SGER: Evaluation of Sediment Trap Fluxes by Thorium Scavenging, a Three Dimensional Approach

这项活动将使用234-钍的原位清除作为下沉通量的独立预测因子，对自由漂流的圆柱形沉积物捕集器进行明确（或几乎如此）校准。沉积物捕集器测量的钍通量将与原位清除预测的钍通量进行比较。为了避免单一钍剖面解释的历史问题，将进行一个扩展实验，其中钍的时间清除和空间变化都将被跟踪。新的剖面技术还对整个水柱进行垂直平均，从而确保剖面中任何小规模的钍最小值都将被定量地包括在内。这组测量结果将提供迄今为止最明确的含钍粒子通量预测，沉淀物捕集器预计将收集到含钍粒子通量。如果沉积物捕集器测量的钍通量与预测值相差很大，则可以得出结论，捕集器不能定量地收集负责钍运输的颗粒，因此可能不太可能对其他颗粒类别也准确。如果这些值一致，则可以得出结论，该捕集器对运输钍的粒子是准确的，从而表明它们对其他粒子类别也可能是准确的。在任何一种情况下，该实验都将展示一种可靠的方法来校准现场的沉积物捕集器数据，这将对捕集器性能（例如水动力学）的其他实验有用。

This activity will conduct an unambiguous (or nearly so) calibration of free-drifting cylindrical sediment traps using the in situ scavenging of 234-thorium as an independent predictor of the sinking flux. Thorium fluxes as measured by the sediment trap will be compared with predicted thorium fluxes from the in situ scavenging. To avoid historical problems with the interpretation of single thorium profiles, an expanded experiment will be performed in which both the thorium scavenging through time and the variability in space will be followed. The new profiling technique also averages the entire water column vertically, thus ensuring that any small-scale thorium minima in the profile will be quantitatively included. This set of measurements will provide the most unambiguous prediction to date of the thorium-bearing particle flux that a sediment trap is predicted to collect. If the sediment trap measured thorium flux differs greatly from the predicted value, it will be able to be concluded that the trap does not quantitatively collect the particles that are responsible for thorium transport and thus may be unlikely to be accurate for other particle classes as well. If the values agree, it can be concluded that the trap is accurate for the particles that transport thorium and thus suggest that they may be accurate for other particle classes as well. In either case, this experiment will demonstrate a robust method for the calibration of sediment trap data in the field that will be useful for other experiments on trap performance (e.g. hydrodynamics).