I really like the gestural nature of the image and its simplicity. My only suggestion is to consider cropping out the lower part of the sand, which lacks interesting detail. I wonder if a square crop would work well with this image?
This has a nice, soft feel. I do like that little pebble. It adds interest. I was wondering what this might look like in b&w and did a conversion to check it out. When doing that, I noticed a very strange pattern in the sand. It’s barely visible in your color version, but stands out in b&w. I’ve never seen anything like it. This does make a nice b&w, btw - you can bring out more detail in the sand because you can push the contrast harder:
