chl a from seven cruises in Chesapeake Bay in 1994–1997. We observed non-conservative distributions of chl a and DOC in half of the cruises, indicating net accumulations within the estuary; however, there were no net accumulations or losses of CDOM, measured as absorption at 355 nm or as fluorescence. Freshwater end member CDOM absorption varied from 2.2 to 4.1 m−1. Coastal end member CDOM absorption was considerably lower, ranging over 0.4–1.1 m−1. The fluorescence/absorption ratio was similar to those reported elsewhere for estuarine and coastal waters; however, in the lower salinity/high CDOM region of the Bay, the relationship was not constant, suggestive of the mixing of two or more CDOM sources. Chl a was not correlated with the absorption for most of the cruises nor for the data set as a whole; however, CDOM and DOC were significantly correlated, with two groups evident in the data. The first group had high CDOM concentrations per unit DOC and corresponded to the conservative DOC values observed in the transects. The second group had lower CDOM concentrations per unit DOC and corresponded to the non-conservative DOC values associated with net DOC accumulation near the chl a maximum on the salinity gradient. This indicates the production of non-chromophoric DOC in the region of the chl a maximum of Chesapeake Bay. In terms of remote sensing, these data show that (1) the retrieval of the absorption coefficient of CDOM from fluorescence measurements in the Bay must consider the variability of the fluorescence/absorption relationship, and (2) estimates of DOC acquired from CDOM absorption will underestimate DOC in regions with recent, net accumulations of DOC. 相似文献
12.
The diffusion coefficient of dissolved silica revisited 总被引：1，自引：0，他引：1
The diffusion coefficient of dissolved silica was determined for two different salinities, 36 and 0, at temperatures ranging from 2 °C to 30 °C and at an average pH value of 8.1. Our results show limited influence of salinity and a variation by a factor of 2 to 3 of the silica diffusion coefficient within the temperature range considered in this study. The values obtained at 25 °C are in agreement with previous work carried out at room temperature for seawater and freshwater. The dependency on temperature and viscosity of the diffusion coefficient agrees well with the Einstein–Stokes equation. The composition of the solvent appears to be an important factor because it modifies the viscosity and allows for the complexation of the dissolved silica with less mobile ions, while its pH controls the dissolved silica speciation. In seawater, the higher viscosity and the presence of dissociated and polymeric species result in a decrease of the diffusion coefficient compared to freshwater systems. 相似文献
13.
Vertical profiles of dissolved Al in the Atlantic Ocean and Mediterranean Sea are presented. Although dissolved Al appears to be involved in the biochemical cycle of elements, Al does not behave solely as a nutrient within the oceans. Physico-chemical processes (i.e. adsorption and/or chemical precipitation) control the concentration and distribution of Alaq within the deep waters.A tentative mass balance model of Alaq in the oceanic system is proposed that takes into account all of the presently known fluxes of Alaq to and through the oceans. To maintain the deep waters of the ocean at steady state, it is necessary to include in the model, processes that remove Alaq from these waters. Thus, model calculations support the conclusions drawn from observations that physico-chemical processes remove Alaq from deep waters. Finally, the proposed model is compatible with the concept that the entire oceanic system is at steady state with respect to dissolved Al. 相似文献
14.
Charcoal column chromatography and a dialysis system using a Visking tube were used for the concentration and separation of dissolved carbohydrates in seawater. Recoveries of mono-, oligo-, and polysaccharides were 46–74, 61–89 and 70%, respectively, relative to the total amount of sugars initially submitted to analysis. The combined charcoal column chromatography and dialysis system was used to separate dissolved carbohydrates in seawater samples from Mikawa Bay into mono-, oligo- and polysaccharide fractions. The polysaccharides are separated into two fractions with molecular weights of <4,000 and >4,000 using Sephadex G-25 column chromatography. Monosaccharides, oligosaccharides, polysaccharides with M.W.<4,000 and polysaccharides with M.W. >4,000 accounted for 7–9, 15–26, 7–13 and 20–33% of total dissolved carbohydrates, respectively. However, 32–38% of dissolved carbohydrates were lost during the analytical procedures. Glucose, galactose, mannose, xylose, arabinose, ribose, fucose, and rhamnose were found upon acid hydrolysis of the oligo- and polysaccharide fractions, while fucose and rhamnose were not present in the monosaccharide fraction. Possible sources of the carbohydrates in these fractions are discussed with reference to the monosaccharide composition of cellular carbohydrate in marine algae. 相似文献
15.
Stuart J. Goldberg Craig A. Carlson Dennis A. Hansell Norm B. Nelson David A. Siegel 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(5):672-685
The dynamics of dissolved combined neutral sugars (DCNS) were assessed in the upper 250 m at the Bermuda Atlantic Time-series Study (BATS) site between 2001 and 2004. Our results reveal a regular annual pattern of DCNS accumulation with concentrations increasing at a rate of 0.009–0.012 μmol C L?1 d?1 in the surface 40 m from March to July and reaching maximum mean concentrations of 2.2–3.3 μmol C L?1. Winter convective mixing (between January and March) annually exported surface-accumulated DCNS to the upper mesopelagic zone (100–250 m), as concentrations increased there by 0.3–0.6 μmol C L?1. The exported DCNS was subsequently removed over a period of weeks following restratification of the water column. Vertical and temporal trends in DCNS yield (% of DOC) supported its use as a diagenetic indicator of DOM quality. Higher DCNS yields in surface waters suggested a portion of the DOM accumulated relatively recently compared to the more recalcitrant material of the upper mesopelagic that had comparably lower yields. DCNS yields and mol% neutral sugar content, together, indicated differences in the diagenetic state of the surface-accumulated and deep pools of DOM. Seasonally accumulated, recently produced DOM with higher DCNS yields was characterized by elevated mol% of galactose and mannose+xylose levels. Conversely, more recalcitrant DOM from depths >100 m had lower DCNS yields but higher mol% of glucose. Lower DCNS yields and elevated mol% glucose were also observed in the surface waters during winter convective mixing, indicating an entrainment of a diagenetically altered DOM pool into the upper 100 m. A multivariate statistical analysis confirms the use of DCNS as an index of shifts in DOM quality at this site. 相似文献
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Distributions of salinity, dissolved total nitrogen (DTN) and dissolved oxygen (DO) were observed once a month throughout a year in Mikawa Bay, one of the most eutrophic bays in Japan. Supply of freshwater, DTN and DO from the land and precipitation was estimated. Hydrography, circulation and transformation of DTN and DO during the stratified period were investigated simultaneously by a two-layered box model analysis dividing the bay into five boxes. The two-layered circulation was confirmed. In the upper layer of the river mouth regions, a high production of particulate organic nitrogen (PON) due to the strong upwelling together with the river inflow was found. On the other hand, in the lower layer of the bay mouth region, a high deposition of PON due to weak upwelling and sometimes downwelling and a high decomposition of PON due to the inflow of DO abundant water were also found. The reason why the eutrophication is more severe in the eastern part than in the north-western part of the bay is discussed. 相似文献
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The chloroform-extractable ‘lipid’ fraction of dissolved organic matter in seawater was analyzed by gravimetry, liquid chromatography, gas chromatography (GC), and gas chromatography—mass spectrometry (GC—MS). Gravimetric concentrations of dissolved lipids in the Gulf of Mexico were in the range of 60–160 μg 1?1 in near-surface waters and 61–116 μg 1?1 in near bottom waters and accounted for ～4% of the dissolved organic carbon. Over a 12-h sampling period and a 5-d sampling period extensive variability in dissolved lipid quantity and quality were observed. The major percentage of extractable weight was collected in the polar liquid chromatographic fraction (55–95%). Gas chromatographic concentrations of the aliphatic fractions were in the range of 0.014-0.187 μg 1?1. Concentrations derived from gas chromatography were consistently lower than gravimetrically-derived concentrations. A number of compounds were tentatively identified by a combination of GC, GC—MS, and authentic standards. The major components of the analyzable dissolved lipids were n-alkanes (C16C32), pristane, phytane, methyl, ethyl and propyl esters of fatty acids. Minor components included olefins and cycloalkanes, aromatics, short-chained acids, and possibly a lactone and an alcohol. All concentrations and compounds were indicative of a fairly pristine environment. The n-alkane distribution appears to be the result of marine and terrestrial inputs superimposed on a chronic low-level background of oil pollution. It is suggested that the fatty acid esters and other fragment molecules are the résult of the degradation of humic substances. A number of potential indicators of source were isolated. 相似文献