Observation and modelling of bubble growth and rise in muddy sediments.

就像面包一样，近岸和沼泽沉积物中的微生物发酵(死亡)有机物产生形成气泡的游离气。这些天然气泡主要由甲烷组成，它们构成了这些气体从海洋和淡水沉积物进入大气的最重要方式。这些气泡使人们几乎不可能用声音(声纳)来成像海底，并可能导致沉积物中的不稳定，从而威胁到海底的结构。我的研究目的是了解和预测这些气泡是如何生长的，它们可以达到多大，一堆沉积物中可以存在多少数字，以及它们如何以及何时上升和离开沉积物。之所以很难知道这些事情，是因为我们看不到沉积物中发生了什么。我们发现了关于这些气泡的一些非常奇怪的事情。在使用X光CT扫描仪时，就像在医院中发现的那样，我们发现这些气泡不是球状的，而是薄薄的圆盘。如果我们假设沉积物像弹性材料(像海绵)一样撕裂，为充满气体的新洞腾出空间，这就是气泡，我们就可以预测其形状和大小。

Just like in bread, micro-organisms in nearshore and marsh sediments ferment (dead) organic matter to produce free gas that forms bubbles.  These natural bubbles are primarily made of methane, and they constitute the most important way this gas enters the atmosphere from marine and freshwater sediments.  These bubbles make it almost impossible to image the bottom with sound (sonar), and can cause instabilities in the sediment which threaten structures on the seafloor.   My research aims to understand and predict how these bubbles grow, what size they can reach, what numbers can exist in a volume of sediment, and how and when they rise and leave the sediment.  The reason it is difficult to know these things is because we cannot see what happens in sediments.  We have discovered some very odd things about these bubbles.  Using an X-ray CT scanner, like those found in hospitals, we have found that these bubbles are not spheres, but thin disks.  And we can predict the shape and size if we assume that the sediment acts like an elastic material (like a sponge) that tears apart to make room for a new hole filled with gas, which is a bubble.