宁夏阅海底泥重金属空间分布特征及来源解析     

马正虎  璩向宁  何志润  赵希妮  刘雅清  张矞勋  杨蕾 《水生态学杂志》2022,43(2):116-124

为了解宁夏阅海底泥重金属污染现状及其潜在生态风险,解析其重金属污染物来源,结合环境现状,分区域采集14个底泥样品,分析底泥理化性质;运用Arcgis反距离空间插值法（IDW）研究阅海底泥重金属元素空间分布特征,采用地累积指数法和Hakanson潜在生态危害指数法对其污染状况和生态风险进行评估,并利用相关性、主成分以及聚类分析等方法对阅海底泥重金属来源进行解析。结果表明,阅海底泥中汞（Hg）和钴（Co）元素平均含量分别为0.16 mg/kg和19.23 mg/kg,分别达到背景值的5.16和2.24倍,其他重金属元素铅（Pb）、铜（Cu）、砷（As）、镉（Cd）、铬（Cr）含量均超过银川平原引黄灌区土壤对应元素背景值含量;阅海底泥重金属空间分布差异性显著,各重金属元素在芦苇分布区域富集趋势十分明显;重金属元素污染程度表现为：Hg>Co>Pb>Cu>Cd>As>Cr,综合潜在生态风险均值达到 277.21,属中等生态危害范畴,其中 Hg 元素超标严重,贡献率达74.42%。阅海底泥重金属Cr和As元素受自然背景影响明显,而Hg、Co、Pb、Cu和Cd元素则主要来源于鸟粪排放以及人类活动。  相似文献   

大鹏澳网箱养殖区沉积物硫酸盐还原菌（SRB）及其与环境因子关系的初步研究   总被引：1，自引：0，他引：1  

胡德蓉  林钦  柯常亮 《南方水产》2007,3(5):14-18

实验采用MPN法测定了大鹏澳网箱养殖区沉积物中硫酸盐还原菌(SRB)的含量,布设的5个站位SRB检出率达100%,SRB平面分布特征是鱼类网箱区>对照区>浮筏贝类区;垂直分布特征为1cm层>5cm层>10cm层,SRB数量是由上向下逐渐减少。探讨了SRB含量与相应沉积物样品中的硫化物含量、氧化还原电位、pH等环境因子的关系。结果表明,沉积物中SRB数量与硫化物含量呈显著性正相关(R=0.96,P<0.05),与氧化还原电位(OPR)呈极显著性负相关(R=-0.97,P<0.01),与pH之间不具有显著性关系。  相似文献   

Soil carbon dioxide and methane fluxes from long-term tillage systems in continuous corn and corn–soybean rotations     

Rex A. Omonode  Tony J. Vyn  Doug R. Smith  Pter Hegymegi  Anita Gl 《Soil & Tillage Research》2007,95(1-2):182-195

Although the Midwestern United States is one of the world's major agricultural production areas, few studies have assessed the effects of the region's predominant tillage and rotation practices on greenhouse gas emissions from the soil surface. Our objectives were to (a) assess short-term chisel (CP) and moldboard plow (MP) effects on soil CO₂ and CH₄ fluxes relative to no-till (NT) and, (b) determine how tillage and rotation interactions affect seasonal gas emissions in continuous corn and corn–soybean rotations on a poorly drained Chalmers silty clay loam (Typic Endoaquoll) in Indiana. The field experiment itself began in 1975. Short-term gas emissions were measured immediately before, and at increasing hourly intervals following primary tillage in the fall of 2004, and after secondary tillage in the spring of 2005, for up to 168 h. To quantify treatment effects on seasonal emissions, gas fluxes were measured at weekly or biweekly intervals for up to 14 sampling dates in the growing season for corn. Both CO₂ and CH₄ emissions were significantly affected by tillage but not by rotation in the short-term following tillage, and by rotation during the growing season. Soil temperature and moisture conditions in the surface 10 cm were significantly related to CO₂ emissions, although the proportion of variation explained by temperature and moisture was generally very low (never exceeded 27%) and varied with the tillage system being measured. In the short-term, CO₂ emissions were significantly higher for CP than MP and NT. Similarly, mean seasonal CO₂ emissions during the 2-year period were higher for CP (6.2 Mg CO₂-C ha⁻¹ year⁻¹) than for MP (5.9 Mg CO₂-C ha⁻¹ year⁻¹) and NT (5.7 Mg CO₂-C ha⁻¹ year⁻¹). Both CP and MP resulted in low net CH₄ uptake (7.6 and 2.4 kg CH₄-C ha⁻¹ year⁻¹, respectively) while NT resulted in net emissions of 7.7 kg CH₄-C ha⁻¹ year⁻¹. Mean emissions of CO₂ were 16% higher from continuous corn than from rotation corn during the two growing seasons. After 3 decades of consistent tillage and crop rotation management for corn and soybean producing grain yields well above average in the Midwest, continuous NT production in the corn–soybean rotation was identified as the system with the least soil-derived C emissions to the atmosphere from among those evaluated prior to and during corn production.  相似文献   

裸露耕地土壤风蚀跃移颗粒分布特征的试验研究   总被引：8，自引：3，他引：8  

李晓丽  申向东 《农业工程学报》2006,22(5):74-77

以内蒙古阴山北部的典型农牧交错带耕地为试验区，利用DEM6型轻便三杯风向风速表和LV50便携式风速仪(可测瞬时风速和任一时段的平均风速)，采用SC—I型沙尘采集器收集跃移沙粒，并对收集到的沙粒进行筛分、称重，详细地分析了不同高度风蚀物百分含量、输沙量等风沙运动主要影响因素的变化特征，得出了耕地土壤在风沙跃移运动中的粒径分布特征，初步了解了该地区土壤风蚀的特点，为今后风沙运动力学理论的深入研究，以及实施保护性耕作和其他土地荒漠化的防治提供依据。  相似文献   

黄土高原不同生长年限植被减水减沙效益整合分析   总被引：2，自引：0，他引：2       下载免费PDF全文

赵跃中  穆兴民  严宝文  赵广举 《水土保持通报》2015,35(3):6-11

[目的]研究不同恢复年限植被减水减沙效益变化特征,为黄土高原地区进一步合理配置林草措施和生态恢复的可持续性研究提供科学依据。[方法]通过文献检索,共收集到18篇相关文献,运用整合分析的方法定量地研究了恢复年限增加对植被减水减沙效益的影响。[结果]4年生以上草地植被和5年生以上林灌植被可以发挥稳定的减水减沙效益,且减沙效益基本保持在80%左右。林地枯落物对植被的减水减沙效益具有一定的促进作用。[结论]受不同恢复阶段限制因素的影响,林草植被减水减沙效益大致可以分为3个阶段:栽植扰动阶段、水土保持阶段、水分限制阶段。  相似文献   

CO₂ emissions from subtropical arable soils of China     

Yunsheng Lou  Zhongpei Li  Taolin Zhang 《Soil biology & biochemistry》2004,36(11):1835-1842

CO₂ efflux plays a key role in carbon exchange between the biosphere and atmosphere, but our understanding of the mechanism controlling its temporal and spatial variations is limited. The purpose of this study is to determine annual soil CO₂ flux and assess its variations in arable subtropical soils of China in relation to soil temperature, moisture, rainfall, microbial biomass carbon (MBC) and dissolved organic carbon (DOC) using the closed chamber method. Soils were derived from three parent materials including granite (G), tertiary red sandstone (T) and quaternary red clay (Q). The experiment was conducted at the Ecological Station of Red Soil, The Chinese Academy of Sciences, in a subtropical region of China. The results showed that soil CO₂ flux had clear seasonal fluctuations with the maximum value in summer, the minimum in winter and intermediate in spring and autumn. Further, significant differences in soil CO₂ flux were found among the three red soils, generally in the order of G>T>Q. The average annual fluxes were estimated as 2.84, 2.13 and 1.41 kg CO₂ m⁻² year⁻¹ for red soils derived from G, T and Q, respectively. Soil temperature strongly affects the seasonal variability of soil CO₂ flux (85.0-88.5% of the variability), followed by DOC (55.8-84.4%) and rainfall (43.0-55.8%). The differences in soil CO₂ flux among the three red soils were partly explained by MBC (33.7-58.9% of the variability) and DOC (23.8-33.6%).  相似文献   

用基于人工神经网络的数据融合法测量水流泥沙含量   总被引：1，自引：1，他引：1  

张明社  李小昱  雷廷武  王为  张征 《农业工程学报》2002,18(4):41-43

在采用电容传感器测量泥沙含量的过程中，电容传感器的输出值受环境温度的影响较大，为消除温度对测量数据的影响，提出了采用人工神经网络法对传感器进行数据融合处理的方法，该方法以传感器的泥沙含量值与温度值作为网络的输入，通过对网络的训练达到消除非目标参量——温度的影响。试验结果表明该方法收敛速度快，输出稳定性可显著提高，能够有效地消除温度带来的影响。  相似文献   

春季裸露沙质农田土壤风蚀量动态与变异特征   总被引：25，自引：2，他引：25  

张华李锋瑞  张铜会李玉霖　苏永中 《水土保持学报》2002,16(1):29-32

以春季风蚀活动高发期为特定研究时段 ,采用地面埋设容器的“陷阱诱捕”法 ,对秋收后翻耕的裸露沙质农田春播前的土壤风蚀量动态进行了定位观测 ,同时对影响土壤风蚀的关键因子表土层紧实度和含水量以及风速动态也进行了同步观测。主要研究结果是 :(1)观测期内 ,平均土壤日风蚀量为 2 4 1.2 0 kg/ hm2 ,土壤日有机碳和氮素损失量平均分别为 1.5 2 ,0 .15 kg/ hm2 。 (2 )土壤风蚀过程以细微土粒的跃移和悬移运动为主 ,损失掉的主要是表层土壤中的细砂 (粒径 0 .1～ 0 .0 5 mm)、粉粒 (粒径 0 .0 5～ 0 .0 0 2 mm)和粘粒 (粒径 <0 .0 0 2 mm)等富含营养元素的细微颗粒 ,分别占风蚀沉积物的 4 6 .0 1% ,2 1.0 3%和 2 1.74 %。这表明土壤风蚀导致了农田的粗化。 (3)相关分析表明 ,土壤风蚀量与表土层含水量呈一定的负相关 ;土壤风蚀量与表土层紧实度呈微弱的负相关。然而 ,土壤日风蚀沉积量与日平均风速呈高度正相关 ;同样 ,土壤日风蚀沉积量与日可蚀风持续时数亦呈高度正相关。利用它们之间的回归关系式 ,可以定量地预测、预报研究区春季风蚀期裸露农田的土壤风蚀量  相似文献   

三江平原湿地CH4排放通量研究   总被引：10，自引：1，他引：10  

郝庆菊王跃思  宋长春刘广仁王毅勇  王明星 《水土保持学报》2004,18(3):194-199

2002年6月到10月在三江平原利用静态暗箱-气相色谱法对不同土壤水分状况或积水深度的毛果苔草沼泽、小叶章草甸以及灌丛进行了CH4排放的测定,结果为毛果苔草沼泽CH4排放通量(11.9 mg/m2·h)>小叶章草甸(8.5 mg/m2·h)>灌丛(0.75 mg/m2·h),差异达到高度显著水平(α=0.01),主要是由土壤水分状况不同而造成的.由于生境的差异,3种湿地类型CH4排放通量的季节变化形式也不尽相同.温度、土壤Eh和毛果苔草生物量是影响CH4排放的重要因素,湿地CH4排放通量和箱内外温度或不同深度的地温均呈显著或极显著正相关,小叶章草甸和毛果苔草沼泽分别与10 cm及15 cm的Eh呈极显著负相关(P<0.01),毛果苔草生物量和CH4排放通量呈显著正相关(P<0.05).  相似文献   

乐清湾养殖区表层沉积物重金属含量分布及污染评价   总被引：1，自引：0，他引：1  

王传花  崔灵周  王栋 《农业工程学报》2015,31(2):204-210

以乐清湾养殖区表层沉积物中Cu等7种重金属为研究对象,在野外实地调查取样及重金属含量测定基础上,以中国海洋沉积物质量(GB18668-2002)一类标准值为评价标准,利用单因子指数评价法、内梅罗综合污染指数评价法和沉积物质量基准(sediment quality guideline,SQG),对单项重金属污染程度、多种重金属综合污染效应及重金属潜在生物毒性风险进行了评价。结果表明,乐清湾养殖区表层沉积物重金属含量分布差别明显,所有采样点表层沉积物均受到Cu污染,局部受到严重Hg污染;大部分养殖区表层沉积物重金属污染达到轻度等级;所有养殖区均可发生由Cu偶尔引起的不利生物毒性效应,个别养殖区可发生由Hg频繁引发的不利生物毒性效应。乐清湾养殖区表层沉积物重金属主要来源于沿岸电镀企业废水排放及农药化肥造成的农业面源污染。开展Cu、Hg污染治理修复是实现乐清湾养殖环境安全的迫切需求。  相似文献