城市生态系统空气微生物群落研究进展

空气微生物是城市生态系统重要的生物组成部分 ,空气中广泛分布的细菌、真菌孢子、放线菌和病毒等生物粒子不仅具有极其重要的生态功能 ,还与城市空气污染 ,城市环境质量和人体健康密切相关。从生态系统角度出发 ,着重论述了城市微生物气溶胶的粒谱范围、空气微生物的主要类型、空气微生物浓度的时空变化和空气微生物群落结构的影响因素。综述结果表明 :城市微生物气溶胶的粒谱范围为 0 .0 0 2～ 30 μm;在调查的城市中 ,空气细菌有 2 1属 ,其中优势菌属为芽孢杆菌属 (Bacillus)、葡萄球菌属 (Staphylococcus)、微球菌属 (Micrococcus)和微杆菌属 (Microbacterium ) ,真菌有 2 1属 ,其中优势菌属为交链孢属(Alternaria)、青霉属 (Penicillium)、曲霉属 (Aspergillus)和木霉属 (Trichoderma) ,放线菌共有 7属 ;一年中冬季空气微生物浓度最低 ,一天中空气微生物浓度在 8:0 0～ 10 :0 0出现高峰 ,2 :0 0～ 4 :0 0或者 12 :0 0～ 14 :0 0出现低峰 ,交通干线和商业区空气微生物的浓度较高 ,公园绿地较低 ,并且随着高度的增加空气微生物浓度随之减少 ;污染因子 SO2 、NO2 、NO和环境因素风速风向、温度、相对湿度、光照、雨、雪等影响空气微生物的数量和浓度。在经济发达 ,人口流动较多的城市如北京、上海、广     

A burrowing ecosystem engineer positively affects its microbial prey under stressful conditions

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Increased ecosystem variability and reduced predictability following fertilisation: Evidence from palaeolimnology

We tested the hypothesis that fertilisation increases community and ecosystem variability while reducing predictability using annual fossil records from fertilised Lake 227, Experimental Lakes Area, Ontario, Canada. Comparison of fossil pigments from unperturbed and eutrophied periods using a median-log Levene's test demonstrated that variability increased significantly during enrichment for total algae (chlorophyll a , sum of carotenoids), cyanobacteria (aphanizophyll, lutein-zeaxanthin), chlorophytes (pheophytin b , lutein-zeaxanthin), and cryptophytes (alloxanthin), but not for other algal taxa (chrysophytes, dinoflagellates) or herbivory (pheophorbides). Dynamic linear models (DLMs) of individual time series showed that forecast accuracy declined during enrichment for taxa which showed increased variability, while forecast uncertainty increased for all fossil pigments. DLMs of simulated data identified a strong inverse relationship between variability and predictability, suggesting that predictability will decline whenever variability increases. These findings imply that anthropogenic eutrophication of ecosystems may destabilise lakes, obscure impacts of global change, and reduce the sensitivity of whole-ecosystem experiments.     

Coastal wetland restoration through the lens of Odum's theory of ecosystem development

Advancing ecological restoration assessments requires a more detailed consideration of species interactions and ecosystem processes. Most restoration projects rely on a few metrics not always directly linked with ecological theory. Here, we used Odum's theory of ecosystem development to assess and compare the ecosystem structure and services of created marshes (4–6 years old) with preexisting, reference marshes in a brackish water region of the Mississippi River Delta. We built ecosystem models for created and reference marshes that integrated large datasets of stomach contents, stable isotopes, and taxa abundances. Despite strong resemblance in community structure, created marshes were at an earlier succession stage compared to the reference marshes, having lower biomass (including exploited species), higher biomass turnover and production, less dependence on detritus, lower material cycling, and less energy flowing through specialist pathways. Although preserving preexisting marshes should be a priority, created marshes may still be an important tool for the restoration of coastal areas and their ecosystem services. In addition, our results show that comparisons of species biodiversity alone may fail to capture essential differences in ecosystem processes between habitats, which reinforces the importance of ecosystem modeling approaches to assess restoration projects.     

The development of a benthic ecosystem

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Investigating the evolutionary history of the Pacific Northwest mesic forest ecosystem: hypothesis testing within a comparative phylogeographic framework

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Improving the genetic representation of rare taxa within complex microbial communities using DNA normalization methods

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Intraseasonal predictability of natural phytoplankton population dynamics

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Analysis of the unique geothermal microbial ecosystem of the Blue Lagoon

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Summary The life history strategy of the dung beetleKheper nigroaeneus was studied in Mkuzi Game Reserve, South Africa.K. nigroaeneus, a large ball-rolling dung beetle, brood-cares a single offspring per nesting occasion. Adults emerged from the ground following the first spring rain (≥17 mm) in October or November, occasionally September, and trap catches were at a maximum 1–2 weeks later. Females outnumbered males by 3:1 at the time of maximum catches, but thereafter declined steadily, as the numbers of females involved in brood-care increased. Brood-care lasted 12 weeks, and parental females then (a) entered a second brood-care period, or (b) remained underground in diapause, or (c) emerged to feed. Reproductive activity stopped after February, ensuring that the entire population reached the adult stage by winter. Females active above ground after February, in reproductive diapause, had low fat levels and resorbed oocytes. Females buried underground, in reproductive diapause prior to and during winter, had high fat levels, resorbed oocytes, a reduced metabolic rate and empty guts. The Mkuzi habitat is predictable forK. nigroaeneus in spring, since only one good fall of rain is sufficient to drive population events for the next three months. In the latter half of the season the life history ofK. nigroaeneus is more flexible, and hence less constrained by climate.     

The development of ecosystem objectives for the Laurentian Great Lakes

Historically management of human use of ecosystems has been based around engineering and chemical approaches and through the construction of treatment facilities, effluent controls and setting chemical concentrations, both at end of pipe and in the aquatic environment. However, the general continued degradation of many ecosystems shows these approaches alone are insufficient. In the Laurentian Great Lakes the Great Lakes Water Quality Agreement was first signed in 1972 and ratified in 1978 and in 1987 tacitly acknowledged the problems with a chemical only approach by requiring the development of ecosystem objectives in the 1978 agreement. Furthermore, the agreement specifically identified numerical ecosystem objectives in the 1987 agreement. The evolution of ecosystem objectives in the Great Lakes has expanded from the strictly numerical objectives such as production of lake trout and abundance of the amphipod Pontoporeia hoyi. More recent developments in ecosystem objectives have been the inclusion of indicators for wildlife, habitat, human health and stewardship.Prepared as a discussion paper presented to the United Nations Economic Commission for Europe's seminar on an Ecosystems Approach to Water Management (May 27–31, 1991).     

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群落食物网间的相似性测度

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