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1.
对珠江口淇澳岛海岸带3个站位(QA-11,QA-9和QA-14)的沉积物中不同形态的还原硫(酸可挥发性硫,黄铁矿和有机硫)、总有机碳(TOC)和孔隙水中SO42-,甲烷浓度进行了测定,并且利用稳态扩散模型计算其中2个站位(QA-9和QA-14)硫酸盐还原通量[1.74和1.14 mmol/(m2.d)]和甲烷厌氧氧化通量[0.34和0.29 mmol/(m2.d)]。研究结果表明由于潮间带沉积物受到SO42-供给的限制,因此位于潮间带的QA-11站位硫酸盐还原带较浅(约16 cm);在潮下带的QA-9和QA-14站位,随离海岸距离和水深的增加,硫酸盐还原通量呈现减小的趋势,并且硫酸还原逐渐受到可利用活性有机质的限制;甲烷厌氧氧化对硫酸盐还原的贡献表现出增加的趋势,由19.2%增加至25.5%。三个站位沉积物中按不同形态还原硫含量由大到小列出,它们是有机硫(OS)、黄铁矿(DS)、酸可挥发性硫(AVS)。沉积物中AVS的空间分布与硫酸盐还原通量有正相关性。QA-11和QA-14站位的黄铁矿与AVS硫的含量比值大于3,分别为7.9和3.6,表明两个站位的黄铁矿形成可能受硫酸盐还原作用的控制;QA-9站位黄铁矿与AVS硫的含量比值为2.2,暗示AVS向黄铁矿转化受到可利用活性铁的限制。  相似文献   

2.
环雷州半岛近海表层沉积物有机碳分布及其控制因素分析   总被引：1，自引：0，他引：1  
对环雷州半岛近海43个海底表层沉积物的总有机碳(TOC)、总氮(TN)、沉积介质条件(包括沉积物粒度)进行了分析,探讨了沉积物TOC、TN的区域分布特征以及影响有机碳分布的主要因素。结果表明,环雷州半岛近海海域海底表层沉积物有机碳含量在0~0.79%之间,平均值为0.26%。与中国其它近海海域相比,环雷州半岛大部分近海区域海底表层沉积物有机碳含量明显偏低,为有机质贫乏区,仅雷州半岛西南部流沙湾近海海域为TOC相对高值区。总氮含量也不高,在0.011%到0.100%之间,TOC与TN存在较强的正相关性,且平面上TOC与TN分布高度重合,显示氮元素主要以有机化合物形式存在。TOC/TN比值在5.1~14.3之间,表明沉积有机质具有陆源输入和海洋自生来源的混合特征,但以雷州半岛西侧北部及东侧中部海域受陆源有机质输入影响更大。大多数站位海底沉积物粒度构成以粉砂为主、粘土次之,少数站位以砂质沉积为主。沉积物有机碳含量与粘土及粉砂含量呈弱正相关性,与沉积物pH值、Eh值及砂含量呈弱负相关性,这表明海底沉积物有机质丰度受有机质来源输入、海底氧化还原状态和沉积水动力条件(沉积物粒度)等因素综合控制。  相似文献   

3.
河流输入的陆源有机碳在河口和陆架区的生物地球化学过程是全球碳循环的重要环节,对陆源有机质的输入量的估算是研究陆架区的生物地球化学过程的基础。黄河输沙量极大,为探究其携带的陆源有机质对陆架边缘海有机碳库的影响,以黄河河口及邻近渤海海域为研究对象,分析了表层沉积物中的木质素,结合总有机碳含量、总氮含量和有机碳稳定同位素评估了表层沉积物中有机碳的组成、来源和分布。8种木质素酚单体中,紫丁香基酚类(S)与香草基酚类(V)的含量比值S/V(0.63±0.31)和肉桂基酚类(C)与香草基酚类含量比值C/V(0.25±0.15),反映出研究区陆源有机碳主要来自草本被子植物。V系列中木质素酸(Ad)与木质素醛(Al)的比值(Ad/Al)V较高(0.53±0.14),表明陆源有机质的降解程度较高。利用稳定碳同位素比值δ13C和木质素含量Λ8相结合的土壤有机质-陆生维管植物-水生有机质三端元模型对陆源有机物的贡献的分析结果显示,土壤有机质、陆源维管植物和水生有机质的平均贡献分别为59.9%±15.0%、7.3%±7.0%、32.8%±11.8%。土壤在陆源有机质中的贡献占有绝对优势,可能与该区域沉积物的主要源区——黄土高原植被覆盖率低、土壤侵蚀严重有关。  相似文献   

4.
近海沉积物中腐殖质和腐殖酸对海洋环境污染具有一定的指示作用,其对重金属、持久性有机污染物的迁移转化具有较大的影响。文章采用焦磷酸钠-氢氧化钠提取重铬酸钾氧化容量法对沉积物腐殖质的组成进行测定,Na OH碱提取法对沉积物腐殖酸进行提取,使用元素分析、紫外光谱、傅里叶变换红外光谱(FTIR)等方法对提取的腐殖酸进行表征。研究结果表明:雷州半岛近海表层沉积物腐殖质含量较低,在0.26%~2.36%之间,平均值1.49%,其中富里酸占51%,胡敏素占35%,胡敏酸占14%,腐殖酸占整个腐殖质的比例是65%。柱状沉积物腐殖化程度高于表层沉积物。雷州半岛近海沉积物中腐殖酸以富里酸和小分子有机物为主,碳含量高,硫含量低,具有苯环、羧基、醇羟基、酚羟基、羰基及氨基等官能团,腐殖化程度不高。研究结果将为雷州半岛沿海经济的开发和环境保护提供一定的指导意义。  相似文献   

5.
环渤海地区河流河口及海洋表层沉积物有机质特征和来源   总被引：4，自引：0，他引：4  
2013年8月采集了环渤海地区35条主要河流河口表层沉积物样品,12月采集了渤海与北黄海24个表层沉积物样品,分析了其生物地球化学指标:总有机碳(TOC)、总氮(TN)、有机碳同位素(δ13C)和氮同位素(δ15N),探讨该区域表层沉积物有机质特征及组成。研究表明:河流河口表层沉积物有机碳同位素(δ13C)值在–26.4‰—–21.8‰,平均值为–24.5‰;渤海表层沉积物有机碳同位素(δ13C)值在–23.8‰—–21.7‰,平均值为–22.3‰。河口表层沉积物TOC含量在0.06%—3.87%,平均值为1.31%;渤海表层沉积物TOC含量在0.52%—2.09%,平均值为1.08%。河流δ13C富集较轻,偏向陆源;海洋δ13C富集较重,偏向水生有机质来源。河流河口表层沉积物的δ13C值差异较明显,最大值与最小值相差4.6‰,但是流域地理位置距离近的河流δ13C值差异不大。河流河口表层沉积物δ15N在1.5‰—10.2‰,平均值为5.5‰;渤海表层沉积物δ15N在4.4‰—5.6‰,平均值为5.0‰。河流表层沉积物δ15N范围比渤海表层沉积物δ15N范围广,原因是河流受陆源有机物影响,且陆源有机物来源差异大。海洋表层沉积物δ15N相对均一,说明海洋表层沉积物δ15N受物源影响较小,体现了水体中有机质的转化和微生物活动对氮同位素的影响。本研究中表层沉积物的δ13C与δ15N没有明显的相关性,也体现了陆源有机质输入的影响。根据经典的二元模式计算,35条河流陆源有机质的贡献比例范围为10%—90%,平均值为60%;渤海陆源贡献比例范围为10%—50%,平均值为20%。河流有机质的来源以陆源有机质为主,水生有机质为辅。渤海有机质的来源以水生有机质为主,环渤海河流的陆源输入也有重要贡献。需要指出的是,有机碳同位素(δ13C)、氮同位素(δ15N)和Corg/Ntotal对有机质来源判别有一定局限性,虽然稳定同位素有示踪性,然而其成分仍然不可避免地受到生物地球化学等过程的改造,在使用稳定同位素技术示踪物源时,须小心谨慎。  相似文献   

6.
河口沉积物作为承接陆海过程的重要载体, 是有机质赋存的主要形式之一。本文研究了珠江口沉积物总有机碳、总氮含量和沉积物可溶性有机物三维荧光特征, 以及其在口内区、混合区和口外区空间差异和影响因素, 并结合碳稳定同位素(δ13C)估算了珠江口各区域沉积物中不同来源有机质的贡献。结果显示: (1)沉积物总有机碳和总氮含量空间变化相似, 口内区和混合区域沉积有机质含量显著高于口外区; 主成分分析发现, 口内区沉积有机质含量主要受径流输入的影响, 口外区主要受Fe3+的影响; (2)MixSIAR稳定同位素混合模型结果显示, 口内区和混合区沉积有机质以陆源为主, 口外区则以海源为主; (3)珠江口沉积物新生有机质较多, 可快速被利用, 总体上不利于有机碳存储; 而陆源输入导致口内区和混合区沉积有机质腐殖化程度较高, 有机碳可存储性相对较高, 口外受海源有机质和铁氧化物—有机质复合体的影响, 有机碳可存储性相对较低。本研究可为深入认知河口区沉积有机质的生物地球化学过程及有机碳存储提供参考。  相似文献   

7.
南极普里兹湾沉积物中有机碳和总氮的含量与分布   总被引：1，自引：1，他引：0  
利用中国多次南极科学考察获得的沉积物样品,对普里兹湾沉积物中有机碳(OC)、总氮(TN)的含量和分布以及OC/TN进行了分析。结果表明:普里兹湾表层沉积物中OC和TN的含量变化范围分别为0.14%~1.20%和0.02%~0.20%,平均值分别为0.63%和0.11%。OC/TN的变化范围为5.5~8.2,平均值为6.8。OC和TN含量呈现明显的正相关性,表明有机质来源相同,比值接近6.6,说明有机质主要为海洋生源沉积。两者平面分布趋势非常一致,且与沉积物中泥质含量呈显著正相关,湾内73°E以西区域OC和TN含量较低,而以东区域含量较高,这是上层水体生产过程和冰川携带陆源砂等因素共同作用的结果。垂直分布上,OC和TN含量总体上表层高于深层,OC含量随深度增加逐渐降低,达到一定深度后趋于稳定。较高的沉积速率加速OC的埋藏,5根柱样中OC的埋藏率为39%~91%,平均为66%,表明普里兹湾是重要的碳汇区。  相似文献   

8.
渤海中南部沉积物中生源要素的分布特征   总被引：3，自引：0，他引：3  
从化学结合形式出发,对渤海中南部海区沉积物中OC、N、P、BSi等生源要素的含量进行调查分析,讨论了各生源要素的分布及其影响因素。结果表明:受陆源输入的影响,表层沉积物中各形态氮、磷及有机碳均呈现"近岸高,远岸低"的分布趋势,生物硅的含量分布则与海区浮游硅藻的分布趋势相一致;可交换态氮是总氮中较活跃的部分,占总氮的比例约为3.7%;固定态铵是总氮的主要组成部分,约占总氮的38.4%,其主要与有机质含量及黏土矿物组成有关;渤海表层沉积物中OC/BSi、ON/BSi以及OP/BSi的比值分别为2.38、0.19、0.03,低于Redfield比值,说明有机质优先于生物硅分解;OC/ON平均值在6.0~14.0之间,判断渤海沉积物中有机质受陆源输入和海洋自生共同影响;其中,有机碳主要以陆源输入为主,而有机氮在沉积物表层主要以陆源输入为主,在沉积物下层则主要来源于海洋自生。  相似文献   

9.
从分析结果，有机质、氮磷的含量分布与流的方法基本一致，它们的含量大小与沉积物粒度呈相关关系，颗粒愈细含量愈大；氮以有机氮为主要存在形式，磷则以无机磷和有机磷同时并存；闽江口附近及福建近岩沉积物中有机质的还原以陆源为主，海峡中央以海相输入法为主。  相似文献   

10.
孟加拉湾中部表层沉积物有机碳分布特征及来源   总被引：1，自引：0，他引：1  
通过对孟加拉湾中部110个表层沉积物样品有机碳、氮含量及粒度进行测试分析,揭示了研究区表层沉积物平均粒径、有机碳(TOC)、总氮(TN)、有机碳/总氮(TOC/TN)的分布特征,并讨论了其有机质来源及控制因素。结果表明,研究区表层沉积物的平均粒径值为6.2~7.6Φ,平均为7.1Φ,其分布呈现出以16°N和15°N为界南北两侧海域粒度相对较细(7Φ),中间海域相对较粗(7Φ)的特点;研究区TOC的质量分数为0.37%~1.24%,平均为0.84%,TN质量分数为0.05%~0.15%,平均为0.10%,两者分布特点相似,大致以15°N和16°N为界表现出南北两侧海域高,中间海域低的特点;TOC/TN比值为6.05~12.88,平均为8.38,中部海域比值高,南北两侧低。根据TOC/TN比值估算研究区陆源和海洋自生有机质的贡献,结果表明研究区陆源与海洋自生有机质平均相对贡献分别为60%和40%。研究区有机质的分布主要受控于有机质来源及输运方式,其中浊流输运导致的溢流沉积是其最主要的控制因素。另外,粒度、河流悬浮体的输入沉降和有机质保存条件等因素也起着重要作用。  相似文献   

11.
Organic carbon (OC) and nitrogen (N) contents and δ13C and δ15N values in total organic matter (OM) were measured in sub-surface sediments (0–30 cm sub-bottom) from 21 cores raised from the Laurentian Channel of the Gulf of St. Lawrence and the Labrador Sea, to document OM fluxes and storage along the eastern Canadian margin. Storage rates as high as 2.5 g m−2 yr−1 for OC and 0.2 g m−2 yr−1 for N are observed in the Laurentian Channel, suggesting that the shelf plays a significant role in terms of OM storage (from 1 to 2% of the primary production). Based on the isotopic composition of the essentially marine OM of the Labrador Sea (δ13C/V-PDB=−21.9±0.4‰; δ15N/AIR=7.6±0.6‰; n=12), there is no isotopic evidence for a significant relative input of terrestrial OM along the Laurentian Channel (δ13C/V-PDB=−21.9±0.4‰; δ15N/AIR=8.0±0.9‰; n=10), either due to high relative fluxes of marine OM and/or to the trapping of continental OM in the estuary and upstream. High storage rates of OM are also observed on the continental rise of the Labrador Sea (as high as 1.1 g C m−2 yr−1 and 0.09 g N m−2 yr−1). They contrast with one order of magnitude lower rates on the slope, due to low sedimentation rates (SR) and sediment winnowing by the Western Boundary Undercurrent (WBUC). Reduced early diagenetic alteration of OM is observed, particularly in the Laurentian Channel. It results in discrete (i) losses of OC and N, (ii) shifts in C/N ratios, suggesting preferential removal of N-bearing OM also highlighted by losses in total hydrolysable amino acids (HAA). In the Labrador Sea slope records, due to low SR, OM concentration changes linked to long term temporal variations may superimpose on these diagenetic trends, and some influence of the WBUC is noticeable.  相似文献   

12.
The sources and distribution of organic matter (OM) in surface waters and sediments from Winyah Bay (South Carolina, USA) were investigated using a variety of analytical techniques, including elemental, stable isotope and organic biomarker analyses. Several locations along the estuary salinity gradient were sampled during four different periods of contrasting river discharge and tidal range. The dissolved organic carbon (DOC) concentrations of surface waters ranged from 7 mg l−1 in the lower bay stations closest to the ocean to 20 mg l−1 in the river and upper bay samples. There was a general linear relationship between DOC concentrations and salinity in three of the four sampling periods. In contrast, particulate organic carbon (POC) concentrations were significantly lower (0.1–3 mg l−1) and showed no relationship with salinity. The high molecular weight dissolved OM (HMW DOM) isolated from selected water samples collected along the bay displayed atomic carbon:nitrogen ratios ([C/N]a) and stable carbon isotopic compositions of organic carbon (δ13COC) that ranged from 10 to 30 and from −28 to −25‰, respectively. Combined, such compositions indicate that in most HMW DOM samples, the majority of the OM originates from terrigenous sources, with smaller contributions from riverine and estuarine phytoplankton. In contrast, the [C/N]a ratios of particulate OM (POM) samples varied significantly among the collection periods, ranging from low values of 5 to high values of >20. Overall, the trends in [C/N]a ratios indicated that algal sources of POM were most important during the early and late summer, whereas terrigenous sources dominated in the winter and early spring.In Winyah Bay bottom sediments, the concentrations of the mineral-associated OM were positively correlated with sediment surface area. The [C/N]a ratios and δ13COC compositions of the bulk sedimentary OM ranged from 5 to 45 and from −28 to −23‰, respectively. These compositions were consistent with predominant contributions of terrigenous sources and lesser (but significant) inputs of freshwater, estuarine and marine phytoplankton. The highest terrigenous contents were found in sediments from the river and upper bay sites, with smaller contributions to the lower parts of the estuary. The yields of lignin-derived CuO oxidation products from Winyah Bay sediments indicated that the terrigenous OM in these samples was composed of variable mixtures of relatively fresh vascular plant detritus and moderately altered soil OM. Based on the lignin phenol compositions, most of this material appeared to be derived from angiosperm and gymnosperm vascular plant sources similar to those found in the upland coastal forests in this region. A few samples displayed lignin compositions that suggested a more significant contribution from marsh C3 grasses. However, there was no evidence of inputs of Spartina alterniflora (a C4 grass) remains from the salt marshes that surround the lower sections of Winyah Bay.  相似文献   

13.
This study investigates the benthic microbial responses to organic matter (OM) variations in quantity and sources in two shallow water bays (Fortaleza and Ubatuba Bays) on the SE coast of Brazil on six occasions during the year. The pelagic and benthic compartments of the bays were evaluated by: (i) nutrients and chlorophyll a (Chl a) in the water column; (ii) quantity and sources of OM in the sediment (Chl a, total organic carbon and total nitrogen and lipid biomarker composition); and (iii) microbial biomass in sediments as an indicator of active benthic response. Although there were changes in water‐column nutrients during the year, Chl a was fairly constant, suggesting a regular supply of microalgae‐derived OM to the sea bottom. Based on the composition of lipid biomarkers in sediments, OM sources were classified as mostly marine and with high contributions of labile (microalgae‐derived) OM. Labile OM composition varied from diatoms in the summer to phytoflagellates in the winter and tended to accumulate in areas protected by physical disturbances in one of the bays. Microbial biomass followed this trend and was 160% higher in protected than in exposed areas. This study suggests that the coupling between labile OM and benthic microbial biomass occurs primarily in protected areas, irrespective of the time of the year. Since meio‐ and macrofaunal assemblages depend upon secondary microbial production within the sediments, this coupling may have an important role for the benthic food‐web.  相似文献   

14.
Sinking particles were collected using time-series sediment traps deployed at 350 and 20 mab at Site SB (34° 58.5’N, 139° 20.9’E, 1544 m depth) near the center of Sagami Bay, off Japan with high time resolutions of 5-8 days (March 1997 to August 1998) and 3-4.5 days (March 1998 to August 1998), respectively. The major components (CaCO3, OM, opal, and clay) of these sinking particles and surface bottom sediments were determined using a stepwise leaching method combined with gravimetry. Average total mass fluxes were 1480, 5560 and 3068 mg/m2/year at 350 mab, at 20 mab, and in the surface sediments, respectively, indicating an enhanced collection of sinking particles at 20 mab. Clay was the dominant component and biogenic components (opal+OM+CaCO3) were dominated mainly by opal and secondly by OM. On average, opal and CaCO3 contents decreased gradually as clay content increased with increasing depth from 350 mab-20 mab and in the surface sediments, indicating dissolution of opal and CaCO3 through sinking, rebound, resuspension or sedimentation processes. Thirteen total mass flux peaks at 17--40-day intervals were observed at 350 mab during the period from March 1997 to August 1998 except for winter, while eight peaks were observed at 20 mab for the period from March 1998 to August 1998. Two types of total mass peaks can be distinguished: one with a clear increase in biogenic flux (opal+OM+CaCO3) and little or no increase in clay flux and termed a bloom type (B-type), and the other with a clear increase in clay flux, little increase in biogenic flux and termed a resuspension type (R-type). Some R-type peaks, but not all, coincided with total mass flux peaks observed at the mouth of Tokyo Bay and suggested the possibility of the effect of particulate materials transported from Tokyo Bay to site SB. The enormously large peak observed at 20 mab in late May 1998 and that at 350 mab in early June 1998 were considered to be due to some physical perturbations from an earthquake swarm near site SB during the period from April to June 1998. The 17--40-day periodicity was associated clearly with the change in biogenic flux dominated by opal flux and is thought to reflect the periodicity of biological productivity dominated by diatoms in the euphotic zone of Sagami Bay.  相似文献   

15.
根据2015年5月对长江口及其邻近海域的生态环境调查资料, 探讨长江口春季表层沉积物总有机碳(TOC)、总氮(TN)、总磷(TP)和生源硅(BSi)4类生源要素的空间分布和来源。结果表明: 2015年春季长江口表层沉积物TOC、TN、TP和BSi平均含量分别为0.315%、0.041%、0.066%和0.450%, 其中, 沉积物中TOC、TN受到陆源输入和海洋自生输入双重影响, 且海洋自生组分的贡献较大, 二者空间分布均呈现南部分布最高并沿西北方向递减趋势; TP分布主要受陆源输入影响, 并呈西北向东南递减趋势; BSi来源于生物沉积, 总体呈现南部高、北部低的分布趋势。与2007年相比, 长江口表层沉积物有机碳、氮含量降低, 东南外海区域替代浑浊区域成为表层沉积物生源要素含量最高区域, 且陆源输入对长江口表层沉积物生源要素的贡献趋于减弱。  相似文献   

16.
渤海表层沉积物中有机碳的分布和来源   总被引：3，自引：0，他引：3       下载免费PDF全文
大河影响下的陆架边缘海沉积有机碳的分布和来源是全球碳循环研究的重要内容。本研究于2012年5月采集了渤海海域的29个表层沉积物样品,分析了粒度组成、总有机碳(TOC)、总氮(TN)、木质素含量和稳定碳同位素丰度(δ13C)等参数,结合基于蒙特卡洛模拟的三端元混合模型,定量研究了沉积物中有机碳的分布和来源情况,并讨论了其影响因素。结果表明,研究区域表层沉积物中TOC含量为0.19%~0.81%,渤海中部泥质区站位(大于0.65%)明显高于其周围砂质区域站位(小于0.40%);TOC与黏土含量也有显著的正相关性,说明细颗粒沉积物容易富集有机碳。沉积有机碳的δ13C范围为-23.7‰~-21.8‰,显示沉积有机碳是海源和陆源有机碳的混合输入。木质素参数,如C/V、S/V和LPVI的数值范围显示研究区域表层沉积物中木质素主要来源于被子植物草本组织与木本组织的混合,同时有少量裸子植物的贡献。基于蒙特卡洛模拟的三端元混合模型显示研究区域沉积物中有机碳主要来源于海洋浮游植物,平均为64%,陆源有机碳中来自土壤的贡献最高(平均为27%),C3维管植物的贡献较少(平均为9%)。海洋浮游植物有机碳主要分布在渤海中部泥质区及离岸较远的区域,而土壤有机碳和C3维管植物有机碳则主要沉积在河口附近及近岸区,并可以离岸输运到较远的地方。  相似文献   

17.
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   

18.
ＩＮＴＲＯＤＵＣＴＩＯＮＤｕｒｉｎｇｔｈｅｐｅｒｉｏｄｏｆｅａｒｌｙ 1 980ｓｔｏｍｉｄ 1 990ｓ ,ｗｉｔｈｔｈｅｒａｐｉｄｄｅｖｅｌｏｐｍｅｎｔｏｆｅｘｐｌｏｒａｔｉｏｎｔｏｔｈｅｓｅａｆｌｏｏｒｈｙｄｒｏｔｈｅｒｍａｌａｃｔｉｖｉｔｉｅｓ ,ｔｈｅｓｕｌｆｕｒｉｓｏｔｏｐｉｃｃｏｍｐｏｓｉｔｉｏｎｏｆｈｙｄｒｏｔｈｅｒｍａｓｅｄｉｍｅｎｔｓａｒｏｕｎｄｔｈｅｗｏｒｌｄｈａｄｂｅｅｎｃａｒｒｉｅｄｏｕｔｔｏｓｏｍｅｅｘｔｅｎｔ (ＺｉｅｒｅｎｂｅｒｇａｎｄＳｈａｎｋｓ ,1 988;ＢｌｕｍａｎｄＰｕｃｈｅｌ…  相似文献   

19.
The sources and distributions of terrigenous organic matter (OM) were investigated in a small tropical estuary in the Hainan Island, South China. Plants, suspended particulate matter (SPM), and surface sediments samples in the estuary and coast were collected. Bulk properties [organic carbon (OC%), total nitrogen (TN%), stable carbon isotope (δ13C) and grain size] and lignin phenol concentrations were measured. OC% of mangrove plants was (43.4 ± 2.1)%, which is similar to the values reported for mangrove plants in other regions. OC% of sediment samples ranged from 0.07% to 1.42%, and they were related to the sediment texture. Lignin phenols in the sediment ranged from 5.16 mg/100 mg OC in the uppermost station to 0.51mg/100mg OC in the coast. The molar ratio of organic carbon to total nitrogen (C/N) (～7) and δ 13 C (～-31.1×10-3 ) of riverine SPM revealed that the major OM sources of riverine SPM were aquatic OM (phytoplankton and/or bacteria). Moreover, the lower lignin concentration (Λ8) and higher (Ad/Al)v of lignin phenols suggest that terrestrial OM in riverine SPM were mainly from soil. Furthermore, C/N ratio, δ13C and lignin phenols reveal that mangrove plants were the predominant OM sources of mangrove surface sediment. Based on the δ13C and lignin phenols, it can be concluded that the major OM sources in estuarine and coastal surface sediments were marine phytoplankton, riverine SPM and mangrove surface sediment. In addition, the higher (Ad/Al)v of lignin phenols in those coastal sediments indicate that seagrass might be a potential OM source in coastal sediments, however, the lower (Ad/Al)v in the estuarine sediments in turn suggests that seagrass could not be transported to the mangrove fringed region. A three-end-member model which is based on lignin concentrations and δ13C was applied to evaluate the contribution of mangroves to the organic matter preserved in the surface sediments. Around the mangrove fringed region, mangrove could contribute more than 50% to the sedimentary OM, and this value is much higher than riverine OM. Nevertheless, mangrove OM could not be efficiently transported to the coastal region. Our study suggests that mangrove forest is an important OM source in this small estuary.  相似文献   

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