吉林西部不同土地利用方式下的生长季土壤CO2排放通量日变化及影响因素

利用GXH-3051A红外线分析仪,采用动态闭合气室法对吉林西部4种土地利用方式下土壤CO2排放通量日变化进行了定位测量,系统分析了环境因子及土壤理化性质等因素对土壤CO2排放通量日变化的影响。结果表明,水田、旱田、草地和盐碱地土壤CO2排放通量日变化均呈单峰曲线,但排放通量的日均值有较大差异,其中水田和草地排放量较高,分别为1．69μmol·m-2．S-1和1．24μmaol·m-2s-1;旱田和盐碱地较低,为0．50μmol·m-2．S-1和0．63μmol·m-2．S-1。各地类土壤C02排放通量的日均值与其每天上午10：00土壤CO2排放通量值最为接近,即可用该时间测得的土壤CO2排放通量估测日平均值。土地利用方式和大气温度是造成土壤CO2日排放通量差异的主要因素,多年来该区土地利用方式的变化,改变了土壤表层10cm内的土层温度、土壤含水率、有机碳含量、水解氮含量,进而影响土壤呼吸和CO2排放通量;区内水田土壤CO2排放通量与温度的相关性最高（R2=0．8375）,其次为旱田和草地。     

The impact of fragmentation and density regulation on forest succession in the Atlantic rain forest

The Atlantic Rain Forest, an important biodiversity hot spot, has faced severe habitat loss since the last century which has resulted in a highly fragmented landscape with a large number of small forest patches (<100 ha). For conservation planning it is essential to understand how current and future forest regeneration depends on ecological processes, fragment size and the connection to the regional seed pool. We have investigated the following questions by applying the forest growth simulation model FORMIND to the situation of the Atlantic Forest in the state of São Paulo, SE Brazil: (1) which set of parameters describing the local regeneration and level of density regulation can reproduce the biomass distribution and stem density of an old growth forest in a reserve? (2) Which additional processes apart from those describing the dynamics of an old growth forest, drive forest succession of small isolated fragments? (3) Which role does external seed input play during succession? Therefore, more than 300 tree species have been classified into nine plant functional types (PFTs), which are characterized by maximum potential height and shade tolerance. We differentiate between two seed dispersal modes: (i) local dispersal, i.e. all seedlings originated from fertile trees within the simulated area and (ii) external seed rain. Local seed dispersal has been parameterized following the pattern oriented approach, using biomass estimates of old growth forest. We have found that moderate density regulation is essential to achieve coexistence for a broad range of regeneration parameters. Considering the expected uncertainty and variability in the regeneration processes it is important that the forest dynamics are robust to variations in the regeneration parameters. Furthermore, edge effects such as increased mortality at the border and external seed rain have been necessary to reproduce the patterns for small isolated fragments. Overall, simulated biomass is much lower in the fragments compared to the continuous forest, whereas shade tolerant species are affected most strongly by fragmentation. Our simulations can supplement empirical studies by extrapolating local knowledge on edge effects of fragments to larger temporal and spatial scales. In particular our results show the importance of external seed rain and therefore highlight the importance of structural connectivity between regenerating fragments and mature forest stands.     

西安市灰霾天气时间和区域分布特征及影响因素

依据1961—2005年共45年,西安、户县、长安、蓝田、临潼、高陵和周至7个气象台站灰霾观测资料,分析了灰霾天气时间和区域分布特征,并根据1996—2005年近10年西安逐月平均灰霾日数与近10年逐月主要气象要素相关性分析,得出:西安市20世纪70年代是灰霾日出现的高峰时期,并呈逐年减少趋势,灰霾发生的中心区域也在向郊区东南部转移;从影响灰霾天气形成的气象条件来看,气温越低,降水量和风速越小,日照越少,气压越高,越有利于灰霾天气的形成。     

江西省冬季大气典型污染过程的气象成因研究

选取2019年1月江西省两次大气污染过程为研究对象,利用常规气象观测资料、美国国家环境预报中心（NCEP）再分析资料、全球资料同化系统（GDAS）气象数据和空气质量数据,分别从局地气象要素变化、地面天气形势、大气动力和热力条件及污染潜在源区等进行分析,对比两次污染过程形成机制.两次污染过程地面天气形势分别为冷锋前部型和低压倒槽型.冷锋前部型污染形成主要原因为冷空气南下在江西省减弱辐合导致上游细颗粒物输送并堆积,西北风增大细颗粒物浓度降低.低压倒槽型污染形成原因为较长时间处于高湿、小风或静风、逆温下的污染累积.对两次过程中污染较为严重的九江市进行分析,冷锋前部型九江市近地面主要受西风影响,低压倒槽型主要受东北风影响,低压倒槽型九江市风速多在2 m·s^-1以下.两次污染期间大于3 m·s^-1的风速有利于污染物清除.长时间高湿、小风（< 2 m·s^-1）及风场辐合,是低压倒槽型九江市重污染维持较长时间的重要原因.低压倒槽型大气垂直结构较冷锋前部型稳定.低压倒槽型垂直湍流弱、低层风速小于2 m·s^-1,且存在多层逆温和深厚的湿区,冷锋前部型存在明显下沉运动,逆温强度明显弱于低压倒槽.九江市PM_2.5污染潜在贡献源主要来自河南东部、山东西部和安徽西北部;低压倒槽型九江市潜在源区主要位于江西省内及与江西省接壤的湖北东南部、安徽西南部.     

不同生态区土壤溶磷微生物的分布特征及影响因子

研究了盐渍区、重金属污染区和磷矿区土壤中溶磷微生物的数量、组成及与部分土壤化学因子的关系。结果表明,溶磷微生物在不同生态区土壤中的分布各不相同,磷矿区土壤中溶磷微生物数量和种群丰度普遍高于重金属污染区和盐渍区,但优势种属间数量差异不明显。重金属污染土壤中溶磷细菌比例较高,但种群单一,主要以巨大芽孢杆菌(Bacillus megaterium)为优势种,重金属污染区溶磷细菌比例与土壤重金属综合污染指数呈显著正相关(P<0.01),溶磷细菌丰度与有机质含量呈显著正相关(P<0.05)。盐渍土中溶磷细菌比例小,优势种群为巨大芽孢杆菌、假单胞杆菌属(Pseudomonassp.)和黄单胞杆菌属(Flavobacteriumsp.),其数量和种群丰度分别与有机质和有效磷含量呈显著相关关系(P<0.05)。     

拉萨市环境空气中NO2变化特征分析

选取用长光程差分光谱法监测的拉萨市2000年7月-2004年6月环境空气质量监测数据,分析了NO₂变化特征.结果表明:目前拉萨市ρ(NO₂)在<环境空气质量标准>(GB3095-1996)一级标准之内,但呈逐渐上升趋势.拉萨市ρ(NO₂)月均值呈明显的"U"字型分布规律,即1月和年末10-12月高,其他时间低;每年10月至次年1月,ρ(NO₂)月均值超过年均值,月均最高值均出现在12月;每日在8:00-12:00,20:00-24:00有2个高峰值区.汽车尾气、当地居民生活中的燃烧过程是目前拉萨市NO₂的主要产生源,特殊边界层气象条件影响拉萨市环境空气中ρ(NO₂)的变化规律.      

Ecological Analysis of Spleen Hypertrophy in Cyclomorphic Rodents Taking into Account the Type of Ontogeny

The functional approach at the level of physiological functional groups (PFGs) reflecting two types of ontogeny was used to analyze spleen hypertrophy in five species of rodents. In addition to a wide variation of spleen weight, its hypertrophy was observed: in bank voles (Clethrionomys glareolus), the spleen weight was as great as 3.5 g versus the normal value of 100–150 mg. The variation range of the relative spleen weight was estimated. For example, in the dominant species, C. glareolus, this range was considerable (from 2 to 125). A distinct relationship with the types of animal ontogeny was revealed. The genus specificity of the phenomenon—its occurrence in three species of Clethrionomys voles and absence in Microtus voles and mice—was determined in the study region. The animals with normal and hypertrophied spleens did not differ from each other significantly in their vital activity (at least, with respect to the parameters studied). The voles with hypertrophied spleens normally reproduced, and the hypertrophy was asymptomatic. These findings suggest that the populations have adapted to a damaging factor (or factors) in the course of a prolonged coevolution. This parameter is regarded as the indicator of the presence of a damaging factor in the population.     

Alternative Types of Ontogeny in Cyclomorphic Rodents and Their Role in Population Dynamics: An Ecological Analysis

Two alternative ontogenetic pathways regularly effected in the populations of small mammals are analyzed as a manifestation of developmental multiversality. The types of ontogeny in rodents are characterized. These data are reflected in the concept of the functional approach. Multiversality of development in plants and animals is considered. Based on the results of long-term (26-year) observations on the natural populations of six rodent species, the dynamics of relationships between the types of ontogeny, abundance, and basic population parameters are analyzed using an example of a background species (Clethrionomys glareolus). A trigger mechanism of switching to a certain type of ontogeny, the role of environmental factors in actuating this mechanism, and the role of the genotype as a basis of multivalence are discussed. The existence of two developmental variants is regarded as a basis for functional rearrangements providing for a high flexibility of population responses and as a mechanism of population regulation determining the dynamics of rodent fauna. An adaptive population response to a board spectrum of influences, including anthropogenic damage, depends not only on the type and strength of the influence, but also on the functional structure of the population. The concepts described in the paper may explain the significance of critical periods in the life of populations.     

长江产业带开发区现状特点与发展前景

长江产业带开发区处于超常规发展期，以工业开发为主导，开发水平不断提高，地区之间发展不平衡。开发区总方向应坚持以工业、外贸、出口为主的方针，以浦东为龙头，发挥地区优势，加快发展外向型经济，推动长江产业带经济发展。开发区大体划分为六种类型：工业加工型、高新技术产业型、贸易型、工业港口型、综合型和度假型     

秦皇岛区域几类极端天气、气候灾害的特征分析及防灾减灾探讨

秦皇岛区域是气象灾害频发地区，危害最大的有冰雹、暴雨、干旱、洪涝等。通过对秦皇岛地区48年来比较典型的极端天气事件和气候灾害的统计分析，找出极端天气和气候灾害的演变规律，为建立有效的气象灾害监测、预警系统，完善、提高防灾减灾体系提供参考，对提高当地社会和经济，抵御气象灾害的能力，减轻气象灾害具有重要意义。