Bottom dynamics in lakes
Bottom dynamics in lakes
复制标题
湖泊底部动态
DOI：
10.1007/bf00940092
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发表时间：
1982
期刊：
影响因子：
2.6
通讯作者：
L. Håkanson
中科院分区：
文献类型：
--
作者：
L. Håkanson
在大多数沉积学背景下，对湖泊底部动力条件（侵蚀、搬运、堆积）的正确理解至关重要。细的粘性物质通常在开阔水域占主导地位，而较粗的沉积物（沙子、砾石）在浅水区域占主导地位，在那里细物质的侵蚀和运输占主导地位。目前，还没有物理模型来描述开放水域中水团的能量含量与泥沙夹带能力之间的联系。水团能量取决于风向、持续时间、速度、风的吹袭以及温跃层的存在。夹带取决于沉积物的密度、压实度、含水量和有机物含量以及底栖动物的数量和类型。四种不同的方法用于确定底栖动力学，两种是典型的阿雷西特方法，两种是典型的阿雷雷克方法。典型的现场和湖泊方法各包括一种基于收集的现场数据的方法和一种基于理论数据的方法。其中一种方法，圆锥装置，首次提出。它由两个锥体组成，其中一个锥角窄，另一个锥角宽，在释放以穿透沉积物之前，在沉积物表面进行调零。用压入比来表示表层沉积物的压实程度。这一简单、廉价的仪器提供了可能与海底动力条件有关的沉积物物理特性的定量数据。
A proper understanding of the bottom dynamic conditions (erosion, transportation, accumulation) in lakes is essential in most sedimentological contexts. Fine cohesive materials generally dominate the open water areas, whereas coarser deposits (sand, gravel) dominate shallow regions where erosion and transportation of fine materials prevail. At present, there is no physical model available which describes the linkage between the energy content of the water-mass and the capacity for sediment entrainment in open water areas. Water-mass energy depends on, e.g. wind direction, duration, velocity, fetch, and the presence of a thermocline. Entrainment depends on, e.g. density, compaction, water and organic content of the sediments and the number and type of bottom fauna.Four different methods are used to determine bottom dynamics, two aresite typical and two arelake typical.Site andlake typical methods each include one method based on collected field data and one based on theoretical data. One method, the cone apparatus, is presented for the first time. It consists of two cones, one of which has a narrow angle and the other a wide angle, which are zero adjusted at the sediment surface before being released to penetrate the sediments. The differential cone penetration, refered to as the penetration ratio, is used to indicate the degree of surficial sediment compaction. This simple, inexpensive instrument provides quantitative data on physical sediment characteristics which may be related to bottom dynamic conditions.