Thorium-234 based estimation of residence time of bottom-near particulate matter in the Mecklenburger Bucht .

水和沉积物之间的颗粒通量是水层和底栖系统之间物质循环的重要组成部分。因此，海底浑浊区（BTZ）和生物扰动沉积层之间存在永久交换，在深海的情况下，这种交换发生在几天的时间尺度内（再悬浮循环）。该提案旨在确定颗粒在水中的停留时间，BTZ和使用234钍/238铀平衡的梅克伦堡湾西南部的沉积物。为了在浅水环境中应用这一已被证明适用于深海的方法，必须考虑到一些具体的限制，特别是钍在矿物含量较高的颗粒和相对新鲜的有机化合物上的吸附（藻酸蛋白、岩藻多糖和软骨素;与美国查帕尔山Carol Arnosti教授合作）。此外，还应进行水槽实验，以测试增加的电导率和底部谢雷对钍吸附的影响。第二年是专门的实地研究，以测量从浅桑迪到较深的粉质沉积物的横断面上的停留时间和POC。从而可以计算POC在不同类型沉积物和再悬浮回路其他隔室中的停留时间。

Particle fluxes between water and sediments represent a significant fraction of the matter cycling between the pelagic and benthic system. Thus a permanent exchange between the benthic turbidity zone (BTZ) and the bioturbated sediment layers is provided, which in the case of the deep-sea occurs in the time scale of a few days (resuspension loop).This proposal aims to determine residence time of particles in the water, the BTZ and the sediment of the south-western Mecklenburger Bucht using the 234 Thorium/238Uranium equilibrium. In order to apply this approach, which was proven for the deep-sea, in a shallow water situation, some specific constraints have to be considered, especially the adsorption of Thorium on particles with higher mineral content and with relatively fresh organic compounds (Alginin, Fucoidan und Chondroitin; Co-operation with Prof. Carol Arnosti, Chapal Hill, USA). In addition flume experiments should be carried out in order to test the effect of increased turbulences and bottom shere on the thorium adsorption. The second year is dedicated to a field study to measure residence time and POC on a transect from shallow sandy to deeper silty sediment. Thus the residence time of POC in different types of sediments and the other compartments of the resuspension loop can be calculated.