两种大型海藻自然环境下的营养动力学研究

在室外条件下,对菊花江蓠(Gracilaria lichenoides)及龙须菜(G.Lemaneiformis)的N、P吸收动力学及生长动力学进行了研究.两海藻对NO3-N、NH4-N及PO4-P的最大吸收速率(Vmax)分别为55.88、35.17 μmol/(g·h)、3.106 μmol/(g·h)和53.17、32.24 、3.064 μmol/(g·h);半饱和常数(Ks)分别为7.762、3.414 、0.222 μmol/L和6.331、2.345、0.110 μmol/L,两海藻对N营养的竞争能力相似;从生长动力学结果看:菊花江蓠N、P的最大生长浓度为60 和30 μmol/L,龙须菜为100和40 μmol/L.     

保留带与造林带水土和养分再分配效应

保留带（ 保留现有灌丛的带状区域）与造林带（ 砍掉现有灌丛用于栽植林木的带状区域） 沿等高线交替配置的生态技术在四川西部逐渐被推广应用,本文定量分析了该技术中保留带与造林带的水土和养分再分配效应．结果表明：①坡度和雨量级是影响保留带与造林带水土流失的重要因子,其越大则水土流失量越大．②保留带净存储水６１ ４６４ ～１２５ １７９ｔｋｍ －２ａ－１ ,拦截土壤２ １３６ ～２ ８１７ｔｋｍ －２ａ－１ ．③保留带表土层的养分比造林带的提高了１４．６８％ ～７４．８９％ ,造林带表土层的养分比对照提高了３ ．３１％ ～１１４．１６％ ．④保留带和造林带内从上至下的表土层养分有逐渐富积的趋势,且保留带与造林带相邻处的养分变化速率最大．⑤保留带通过地表径流的养分流动净积累了５７５ ．５９ ～１ ６９０ ．６６ ｋｇ ｋｍ －２ａ－１有效Ｎ;而对Ｐ、Ｋ 而言,保留带是否能通过地表径流来净积累养分则主要取决于坡度,坡度越大,越有利于保留带通过地表径流来净积累有效Ｐ、Ｋ．     

The effect of the time of sampling on the compliance of bathing water in NW England with the EU Directive on bathing water quality

The ability of Morecambe’s three designated bathing waters to pass the EU Directive on Bathing Water Quality depends on the time of day when the sample is taken, the indicator organism tested for and whether the test uses the most strict (Guideline) or the least strict (Imperative) criteria. Morning and afternoon sampling for faecal coliforms, faecal streptococci and the pathogenCampylobacter was carried out monthly over the 1996 and 1997 bathing seasons. In the afternoons average faecal coliforms declined by 77% in 1996 and 87% in 1997 compared with the mornings, faecal streptococci by 79% and 83% and campylobacters by 66% and 86%. This decline in bacterial numbers between morning and afternoon was related to variations in water temperature and levels of ultraviolet radiation. All three bathing waters failed the Guideline criteria of the EU Directive on Bathing Water Quality. Using the Imperative criteria, no bathing waters passed in the mornings of either year, some passed in the afternoons of 1996 and all passed in the afternoons of 1997. The increased pass rate in 1997 coincided with improved sewage treatment, high temperatures and increased levels of sunshine. In 1997 sampling by the Environment Agency produced fewer failures than our morning sampling but more than our afternoon sampling. Their sampling was done around midday. It is suggested that where possible all sampling of EU designated bathing waters should be carried out in the early morning.     

长江口营养盐浓度变化及分布特征

根据2003年11月(枯季)和2004年8月(洪季)对长江口的2次现场调查,分析探讨了长江口的营养盐浓度变化及分布特征.结果表明,长江口水体3种不同形态的溶解无机氮中,以NO3--N含量最高,洪、枯季分别占溶解态无机氮的92.8%～97.7%和84.3%～98.4%.洪季NO3--N和NH+-N含量高于枯季,洪季与枯季NO2--N含量接近.洪、枯季长江口ρ(PO43-P)平均值分别为0.014和0.016 mg/L,接近国家海水一类标准.洪、枯季N3--N和PO3-4P含量均是由长江口内向口外近海逐渐降低,而NH4+-N含量则表现出相反的空间分布规律,即口外高于口内.通过计算长江口营养盐比值发现,枯季长江口氮、磷供应充分,不存在磷受限的情况,而洪季长江口水体受到磷的限制.      

Investigating the Uncertainties in the Simple Mass Balance Equation for Acidity Critical Loads for Terrestrial Ecosystems in the United Kingdom

The Simple Mass Balance (SMB)equation has been developed and used as one ofthe principal methods for calculating criticalloads of acidity for forest ecosystems. Criticalloads have formed the basis for informing policyrelated to the control and abatement of emissionsof acidifying pollutants. The SMB equationrelies on a variety of assumptions and dataderived from a variety of sources. Each of thesecomponent constituents has a potential source oferror depending on the method(s) used for theirderivation and the value(s) assigned. The resultis the possibility of generating a range ofcritical load values for a single ecosystem. This paper summarises the SMB equation, examinesthe uncertainties in deriving input values andreviews other works on the key assumptions.     

长江流域地表水中镉生态风险的区域差异分析

围绕长江流域地表水中镉（Cd）的水质基准和生态风险的区域差异展开分析.首先,根据我国《淡水水生生物水质基准——镉》推荐的方法,结合长江流域地表水的硬度分布对Cd长期水质基准值进行了校正;在此基础上,考虑长江流域的物种区系特征,进一步修正得到了Cd长期水质风险阈值,并依此阐释了长江流域的Cd长期水质风险阈值分布和风险商分布的区域差异性.结果发现,经硬度校正和物种修正后,长江流域不同城市间Cd长期水质风险阈值的最大值为0.75 μg·L^-1,最小值为0.08 μg·L^-1,二者相差近10倍;不同城市间Cd风险商的最高值为1.12,最低值为0.035,二者相差达32倍.长江流域上中游交界区和洞庭湖水系等重点区域的Cd生态风险高,尚需深入研究.     

区域沉积物质量基准常用建立方法的改进与优化

建立区域沉积物质量基准（SQC）具有重大的社会、经济和环境价值。本文选择两种当前流行的基准建立方法,相平衡分配法（EqP）和质量三合一法（Triad）,重点阐述在指标选择与定量、误差模拟校正、模式拟和运算等实施操作方面各自的改进与优化。同时探讨了SQC的发展趋势以及在污染沉积物治理与恢复决策中的作用。     

江苏启东邻近海域氮磷营养盐分布特征、组成及营养水平评价

基于江苏启东邻近海域2019年4月 、10月海水的调查数据,探讨该海域溶解无机氮(DIN)、溶解无机磷(DIP)的分布特征及成因,分析氮磷营养盐的构成特点,评价该海域的营养水平,通过DIN、DIP与环境因子的相关性分析,探讨影响DIN和DIP的主要环境因素.结果表明,春季各监测站位DIN、DIP平均质量浓度分别为0.3...     

氮沉降下西南亚高山针叶林生长的养分限制特征

长期氮(N)沉降及其诱导的N、磷(P)养分平衡性对森林生长与生产力的生态反馈效应已成为当前森林生态学研究的前沿与热点,但目前大多研究主要基于已有文献数据整合分析,而缺乏野外原位系统性研究与试验证据.以西南亚高山两种典型人工针叶林——云杉(Picea asperata)林和华山松(Pinus armandii)林为对象,...     

工业设施易受攻击性评价方法研究

9.11事件以来,恐怖袭击的威胁引起各国政府、媒体和公众的广泛关注,恐怖袭击的风险研究成为安全科学的新课题.工业设施,特别是化学物质和能量聚集的工业设施,由于潜在的失控后果的严重性,遭恐怖袭击的威胁更大.本文基于恐怖袭击目标选择与工业设施某些固有特征的相关性,从攻击者的角度分析工业设施固有特征中影响其目标效用的诸因素,建立工业设施易受攻击性评价方法.