Snowmelt Runoff and Water Yield Along Elevation and Temperature Gradients in California’s Southern Sierra Nevada1

Hunsaker, Carolyn T., Thomas W. Whitaker, and Roger C. Bales, 2012. Snowmelt Runoff and Water Yield Along Elevation and Temperature Gradients in California’s Southern Sierra Nevada. Journal of the American Water Resources Association (JAWRA) 48(4): 667‐678. DOI: 10.1111/j.1752‐1688.2012.00641.x Abstract: Differences in hydrologic response across the rain‐snow transition in the southern Sierra Nevada were studied in eight headwater catchments – the Kings River Experimental Watersheds – using continuous precipitation, snowpack, and streamflow measurements. The annual runoff ratio (discharge divided by precipitation) increased about 0.1 per 300 m of mean catchment elevation over the range 1,800‐2,400 m. Higher‐elevation catchments have lower vegetation density, shallow soils with rapid permeability, and a shorter growing season when compared with those at lower elevations. Average annual temperatures ranged from 6.8°C at 2,400 m to 8.6 at 1,950 m elevation, with annual precipitation being 75‐95% snow at the highest elevations vs. 20‐50% at the lowest. Peak discharge lagged peak snow accumulation on the order of 60 days at the higher elevations and 20 to 30 days at the lower elevations. Snowmelt dominated the daily streamflow cycle over a period of about 30 days in higher elevation catchments, followed by a 15‐day transition to evapotranspiration dominating the daily streamflow cycle. Discharge from lower elevation catchments was rainfall dominated in spring, with the transition to evapotranspiration dominance being less distinct. Climate warming that results in a longer growing season and a shift from snow to rain would result in earlier runoff and a lower runoff ratio.     

接种比对餐厨垃圾干式厌氧发酵启动的影响

针对不同接种比对餐厨垃圾干式厌氧发酵启动的影响,对比分析了VS接种比分别为0.36和0.90两种情况下,餐厨垃圾干式厌氧发酵启动过程中pH、NH4-N、COD、VFA、甲烷含量等指标的变化。实验结果表明,启动初期2组样品pH分别快速降至4.74和5.68,均呈酸化状态,经碱液调整后,接种比为0.36的处理仍无法正常产气,接种比为0.90的处理,pH逐步提高,系统正常运行,经72 d的发酵实验,COD去除率达90.29%,甲烷含量高于60%的沼气产量达255.4 L,分析可见,VS接种比是干式厌氧发酵处理的重要参数;此外,与传统湿式厌氧发酵处理相比,餐厨垃圾干式厌氧发酵在较高的VFA和氨氮浓度下,仍能正常运行,采用干式厌氧发酵技术处理餐厨垃圾是可行的。     

Experimental research on recolonisation with <Emphasis Type="Italic">Anemone nemorosa</Emphasis> of the beech forests of the Ruhr district (Germany) floristically impoverished by air pollution

BACKGROUND, AIM, AND SCOPE: High SO(2) concentrations as have been observed over decades in the Ruhr district lead to a remarkable reduction of leaf area in the majority of the characteristic broad-leafed herbs of the Central European beech forests even after only a few months of experimental fumigation. Thus, it is no wonder in the time of high SO(2) pollution, e.g., in the town of Herne (centre of the Ruhr district), that there was not a single beech forest hosting, for instance, Viola reichenbachiana or Anemone nemorosa. As air quality has improved very much over some decades in the Ruhr district, one can expect a recolonisation of the beech forests by the species of former time characteristic for the herb layer. However, one has to consider that only the air pollution was reduced, while soil acidification and contamination with heavy metals and PAH are, on the short run, irreversible. That is why experiments were carried out, considering the question as to whether recolonisation of the forests of the Ruhr district by the aforementioned species is possible and why such a recolonisation up to now has not occurred. MATERIALS AND METHODS: The experiments were carried out in a beech forest situated in the centre of the Ruhr district in the City of Herne. The wood anemone (A. nemorosa) was chosen as test plant because of its high frequency in beech forests on loess soils outside the Ruhr district, and its absence in beech forests in the Ruhr district. The experiments with A. nemorosa were carried out in three variants with different soils: (a): soil of the local forests (R); (b): soil of the local forests whose soot layer was removed (r); (c): imported soil from a clean air region far away from the Ruhr district (Odenwald). RESULTS: Survival of rhizomes of A. nemorosa is possible for some years in the soils of the Ruhr district; however, the establishment of a population could not be achieved. The results obtained by the imported soil show that it is no longer air pollution, but the soil which prevents the establishment of a population. Sexual reproduction is rather impossible because of the thick litter layer with which all of the Ruhr district's beech forests are covered. DISCUSSION: With respect to the unfavourable chemistry of the soil of the Ruhr district and in consideration of the unfavourable attributes of the soot layer, the author expected the following order of the development of shoot numbers: O > r > R. However, the result is: O > R > r. In contrast to the expected result, the soot layer has no negative but slightly positive effects on the implanted rhizomes. A possible explanation is that the soot layer, which is situated immediately below the top soil, prevents the top soil from drying up and thus even protects the rhizomes from desiccation. Also, the possibility has to be considered that the soot layer functions as a nutrient storage area. CONCLUSIONS: At present, a survival of the rhizomes of A. nemorosa in the soils of the Ruhr district is temporarily possible but does not lead to the establishment of a permanent population. This only can be achieved by additional sexual reproduction. However, the thick litter layer present in all beech forests of the Ruhr district prevents the establishment of seedlings, i.e., it does not allow sexual reproduction to contribute to the population. The soot layer situated below the litter layer represents a second hindrance for germination. Other than seedlings, rhizomes are not negatively affected by the soot layer but even a slight stabilisation has to be stated. As a reason for this slightly positive effect, a protection of the upper mineral soil from desiccation by the hydrophob soot layer has to be considered. Secondly, the soot layer may serve as a nutrient storage which is of particular importance in acid soils, because acidification generally leads to a leeching of nutrients. To answer these questions, detailed further research is necessary. RECOMMENDATIONS AND PERSPECTIVES: In order to restore the formerly rich herbaceous layer of the forests of the Ruhr district, experiments (removal of the litter layer; liming; ploughing) should be carried out at broad-scale to solve the question of how the strong negative effects of the established thick raw humus layer can be reduced or even be avoided. When the problem of the humus layer is solved, the beech forests of the Ruhr district today highly impoverished in species will become a vivid ecosystem, rich in flowering herbaceous species and thus much more attractive for the people of the Ruhr district than at present.     

Specific features of the oribatid fauna in high-mountain pine forests of the Eastern Caucasus in relation to altitudinal zonality

The abundance, structure, and distribution of oribatid communities in high-mountain pine forest biotopes of the Eastern Caucasus are described in dependence on elevation above sea level. The oribatid fauna of high-mountain pine forests proved to be characterized by high abundance, an assortment of dominants, and species richness. It was shown that, as the elevation increases, specific dominants typical of particular altitudinal zones appear in communities, and changes in the mass species occur. These species are stable in terms of their long-term dynamics, and zonal groups (communities) demonstrate a high species diversity.     

大气氟污染治理技术

氟化物是当今重要的大气污染物之一,其毒性超过二氧化硫。文章概要叙述我国近年工业废气的氟排放和治理状况。面对日益严峻的污染形势,提请企业界加以关注和治理。文中着重介绍几种常用的技术装备和工艺流程。     

深耘断根对旱地小麦花后根系衰老及产量的影响

在旱地大田条件下研究了深耘断根对旱地高产小麦花后根系衰老及产量的影响。结果表明,４个处理中以冬前深耘断根最好,起身期深耘断根与对照（不断根）次之,冬前和起身期都深耘断根的效果最差。冬前深耘断根可延迟花后根系活力、根系ＳＯＤ与ＣＡＴ活性、根系可溶性蛋白质含量下降及根系ＭＤＡ含量的升高,从而延迟根系衰老。同时,冬前深耕提高了成穗数及成穗率,使产量提高,因而在旱地高产麦田应提倡冬前深耘断根。图５表１参１     

Visual preference and ecological assessments for designed alternative brownfield rehabilitations

This paper describes an integrative method for quantifying, analyzing, and comparing the effects of alternative rehabilitation approaches with visual preference. The method was applied to a portion of a major industrial area located in southern Italy. Four alternative approaches to rehabilitation (alternative designs) were developed and analyzed. The scenarios consisted of the cleanup of the brownfields plus: (1) the addition of ground cover species; (2) the addition of ground cover species and a few trees randomly distributed; (3) the addition of ground cover species and a few trees in small groups; and (4) the addition of ground cover species and several trees in large groups. The approaches were analyzed and compared to the baseline condition through the use of cost-surface modeling (CSM) and visual preference assessment (VPA). Statistical results showed that alternatives that were more ecologically functional for forest bird species dispersal were also more visually preferable. Some differences were identified based on user groups and location of residence. The results of the study are used to identify implications for enhancing both ecological attributes and visual preferences of rehabilitating landscapes through planning and design.     

Influence of furfural concentration on growth and ethanol yield of Saccharomyces kluyveri

Furfural is an important inhibitor in ethanol fermentation process using lignocellulosic hydrolysates as raw materials.In order to find out the fuffural concentration range in which furfural inhibits the fermentation process,we used one strain Saccharomyces kluyveri selected from soil and cultured in several different furfural content media under low glucose concentration condition.Experiment results showed that microorganism growth was stimulated and dry cell weight decreased when furfural concentration in the medium was 0.25 mg/ml.Furfural had negative effect on cell growth when its concentration was above 1.00 mg/ml.At the same time,the strain growed better and had a higher glucose consumption rate in 5% original glucose concentration condition than in 3% original glucose concentration condition.The results showed that appropriate exaltation of original glucose concentration in stalk hydrolysates will increase the strain resistance to furfural.     

退耕还林(草)的生态补偿机制完善研究——以西部黄土高原地区为例

生态补偿措施是退耕还林（草）工程顺利进行的重要保障。以退耕还林（草）在黄土高原地区的实施情况为例，通过问卷调查，应用生态经济学的相关理论进行分析，认为应从以下几个方面完善退耕还林（草）工程的生态补偿机制：首先，建立退耕还林（草）的补偿组织体系；其次。以退耕还林（草）所造成的农民机会成本的损失来确定补偿标准。根据工程的进程和资金的投入情况．可将生态补偿划分为基本补偿、产业结构调整补偿和生态效益外溢补偿三个阶段；第三，根据产业结构调整取得显著成效所需的时间来确定补偿年限；最后提出退耕还林（草）的补偿方式及可能的资金渠道来源。生态补偿计量方法的研究将是今后研究的重点和难点。