Regional Ontogeny of New England Salt Marsh Die‐Off

Coastal areas are among the world's most productive and highly affected ecosystems. Centuries of human activity on coastlines have led to overexploitation of marine predators, which in turn has led to cascading ecosystem‐level effects. Human effects and approaches to mediating them, however, differ regionally due to gradients in biotic and abiotic factors. Salt marsh die‐off on Cape Cod, Massachusetts (U.S.A.), triggered by a recreational‐fishing‐induced trophic cascade that has released herbivorous crabs from predator control, has been ongoing since 1976. Similar salt marsh die‐offs have been reported in Long Island Sound and Narragansett Bay (U.S.A.), but the driving mechanism of these die‐offs has not been examined. We used field experiments to assess trophic interactions and historical reconstructions of 24 New England marshes to test the hypotheses that recreational fishing and predator depletion are a regional trigger of salt marsh die‐off in New England and that die‐offs in Long Island Sound and Narragansett Bay are more recent than those on Cape Cod. Predator depletion was the general trigger of marsh die‐off and explained differences in herbivorous crab abundance and the severity of die‐off across regions. Die‐offs in Long Island Sound and Narragansett Bay are following a trajectory similar to die‐off on Cape Cod, but are approximately 20 years behind those on Cape Cod. As a result, die‐off currently affects 31.2% (SE 2.2) of low‐marsh areas in Long Island Sound and Narragansett Bay, less than half the severity of die‐off on Cape Cod. Our results contribute to the growing evidence that recreational fishing is an increasing threat to coastal ecosystems and that studying the effects of human activity at regional scales can provide insight into local effects and aid in early detection and potential remediation. Ontogenia Regional de un Incremento en la Mortandad en una Marisma Salada de Nueva Inglaterra     

长江南京段入江支流底质多营养级微生物多样性研究

基于16S rRNA和18S rRNA高通量测序技术，研究了长江南京段21条主要入江支流不同水期底质多营养级微生物的群落结构特征，利用Shannon指数等分析了样品中微生物群落的多样性。结果表明，42个样品的细菌群落归属于285个纲水平上的OTUs (operational taxonomic units)，归属于62个门；优势菌门为变形菌门（Proteobacteria）、酸杆菌门（Acidobacteria）、绿弯菌门（Chloroflexi）等，优势菌纲为β-变形菌纲、α-变形菌纲、δ-变形菌纲等。原生动物中的优势类群为不等鞭毛类(Heterknta)、囊泡虫类（Alveolata）和绿色植物（Chloroplastida），后生动物中的优势类群为节肢动物(Arthropoda)、轮虫（Rotifera）和线虫（Nematoda）。平水期底质的细菌、原生及后生动物的多样性相对较低，入江支流的水生态系统相对不稳定，尤其是金川河、七里河等。     

三峡水库135m水位蓄水典型次级河流回水段富营养化监测评价

通过2004年3月份对三峡水库135m水位蓄水状态下库区成库河段典型次级河流朱衣河、梅溪河、大宁河回水河段富营养化监测与评价,掌握了在这一季节三峡库区成库河段次级河流回水河段营养状态不同的分布模式.     

山仔水库叶绿素a与环境因子的相关分析及富营养化评价

依据2003年3～11月对山仔水库的逐月调查和监测数据,分析叶绿素a含量的时空分布情况，探讨叶绿素a与相关环境因子的关系,并应用修正的卡尔森营养状态指数对山仔水库水质进行分析评价。结果表明，山仔水库除了3、10、11月份处于中营养状态,其余月份都处于富营养化状态。叶绿素a具有明显的时空分布特征。日溪进口和山仔水库坝前的叶绿素a含量较高;初夏和秋末出现高峰，叶绿素a含量分别高达211 mg/m^3和93mg/m^3。多元统计分析表明，与山仔水库叶绿素a含量显著相关的因子是水温和溶解氧。生物因子评价表明，山仔水库浮游藻类的种类和数量都达到了富营养化水平。     

基于人工神经网络模型的舰船防火设计方法

根据舰船实际和火灾理论,建立了舰船舱室火灾危险性的动静二类4个指标:失火危险性指标、舱室相关度指标、设备使用状态指标和人员状态指标,对舰船各种舱室的火灾危险性进行量化。笔者先给出规范中9类舱室的各指标值,应用笔者所开发的神经网络模型,建立舱室火灾危险性指标值与舱室分隔等级的关系模型,求出舱室防火分隔等级值,降低了对设计者经验的要求。运用开发的模型对某大型舱室进行防火设计,获得的结果与其他方法的结果基本一致,可供舰船防火设计时参考。     

企业分级监察模型及其应用研究

企业监察级别的划分是有效利用监察资源,提高监察绩效,实现集约型分级安全生产监察的基础.本文通过分析研究,结合我国安全生产现状,综合考虑企业自身特点和行业特性,建立了基于企业职业伤亡统计的分级监察模型,并利用该模型对柳州市502家企业的2005年监察级别进行了划分.最后,对企业分级监察模型研究中存在的问题进行了探讨.     

建筑火灾风险评价技术初探

在分析建筑火灾发生原因的基础上 ,建立了建筑火灾风险评估因素集。并运用模糊评价法对建筑物的火灾安全进行了风险评价 ,通过评价得出建筑物所属的安全等级。该方法可用于保险公司对投保建筑的鉴别与筛选 ,同时可使管理者及时采取措施 ,以减少火灾危险性。     

Regional Lake Trophic Patterns in the Northeastern United States: Three Approaches

N   = 11,076). Results were compared to a large, nonrandomly sampled data set for the same area compiled by Rohm and others and contrasted with lake trophic state information published in the National Water Quality Inventory: 1994 Report to Congress [305(b) report. Lakes across the entire Northeast were identified by EMAP data as 37.9% (±8.4%) oligotrophic, 40.1% (±9.7%) mesotrophic, 12.6% (±7.9%) eutrophic, and 9.3% (±6.3%) hypereutrophic. Lakes in the ADI and NEU generally are at a low, nearly identical trophic state (96% oligotrophic/mesotrophic), while those in the CLP are much richer (45% eutrophic). EMAP results are similar to results of the Rohm data set across the entire region. In the CLP, however, EMAP identified approximately 45% of the lakes as eutrophic/hypereutrophic, while the Rohm data set identified only 21% in these categories. Across the entire Northeast, the 305(b) report identified a much higher proportion (32.2%) of lakes in eutrophic condition and a much smaller proportion (19.8%) in oligotrophic condition than did the EMAP survey data (12.5% ± 7.9% and 37.9% ± 8.5%, respectively). Probability sampling has several advantages over nonrandom sampling when regional resource condition assessment is the goal.     

Investigation of polycyclic aromatic hydrocarbons from coal gasification

The hazardous organic pollutants generated from coal gasification, such as polycyclic aromatic hydrocarbons(PAHs), are highly mutagenic and carcinogenic. More researchers have paid particular attention to them. Using air and steam as gasification medium, the experiments of three kinds of coals were carried out in a bench-scale atmospheric fluidized bed gasifier. The contents of the 16 PAHs specified by US EPA in raw coal, slag, bag house coke, cyclone coke and gas were measured by HPLC to study the contents of PAHs in raw coal and the effects of the inherent characters of coals on the formation and release of PAHs in coal gasification. The experimental results showed that the distributions of PAHs in the gasified products are similar to raw coals and the total-PAHs content in coal gasification is higher than in raw coal(except Coal C). The totaI-PAHs contents increase and then decrease with the rise of fixed carbon and sulfur of coal while there has an opposite variation when volatile matters content increase. The quantities of PAHs reduce with the increase of ash content or the drop of heating value during coal gasification.     

主分量分析法用于湖泊富营养化评价的相互比较

应用主分量分析法,建立一个度量湖泊富营养化程度的综合指标,根据该综合指标的大小,可以进行湖泊富营养化程度的相互比较.通过实例分析并与统计评分评价结果比较表明,该法具有显著辨别不同富营养程度的变异性能力.