喀斯特地区阿哈水库水环境中毒性物质潜在健康风险评价

评价阿哈水库中化学致癌物与非致癌物通过饮水途径对成年人和儿童身体健康造成的潜在风险,为污染物治理和水环境风险管理提供科学参考。设置12个采样点,测定砷As、镉Cd、六价铬Cr~(6+)和汞Hg、铅pb、铜Cu、铁Fe、锰Mn、挥发酚、氰化物、氟化物、氨氮NH_3-N,采用美国环境保护署(USEPA)推荐的环境健康风险评价方法进行健康风险评价。结果表明:(1)该水库中毒性物质对成年男性、成年女性、儿童产生的健康总风险度在10~(-3)数量级,达到评价标准中最高危险级别,其中儿童受到的健康风险最高,其次是成年男性,再次是成年女性;(2)化学致癌物的健康总风险及单项风险远高于非致癌物,风险度高出5～6个数量级;(3)化学致癌物中的Cr~(6+)健康风险度最高,风险比重高达99.8%,是主要健康风险贡献源;(4)4个采样断面对3类饮水人群造成的健康危害风险顺序一致,均是入库口2入库口1水厂取水口库中心。Cr~(6+)是首要管控因子;入库口2的健康风险最高,其次是入库口1。     

Effect of ocean conditions on the cross-shelf distribution of walleye pollock (Theragra chalcogramma) and capelin (Mallotus villosus)

Acoustic trawl surveys were conducted in 2000 and 2001 in two troughs located off the eastern coast of Kodiak Island in the Gulf of Alaska as part of a multiyear, multidisciplinary experiment to examine the influence of environmental conditions on the spatial distribution of adult and juvenile walleye pollock (Theragra chalcogramma) and capelin (Mallotus villosus). Continuous underway sea surface temperature samples and water column profiles collected in 2000 and 2001 showed the presence of a sharp shelf‐break front in Chiniak Trough and a mid‐trough front in Barnabas Trough. At distances <22 km from shore, the water column was well mixed, whereas a well‐defined mixed layer was present beyond approximately 22 km from shore. Satellite drifter tracks in Barnabas Trough entered along the upstream edge of the trough and appeared to follow the frontal boundary across the middle portion of the trough. A storm in 2001 weakened stratification and cooled surface water temperature by 1.6–2.1°C. Wind mixing associated with the storm event mixed subsurface chlorophyll a to the surface and enhanced nutrients in the surface waters. The storm event revealed spatial partitioning of summer production in Barnabas Trough, with production concentrated in regions inside the mid‐trough front. In contrast, post‐storm summer production was distributed throughout Chiniak Trough. The spatial distribution of walleye pollock and capelin differed and appeared to be related to differences in habitat characteristics. Acoustic survey data identified four acoustic sign types: age‐1 pollock, adult pollock, capelin, capelin–age‐0 pollock mix. The spatial distribution of these four sign types appears to be influenced by the oceanographic and topographic features of the two troughs. Adult pollock were broadly distributed throughout Chiniak Trough, whereas adult pollock were aggregated on the coastal side of the frontal system in Barnabas Trough. In 2000, capelin occurred with age‐0 pollock. In Chiniak Trough, capelin were most abundant along steep topographic gradients at the edges of the trough and in a deep region near Cape Chiniak, whereas the capelin–age‐0 mix (2000) or capelin (2001) concentrations were observed in slope water intrusions over the outer shelf in Barnabas Trough. Results suggest that habitat selection of walleye pollock and capelin are controlled by different processes. Capelin distributions appear to be limited by oceanographic conditions while other factors appear to be more important for pollock.     

棉花高产高效栽培替代技术研究

以金农棉1号F1代杂交种为材料,研究了棉花漂浮育苗移栽棉和免耕直播棉不同播期和不同密度下对棉花的产量构成因素、成铃分布情况及各种成本、产值及利润的影响。研究结果表明：在单株成铃方面,只有处理1和处理6高于对照：各处理的单铃重都大于ck．其中以处理1的最重．迭到了6．59g．比ck大;各处理之间表分差异不显著;而在皮棉产量和籽棉产量、产值以及利润上．处理3最大。其次是处理4。     

光照强度对樱桃谷肉鸭c-fos、生物钟基因表达及褪黑激素的影响

【目的】研究持续黑暗下给予樱桃谷肉鸭不同强度的瞬时光照,对下丘脑、间脑、垂体和中脑中c-fos基因及相关生物钟基因的表达及血浆和肝脏中褪黑激素含量的影响。【方法】选用144只健康且体重接近的1日龄樱桃谷肉鸭饲养至21日龄,22日龄时随机分为2组,每组6个重复,持续黑暗7 d,期间自由采食和饮水,分别采用10 Lx和80 Lx的LED白光刺激1.5 h,暗适应1.5 h后立即从每个重复选取1只接近平均体重的肉鸭,检测下丘脑、间脑、垂体和中脑c-fos和生物钟基因的表达量,检测血浆和肝脏褪黑激素含量。【结果】10 Lx组的下丘脑和中脑c-fos表达量显著高于80 Lx光照组(P<0.05),间脑中c-fos的表达量显著低于80 Lx光照组(P<0.05),两组垂体组织中c-fos表达无显著影响(P>0.05)。与80 Lx组相比,10 Lx组下丘脑生物钟基因Bmal1、Bmal2、Clock和Per2表达量均显著提高(P<0.05),Cry1表达量也有提高的趋势。10 Lx组间脑Bmal1的表达量显著提高(P<0.05),Bmal2、Clock、Per2和Cr...     

岩溶生态系统土壤酶活性的时空动态及其与土壤肥力的关系——以桂林丫吉村岩溶试验场为例

以桂林丫吉村岩溶试验场为考察基地,研究了不同地貌部位(洼地、坡地和垭口)土壤酶活性(转化酶、蛋白酶、脲酶、碱性磷酸酶和过氧化氢酶)的时空变化特征,结果表明,不同地貌部位土壤酶活性存在明显差异,洼地和垭口土壤水解酶类活性较高,与这两个地貌部位微生物数量较多的结果相对应.试验场不同地貌部位土壤水解酶类活性随土壤深度的增加而逐渐降低,但对于不同的酶和不同的地貌部位,酶活性降低的幅度有所差异.各地貌部位各层次土壤过氧化氢酶活性差别不大.4种水解酶活性的季节变化规律一般是春季上升,夏季或秋季为最高.此外,土壤水解酶类活性与不同地貌部位的土壤养分水平密切相关,一般与土壤有机质、全N、有效N、速效P之间呈显著或极显著正相关,这既说明土壤酶活性在一定程度上反映了岩溶土壤肥力水平的高低,可作为评价岩溶土壤肥力水平的重要指标之一,而且也为评价西南岩溶生态系统脆弱程度提供了新的生物学方面的指标,为不同地貌部位的土地利用方式和植被重建模式提供了一定的理论依据.     

巢湖市北山地貌与岩溶发育演化

岩性和构造控制了巢湖市北山地区的地貌格局和碳酸盐岩山地岩溶地貌发育.研究表明:该区岩溶演化具有长期性、多代性和继承性的特点.     

Restoration of a Danish headwater stream: short‐term changes in plant species abundance and composition

1. This paper describes the short‐term effects (2 years) of stream restoration on vascular plant communities in a 1.4 km upper reach of the River Gudenå, Denmark. The effects of restoration were assessed in terms of the abundance and composition of plant species in the stream, on the banks and in the stream valley. 2. Total species richness was similar before and after restoration, and comprised approximately 150 species representing 12% of the entire Danish vascular plant flora. 3. In the stream, total plant cover had not recovered to pre‐restoration levels 2 years after restoration. Cover by submerged, amphibious and terrestrial species growing submerged decreased, as did the number of amphibious and terrestrial species growing submerged. 4. On the banks, total plant cover almost attained pre‐restoration levels the second year after restoration. The plant communities changed from dominance by non‐riparian species to more diverse communities with a greater number and increased cover of riparian gramineous species requiring a higher soil moisture content. 5. In the valley, the plant communities only changed slightly after restoration, although growth of riparian species was enhanced on the southern side of the stream. Copyright © 2000 John Wiley & Sons, Ltd.     

元江自然保护区土壤与保护

元江自然保护区境内土壤垂直分布明显,主要有黄棕壤、红壤、赤红壤、燥红土和石灰土5个土类.元江自然保护区土壤质地较轻,酸性反应.土壤全量养分以黄棕壤为最高,燥红土最低,其余土类介于二者之间.土壤的速效养分,以水解性N、速效K量较高,而土壤速效P普遍偏低.本区属干热河谷区,生境脆弱,应加强保护区的科学管理,开发利用应十分谨慎.     

四川干旱河谷的分布与面积调查

按照干旱河谷划分的技术标准,采用遥感技术结合地面调查的方法,调查界定了四川干旱河谷的分布与面积。四川干旱河谷分布于川西地区,涉及金沙江、雅砻江、安宁河、大渡河、岷江、白龙江的干流及部分支流,涵盖攀枝花市、凉山州、甘孜州、阿坝州、雅安市的40个县（市、区）,面积锣50885．3hm^2。     

刈割对元谋干热河谷区海狮苏丹草生长及生产性能的影响

以牧草鲜草产量、再生速度、分蘖数等为观测指标,研究不同刈割处理和刈割茬数对元谋干热河谷区海狮苏丹草[Sorghum sudanense(Hay king)Stapf.]生长及生产性能的影响。研究结果表明：海狮苏丹草在干热河谷区具有较好的适应性,在其生长季内可刈割5次;留茬高度和茬数对其再生性能和分蘖能力均有显著影响,其中刈割茬数对其再生速度和分蘖数影响最大,随着刈割茬数增加再生速度显著减慢而分蘖数则明显增加;海狮苏丹草不同留茬高度、刈割茬数对生物量均存在显著差异;就生物量和再生能力来看,海狮苏丹草留茬高度