Diet of Littoraria scabra, while vertically migrating on mangrove trees: Gut content, fatty acid, and stable isotope analyses

The snail, Littoraria scabra, is a dominant grazer on tropical mangrove trees, and may play an important role in the food web dynamics of these ecosystems. Its daily vertical migration to avoid tidal submersion results in exposure to varying food types and abundances. A comprehensive diet analysis – gut contents, fatty acid profiles, and stable isotopes (δ¹⁵N and δ¹³C) – was conducted on snails migrating along mangrove trees and snails maintained in non-tidal mesocosms at Nananu-i-ra, Fiji Islands. In addition, fatty acid profiles and stable isotope signatures were obtained from surface scrapings of mangrove roots, trunks, branches, and leaves. Results from this multi-technique study indicate that L. scabra is mainly a generalist herbivore, which easily shifts diets depending on food availability, and which also has the ability to ingest and assimilate zooplankton. Ingestion of greater quantities of diverse foods (i.e., microalgae, foliose/corticated macrophytes, filamentous algae, mangrove tissues, zooplankton) takes place in the bottom areas of mangrove trees (roots and trunks) during low tides, while top areas (branches and leaves) provide limited food resources for snails feeding during high tides. However, snails preferentially assimilate microalgae and bacteria, regardless of their feeding habitat (different areas within mangrove trees and non-tidal mesocosms). The daily vertical movements of this snail result in variable feeding times, ingestion of different food types and amounts, and different assimilations. These findings also suggest that organic matter derived from mangrove tissues may not be readily transferred to higher trophic levels through this grazing pathway.     

涠洲11-1-A1井酸化实验分析

根据对涠洲11-1-A1井的油层物性、储层特征及敏感性分析,采用醇基酸作为酸化施工主处理液,这样既减少了对开发层位的损害,又保证了处理液对地层有适宜的、较高的溶蚀率,对解除钻井液和固井水泥浆造成的污染堵塞具有明显效果。经过酸液类型及浓度的确定、添加剂的筛选、流动模拟及残酸分析等室内试验研究,确定了适用于该井海上酸化的酸液配方。     

DEGRADATION OF NATURAL RESOURCES BY ENVIRONMENTAL POLLUTION——A Comparative Study Between Huizhou City and Zhaoqing City

１　ＩＮＴＲＯＤＵＣＴＩＯＮＢｏｔｈｒｅｓｏｕｒｃｅａｎｄｅｎｖｉｒｏｎｍｅｎｔａｒｅｒｅｌａｔｉｖｅｃｏｎｃｅｐｔｉｏｎｓ,ｗｈｉｃｈａｒｅｒｅｌａｔｉｖｅｔｏｔｈｅｓｙｓｔｅｍｓｔｈｅｙｒｅｆｅｒｔｏ．Ｔｈｅｅｎｖｉｒｏｎｍｅｎｔｏｆａｃｅｒｔａｉｎａｒｅａ（ｏｒａｃｅｒｔａｉｎｂｕｓｉｎｅｓｓ）ｉｓｐｏｓｓｉｂｌｙｔｈｅｒｅｓｏｕｒｃｅｓｏｆｔｈｅｓｕｒｒｏｕｎｄｉｎｇａｒｅａｓ（ｏｒａｎｏｔｈｅｒｂｕｓｉｎｅｓｓ）．Ｔｈｅａｔｍｏｓｐｈｅｒｅ,ｗａｔｅｒｂｏｄｉｅｓａｎｄｓｏｉｌｏｎｔ…     

STUDY ON THE ISOTHERMS OF THE INTERACTION BETWEEN SUSPENDED PARTICLES AND Cu (Ⅱ) IN THE HUANGHE RIVER

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｖａｒｉｏｕｓｐｈｙｓｉｃａｌａｎｄｃｈｅｍｉｃａｌｒｅａｃｔｉｏｎｓｔｈａｔｏｃｃｕｒｂｅｔｗｅｅｎｔｈｅｓｕｓｐｅｎｄｅｄｐａｒｔｉｃｌｅｓ,ｓｅｄｉｍｅｎｔｓ,ｅｔｃ.ａｎｄｈｅａｖｙｍｅｔａｌｓｉｎａｎａｔｕｒａｌａｑｕａｔｉｃｓｙｓｔｅｍｐｌａｙｅｘｔｒｅｍｅｌｙｉｍｐｏｒｔａｎｔｐａｒｔｓｉｎｃｏｎｔｒｏｌｌｉｎｇｔｈｅｄｉｓｔｒｉｂｕｔｉｏｎｐａｔｔｅｒｎ,ｍｉｇｒａｔｉｏｎａｎｄｔｒａｎｓｆｏｒｍａｔｉｏｎｏｆｈｅａｖｙｍｅｔａｌｓｔｈｅｒｅ.Ｓｉｎｃｅ…     

丁二酸柱撑水滑石的制备及表征

以镍铝水滑石为前体（主体）,以蒸馏水为分散介质,用离子交换法组装丁二酸根（客体）插层水滑石,同时用一步合成法合成丁二酸根插层水滑石,并用XRD,IR,TG-DTA和元素分析等手段对样品进行了表征。结果表明,离子交换法制得的产品中丁二酸根阴离子取代了镍铝水滑石前体层间的碳酸根离子,组装得到晶体结构良好的丁二酸根插层水滑石,层间距为1．23nm。     

原子吸收光谱法测定氰化液中的铅

通过对比实验,选用柠檬酸钠做络合剂,实现了在碱性介质中用原子吸收光谱测定铅的方法。应用该方法测定实际样品的结果与其他方法相符,对于2.19mg/L Pb浓度的试液10次测定的RSD为1.8%。     

柠檬酸—硝酸铝溶剂溶解磷灰石中全磷

试验了用柠檬酸＿Ａｌ（ＮＯ３）３溶液做溶剂分解磷灰石的预处理方法。结果表明,在微沸加热６ｍｉｎ条件下,质量浓度分别为３２ｇ／Ｌ和９０ｇ／Ｌ的柠檬酸＿Ａｌ（ＮＯ３）３混合溶剂可以有效地分解磷灰石,测定全磷的回收率＞９９％,与王水溶样结果相符,并用测定磷灰石标样中全磷进行验证,说明方法可靠。     

非饱和带水气二相渗流动力学模型

非饱和带地下水运动实质上是一个水气二相渗流过程。本文以多相渗流理论为基础,从水气二相渗流的连续性方程和达西定律出发,推导了非饱和带水气二相渗流的耦合动力学模型,讨论了模型的IMPES和全隐式联立求解方法的原理和步骤,认为IMPES求解方法由于达西系数项的处理,饱和度的计算均采用显式,因此该解法具有稳定性差、精度低且要求计算时间步长小的局限性;而全隐式联立求解方法是联立求解气相、水相方程,同时求出压力和饱和度值,因此压力和饱和度值都是隐式求出,具有较高精度,且无条件稳定,应是今后模型求解的重点研究内容     

利用脂肪酸标记法对南极罗斯海桡足类优势物种的食性研究

脂肪酸标记法是浮游动物食性研究的一种重要方法.将提取的脂质区分为中性脂和极性脂,可以进一步查明不同脂质在浮游动物食性研究中的作用.本研究通过分析不同脂质的脂肪酸构成,对2013年1月中国第29次南极考察期间在罗斯海采集的5种优势种桡足类的食性进行了研究.结果显示:5种桡足类的极性脂脂肪酸具有相似的组成,无法给出桡足类食...