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981.
The sediments of two tidal flats in Yaquina Bay, Oregon, USA, were studied to determine the distribution and abundance of the interstitial microalgal communities. The hydrography of the bay, as well as fluetuations in various physical and chemical parameters appear to regulate the biomass and the vertical and intertidal distribution of these organisms.  相似文献   
982.
983.
984.
985.
Benthic ecology of the high arctic deep sea   总被引:2,自引:0,他引:2  
An analysis is made of 75 quantitative benthic samples collected by Mini-LUBS, and 28 qualitative benthic samples collected with the small biological trawl, from Fletcher's Ice Island, T-3, while it was drifting over the Alpha Cordillera region of the High Arctic Ocean during October, 1969 through February, 1970 and in March, 1972. The depth range was 1000 to 2500 m. Benthic foraminiferans account for about 53%, bivalves for 27%, sponges for 7%, and polychaetes for 5% of the total biomass. Other groups make up the remaining 8%. The weight ratio of macro- to meiofauna is 1:1. Numerically, excluding Foraminifera, polychaetes comprise 42%, nematodes 16%, sponges 11%, and bivalves 8% of the total fauna. The remaining 23% is composed of 13 other taxa. Biomass in the Amerasian Basin at depths of 1000 to 2000 m is extremely low (0.04 g/m); it is comparable to depths of 5000 to 6000 m in the oligotrophic red-clay area of the mid-Pacific Ocean, and is 40 times less than biomass at comparable depths from Antarctica and off Peru. Diversity, as calculated by the Shannon-Weaver method, is low, suggesting that the Arctic ecosystem is young, as reported in earlier studies (Dunbar, 1968; Menzies et al., 1973). Although the H' values are low, no biocoenoses of oligomixity in the deep Arctic are revealed, contrary to previous statements and beliefs. There may be fewer major benthic groups in the Arctic Ocean than in other parts of the world oceans. Following the conventional terminology of Petersen (1913) and Thorson (1957), we have called the High Arctic biocoenoses of the Alpha Cordillera region a Thenea abyssorum-Spirorbis granulatus community.  相似文献   
986.
In capture-recapture experiments, fish populations can be studied by two different sampling procedures. In both procedures, tagged fish are released on capture, but untagged fish are in one procedure released after tagging, in the second procedure they are retained. Using the two sampling techniques, Rafail (1971a,b) gave expressions for the estimation of an assumed constant (C) of proportionality between probabilities of capture of tagged to untagged fish which are simplified here to forms easier for calculation. The estimation of this constant (C) aids in estimation of abundance and mortality rates of untagged fish which are assumed to differ from those of tagged fish.  相似文献   
987.
The phenol and m-cresol biodegradations were studied using the mutant strain CTM 2 obtained by the He-Ne laser irradiation on wild-type Candida tropicalis. The results showed that C. tropicalis exhibited the increased capacity of phenolic compounds degradation after laser irradiation. It could degrade 2600 mg/L phenol and 300 mg/L m-cresol by 5% inoculum concentration, respectively. In the dual-substrate biodegradation system, 0-500 mg/L phenol could accelerate m-cresol biodegradation, and 300 mg/L m-cresol could be completely utilized within 46 hr at the presence of 350 mg/L phenol. Besides, the maximum biodegradation of m-cresol could reach 350 mg/L with 80 mg/L phenol within 61 hr. Obviously, phenol, as a growth substrate, could promote CTM 2 to degrade m-cresol, and was always preferentially utilized as carbon source. Comparatively, low-concentration m-cresol could result in a great inhibition on phenol degradation. In addition, the kinetic behaviors of cell growth and substrate biodegradation were described by kinetic model proposed in our laboratory.  相似文献   
988.
An air quality modeling system was used to simulate the effects on ozone concentration in the northeast USA from climate changes projected through the end of the twenty-first century by the National Center for Atmospheric Research’s (NCAR’s) parallel climate model, a fully coupled general circulation model, under a higher and a lower scenario of future global changes in concentrations of radiatively active constituents. The air quality calculations were done with both a global chemistry-transport model and a regional air quality model focused on the northeast USA. The air quality simulations assumed no changes in regional anthropogenic emissions of the chemical species primarily involved in the chemical reactions of ozone creation and destruction, but only accounted for changes in the climate. Together, these idealized global and regional model simulations provide insights into the contribution of possible future climate changes on ozone. Over the coming century, summer climate is projected to be warmer and less cloudy for the northeast USA. These changes are considerably larger under the higher scenario as compared with the lower. Higher temperatures also increase biogenic emissions. Both mean daily and 8-h maximum ozone increase from the combination of three factors that tend to favor higher concentrations: (1) higher temperatures change the rates of reactions and photolysis rates important to the ozone chemistry; (2) lower cloudiness (higher solar radiation) increases the photolysis reaction rates; and (3) higher biogenic emissions increase the concentration of reactive species. Regional model simulations with two cumulus parameterizations produce ozone concentration changes that differ by approximately 10%, indicating that there is considerable uncertainty in the magnitude of changes due to uncertainties in how physical processes should be parameterized in the models. However, the overall effect of the climate changes simulated by these models – in the absence of reductions in regional anthropogenic emissions – would be to increase ozone concentrations.  相似文献   
989.
介绍了中国石油化工股份有限公司济南分公司采用双膜法处理炼油达标污水回用于锅炉的中试及应用情况,提出了工艺设计及运行中可以采用的几项节能减排措施.  相似文献   
990.
环境样品中多氯联苯的分析技术   总被引:4,自引:0,他引:4  
作为一种持久性有机污染物,多氯联苯在地球上的分布十分广泛。然而由于多氯联苯在环境样品中残留浓度低、干扰物质多且组成复杂,必须对环境样品进行预处理。目前较为常用的含多氯联苯样品的前处理技术有:溶剂萃取技术、固相萃取技术、固相微萃取技术、超临界萃取技术、微波萃取技术和加速溶剂萃取技术等,分析经过技术处理以后的样品常用的方法有化学分析方法和生物分析方法,化学方法包括气相色谱法,气相色谱质谱分析法等;生物方法有生物传感器测定法、表面胞质团共振检测、以Ah受体为基础的生物分析法和酶联免疫检测法。中国在这方面的研究投入不够,应加大人力、财力和物力的支持,提高环境样品中多氯联苯的检测水平。  相似文献   
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