Comparison of ecophysiological characteristics between introduced and indigenous mangrove species in China

Due to its rapid growth, the introduced mangrove species Sonneratia apetala from Bangladesh has been widely used in mangrove restoration in southeastern China since 1985. As an indigenous mangrove species in Hainan, China, Sonneratia caseolaris was also planted in Guangdong Province for afforestation purposes. Both species have developed well in their new habitats, but their ecophysiological differences with the native mangrove species have not been studied. In this study, leaf gas exchange, water and nitrogen use efficiencies of two Sonneratia species were compared with those of selected native mangrove species (Avicennia marina, Aegiceras corniculatum, Kandelia candel, and Excoecaria agallocha) in Hainan and Shenzhen. The introduced S. apetala maintained lower carbon assimilation rate (A) and photosynthetic nitrogen use efficiency (PNUE) than the indigenous S. caseolaris. In Shenzhen, the two introduced Sonneratia had comparable photosynthetic rates and water use efficiency (WUE) with the native mangrove species, except that PNUE in S. caseolaris was significantly higher than in the native mangrove species. The two Sonneratia species showed significant overlap in PNUE and long-term WUE. Photosynthetic parameters derived from leaf photosynthetic light–response curves and A–C_i curves also suggested lower carbon assimilation capacities for the introduced Sonneratia than for the native mangrove species in both study sites. The lower light compensation point (LCP) of two introduced Sonneratia in both study sites also indicated a better adaptation to a low light regime than the native mangrove species. The results of photosynthetic capacities indicated that the introduced mangrove species have little competitive advantage over local native mangrove species in their respective new habitats.     

Numerical study on salinity stratification in the Pamlico River Estuary

The variations of current circulation, salt intrusion, and vertical stratification under different river flow and wind conditions in the Pamlico River Estuary (PRE) were investigated in this paper using a three-dimensional numerical model. The model was calibrated and verified against water level variation, temperature, and salinity variations during 2003 and 2001, respectively. Eight sensitivity tests were conducted with different river flow and wind conditions specified in the model. Model results show that salinity intruded further upstream under scenarios with low flow, downriver local wind, and remote-wind-caused water level set-up conditions. In contrast, the responses of salinity stratification to different environmental forcing functions were different in different portions of the estuary. Salinity stratification was enhanced under high flow condition at the lower part of the estuary, under upriver wind near the river mouth, under downriver wind at the upstream to middle portion of the estuary, and under remote-wind-caused water level set-up condition at the majority of the estuary except near the river mouth. Model results also show that across-channel wind tended to reduce salt intrusion and salinity stratification in the PRE through increased vertical mixing.     

胶州湾海水中悬浮颗粒对溶解态微量元素的影响

运用离子色谱离线螯合结合ICP-MS的方法,对胶州湾海水中的微量元素(V,Co,Ni,Cu,Mo,Cd,Pb,U,REEs)进行了精确的定量分析。在测试前对在同一站位不同层位采集的平行海水样品进行了两种不同的酸化处理:一份采取先过滤后酸化的方式,以获得海水中溶解态微量元素的含量;另一份采取直接酸化后分析的方式,以评估悬浮颗粒中的可交换态微量元素对溶解态微量元素测定结果可能造成的影响。通过对比研究发现,不同处理方法得到的V、Ni、Cu、Co、Pb以及稀土元素(REEs)的质量浓度存在很大差异,说明悬浮颗粒物质可能对海水中相应元素的测定产生较大的影响。各种微量元素之间的差异和相应离子或离子团的电荷性质、在海水中的配位作用以及悬浮颗粒物质的表面电荷性质有关。初步研究结果表明,在类似于胶州湾这样的近海海域,悬浮颗粒物质是控制微量元素分布特征的一个重要因素。     

热带风暴热力非对称结构对其运动的影响

研究了热力非对称结构对0421号热带风暴"海马(Haima)"的移动和强度变化的影响。通过物理量场诊断分析发现,热带风暴(气旋)的热力结构在垂直、水平方向均呈非对称分布。热力因子对热带风暴的影响,主要体现在低层。热带风暴朝其移向前方的风暴内部的非绝热增温中心偏折,并有向此方向加速的趋势。了解热带风暴的热力结构分布特征及其对热带风暴移动的影响,对短期预报热带风暴的移动有一定的指示意义。     

应用能量色散X荧光衍射仪分析海绵元素组成

通过能量色散X荧光衍射仪（EDXRF）对3种南海潮间带海绵：细薄星芒海绵Stelletta tenui（Lindgren）、澳大利亚厚皮海绵Craniella australiensis （Carter）和多皱软海绵Halichondria hugosa （Ridley＆Dendy）的元素组成和含量进行了研究,并与两种黄海潮间带海绵进行了比较。结果表明,海绵体内的元素组成受种属差异的影响较大,溴元素的含量可能同一定的活性物质产生相关。另外,不同海绵具有骨针形态的多样性,为深入研究内部合成机制提供了材料。     

弱流场调制下的海面微波散射模拟研究

根据海面微波散射的多尺度模型以及波流相互作用理论,对一维弱流场调制下的海面微波散射截面进行了数值模拟。结果表明,利用数值方法直接求解波作用量方程获得的海浪调制谱并结合多尺度模型可以较好地模拟弱流场引起的雷达散射截面的变化。内波等海洋现象调制了海浪谱,使得雷达散射截面反映出这些海洋特征,整个调制过程的模拟对于分析这些海洋现象并更好地利用其雷达数据具有重要意义。     

抽水和建筑荷载双重作用下的地面沉降模型

依据含水层质量守恒原理,推导了非固结地层在建筑荷载作用下的地面沉降机理模型,并将其与Jacob假定下抽水引起的地面沉降弹性模型相比较,结果发现两种模型的机理表达式完全一致,仅区别于水动力原因或实质的不同.在同一坐标系中,根据线性叠加原理,抽水沉降漏斗和荷载沉降漏斗可能都落在地下水位降落漏斗内.假定两者为相互独立事件,给出了抽水和建筑荷载双重作用下的地面沉降模型,表明其如果以水位降深为制约因子,则可以对水动力实质完全不同的两种沉降过程进行线性叠加计算.     

山东省地籍管理信息系统建设中应注意的几个问题

地籍管理是国土资源管理的一项基础工作,它通过地籍调查和土地登记工作,对土地的利用状况、产权产籍状况及其法律关系依法进行确认,从而为国土资源管理工作和社会经济发展提供服务。     

湛江海区8种常见海藻营养成分分析

对采自湛江沿海的8种常见海藻的营养成分进行分析。结果显示:碳水化合物是构成这8种藻体的主要成分,占藻体干重的48.22%～69.16%。蛋白质占2.81%～15.44%,平均为9.25%,且蛋白质中氨基酸含量高,平均16.01%,氨基酸组成中天冬氨酸、谷氨酸、甘氨酸、缬氨酸和亮氨酸含量多;绿藻门种类无论是蛋白质还是氨基酸含量都高于红藻门和褐藻门的种类,4种绿藻的氨基酸评分最高。粗脂肪占0.15%～1.17%,平均0.56%。粗纤维的平均含量近似于碳水化合物的一半。根据蛋白质和粗脂肪的比例,叉枝藻Cymogongrus flabelliformis和盾叶蕨藻Caulerpa racemosa var.peltata均可作为高蛋白、低脂肪的良好食物来源。矿物质中铁、锌含量丰富,介于0.311～1.722mg/g间,铜、砷和镍含量超标。