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

这项活动将利用现场清除234-Th作为下沉通量的独立预测指标，对自由漂移的圆柱形沉积物陷阱进行明确(或接近如此)的校准。沉积物捕集器测得的钍通量将与现场清扫所预测的钍通量进行比较。为了避免在解释单一钍剖面方面的历史问题，将进行一项扩大的实验，其中将跟踪钍在时间上的清除和空间上的变化。新的剖面技术还垂直平均了整个水柱，从而确保剖面中任何小规模的最小钍都将被定量包括在内。这组测量将提供迄今为止对沉积物捕集器预计收集的含钍颗粒通量的最明确预测。如果沉积物捕捉器测得的钍通量与预测值相差很大，就能得出结论，捕捉器没有定量地收集负责钍运输的颗粒，因此对其他颗粒类别也不太可能准确。如果这些值一致，就可以得出结论，陷阱对于传输钍的粒子是准确的，因此表明它们对于其他粒子类别也是准确的。无论在哪种情况下，这项实验都将展示一种可靠的现场沉积物捕获器数据校准方法，这将对其他捕集器性能实验(如水动力学)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).