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1.
桑沟湾养殖海域沉积物中碳埋藏通量的长期记录 总被引：1，自引：0，他引：1
对取自桑沟湾北部和南部养殖海域2个站位柱状沉积物样品进行研究,测定了它们的总碳(TC)、有机碳(TOC)、无机碳(TIC)含量,估算了海源有机碳(Ca),结合沉积物年代序列测定,对碳的来源和埋藏通量(BF)进行分析。结果表明:从19世纪到20世纪初,桑沟湾碳埋藏基本处于平稳期;20世纪初开始,伴随着中国工业革命兴起,湾内营养水平提高,大量天然小型贝类繁殖及残骸埋藏使桑沟湾碳埋藏量有大幅度突跃;20世纪60年代以来人工养殖活动兴起及到90年代大规模养殖后,天然贝类繁殖受抑制且伴随养殖产品的不断收获,使此期间碳埋藏量又处于平稳期。20世纪60年代前BFCa/BFTOC和BFCa/BFTC的比值分别在20%和4%以下波动,其后随养殖活动增加呈显著增大趋势;但BFTOC/BFTC比值基本在40%以下范围内波动。并将该区与取自黄海中部一柱状沉积物的BFTIC/BFTC比值作对比,桑沟湾BFTIC/BFTC比值基本在60%~98%之间远高于黄海中部(约15%)的比值,桑沟湾TIC与TC含量高比值使仅应用TOC或Ca含量估算碳埋藏通量可能带来巨大误差。 相似文献
2.
近200年桑沟湾养殖海域柱状沉积剖面的污染有机质记录与评价 总被引：2，自引：1，他引：1
通过对取自桑沟湾南部和北部养殖海域2个站位的柱状沉积物样品进行TOC和TN测定,分析了桑沟湾沉积物中TOC和TN的分布情况,结合沉积物年代序列的测定,估算了工业革命之前、之中及规模化养殖之后桑沟湾海域沉积物中水生有机碳和总氮的含量,并对近200年来桑沟湾养殖海域有机质沉积情况进行了评价。结果显示:19世纪70年代以前,TOC含量较稳定,TN含量随深度增加而缓慢降低;19世纪70年代至20世纪70年代,TOC,TN含量波动均较大;20世纪70年代以后,TOC含量逐渐减小并趋于稳定,TN含量随养殖规模的扩大显著增加,且扇贝养殖区表层沉积物中TOC,TN的含量均低于海带养殖区。近200年桑沟湾沉积物中有机质来源变化趋势为混源-陆源-混源,近40年来的规模化养殖明显增加了水生有机碳及水生总氮在TOC和TN中所占比例。对桑沟湾沉积物中有机质污染评价结果显示,大规模的养殖活动增加了底质中沉积物TOC和TN的含量,海带筏式养殖对沉积物中的TN造成了一定的累积性自身污染。 相似文献
3.
为了研究长江古河谷地区早中全新世沉积物的碳埋藏速率及来源，进行了ZK1孔沉积物总有机碳(TOC)、总氮(TN)及δ13C的测定，结合AMS14C(植物碎屑、贝壳)测年、有孔虫及粒度数据，分析了长江古河谷碳埋藏的时空分布特征与TOC来源。采用历史地理学、沉积地质学结合测年数据进行了年代地层划分，自下而上分别为U1潮汐河道、U2河口湾、U3潮流砂脊和U4前三角洲。沉积物受到水深、径流、河口余环流、潮流、波浪、风暴与再矿化等作用或因素影响，TOC平均值为0.41%，低于长江河口表层沉积物基准值0.46%。ZK1碳埋藏通量(TOCBF)介于7.4～110.5 g/(m2·a)之间，差异较大。TOCBF数值主要受控于沉积速率。δ13C与TOC/TN(C/N)投影点结果表明，TOC来源表现为多源特征，且整体表现为偏陆源特征。C/N与δ13C线性拟合相关性高，适合采用C/N与δ13C进行TOC来源的定量分析。基于C/N与δ 相似文献
4.
胶州湾沉积物中氨基酸对有机质降解及细菌源贡献的指示作用解析 总被引：2，自引：2，他引：0
基于对胶州湾表层沉积物中总可水解氨基酸（THAA）的含量、组成、构型及分布特征的系统研究，通过氨基酸碳氮归一化产率（THAA-C%，THAA-N%）、降解因子DI、反应活性指数RI以及D型氨基酸占比（D-AA%，摩尔百分比）等指标结合碳氮比（TOC/TN）、碳稳定同位素（δ13C）探析了胶州湾沉积物中有机质的来源与降解状态，利用细菌源有机质及胞外肽酶活性（EEA）探讨了微生物在有机质迁移转化过程中的作用与贡献。结果表明，胶州湾表层沉积物中氨基酸平均含量为（7.60±3.64）μmol/g，在陆源与海源混合影响下，其水平分布呈现湾内高于湾外、湾内东部高于西部的特点，表明湾内东部陆源输入对沉积物THAA具有较高贡献。THAA-C%、THAA-N%、DI、RI以及D-AA%等指示因子均显示胶州湾表层沉积物中有机质的降解程度呈现湾外高于湾内、湾内东部高于西部的变化趋势，有机质来源、微生物活性与上覆水水深共同影响了有机质的降解程度。胶州湾表层沉积物中细菌源有机碳的贡献率为（29.35±18.73）%，其水平分布显示出湾内西部与湾外相近且高于湾内东部的特点。细菌胞外肽酶活性（EEA）平均为（0.81±1.31）nmol/（g·h）（以MCA计），整体分布趋势与细菌贡献率相反，呈现湾内东部高于湾内西部和湾外的特性。沉积物中有机质的不同海源、陆源占比决定了有机质的可降解性，而有机质的降解程度进一步影响了细菌源有机质的贡献与胞外肽酶活性。 相似文献
5.
洞头近海养殖水域沉积物碳含量空间分布格局 总被引：1，自引：0，他引：1
《应用海洋学学报》2015,(4)
为揭示近海养殖活动在碳埋藏中的作用,对洞头近海3个不同养殖年份(2、10、30a)的紫菜养殖区沉积物总有机碳(TOC)、总无机碳(TIC)、水溶性有机碳(WSOC)及水溶性无机碳(WSIC)含量的空间分布格局进行了研究.近岸养殖区沉积物TOC、WSOC含量高于远岸.沉积物柱样中TOC含量在上层0~20 cm最高,而WSOC含量在下层40~60 cm最高.不同养殖年份的养殖区沉积物WSOC含量有显著差异,最高值出现在养殖30a的水域.近海养殖水域沉积物碳库中TIC含量高于TOC含量,TIC含量占总碳(TC)含量的58%,远岸TIC含量高于近岸.沉积物水溶性碳库以有机碳形式为主,WSOC含量占总水溶性碳库的73%.研究表明,洞头近海紫菜养殖区沉积物中不同形态碳含量的空间分布格局有一定差异,无机碳特别是深层无机碳对近海沉积物中碳的长期固定贡献较大. 相似文献
6.
海底地下水排放对典型红树林蓝碳收支的影响 总被引：1，自引：0，他引：1
海底地下水排放(Submarine Groundwater Discharge，SGD)是陆海相互作用的重要表现形式之一，其携带的物质对近岸海域生源要素的收支有重要影响。本文利用222Rn示踪技术估算了我国典型红树林海湾—广西珍珠湾在2019年枯季(1月)SGD携带的碳通量。调查发现，地下水中222Rn活度、溶解无机碳(DIC)和溶解有机碳(DOC)的平均浓度均高于河水和湾内表层海水。利用222Rn质量平衡模型估算得到珍珠湾SGD速率为(0.36±0.36) m/d，SGD输入到珍珠湾的DIC和DOC通量分别为(2.41±2.63)×107 mol/d和(1.96±2.20)×106 mol/d。珍珠湾溶解碳的源汇收支表明，SGD携带的DIC和DOC分别占珍珠湾总DIC和总DOC来源的91%和89%。因此，SGD携带的DIC和DOC是珍珠湾DIC和DOC的主要来源，是海岸带蓝碳收支和生物地球化学循环过程中的重要组成。 相似文献
7.
潮滩作为重要的湿地类型和高效的有机碳汇备受关注,近期围垦、养殖等人类活动和互花米草入侵对潮滩生化环境和有机碳埋藏产生了重要影响。本研究选取了福建三沙湾三处不同植被类型的潮滩各取得沉积物短柱样,测定沉积物的总有机碳含量(TOC)、稳定碳同位素(δ13C),结合210Pbex测试计算的沉积速率,估算了不同区域的有机碳埋藏通量(BC)。结果表明,互花米草阶段和红树林阶段TOC含量分别为0.67%和0.95%,比对应的光滩阶段分别提高了13.6%和26.7%,表明红树林对潮滩固碳效率的提升比互花米草更加显著。在两者的共同生长区域,随时间推移TOC含量显著下降,表明互花米草入侵挤占红树林生长空间之后,降低了潮滩的固碳效率。短柱样沉积物δ13C值分布范围在-24.70~-21.87‰,主要体现海源有机质同位素特征,但也会受潮滩植被生长类型影响。对各短柱样有机碳埋藏通量进行估算,得到研究区红树林生长阶段BC平均值为149.53 g/m2/yr,远高于互花米草生长阶段的平均值57.37 g/m2/yr。 相似文献
8.
种类繁多的海洋生物,生活习性分别适于在水体上层、中层、甚至于海底。人们根据海洋生物的这些生态特点,在近海水域进行多品种的养殖,这种养殖形式被称之为“立体养殖”。现将我们1986年在山东荣成县桑沟湾开展立体养殖的情况简报如下。 桑沟湾是山东荣成东部沿海的一个半封闭式海域。湾内水面20万亩,平均水深7—8m,最大水深15—17m。湾内底质大致分为基石、砂砾石、中细砂、粉砂及泥质粉砂5类。湾内潮汐为不正规半日潮型,平均大潮差1.47m,平均大潮流速24cm/5(湾口处为60 相似文献
9.
贝类通过生物沉积作用加速了养殖海区水体中的颗粒物质向海底的输送。在桑沟湾中筏式养殖的长牡蛎(Crassostrea gigas),将大量的有机物以生物沉积物(真粪和假粪)的形式排向养殖区海底。为完成对桑沟湾筏式养殖长牡蛎生物沉积物对环境底质影响的量化研究,作者通过在桑沟湾内不同的海区设置采样点(5个养殖区,3个对照点),对采样点SG 2与SG 6两个点的长牡蛎生物性沉积物与海区悬浮颗粒物进行了稳定同位测定及有机物来源分析。实验结果表明:选取的采样点沉积物稳定碳氮同位素丰度集中于δ~(13)C–22.82‰~–21.62‰,δ~(15)N 4.73‰~6.21‰。在SG 2点的悬浮颗粒物中,长牡蛎生物性沉积物贡献有机物占9.95%,对照区沉积物与SG 2区沉积物贡献分别为54.19%和35.86%。在典型的采样点,稳定同位素法能较准确地量化出各有机物来源的贡献比例。以SG C点为对照,其余7个采样点长牡蛎生物性沉积物有机物贡献在4.06%~28.64%,平均贡献率为13.96%±8.62%,牡蛎养殖已经对桑沟湾底质造成了一定的影响。 相似文献
10.
本文测定了海南儋州湾南岸柱状沉积物的粒度、总有机质参数(TOC、C/N和δ13C)和类脂生物标志物含量,并通过端元混合模型使用红树植物特征标志物蒲公英萜醇含量、长链正构烷烃含量和δ13C值半定量区分了海南儋州湾南岸沉积有机质来源,尤其是红树林的贡献。另外,通过估算沉积物的有机碳储量来评估儋州湾红树林区域的储碳能力。在沉积有机质中,陆源、水源和红树植物有机质所占平均比例分别为47%,36%和17%。沉积物柱状样中单位厘米深度沉积物的碳储量范围在0.12~2.90 t/ha。本研究表明,儋州湾地区沉积物中来自于红树林的有机质比例较低,且其碳埋藏量可能低于全球平均水平。修复和保护儋州湾红树林,能够有效提升湿地的碳埋藏效率,从而减缓大气CO2上升对环境的负面影响。本文应用生物标志物和碳同位素方法,半定量区分了红树林生态系统各种来源有机碳的贡献,将蒲公英萜醇作为红树林特征生物标志物应用在计算模型中,能够量化红树植物来源有机碳的贡献,加深对红树林系统有机碳埋藏情况的了解。 相似文献
11.
In this study,we assessed the burial fluxes and source appointment of different forms of carbon in core sediments collected from culture areas in the Sanggou Bay,and preliminarily analyzed the reasons for the greater proportion of inorganic carbon burial fluxes(BFTIC).The average content of total carbon(TC) in the Sanggou Bay was 2.14%.Total organic carbon(TOC) accounted for a small proportion in TC,more than 65% of which derived from terrigenous organic carbon(Ct),and while the proportion of marine-derived organic carbon(Ca) increased significantly since the beginning of large-scale aquaculture.Total inorganic carbon(TIC) accounted for 60%–75%of TC,an average of which was 60%,with a maximum up to 90% during flourishing periods(1880–1948) of small natural shellfish derived from seashells inorganic carbon(Shell-IC).The TC burial fluxes ranged from 31 g/(m2·a)to 895 g/(m2·a) with an average of 227 g/(m2·a),which was dominated by TIC(about 70%).Shell-IC was the main source of TIC and even TC.As the main food of natural shellfish,biogenic silica(BSi) negatively correlated with BFTIC through affecting shellfish breeding.BFTIC of Sta.S1,influenced greatly by the Yellow Sea Coastal Current,had a certain response to Pacific Decadal Oscillation(PDO) in some specific periods. 相似文献
12.
Long-term changes of composition,sources and burial fluxes of TOC(total organic carbon) in sediments of the central Yellow Sea mud area and their possible affecting factors are discussed in this paper.Firstly,similarity analysis is employed to confirm that the carbon burial features resulted from two collected cores are typical in the central Yellow Sea mud area where YSWC(Yellow Sea Warm Current) is prevalent.On this basis,the burial flux of TOC here was considered to be 235.5–488.4 μmol/(cm2?a) since the first industrial revolution,accounting for about 70%–90% among burial fluxes of TC(total carbon) in the sediments.Compared TOC/TC ratio in the two cores with that in other marine sediments worldwide,we suggest that the growth of calcareous/non-calcareous organisms and dissolution of IC(inorganic carbon) are important factors controlling the TOC/TC ratio in sediment.Results of two-end mixed model based on δ13C data indicate that marine-derived organic carbon(OCa)is the main part among total burial organic carbon which accounts for a ratio over 85%.Due to the high TOC/TC ratio in the two cores,TC in the sediments also mainly exists as OCa,and the proportion of OCa is about 60%–80%.Away from the shore and relatively high primary production in upper waters are the main reasons that OCa is predominant among all burial OC in sediments of the central Yellow Sea mud area.Burial of OC in this mud area is probably mainly influenced by the human activities.Although the economic development during the late 19 th century caused by the first industrial revolution in China did not obviously increase the TOC burial fluxes in the sediments,the rise of industry and agriculture after the founding of new China has clearly increased the TOC burial flux since 1950 s.Otherwise,we also realize that among TC burial fluxes,TIC account for about 10%–30% in sediments of the central Yellow Sea mud area,so its burial could not be simply ignored here.Distinct from TOC burial,long-term TIC burial fluxes variations relate with climate changes more closely:the East Asian summer monsoon may influence the strength of the Huanghe River(Yellow River) flood,which could further affect the transport of terrestrial IC from land to the central Yellow Sea as well as the burial of these IC in the sediments. 相似文献
13.
There are two sets of carbonate source rocks in the Lower Carboniferous layers in Marsel: the Visean (C1v) and Serpukhovian (C1sr). However, their geochemical and geological characteristics have not been studied systematically. To assess the source rocks and reveal the hydrocarbon generation potential, the depositional paleoenvironment and distribution of C1v and C1sr source rocks were studied using total organic carbon (TOC) content, Rock-Eval pyrolysis and vitrinite reflectance (Ro) data, stable carbon isotope data, gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis data. The data were then compared with well logging data to understand the distribution of high-quality source rocks. The data were also incorporated into basin models to reveal the burial and thermal histories and timing of hydrocarbon generation. The results illustrated that the average residual TOC contents of C1v and C1sr were 0.79% and 0.5%, respectively, which were higher than the threshold of effective carbonate source rocks. Dominated by type-III kerogen, the C1v and C1sr source rocks tended to be gas-bearing. The two source rocks were generally mature to highly mature; the average Ro was 1.51% and 1.23% in C1v and C1sr, respectively. The source rocks were deposited in strongly reducing to weakly oxidizing marine–terrigenous environments, with most organic material originating from higher terrigenous plants and a few aquatic organisms. During the Permian, the deep burial depth and high heat flow caused a quick and high maturation of the source rocks, which were subsequently uplifted and eroded, stopping the generation and expulsion of hydrocarbons in the C1v and C1sr source rocks. The initial TOC fitted by the △logR method was recovered, and it suggests that high-quality source rocks (TOC ≥ 1%) are mainly distributed in the northern and central local structural belt. 相似文献
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15.
本研究选择杭州湾庵东浅滩作为研究区,选取盐沼区三个不同植被带进行柱状样的采集,通过测量沉积物的粒度、沉积速率、碳氮含量(有机碳、总碳、总氮、碳氮比)等参数,系统分析研究区盐沼湿地植被演替对盐沼物质循环产生的影响。研究结果发现,不同植被覆盖下沉积物粒径差异显著,沿海向陆逐渐变细;沉积速率从海三棱藨草滩、互花米草滩、植被交错区依次递减;总碳、总氮、有机碳含量特征为互花米草滩植被交错区海三棱藨草滩,碳氮比介于6～9,有机碳以海源物质为主;通过计算,发现有机碳埋藏速率为互花米草[159 g/(m2·a)]海三棱藨草[140 g/(m2·a)]植被交错区[119 g/(m2·a)]。从整体上来看,杭州湾南岸盐沼从海三棱藨草群落向互花米草群落演替时,沉积物颗粒发生细化,沉积速率有所变化,而总碳、有机碳、总氮含量增加,盐沼有机碳埋藏速率增加。 相似文献
16.
Settling particles from duplicate free-drifting sediment traps were collected at 150 m depth in May and July at a landward and a seaward site in the 350 m deep Laurentian Trough. The total organic carbon (TOC) fluxes were high (95–454 mg/m2/d), comparable to those reported for Dabob Bay (a similar moderately productive deep coastal environment) and for the highly productive Peru upwelling region. The TOC (26–67 mg C/g) consisted of lipids (17–37%), carbohydrates (7.9–16%), hydrolysable amino acids (8.4–16%), labile proteins (0.3–2.6%), and a non-characterized fraction (40–64%). Amino acids, proteins and uncharacterized compounds accounted for 24–42, 1–10 and 58–76%, respectively, of total nitrogen (2.3–7.7 mg N/g). The pigment fraction was largely dominated by pheopigments (0.06-1.15 mg/g vs 0.004–0.15 mg/g for chlorophyll a). C/N and C/pigment ratios indicated that on average, about half of the carbon flux was of terrigenous origin. Marine sources included a dominant zooplanktonic contribution, indicated by the abundance of fecal pellets, lipids and pheopigments, and a smaller contribution from fresh algae. Cluster and correlation analyses confirmed the decoupling of pigment and TOC fluxes and the strong zooplanktonic influence of the trap material. Despite large day-to-day and inter-trap variability, clear differences were observed in the fluxes, TOC content and composition at both sampling sites and months. Such trends are attributed to the relative contribution from terrestrial and marine sources and seasonal patterns of primary production. 相似文献
17.
Aurélia Mouret Pierre Anschutz Bruno Deflandre Gwénaëlle Chaillou Christelle Hyacinthe Jonathan Deborde Henri Etcheber Jean-Marie Jouanneau Antoine Grémare Pascal Lecroart 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(4):528-540
The relationship between particulate organic carbon (POC) concentrations measured in modern sediment and fluxes of exported POC to the sediment surface needs to be understood in order to use POC content as a proxy of paleo-environmental conditions. The objective of our study was to compare POC concentrations, POC mineralization rates calculated from O2 consumption and POC burial rates. Benthic O2 distributions were determined in 58 fine-grained sediment cores collected at different periods at 14 stations in the southeastern part of the Bay of Biscay with depths ranging from 140 to 2800 m. Depth-dependent volume-specific oxygen consumption rates were used to assess rates of aerobic oxidation of organic matter (OM), assuming that O2 consumption solely was related to heterotrophic activity at the sediment–water interface. Heterogeneity of benthic O2 fluxes denoted changes in time and space of fresh organic material sedimentation. The most labile fraction of exported POC engendered a steep decrease in concentration in the upper 5 mm of vertical O2 profiles. The rupture in the gradient of O2 microprofile may be related to the bioturbation-induced mixing depth of fast-decaying carbon. Average diffusive O2 fluxes showed that this fast-decaying OM flux was much higher than buried POC, although diffusive O2 fluxes underestimated the total sediment oxygen demand, and thus the fast-decaying OM flux to the sediment surface. Sedimentary POC burial was calculated from sediment mass accumulation rate and the organic carbon content measured at the top of the sediment. The proportion of buried POC relative to total exported POC ranged at the most between 50% and 10%, depending on station location. Therefore, for a narrow geographic area like the Bay of Biscay, burial efficiency of POC was variable. A fraction of buried POC consisted of slow-decaying OM that was mineralized within the upper decimetres of sediment through oxic and anoxic processes. This fraction was deduced from the decrease with depth in POC concentration. At sites located below 500 m water depth, where the fast-decaying carbon did not reach the anoxic sediment, the slow-decaying pool may control the O2 penetration depth. Only refractory organic material was fossilized in sedimentary records at locations where labile OM did not reach the anoxic portion of the sediment. 相似文献
18.
Surface sediment from the coastal bays of Gwangyang and Masan in South Korea were analyzed for their contents and isotopic
values of organic carbon and total nitrogen. The sources and diagenetic alteration of organic matter were also assessed. Total
organic carbon varied from 0.22% to 3.48% (average = 1.40%, n = 75), and C/N ratios varied from 2.4 to 15.2 (average = 8.79,
n = 75). δ13Corg ranged from −19.92‰ to −25.86‰ (average = −21.21‰, n = 75), and δ15NTN ranged from 8.57‰ to 3.93‰ (average = 6.49‰, n = 75). Total organic carbon in both areas was associated with grain-size,
with higher contents in finer grained sediment. The high carbon content observed in Masan Bay sediment correlated with its
higher C/N ratio. δ13Corg and δ15NTN varied widely, attributable to various influences such as the input of terrestrial organic matter and diagenetic alteration.
The depleted δ13Corg and higher δ15NTN observed in the sediment of Gwangyang Bay reflected terrestrial supply, implying that biogeochemical processes, i.e. bacterial
degradation, were more active in Masan Bay sediment, which showed less depleted δ13Corg and higher δ15NTN than Gwangyang Bay sediment. δ15NTN was the more useful indicator of biogeochemical processes in the highly anoxic sediment. These results indicate that the
δ13Corg and δ15NTN of sedimentary organic matter in coastal bays can indicate the source and degree of diagenetic alteration of sedimentary
organic matter. 相似文献