A simulation model to explore the response of the Gulf of Maine food web to large-scale environmental and ecological changes

A dynamic simulation model was constructed using outputs from a balanced Gulf of Maine (GOM) energy budget model as the initial parameter set. The model was structured to provide a recipient control set of dynamics, largely based off of flows to and from different biological groups. The model was used to produce Monte Carlo simulations that were compared (percent change in biomass) with basecase simulations for a variety of scenarios. Changes in primary production, large increases in pelagic and demersal fish biomass, increases in fishing mortality, and large increases in top predators such as baleen whales and pinnepids were simulated. These scenarios roughly simulated the potential impacts of climate change, altered fishing pressure, additional protected species mitigations, and combinations thereof. Results suggest that the GOM system is primarily influenced by bottom-up processes involving phytoplankton, zooplankton, and bacterial biomass. Pelagic and demersal fish were important in determining trends in some of the scenarios. Marine mammals, large pelagic fish, and seabirds have a minor role in the GOM system in terms of biomass flows among the ecosystem components. The system is resilient to large-scale change due, in part to many predator–prey linkages. However, major alterations could occur from sustained climate change, high fishing rates, and by combinations of these types of external forcing mechanisms.     

多溴联苯醚的生物富集效应研究进展

研究污染物的生物富集效应对于预测污染物在生物体内的含量、建立环境标准以及评估污染物的生态风险具有重要的意义.论文结合近年来国内外有关多溴联苯醚(PBDEs)的生物富集及其沿食物链(网)生物放大效应的研究文献,对PBDEs的生物富集效应进行了综述.文献计算的生物富集因子(BAFs)、生物-沉积物/土壤生物富集因子(BSAFs)和生物放大因子(BMFs)表明,生物对大多数PBDEs具有生物富集作用,且生物对PBDEs的富集能力与其生物进化等级及其营养级有关.文献计算的营养级放大因子(TMFs)表明,大多数PBDE单体可以在食物网上产生生物放大效应,但只有较少单体具有统计上的显著性.生物的生理生化参数、化合物本身的特性以及环境条件等因素影响了PBDEs在生物体内及食物链(网)上的富集与放大.     

基于时间序列模型的饮用水源地重金属健康风险分析与预测

饮用水源地作为高敏感环境风险受体,重金属健康风险的时间变化特征和预测分析对于饮用水源地的风险管控、水环境治理和生态系统安全保障等具有积极的意义.为评价饮用水源地重金属健康风险及掌握健康风险的时间变化特征,以某饮用水源地为研究对象,监测并记录了该点位重金属As、Cd、Cu、Hg、Ni和Zn在2015年1月至2018年12月的浓度值,并以月均值作为研究基础数据,对饮用水源地重金属健康风险评价,并进一步利用Spearman秩相关系数法和ARIMA模型对重金属健康风险时间变化特征进行分析.结果表明,部分月份的重金属浓度值超过我国地表水环境质量标准（GB 3838-2002）规定的Ⅲ类水质的标准限值,尤其是Hg,其浓度最小值超过该标准的4倍;饮用水源地重金属致癌风险和非致癌风险的大小顺序分别为：As>Cd和As>Hg>Cd>Zn>Cu>Ni,儿童健康风险均高于成人健康风险,在2015年2月之外的所有月份的成人综合非致癌风险均低于1,儿童综合非致癌风险在2017年10月之后均低于或接近1,而儿童综合致癌风险均超过10^-4;As的儿童致癌风险、儿童综合非致癌风险和儿童综合致癌风险在数据监测期间总体上具有明显的下降趋势,其Spearman秩相关系数分别为-0.714069、-0.773122和-0.62234,但是儿童综合致癌风险在2018年的Spearman秩相关系数为0.902098,均有显著地上升趋势,对应的儿童综合致癌风险均值为0.000234;基于ARIMA （3,1,3）模型预测的饮用水源地重金属儿童综合致癌风险具有较高的预测效果,预测结果表明后续两年内的儿童综合致癌风险的范围为0.000200~0.000302,需引起关注.     

河口与近海营养状况评价方法及其应用验证

基于压力-状态-响应(PSR)模型,建立了我国河口与近海营养状况评价法. 通过分析当前富营养化概念模型研究结果,引入A(人为影响指数)和表征过滤与调节作用的ΔSA/SA(层化系数)作为压力指标,从富营养化负面效应筛选出高效的表层ρ(Chla)、d(浮游植物细胞密度)、底层ρ(DO)、a(底栖生物个体丰度)和RT(赤潮指数)作为状态指标,并以v(未来营养盐通量年均变化)作为响应指标. 综合考虑国内外相关标准来界定评价指标分类标准,采用统计处理、矩阵法集成得到G(营养状况等级),并成功应用于九龙江河口区. 应用验证结果表明:2010年九龙江河口区G为“差”,北部采样点优于南部,与人为环境压力空间分布一致;Kolmogorov-Smirnov非参数检验显示,G为“中”和“差”的两类采样点之间的ρ(COD)、ρ(DIN)、ρ(TN)、ρ(DSi)、ρ(SPM)(其中DSi和SPM分别为溶解态硅酸盐、悬浮颗粒物)差异显著(p<0.05),ρ(TP)、ρ(DIP)因“磷缓冲”机制而趋于均匀分布(p>0.05),评价结果可识别出评价体系并未包含的主要环境因子状况;与第一阶段评价法相比,河口与近海营养状况评价法注重富营养化症状的评价,因此具有更易识别营养状况恶化与否的优势.      

Fertility signaling in queens of a North American ant

In most species of advanced eusocial insects, the partitioning of reproduction between nestmates is thought to be regulated by means of primer pheromones or other chemical cues, which presumably influence the behavior of co-queens and workers such that they maximize their own inclusive fitness. Here we show that in multi-queen colonies of the Nearctic ant, Leptothorax sp. A, physical dominance in concert with chemical cues, which signal the ovarian development of a queen, are used to control reproduction of competing queens and to influence worker behavior. The analysis of ranks obtained during two fighting periods in the annual colony cycle revealed a strong link between individual aggressiveness of a queen and her fertility. During the adoption of newly mated queens in autumn, the resident, egg-laying α-queen was more likely to start aggression first and keep her high rank position compared to the fighting period after hibernation. We suggest that this is proximately caused by the α-queen having much stronger developed ovaries in autumn than the young queens, whereas after hibernation, the ovaries of all queens are similarly inactive. Interactions during the first weeks after the end of hibernation and intrinsic, individual differences in aggressiveness appear to be crucial for the dominance rank achieved later. Queens which were allowed to become fertile when their nestmate queens still were kept under prolonged hibernation, were immediately socially dominant over the latter when all queens were reunited, though no aggression occurred. In another experiment, queen antagonism was prevented by spatial separation in different parts of the same nest and all queens began to lay eggs. Workers stayed preferentially with queens with high actual fecundity rather than with those which had had high social status before separation. This and further evidence suggest that ovarian status is communicated, most likely by a chemical cue perceived by co-queens and workers, affects the direction of their aggressive behavior, and allows them to discriminate among queens. Received: 5 May 1998 / Accepted after revision: 29 August 1998     

煤矿安全预评价的可变模糊识别方法

煤矿安全预评价涉及诸多不确定信息,用传统评价方法难以获得可靠的评价结果。为此,将可变模糊模式识别模型与方法引入煤矿安全领域,提出了煤矿安全预评价的可变模糊识别方法。可变模糊识别方法首先根据指标特征值与指标标准特征值矩阵确定样本的级别上下限,然后利用可变模糊模式识别模型对样本进行识别,得到样本在各级别下的相对隶属度,进而计算级别特征值,并以此为依据进行评价。将该方法应用于黄陵双龙煤矿,得出该矿井的安全等级。结果表明:可变模糊识别方法较文献中方法可更准确地给出安全性等级评价结果,为煤矿安全预评价提供一条新的途径。     

锦标机制理论下企业低碳经济发展激励机制研究

按照企业发展与环境相容的原则,低碳经济是应对全球变暖的最佳经济模式,低碳经济以低能耗、低排放、低污染为基本特征,以应对碳基能源对于气候变暖影响为基本要求,以实现经济社会的可持续发展为基本目的.鉴于当前文献关于企业发展低碳经济的激励机制研究还略显不足,文章借鉴激励理论中的委托代理理论,根据Malcomson模型的研究方法,构建了包括1阶段合约和2阶段合约的企业发展低碳经济的激励机制框架,设立基于相对业绩的"锦标机制"模型并对模型进行系统分析,推导出政府在制定企业发展低碳经济激励政策时的注意事项,即中央政府要加大财政转移支付力度,支持地方发展低碳经济;地方政府要设立专门的低碳经济发展激励基金,并纳入财政预算管理;地方政府在激励企业发展低碳经济时,要有层次、有针对的对企业给予政策支持或财政补贴,形成阶梯式的支持结构,使有限财政资金得到合理配置;地方政府应该以区域内企业实施低碳经济活动的努力水平为评判标准对企业进行激励.     

Trophic structure of ecosystems and ecotoxicology of soil organisms

Studies on the ecotoxicology of soil organisms have led to the revision of views on the trophic structure of ecosystems. It was found that the microbial link is obligatory and controls the migration of toxicants and their effects in the food chain. Differences in effects are accounted for by both the physiological stability of organisms and their affliation with relatively independent and biogeochemically closed ecosystems differing in their spatiotemporal scales. The latter form a hierarchical three-level structure: ecosystems of unicellular organisms—ecosystems of small multicellular organisms—the ecosystem of large multicellular organisms, or of biogeocenosis. Trophic networks within the structure are united by ecosystemophagy as the type of feeding of large multicellular organisms, and this accounts for the importance of the latter as indicators of long-term changes in a biogeocenosis.     

工业复合源大气污染长期扩散浓度模拟计算

在工业复合源大气扩散模式研究的基础上,改造传统大气污染物长期扩散模型,引入了平滑函数,使相邻扇区的交界处具有连续性,提出了计算精度。对于复合源采用坐标变换的方法,解决不同种类,多源污染物季平均浓度值叠加的难题。     

Spillover of Agriculturally Subsidized Predators as a Potential Threat to Native Insect Herbivores in Fragmented Landscapes

Abstract:  Habitat loss and fragmentation can have strong negative impacts on populations of some native species. Spillover of generalist natural enemies from the surrounding landscape matrix is one mechanism potentially generating such effects, yet this has been rarely studied in insects. We examined the influence of habitat conversion to agriculture on the abundance and potential effects of predatory coccinellid beetles on native insect herbivores within 12 grassland remnants in central Nebraska (U.S.A.). Results of sweep sampling revealed that coccinellids were three to six times more abundant at native grassland sites embedded within cropland-dominated landscapes compared with control sites in grassland-dominated landscapes over the 3 years of the study. Exclusion experiments further demonstrated that predation intensity was strongly related to coccinellid abundances across sites and that coccinellids can dramatically reduce densities of a native aphid herbivore. In contrast to studies of specialized insect parasitoids, which have generally found reduced enemy pressure in fragmented landscapes, our results suggest that native herbivores may in some cases experience increased consumer pressure in landscapes with increasing habitat loss because of spillover of generalist predators from surrounding cropland habitats.