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Vincent WF Gibson JA Pienitz R Villeneuve V Broady PA Hamilton PB Howard-Williams C 《Die Naturwissenschaften》2000,87(3):137-141
The Ward Hunt Ice Shelf (83°N, 74°W) is the largest remaining section of thick (>10 m) landfast sea ice along the northern
coastline of Ellesmere Island, Canada. Extensive meltwater lakes and streams occur on the surface of the ice and are colonized
by photosynthetic microbial mat communities. This High Arctic cryo-ecosystem is similar in several of its physical, biological
and geochemical features to the McMurdo Ice Shelf in Antarctica. The ice-mats in both polar regions are dominated by filamentous
cyanobacteria but also contain diatoms, chlorophytes, flagellates, ciliates, nematodes, tardigrades and rotifers. The luxuriant
Ward Hunt consortia also contain high concentrations (107–108 cm–2) of viruses and heterotrophic bacteria. During periods of extensive ice cover, such as glaciations during the Proterozoic,
cryotolerant mats of the type now found in these polar ice shelf ecosystems would have provided refugia for the survival,
growth and evolution of a variety of organisms, including multicellular eukaryotes.
Received: 30 August 1999 / Accepted in revised form: 15 December 1999 相似文献
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印染行业清洁生产技术 总被引:3,自引:0,他引:3
论述了目前印染行业水污染的现状及原因,指出调整产业结构、应用新工艺、大力提倡节约用水、清沽生产将是印染行业实现可持续发展的必由之路。 相似文献
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将时间-活动模式与微环境空气污染物监测相结合估计儿童个体NOx暴露水平. 分别在北京和青岛两市各选择3所学校监测校园环境污染物,并在每个学校选择10名儿童监测其家庭居室空气中ρ(NOx)及个体24 h NOx暴露水平,同时收集其时间-活动信息,采用时间-活动模式估计儿童的个体暴露水平. 交通工具中的NOx暴露水平可通过校门口空气中ρ(NOx)和交通工具的污染水平系数(λ)估计.结果表明:利用时间-活动模式模拟的儿童个体24 h NOx暴露水平为0.041 mg/m3,与调整后的个体暴露实测水平相关性较好(R0.785,P<0.01),差值为(-0.002 6±0.013 0) mg/m3,二者的差异无统计学意义 (t0.139,P>0.05).表明采用时间-活动模式与微环境空气质量监测结果相结合方法估计的儿童NOx暴露水平与个体实际暴露水平一致. 相似文献
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