Scientia Geographica Sinica  2015 , 35 (6): 782-789

Orginal Article

沿海不同年限围垦区土壤剖面有机碳同位素与粒度特征——以江苏省东台市为例

陈影影, 张振克, 徐华夏, 张凌华, 赵一飞, 张云峰, 符跃鑫

南京大学地理与海洋科学学院海岸与海岛开发教育部重点实验室,江苏 南京 210023

Stable Carbon Isotope and Particle Size Characteristics in Coastal Saline Soil with Different Reclamation Age of Dongtai, Jiangsu Province

CHEN Ying-ying, ZHANG Zhen-ke, XU Hua-xia, ZHANG Ling-hua, ZHAO Yi-fei, ZHANG Yun-feng, FU Yue-xin

School of Geographic and Oceanographic Sciences, Ministry of Education Key Laboratory for Coast and Island Development, Nanjing University, Nanjing,Jiangsu 210023, China

中图分类号:  P737

文献标识码:  A

文章编号:  1000-0690(2015)06-0782-08

通讯作者:  张振克,教授。E-mail:zhangzk@nju.edu.cn

收稿日期: 2014-03-12

修回日期:  2014-06-25

网络出版日期:  2015-06-20

版权声明:  2015 《地理科学》编辑部 本文是开放获取期刊文献,在以下情况下可以自由使用:学术研究、学术交流、科研教学等,但不允许用于商业目的.

基金资助:  国家自然科学基金项目(41371024、41230751)和国家科技支撑计划项目(2012BAC07B01)资助

作者简介:

作者简介:陈影影(1984-),女,山东成武人,博士研究生,主要从事第四纪环境演变方面的研究。E-mail:chenyy1023@163.com

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摘要

根据江苏沿海不同年限围垦区土壤剖面有机碳稳定同位素(δ13C)与粒度资料,研究了不同年限围垦区土壤粒度特征变化情况与有机质来源变化特征。结果表明,在气候和母质基本相同的条件下,土壤δ13C和粒度特征主要受围垦年限和人类活动干扰影响。随着围垦年限的增加,土壤平均粒径显著降低,表现为DT7(33.93 μm,林地,已围垦近60 a)<DT1(46.10 μm,农用地,已围垦16 a)<DT6[48.21 μm,盐蒿(Suaeda salsa)滩,已围垦2 a]。其中,DT6、DT7(30 cm以下)、DT1剖面粒度记录均具有自下向上逐渐变细的特点,粗颗粒组分逐渐减少,反映了粉砂淤泥质海岸围垦前原始潮滩沉积物的自然演化特点,DT7剖面30 cm以上逐渐变粗则可能主要由于已围垦近60 a里表层堆积了大量枯枝落叶所致。人类活动干扰在沉积记录中也较明显,DT6盐蒿滩剖面δ13C值总体上表现为海洋自生有机碳,主要反映原始沉积母质特征。DT1农用地剖面0~40 cm耕作层由于受开垦、翻耕、除草、施肥等各种人类活动干扰较大,各粒度组成及粒度参数均开始出现显著变化,这在表层迅速变轻的δ13C值也有所反映。DT7林地剖面尽管受人类干扰相对较小,但由于受到表层堆积的大量枯枝落叶等凋落物的影响,各粒度组成及参数在上部均也表现出明显变化,特别是表层0~10 cm δ13C值已呈明显的陆源性。δ13C值所表现出的陆源和海洋自生有机碳特征与根据经验公式计算的结果也具有较好的一致性。

关键词: 滩涂围垦 ; 有机碳稳定同位素 ; 粒度 ; 东台市

Abstract

Based on stable carbon isotope (δ13C) signatures and particle size of coastal saline soil of Dongtai, changes in the particle size characteristics and soil organic matter source with different reclamation age were analyzed. Results showed that under the same climate and parent material conditions, soil organic carbon isotope and particle size were mainly affected by reclamation age and human disturbance. Along with the increasing reclamation age, the mean particle size significantly reduced, with DT7 (33.93 μm, forest, with the reclamation age of ~60 a) <DT1 (46.10 μm, farmland, 16 a) <DT6 (48.21μm, salt artemisia beach, 2 a). Particle size of DT6, DT7 (below 30 cm) and DT1 showed an decreasing trend from the bottom to the top, with coarse particle component reduced gradually, reflecting the natural evolution process of tidal flat environment in the silt muddy coast.The gradually coarsening of the top 30 cm layer of DT7 may be mainly due to the large amount of forest litter. The disturbance of human activities was also very apparent in the sedimentary record. δ13C values of core DT6 mainly reflect the characteristics of the original marine sediment. Due to large interference by human activities, all the particle size parameters show an obvious change in the top 0-40 cm soil layer (cultivated layer) of core DT1, a quick lighter shift of δ13C values also support this. Although core DT7 was less interfered by human activities, but due to the large accumulation of forest litter, the particle size parameters in the upper layers showed significant change, the dramatic variation of δ13C value at 0-10 cm layer in core DT7 also suggested the obvious presence of a land-derived component. Relative contribution of terrestrial-derived and marine-derived organic matter showed by δ13C values were in good agreement with the empirical formula calculation results.

Keywords: tidal flat reclamation ; stable carbon isotope ; particle size ; Dongtai

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陈影影, 张振克, 徐华夏, 张凌华, 赵一飞, 张云峰, 符跃鑫. 沿海不同年限围垦区土壤剖面有机碳同位素与粒度特征——以江苏省东台市为例[J]. , 2015, 35(6): 782-789 https://doi.org/

CHEN Ying-ying, ZHANG Zhen-ke, XU Hua-xia, ZHANG Ling-hua, ZHAO Yi-fei, ZHANG Yun-feng, FU Yue-xin. Stable Carbon Isotope and Particle Size Characteristics in Coastal Saline Soil with Different Reclamation Age of Dongtai, Jiangsu Province[J]. Scientia Geographica Sinica, 2015, 35(6): 782-789 https://doi.org/

海岸带是陆地和海洋的结合部,是水圈、生物圈、岩石圈和大气圈在地球表层的交汇地带,是地球上人口最密集、经济最发达地区,也是海陆相互作用和人类活动最为活跃的地区,同时也是自然生态环境相对脆弱、资源环境承载力相对有限的地区。全世界>37%(1994年21亿)的人口居住在距离海岸线100 km的范围内,约44%的人口居住在距离海岸线150 km的范围内【① 中国地质调查局.我国“十二五”海岸带地质工作规划(征求意见稿).2011.】。中国占陆域国土13%的沿海经济带承载着全国40%左右的人口,创造全国60%左右的国民经济产值[2],沿海地区日益增加的人口和不断加剧的人类活动导致海岸带地区环境压力增加。每年世界经河流入海的沉积物总量达13.5×109t[3],这些大量的入海物质对大陆架浅海沉积作用有着巨大贡献,在海陆相互作用下塑造了不同类型的河口三角洲和淤涨型海岸,成为人类文明和现代社会赖以发展的重要土地资源。海岸滩涂是重要的自然资源之一,也是海岸带的重要组成部分。作为得天独厚的土地资源,特别是在全国耕地面积持续减少、建设用地日趋紧张的背景下,沿海滩涂也是非常可贵的战略资源。围垦是沿海国家拓展陆域,缓解人地矛盾的最主要方式之一,同时也为经济社会可持续发展预留了一定的空间。潮滩匡围及其开发利用在中国已经有1 000多a的历史,浙东大沽塘、苏北范公堤代表了中国历史围海工程的最高成就[4],荷兰、苏格兰、英国、威尔士等国的潮滩匡围也有几百至近千年的历史[5,6]

围垦是对滩地影响最严重的人为干扰,由于沿海滩涂地区能量交换、物质迁移转化频繁,在自然和人为综合作用下其演化速率相对较快。滩地围垦后改变了原有的土地利用方式,产生了多种不同的土地覆盖类型,使得海岸湿地生态系统逐渐向陆地生态系统演替,土壤理化性质发生显著改变,生态系统结构、生态过程及生态系统服务功能发生根本性变化,并且人类活动的影响也加速了这种改变[7,8]。已有研究表明,围垦后不同土地利用方式和利用年限也会显著改变土壤的粒径分布特征[7],连年的耕作施肥会使土壤总磷和有机碳含量显著增加[9]。此外,沿海滩地围垦后由于受到人类活动等的影响,土壤中碳的来源也会发生改变。海岸地区汇聚的有机质有多种来源,既来自海洋藻类,又包括陆源C3和C4植物,另外还有部分有机质的输入来自人类活动,使得海岸地区有机质的同位素来源信号变得非常复杂[10]。C3植物和海洋藻类产生的有机质δ13C值存在约7‰的差异,已经被成功地用于指示海岸海洋沉积物有机质的来源和分布[11,12],还可用来反映人类活动的影响[10]

历史时期,中国最大的2条河流——长江和黄河,均曾在江苏海岸入海,大量的泥沙供给使江苏海岸由沙质海岸变为淤泥质海岸,同时形成江苏广阔的滨海平原并为现有滩涂的持续淤长提供了主要的物质来源[13]。目前江苏的滩涂面积约68.5×104hm2,位居全国第一,约占全国海岸滩涂总面积的1/4[14]。随着海岸线的不断向外扩展,海岸生态系统也在不断演替,加上当地人类活动作用,这种演替变化表现的更加明显。因此,有关江苏沿海滩涂地区的研究已经引起诸多海洋学家、生物学家、地球化学家和生态学家等的高度关注。目前对苏北海岸带潮滩围垦、海岸发育、海岸线演变、土壤肥力特征及沉积物特征等已开展了大量研究[15~20],而有关不同年限围垦后滩地土壤有机碳同位素、粒径变化特征还鲜有报道。鉴于此,本文选择了东台市作为研究区域,近半个世纪以来,通过几次大规模的滩涂围垦,东台市陆地面积不断扩大,由陆向海不同成陆时间的土壤形成了许多不同时期的围垦区域。通过研究不同年限围垦区滩地土壤有机碳同位素、粒径的演化特征及其主要影响因素,有助于了解围垦后人类活动影响对土壤性质自然演变过程的影响,为围垦后滩地土壤发育和土壤性质的演化提供理论依据,同时也为进一步促进沿海滩涂土壤资源的可持续开发与利用提供指导。

1 研究区概况

东台市位于江苏省中部沿海,盐城市南端(32°33′N~32°57′N,120°07′E~120°53′E)(图1)。滩涂面积1 000 km2,约占江苏沿海滩涂总面积的22%,居全省之首。该区属亚热带和暖温带过渡区,季风显著,四季分明,雨量集中。常年平均气温14.6℃,无霜期220 d,降水量1 051.0 mm,日照2 169.9 h。全市总面积3 221 km2,境内地势平坦,地面高程1.4~5.1 m,大部分地区在2.6~4.6 m[21]。以范公堤为脊线,形成堤西与堤东2种不同地貌。

图1   采样点位置

Fig.1   Location of sampling sites

东台滨海围垦滩涂根据海堤划分,最早的有204国道旁的范公堤(建于宋1027年),近代以来由西向东分别有1955年、1975年、1995年、2004年、2007年海堤[21]。随着2009年东台百万亩滩涂围垦工程的启动,东台市2009~2020年滩涂围垦规模将达到667 km2,目前该项目正在实施。

2 材料与方法

2.1 样品采集

2013年4月9~11日,利用便携式重力采样器,在江苏省东台市沿海滩涂围垦区黄海森林公园[DT7,林地,水杉(Metaseguoia glyptostrodoides),林相较好,林木生长旺盛,表层堆积了较多枯枝落叶,1950s围垦]、三仓片垦区(DT1,农用地,1990s围垦)和条子泥垦区[DT6,盐蒿(Suaeda salsa)滩地,滩面平整,2011年围垦]采集了3个土壤剖面(图1,表1)。DT1、DT6、DT7剖面采集深度为0~100 cm,其中DT1、DT6每隔10 cm采集一个土壤样品,DT7剖面每隔5 cm采集一个土壤样品,将样品装入专用的样品袋中,密封保存。所采样品带回南京大学海岸与海岛开发教育部重点实验室,自然风干备用。

表 1   采样剖面DT1、DT6和DT7概况

Table 1   Overview of investigated core DT1, DT6 and DT7

剖面地理坐标采样位置土地利用围垦年限(a)
DT632°45′42.6″N, 120°55′50.6″E条子泥垦区盐蒿滩2
DT132°47′39.0″N, 120°52′55.4″E三仓片垦区农用地16
DT732°52′38.8″N, 120°50′09.1″E黄海森林公园林地约60

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2.2 实验方法

2.2.1 粒度测定

样品粒度前处理和测试按照国家《海洋底质调查技术规程》的方法和步骤进行[22],使用英国马尔文公司生产的Mastersizer 2000型激光粒度仪进行测试,仪器的测试范围为0.02~2 000 μm,多次重复测量误差一般<2%。粒度参数采用Folk和Ward图解法计算公式[23],并使用Blott和Pye的GRADISTAT软件进行具体计算[24]。所有样品的粒度测试在南京大学海岸与海岛开发教育部重点实验室完成。

2.2.2 有机碳稳定同位素(δ13C)测定

取一定量的风干研磨后的样品,加入10%盐酸并放入水浴锅水浴(50℃)12 h以上,以充分去除样品中的碳酸盐。将样品用蒸馏水反复洗至中性,每次水洗后都用离心机离心,分离沉积物和孔隙水。再将分离出的沉积物样品置于恒温干燥箱45℃烘干并研磨至80目以下。取适量样品用锡纸筒包紧压实,最后在Finnigan MAT公司生产的DELTAplus Advantage稳定同位素质谱仪上测定样品有机碳同位素含量(以VPDB标准表示)。有机碳稳定同位素的测试在中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室完成。

3 结 果

3.1 土壤粒度及其剖面分布

东台市沿海垦区不同围垦年限下不同土层间粒度特征变化很大(图2)。农用地DT1剖面平均粒径为46.10 μm;粘土含量变化范围为2.73%~5.26%,平均3.70%;粉砂含量变化范围为61.63%~70.46%,平均66.20%;砂含量变化范围为25.90%~35.64%,平均30.11%。盐蒿滩地DT6剖面平均粒径为48.21 μm;粘土含量变化范围为2.39%~6.09%,平均4.25%;粉砂含量变化范围为50.09%~66.63%,平均60.79%;砂含量变化范围为27.93%~47.53%,平均34.96%。林地DT7剖面平均粒径为33.93μm;粘土含量变化范围为3.91%~8.82%,平均6.24%;粉砂含量变化范围为69.10%~84.13%,平均77.39%;砂含量变化范围为8.59%~26.99%,平均16.36%。总体来看,DT1和DT6的粒度特征在剖面上的变化具有相同的规律,土壤平均粒径和砂含量在表层(0~10 cm)最低,随着土层加深,土壤平均粒径逐渐增大,至最底层(90~100 cm)达到最高;粘土和粉砂含量基本在表层(0~10 cm)最高,随着土层加深,其含量逐渐降低。DT7土壤平均粒径自底层至30 cm逐渐减小,30 cm以上变化不大;砂含量自底层至表层先逐渐减少,至40 cm处其含量又开始逐渐增加;粘土和粉砂含量自底层至表层先逐渐增加,至30 cm处其含量开始逐渐降低。总体来看,DT1、DT6、DT7剖面沉积物以粉砂为主,土壤平均粒径DT6(盐蒿滩地)>DT1(农地)>DT7(林地),粘土含量DT7(林地)>DT6(盐蒿滩地)>DT1(农地),粉砂含量DT7(林地)>DT1(农地)>DT6(盐蒿滩地),砂含量DT6(盐蒿滩地)>DT1(农地)>DT7(林地)。

图2   DT1、DT6和DT7剖面粒度变化特征

Fig.2   Purticle size changes of DT1、DT6 and DT7 cores

各粒度参数在剖面上变化也较大(图2)。DT1剖面标准偏差为0.8~1.6,其中40 cm以下分选性中等,表层0~40 cm分选性较差;偏度为0.1~0.3,呈正偏态;峰态为1.6~2.1,属很尖锐。DT6标准偏差从底层约0.8上升至表层1.4,分选性由中等逐步变为较差;偏度自底层向表层逐渐上升,从0.24升至0.37,由正偏态逐渐向明显正偏态转变;峰态变化幅度较小,为1.6~1.7,属很尖锐。DT7各粒度参数在20 cm以下相对较稳定,表现为分选较差,标准偏差约1.2,偏度基本呈明显正偏态(0.32),峰态很尖锐(1.7);20 cm以上各粒度参数开始迅速变化,分选性变进一步变差,明显正偏态更加显著,峰态也变得更加尖锐。

3.2 土壤有机碳同位素及其剖面分布

由于不同土壤剖面围垦发育历史不同,且受人类干扰强度也不同,因此剖面土壤δ13C值的深度分布特征差异较大(图3)。DT6剖面δ13C值总体上相对较稳定,变化不大,在-22.42‰~-21.43‰之间变化。DT1剖面δ13C值自底部至表层逐渐变轻,在-24.48~-21.61‰之间变化,40 cm以下变化不大,40 cm以上δ13C值呈迅速变轻趋势。DT7剖面δ13C值10 cm以下在-22.26‰~-20.38‰之间变化,相对稳定,但在表层0~10 cm突然变轻至-26.55‰。

图3   DT1、DT6和DT7剖面δ13C变化特征

Fig.3   Variations of δ13C values of total organic matter with depth in core DT1, DT6 and DT7

4 讨 论

4.1 不同年限围垦区土壤粒度变化特征及其原因

土壤粒径分布是由各种成土因素和成土过程相互作用所决定,它影响着土壤强度、水力特性、养分状况、土壤侵蚀以及热量的传输与保持等,是重要的土壤物理特性之一[25]。沿海滩涂作为经海相和陆相交替沉积形成的水陆交汇区域,其开发利用完全是人为改造滩涂自然形态的过程。滩地围垦后,潮滩沉积物在自然成土和耕作成土的综合作用下逐渐向农业土壤转化,土壤粒径分布也发生着显著的变化[7]。滩地围垦后不同土地利用方式和利用年限显著改变了土壤的粒径分布特征[7]。随着成陆时间的增加,经过淋洗及人为耕种,土壤不断熟化,粒度细粒组份含量不断增加,体现在中值粒径和平均粒径方面,两者均随时间显著不断减小[26]。研究区3个采样剖面土壤粒度组成中粘土与粉砂含量大小分别为DT6<DT1<DT7,平均粒径大小分别为DT7<DT1<DT6,且DT1、DT6、DT7(30 cm以下)粒度记录在整个剖面上自下向上逐渐变细的特点,反映了围垦前原始潮滩沉积物的自然演化特点。王颖等的研究表明,潮滩沉积相原始沉积层自下向上,粒径组成越渐变细[27]。张振克等[28]的研究也发现对于粉砂淤泥质海岸的潮滩地貌而言,潮滩表层沉积物从潮滩中部向高潮滩方向有逐渐变细的变化趋势。

但DT7的粒度记录在30 cm以上逐渐变粗,这可能主要由于DT7为水杉林地,至今围垦年限已近60 a,虽然也受到一定的人类活动干扰,但与耕地相比,这里受人类活动影响相对较小,近60 a里表层不断堆积了大量枯枝落叶等凋落物。此外,林地大量土地长期裸露,受风蚀影响较大,土壤中较大粒径的颗粒易残留[7]。从现场采集的土壤剖面也可明显看出表层0~20 cm呈灰黑色(尤其是表层0~10 cm更明显),有机质含量较丰富,20 cm以下土壤呈棕灰色并含较多水分。DT6成陆时间较短,属盐蒿滩地,暂时还未开发利用,目前受人类活动影响还较小,分选系数、峰态、偏度等粒度参数在整个剖面上也变化不大。DT1为农用地,至今围垦年限已达16 a,主要是种植小麦(Triticum aestivum)、油菜(Brassica campestris)等,人类耕作(如开垦、翻耕、除草等)对土壤的物理扰动和破碎较强,人类活动的影响主要集中在耕作层0~40 cm,这在土壤粒径变化的层次性也可得到反映,尤其是分选系数、峰态、偏度等粒度参数均在表层0~40 cm发生明显变化,粒度的分选性迅速变差,反映了较强的人类活动影响。周学峰等对崇明东滩滩地的研究也表明,施肥等人类活动对耕作层土壤粒度特征有较大影响[7]

4.2 不同年限围垦区土壤δ13C变化特征及原因

江苏沿海滩涂的自然土壤主要以潮滩盐土为主,潮滩盐土以母质的沉积和冲刷、盐分的积累和淋洗为主要特征,土壤母质为河流冲积海相沉积物,土壤盐分含量高,土体发育不明显,理化性状差、肥力水平低,土壤有机质含量较低[29]。不同来源的有机质其δ13C值不同,陆源C3植物产生的有机质δ13C为-25‰~-29‰(平均为-27‰),C4植物产生的有机质δ13C为-12‰~-16‰(平均为-14‰)[30]。海洋有机质的δ13C范围为-20‰~-22‰[31]。δ13C值在此范围之间的有机质可认为是陆源和海洋有机质混合造成的。

研究区内主要种植C3植物,如小麦、水稻(Oryza sativa)等,C4植物较少。δ13C值DT6大于DT1和DT7,这可能主要是由于离海越近沉积物得到越多的海洋有机碳。Naidu等通过测定高纬度地区美、亚大陆及其周围大河大量沉积物样品的δ13C也发现了类似现象,发现δ13C有向海增加的趋势,在白令海西部,由小于-26.5‰增至-23‰[32]。Mueller等的研究也发现Laptev海表层沉积物中δ13C值从河口附近的-26.6‰到大陆架上的-22.8%,也表明越向大洋,陆源物质越少,海洋自生物质越多[33]。DT6剖面δ13C在-22.42‰~-21.43‰之间变化,可以看出沉积物中有机碳主要为海洋有机碳。Wu等[34]认为可以根据海洋沉积物中δ13C值变化推断陆源有机质的输入变化情况,并总结出经验公式:

C13C沉积物)=W陆源C13C陆源)+W海源C13C海源) (1)

W陆源+W海源=1 (2)

W陆源=[C13C沉积物)-C13C海源)]/[C13C陆源)-C13C海源)] (3)

W陆源为沉积物中陆源有机碳的比例;W海源为沉积物中海洋自生有机碳的比例。根据此经验公式,我们对DT6、DT1和DT7沉积物中陆源与海洋自生有机碳的比例进行了计算,结果(图4)也显示DT6剖面中有机碳主要为海洋自生,陆源所占比例基本在40%以下,且在整个剖面中陆源与海洋自生有机碳所占比例变化不大。DT6剖面处于围垦初期,δ13C含量总体上主要反映原始沉积母质特征。

图4   DT1、DT6和DT7剖面陆源和海洋自生有机碳的比例

Fig.4   Relative contribution of terrestrial-derived and marine-derived organic matter with depth in core DT1, DT6 and DT7

DT1有机碳同位素值自底部至表层逐渐变轻,在-24.48‰~-21.61‰之间变化,40 cm以下δ13C值小于22‰,显示沉积物中的有机碳仍主要为海洋有机碳;40 cm以上δ13C含量开始逐渐变轻,至表层(0~10 cm)已降至-24.48‰,说明陆源和海洋来源有机碳的比例发生了明显变化,较轻的陆源有机碳比例显著增加,较重的海洋有机碳比例明显减少。根据经验公式计算的结果(图4)也显示DT1剖面中有机碳陆源与海洋自生比例40 cm以下变化不大,40 cm以上陆源有机碳所占比例逐渐上升,海洋自生有机碳所占比例逐渐减少,至表层0~10 cm陆源有机碳所占比例已达到了64.0%。围垦后的滩涂经过人为的洗盐和压盐处理,缩短了“自然脱盐-淡水环境土壤发育”的自然过程,时间由几十年甚至几百年缩短为几年[35]。由于DT1研究区至今围垦年限已达16 a,研究区内农田经过淋盐、洗盐和耕作管理后,土壤性质得到较大的改善,潮滩沉积物在自然成土和耕作成土的综合作用下逐渐向农业土壤转化。经过长期的农业耕作,由于作物残体、分泌物以及自然凋落物覆盖在土壤表层形成腐殖质并富集,再加上化肥农药的大量使用,造成陆源输入的有机碳含量大幅增加,使得土壤表层有机碳同位素含量逐渐变轻。邵学新等[36]对杭州湾滨海湿地土壤的研究也表明,围垦后期可能由于土壤有机碳除了自然的植物残体归还外,还有人为有机肥源的输入,土壤熟化程度越来越高,有机碳输入量大于输出量,使表层土壤有机碳含量提高,而深层土壤有机碳含量仍维持降低的水平。葛晨东等[10]对海南岛万泉河口沉积物的研究也表明由于经济活动的增加,人口的持续增长,以及化肥农药的大量使用,造成陆源输入的有机碳大幅增加,使δ13C值减小。

DT7有机碳同位素值10 cm以下在-22.26‰~-20.38‰之间变化,变化不大;但在表层0~10 cm突然变轻至-26.55‰。表明10 cm以下土壤中的有机碳仍主要为海洋有机碳;表层0~10 cm陆源和海洋来源的有机碳的比例发生了显著变化,较轻的陆源有机碳比例明显增加,特别是表层0~5 cm已呈明显的陆源有机碳特征。根据经验公式计算的结果(图4)也显示DT7剖面中10 cm以下有机碳以海洋自生为主,表层0~10 cm陆源有机碳所占比例已增至90%以上。这可能主要是由于已围垦近60 a的林地较少受人为翻耕,受人为干扰相对较小,表层长久堆积着厚厚的枯枝落叶,腐殖质含量高,表层总有机碳含量较高。因此,这就使得林地表层(0~10 cm)陆源输入的有机碳含量大幅增加,土壤表层有机碳同位素含量逐渐变轻;而亚表层则受到的影响还较小,土壤有机碳含量仍主要为海洋有机碳。

5 结 论

东台市沿海滩地不同年限围垦下土壤粒径分布存在显著差异,随着围垦年限的增加,土壤平均粒径显著降低,表现为利用围垦约60 a的林地土壤粒径最小,利用16 a的农用地其次,围垦刚2 a的盐蒿滩地粒径最大。人类活动干扰对土壤有机碳同位素含量和粒度特征影响较大,特别是对已围垦16 a农用地影响最明显,由于人类长期耕作(如开垦、翻耕、除草等)及化肥农药的大量使用,使得耕作层(0~40 cm)受到强烈的扰动,这在土壤粒径变化的层次性也可得到反映,尤其是分选系数、峰态、偏度等粒度参数均在该层发生明显变化,粒度的分选性迅速变差,表层迅速变轻的δ13C值也反映了陆源有机碳输入的大幅增加。林地已围垦近60 a,与农用地相比尽管受人类干扰相对较小,但由于受到近60 a表层堆积的大量枯枝落叶等凋落物的影响,各粒度组成及粒度参数在剖面上部也表现出明显变化,特别是表层0~10 cm剖面δ13C值已呈明显的陆源性。围垦于2011年的盐蒿滩,受人类影响还较小,其剖面δ13C值总体上表现为海洋有机碳,主要反映原始沉积母质特征。

致 谢:有机碳同位素测试得到中国科学院南京地理与湖泊研究所张恩楼研究员的帮助,特此感谢。

The authors have declared that no competing interests exist.


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https://doi.org/10.3321/j.issn:1001-7410.2007.05.026      URL      Magsci      [本文引用: 3]      摘要

对海南岛万泉河口沙美内海柱样K3和K4沉积物进行生物地球化学指标总有机碳(TOC)、总氮(TN)、有机碳同位素(δ13C)、氮同位素(δ15N) 的分析,以及210Pb定年了解其近代变化特征,追踪沉积物有机质来源的变化,提取沉积环境演变及人类活动的信息.K3中TOC的变化介于 0.51%~1.12%,K4变化介于0.43%~1.49%,而其随时间的变化反映了流域内人类活动的历史.17世纪TOC含量明显增加记录了明末清初 开始流域内广泛种植农作物的活动,19世纪以来TOC含量逐渐增加,至现代达最高值,对应了工业革命以来人类活动的增强.K3和K4的δ13C值变化分别 在-24.38‰~-21.02‰之间和-24.74‰~-20.17‰之间,δ15N值变化分别在2.20‰~4.62‰之间和2.39‰~5.02‰ 之间,映证了本区沉积物有机质是陆源物质和海洋物质混合的特点.明末清初开始流域内广泛种植玉米等农作物造成δ13C值增加和δ15N值减少; 自19世纪以来至现在,该区的经济活动增加,人口的持续增长,尤其是近50年来化肥农药的大量使用,造成陆源输入的有机碳含量大幅增加,使δ13C值减少 和δ15N比值增加. δ13C值自19世纪以来就逐渐变轻,说明陆源和海洋有机碳的比例发生了变化,较轻的陆源有机碳比例相对增加,较重的海洋有机碳比例相对减少,反映了玉带 滩沙坝的增长、沙美内海封闭、海水交换作用减少的状况.C/N比值分别从底部的16.19和17.36到顶部减小为11左右,自19世纪以来呈明显减小的 趋势也反映了沙美内海泻湖自生的藻类有机质供应越来越多,也说明了其逐渐封闭、水动力条件越来越弱,与外海的交换作用逐渐减少的状况.
[11] Prahl F G,Ertel J R,Goni M A,et al.

Terrestrial organic carbon contributions to sediments on the Washington margin

[J].Geochimica et Cosmochimica Acta,1994,58(14):3035-3048.

https://doi.org/10.1016/0016-7037(94)90177-5      URL      [本文引用: 1]      摘要

Elemental and stable carbon isotopic compositions and biomarker concentrations were determined in sediments from the Columbia River basin and the Washington margin in order to evaluate geochemical approaches for quantifying terrestrial organic matter in marine sediments. The biomarkers include: an homologous series of long-chain n-alkanes derived from the surface waxes of higher plants; phenolic and hydroxyalkanoic compounds produced by CuO oxidation of two major vascular plant biopolymers, lignin and cutin. All marine sediments, including samples collected from the most remote sites in Cascadia Basin, showed organic geochemical evidence for the presence of terrestrial organic carbon. Using endmember values for the various biomarkers determined empirically by two independent means, we estimate that the terrestrial contribution to the Washington margin is ~ 60% for shelf sediments, ~ 30% for slope sediments, and decreases further to 鈮15% in basin sediments. Results from the same geochemical measurements made with depth in gravity core 6705-7 from Cascadia Seachannel suggest that our approach to assess terrestrial organic carbon contributions to contemporary deposits on the Washington margin can be applied to the study of sediments depositing in this region since the last glacial period.
[12] Yamamuro M.

Chemical tracers of sediment organic matter origins in two coastal lagoons

[J].Journal of Marine Systems,2000,26(2):127-134.

https://doi.org/10.1016/S0924-7963(00)00049-X      URL      [本文引用: 1]      摘要

The distribution of chemical tracers in two coastal lagoons was surveyed to assess changes in the contribution of autochthonous and allochthonous (terrestrial and marine) organic matter sources to sediments along a salinity gradient. C:N:P ratios of sediments from both lagoons were closer to the ratios of phytoplankton than to those of terrestrial plants, suggesting that the contribution of terrestrial organic matter was minor. A strong correlation between 未C and the distance from the seawater entrance was attributed to changing 未C of DIC sources used by autochthonous phytoplankton, because sediment N:P reflected the dominant phytoplankton inputs in each lagoon. These results suggest that autochthonous primary production controlled organic matter supply to sediments in both lagoons.
[13] 任美锷,.江苏省海岸带和海涂资源综合调查(报告)[R].北京:海洋出版社,1986.

[本文引用: 1]     

[14] 王建. 江苏省海岸滩涂及其利用潜力[M].北京:海洋出版社,2012.

[本文引用: 1]     

[15] 欧维新,杨桂山,李恒鹏,.

苏北盐城海岸带景观格局时空变化及驱动力分析

[J].地理科学,2004,24(5):610~615.

https://doi.org/10.3969/j.issn.1000-0690.2004.05.016      URL      [本文引用: 1]      摘要

利用RS、GIS手段研究分析了盐城海岸带景观格局的时空变化及其驱动力因子.结果表明:在1983~2000年间,景观斑块数量倍增,平均斑块面积大幅度减小,景观基质构成由比重势均的人工、自然景观变成了以耕地、水域为主的人工景观;海岸带景观异质性整体上有减弱的趋势,主要表现为多样性指数降低、破碎化指数增大、分维数减小,而在空间和类型上又有异于整体的表现;自然地理条件、人口增长、经济收益差异、政府政策是导致盐城海岸带景观格局变化及其区域差异的主要驱动力;随着滩涂围垦利用等人类干扰的不断增加,海岸带景观生态环境保护与经济开发之间的矛盾将愈发突出.
[16] 杨守业,张家强.

苏北滨海平原全新世沉积物物源研究——元素地球化学与重矿物方法比较

[J].沉积学报,1999,17(3):458~463.

Magsci      摘要

运用元素地球化学与重矿物方法对苏北滨海平原全新世沉积物物源进行的比较研究表明,沉积物形成主要由长江与黄河提供物质来源,且又以黄河物源为主。全新世早期长江物质对本区影响范围大于黄河,黄河供给泥沙量较少,对本区影响主要在北部、中部地区。全新世最大海侵之后,黄河曾由苏北入海并携带了大量泥沙,其影响范围明显大于长江,长江仅由狭窄的汊道提供有限的物质而影响范围较小。最近2000年来本区沉积物物源主要由黄河提供。分析表明元素地球化学方法在沉积物物源判别时,可有效的避免水动力因素影响,而相对重矿物方法取得较好的效果。
[17] 吴小根,王爱军.

人类活动对苏北潮滩发育的影响

[J].地理科学,2005,25(5):614~620.

https://doi.org/10.3969/j.issn.1000-0690.2005.05.017      URL      摘要

江苏北部潮滩宽阔而平坦,历史上就是人类活动比较频繁的地区。随着对潮滩开发利用强度和深度的增加,人类对潮滩发育的影响越来越显著。潮滩剖面自然发育的均衡形态为上凸型;潮滩被围垦并建堤后,改变了原有的水沙动态平衡关系,潮滩剖面形态发生了调整,海堤附近的潮水沟则不断被淤积。大米草和互花米草等植被的引种改变了潮滩生态结构,由于植被能降低水流流速和波浪能量,起到捕捉沉积物的作用,因此能增加潮间带滩面的淤积速率,改变潮滩分带结构;此外,植被的存在还影响到滩面潮水沟的形态。港口工程的建设改变了沉积物的输运方向。
[18] 朱诚,程鹏,卢春成,.

长江三角洲及苏北沿海地区7000年以来海岸线演变规律分析

[J].地理科学,1996,16(3):207~213.

https://doi.org/10.1007/BF02029074      URL      Magsci      摘要

贝壳堤是重要的海岸标志物,长江三角洲上海地区有9条贝壳砂堤,苏北北、中部沿海区各有4条贝壳砂堤或沙坝。根据贝壳砂堤分布特点和测年数据结合新石器时代以来文化遣址分布规律,探讨总结华东沿海古海岸线演变规律。
[19] 王建,沙润,汪永进,.

江苏中部粉砂淤泥质滩岸大剖面所揭示的滩岸发育过程与环境演变

[J].沉积学报,1997,15S1:51~56.

URL      摘要

通过对39个钻孔组成的长约10km的江苏中部粉砂泥质滩岸大剖面地层与沉积物的多项指标扫现,江苏大丰一带现代潮滩及潮下带的位置上,40-20KaBp之间曾为潮滩环境,20-10Ka沉积间断,地层缺失,10Ka以来曾一度发育古潮流沙脊群,现代潮滩仅仅是近几百搂来在潮流沙脊群之上发育而成的。
[20] 高建华,杨桂山,欧维新.

苏北潮滩湿地植被对沉积物N,P含量的影响

[J].地理科学,2006,26(2):224~230.

https://doi.org/10.3969/j.issn.1000-0690.2006.02.016      URL      [本文引用: 1]      摘要

文章对比分析了植被和沉积物中 N、P垂向分布和季节变化,探讨不同植被对潮滩湿地N、P动态变化的影响。分析表明:潮滩湿地的分带性差异使N、P在潮滩湿地各地带有不同的分布规律和季 节性变化特性,植被尤其是有较高地下生物量的互花米草和芦苇在整个潮滩湿地N、P的分布以及季节变化中起重要作用,潮滩植被主要是通过N、P在体内的主动 转移,植物对沉积物中N、P的吸收以及富集死亡的地下根茎中分解矿化后释放的N、P来影响沉积物中N、P分布的;1~4月通过枯落生物量回归到地面的N、 P总量分别达到149.4 t和18.2t,对整个湿地生态系统的生源物质循环以及生态环境产生很大影响。
[21] 金雯晖,杨劲松,王相平.

滩涂土壤有机碳空间分布与围垦年限相关性分析

[J].农业工程学报,2013,29(5):89~94.

https://doi.org/10.3969/j.issn.1002-6819.2013.05.012      URL      Magsci      [本文引用: 2]      摘要

中国具有治理和修复潜力的滨海滩涂盐土面积约为2?000?hm2。滨海滩涂盐土作为新成土壤,土体发育不明显、理化性状差、肥力水平低下。该文通过对东台境内表层土壤有机碳的采样分析,在ArcGIS地理信息系统及SPSS16.0系统平台上,利用地统计分析模块中的克里格法分析东台市表层土壤有机碳的空间变异规律,并分析不同滩涂围垦年限下表层土壤有机碳、总氮、pH值、EC1:5的变化特征及其相关关系,结果显示滨海表层土壤有机碳含量与总氮、围垦年限呈极显著正相关,相关系数r分别为0.959和0.749,与pH值、电导率EC1:5呈极显著负相关,相关系数r分别为-0.478和-0.649。围垦3?a以上表层土壤有机碳可增加0.24%左右,总氮质量分数增加0.02%左右;围垦时间大于52?a,有机碳质量分数自0.1%增加到1.6%,全氮质量分数自0.03%增加到0.12%,养分等级也相应从6级增加到3级。该文研究表明,滨海盐土随着围垦年限的增长,土壤碳储量与总氮含量随之增加、pH值与EC1:5随之降低,耕地质量也相应提高。
[22] 国家海洋局908专项办公室.海洋底质调查技术规程[M].北京:海洋出版社,2006.

[本文引用: 1]     

[23] Folk R L,Ward W C.

Brazos River bar:a study in the significance of grain size parameters

[J].Journal of Sedimentary Petrology,1957,27(1):3-26.

https://doi.org/10.1306/74D70646-2B21-11D7-8648000102C1865D      URL      [本文引用: 1]      摘要

A bar on the Brazos River near Calvert, Texas, has been analyzed in order to determine the geologic meaning of certain grain size parameters and to study the behavior of the size fractions with transport. The bar consists of a strongly bimodal mixture of pebble gravel and medium to fine sand; there is a lack of material in the range of 0.5 to 2 mm, because the source does not supply particles of this size. The size distributions of the two modes, which were established in the parent deposits, are nearly invariant over the bar because the present environment of deposition only affects the relative proportions of the two modes, not the grain size properties of the modes themselves. Two proportions are most common; the sediment either contains no gravel or else contains about 60% gravel. Three sediment types with characteristic bedding features occur on the bar in constant stratigraphic order, with the coarsest at the base. Statistical analysis of the data is based on a series of grain size parameters modified from those of Inman (1952) to provide a more detailed coverage of non-normal size curves. Unimodal sediments have nearly normal curves as defined by their skewness and kurtosis. Non-normal kurtosis and skewness values are held to be the identifying characteristics of bimodal sediments even where such modes are not evident in frequency curves. The relative proportions of each mode define a systematic series of changes in numerical properties; mean size, standard deviation and skewness are shown to be linked in a helical trend, which is believed to be applicable to many other sedimentary suites. The equations of the helix may be characteristic of certain environments. Kurtosis values show rhythmic pulsations along the helix and are diagnostic of two-generation sediments.
[24] Blott S J,Pye K.

GRADISTAT:a grain size distribution and statistics package for the analysis of unconsolidated sediments

[J].Earth surface processes and Landforms,2001,26(11):1237-1248.

https://doi.org/10.1002/esp.261      URL      [本文引用: 1]      摘要

Not Available
[25] 王德,傅伯杰,陈利顶,.

不同土地利用类型下土壤粒径分形分析——以黄土丘陵沟壑区为例

[J].生态学报,2007,27(7):3081~3089.

https://doi.org/10.3321/j.issn:1000-0933.2007.07.050      URL      Magsci      [本文引用: 1]      摘要

土壤粒径分布影响土壤的水力特 性、土壤肥力状况以及土壤侵蚀等,是重要土壤物理特性之一。在水蚀严重的黄土丘陵沟壑区,不同的土地利用类型对水土流失的阻截作用不同,因而进一步导致其 土壤粒径分布的差异。对不同土地利用类型下土壤粒径分布的分形和多重分形分析发现:黄绵土土壤粒径分布包含有3个无标度区间,分别为粘粒域、粉粒域和砂粒 域;土壤粒径分布的分形维数D、粉粒域维数Dsilt、砂粒域维数Dsand、信息维数D1、信息维数/容量维数D1/D0与土壤细颗粒含量和有机质含量 成显著的正相关关系;土地利用对分形维数D、粉粒域维数Dsilt、砂粒域维数Dsand、容量维数D0、信息维数D1、信息维数/容量维数比值D1 /D0的影响较显著。这表明这些分形和多重分形参数可以作为反映土壤物理性质和土壤质量的潜在性指标,其实用性有待进一步探讨。
[26] 徐明星.

江苏沿海滩涂地区典型剖面土壤性质演化及其高光谱响应研究[D]

.南京:南京大学,2011.

[本文引用: 1]     

[27] 王颖,朱大奎,曹桂云.

潮滩沉积环境与岩相对比研究

[J].沉积学报,2003,21(4):539~546.

https://doi.org/10.3969/j.issn.1000-0550.2003.04.001      URL      Magsci      [本文引用: 1]      摘要

潮滩沉积是海陆交互作用的产物 ,形成于海岸坡度平缓、有丰富的细粒泥沙供应 ,以潮流动力为主的低能海岸环境 ,尤以河—海作用活跃的边缘海环境最为发育。潮滩沉积以粉砂为主 ,由于涨落潮流往复循环 ,潮滩具有动力、沉积、地貌与生物群体的分带现象。因海平面涨落与波浪参与的扰动筛选 ,导致潮滩沉积中的粗粒沉积物含量及微地貌形态的变化。这些因素反映于潮滩沉积相中具有下列特点 :粉砂与粘土质交互叠置的页状层理 ;原始沉积层自下向上 ,粒径组成逐渐变细 ;下部的粉砂质层具有波痕、鱼刺状或丘状的交错层理、透镜体与扰动结构 ,或潮水沟堆积的镶嵌沙体 ;上部淤泥质层中具有草根、龟裂、虫管与钙质填充物、泥砾、泥块等。将现代潮滩沉积与南京钟山北麓下三叠统的黄马青组砂页岩 ,以及海口马村的下更新统湛江组粘土、粉砂岩进行对比 ,据泥沙粒径、矿物组合与含量 ,盐度 ,特别是薄互层理 ,虫管与钙质填充 ,泥裂块 ,波痕与交错层理等多项对比 ,均具有极好的相似性 ,表明该两组岩层为古潮滩沉积
[28] 张振克,李彦明,孟红明,.

江苏圆陀角附近潮滩沉积岩芯粒度变化及其环境意义

[J].第四纪研究,2008,28(4):690~694.

https://doi.org/10.3321/j.issn:1001-7410.2008.04.022      URL      Magsci      [本文引用: 1]      摘要

江苏圆陀角位于长江北支岸线与 江苏海岸线的交汇处,发育了粉砂淤泥质海岸典型潮滩地貌,潮滩岩芯沉积物粒度变化记录了潮滩环境变化的信息。2007年在圆陀角附近潮滩采集了192cm 长的柱状岩芯,对沉积物的粒度组成进行了分析,分析结果显示,砂质粉砂是主要的沉积类型,岩芯分为三部分,从下部向上,粗颗粒沉积组分减少,反映了采样点 附近潮滩环境由潮滩中部向上部转化的过程。根据岩芯沉积物137Cs的1963年和1986年两个蓄积峰值时标推算,1963年以来的平均沉积速率为 2.3cm/a,1986年以来的平均沉积速率为1.6cm/a,1963~1986年之间的平均沉积速率达到2.9cm/a。沉积速率变化表明20世纪 60年代以来伴随潮滩淤积增高,圆陀角附近潮滩沉积物的沉积速率下降,大体与辐射沙洲南翼淤积型潮滩淤积速率一致,小于长江口外的泥沙沉积速率。泥沙来源 主要是苏北沿岸流携带的部分泥沙在圆陀角附近沉积,伴随研究区围垦活动向海推进,在长江北支口门北侧形成了大片的泥质潮滩和水下沙嘴。
[29] 王遵亲. 中国盐渍土[M].北京:科学出版社,1993.

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[30] O’Leary M H.

Carbon isotopes in photosynthesis

[J].Bioscience,1988,38(5):328-336.

https://doi.org/10.2307/1310735      URL      [本文引用: 1]      摘要

Focuses on studies of carbon isotopes in photosynthesis, which include finely tuned, carefully controlled isotope fractionations under defined environmental conditions. Idea that these fractionation techniques may reveal new aspects of carbon dynamics in plants; Focus of models for plant isotope fractionation on the physical and chemical processes accompanying carbon dioxide (CO2) uptake, including diffusion, dissolution, and the carboxylation method; Absorption of CO2 in desert plants and other succulents by Crassulacean acid metabolism.
[31] Meyers P A.

Preservation of elemental and isotopic source identification of sedimentary organic matter

[J].Chemical Geology,1994,114(3):289-302.

https://doi.org/10.1016/0009-2541(94)90059-0      URL      [本文引用: 1]      摘要

The amount and type of organic matter in the sediments of lakes and oceans contribute to their paleoenvironmental and paleoclimatological records. Only a small fraction of the initial aquatic organic matter survives destruction and alteration during sinking and sedimentation. Selective degradation modifies the character of the surviving small fraction of organic matter which becomes incorporated in bottom sediments. Organic matter alterations can continue to sub-bottom depths of hundreds of meters, corresponding to millions of years. Source and paleoenvironmental information nonetheless remains preserved in the molecular, elemental and isotopic compositions of organic matter. C/N- and 未 13 C-values of total organic matter, in particular, appear to retain paleoenvironmental information for multi-Myr time periods.
[32] Naidu A S,Cooper L W,Finney B P,et al.

Organic carbon isotope ratios (δ13C) of Arctic Amerasiancontinental shelf sediments

[J].International Journal of Earth Sciences,2000,89(3):522-532.

https://doi.org/10.1007/s005310000121      URL      [本文引用: 1]      摘要

Organic matter origins are inferred from carbon isotope ratios (δ 13 C) in recent continental shelf sediments and major rivers from 465 locations from the north Bering-Chukchi-East Siberian-Beaufort Sea, Arctic Amerasia. Generally, there is a cross-shelf increase in δ 13 C, which is due to progressive increased contribution seaward of marine-derived organic carbon to surface sediments. This conclusion is supported by the correlations between sediment δ 13 C, OC/N, and δ 15 N. The sources of total organic carbon (TOC) to the Amerasian margin sediments are primarily from marine water-column phytoplankton and terrigenous C 3 plants constituted of tundra taiga and angiosperms. In contrast to more temperate regions, the source of TOC from terrigenous C 4 and CAM plants to the study area is probably insignificant because these plants do not exist in the northern high latitudes. The input of carbon to the northern Alaskan shelf sediments from nearshore kelp community ( Laminaria solidungula ) is generally insignificant as indicated by the absence of high sediment δ 13 C values (–16.5 to –13.6‰) which are typical of the macrophytes. Our study suggests that the isotopic composition of sediment TOC has potential application in reconstructing temporal changes in delivery and accumulation of organic matter resulting from glacial–interglacial changes in sea level and environments. Furthermore, recycling and advection of the extensive deposits of terrestrially derived organic matter from land, or the wide Amerasian margin, could be a mechanism for elevating total CO 2 and pCO 2 in the Arctic Basin halocline.
[33] Mueller-Lupp T,Bauch H A,Erlenkeuser H,et al.

Changes in the deposition of terrestrial organic matter on the Laptev Sea shelf during the Holocene:evidencefrom stable carbon isotopes

[J].International Journal of Earth Sciences,2000,89(3):563-568.

https://doi.org/10.1007/s005310000128      URL      [本文引用: 1]      摘要

Stable carbon isotope ratios in the organic fraction of surface sediments from the Laptev Sea shelf were analyzed in order to study the modern distribution pattern of terrestrial organic matter. The δ 13 C org signature of the surface sediments range from –26.6‰ near the coastal margin to –22.8‰ in the north towards the outer shelf. Characterizing the possible sources of organic matter by their δ 13 C org signature reveals that the terrestrial influence reaches further north in the eastern than in the western Laptev Sea. Downcore records of the δ 13 C org , measured on three AMS 14 C-dated cores from water depths between 46 and 77m, specify the spatial and temporal changes in the deposition of terrestrial organic matter on the Laptev Sea shelf during the past 12.7ka. The major depositional changes of terrestrial organic matter occurred between 11 and 7ka and comprised the main phase of the southward retreat of the coastline and of the river depocenters due to the postglacial sea level rise.
[34] Wu J P,Calvert S E,Wong C S.

Carbon and nitrogen isotope ratios in sedimenting particulate organic matter at an upwelling site off Vancouver Island

[J].Estuarine,Coastal and Shelf Science,1999,48(2):193-203.

https://doi.org/10.1006/ecss.1998.0409      URL      [本文引用: 1]      摘要

Variations of δCand δNof sedimenting particulate organic matter (POM) were determined at 500 m depth at a site (Station L, 48°39′N, 126°40′W) in the La Perouse Bank upwelling area off Vancouver Island, Canada. δC values were heavier in summer and lighter in winter, the reverse of the changes in δN. These variations are probably governed by the longer trophic transfer lengths in winter than in summer, coupled with a significant difference in δC and similar values of δN between nanophytoplankton and diatoms. High frequency variations in spring, summer and early autumn were probably caused by the periodic injection of subsurface nitrate by upwelling, which leads to diatom blooms, resulting in heavier δC and lighter δN in sedimenting POM. Utilization of regenerated ammonium during periods of nutrient depletion could also cause short-term increases in δN. At 500 m depth, the δN value of the POM (c8‰) is heavier than that of the nitrate reservoir (c. 4‰), suggesting that intensive nitrate utilization at the surface and the lateral input of nitrate with lower δN from the open ocean are important. POM δC data suggest that land input at most comprises 29% of total sedimenting POM.
[35] 严长清,孙伟,陆效平,.

江苏省沿海滩涂土地利用与生态保护研究

[J].生态科学,2007,26(3):263~268.

https://doi.org/10.3969/j.issn.1008-8873.2007.03.013      URL      Magsci      [本文引用: 1]      摘要

为了促进沿海滩涂的合理开发和 加强生态保护,借助遥感和GIS手段,通过历史资料整理、实地调查和数据分析,对江苏沿海滩涂土地利用变化和各种利用方式的生态效应进行评价,将沿海滩涂 土地利用方式划分为适宜利用方式、退化利用方式、超前利用方式,探讨各种开发利用方式存在的生态环境问题,提出沿海滩涂土地利用的生态保护对策。
[36] 邵学新,杨文英,吴摇明,.

杭州湾滨海湿地土壤有机碳含量及其分布格局

[J].应用生态学报,2011,22(3):658~664.

URL      Magsci      [本文引用: 1]      摘要

通过研究杭州湾自然潮滩湿地和围垦湿地土壤有机碳含量及其分布格局,揭示湿地植被演替、外来物种入侵和围垦活动对土壤有机碳分布的影响.结果表明:潮滩湿地土壤表层有机碳含量在4.41~8.58g·kg-1,平均值6 45g·kg-1.不同植被类型下表层土壤有机碳表现为:芦苇(8.56±0.04g·kg-1)>互花米草(7.31±0.08g·kg-1)>海三棱藨草(5.48±0.29g·kg-1)>光滩(4.47±0.09g·kg-1);围垦湿地表层土壤有机碳表现为:20世纪60年代(7.46±0.25g·kg-1)>2003年(5.12±0.16g·kg-1)>20世纪80年代(1.96±0.46g·kg-1),即土壤有机碳含量随围垦时间延长表现为先降低后升高的趋势;土壤有机碳在垂直剖面上均表现为由表向下逐渐降低的趋势.潮滩湿地和围垦湿地的土壤有机碳与ph呈显著负相关,与总氮呈显著正相关,表明在土壤中氮主要以有机氮的形态存在.潮滩湿地有机碳与碳氮比相关性不明显,而围垦湿地具有显著正相关性,说明围垦利用对湿地土壤碳氮比产生了一定影响.研究表明,潮滩湿地土壤固碳能力随着植物群落演替逐步增强,而外来入侵种互花米草的大量入侵和扩散将有可能降低潮滩湿地生态系统土壤的储碳功能.围垦引起的土壤水分、颗粒组成的变化以及耕作、土地利用和利用历史是影响围垦湿地土壤有机碳分布的主要原因.

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