Interesting. I'd say that is some sort of underground gas pocket that pushed through to the surface through a crevasse under the sand. It does seem strange that they are seemingly uniform and in a straight line. You don't typically see that in nature. While they may look man-made, 1.7 miles down is a lot for any man made vehicle to handle. A quick back of the napkin calculation puts hull pressure at nearly 4,000 pounds per square inch at that depth. If they aren't natural then someone has a drilling drone in those waters.