Stromatolite swim...

Back in June this year, I finally got to go on this stromatolite swim tour. I've been trying to book on to this trip for years! This tour almost never runs, simply because you need a minimum of 4 people. This year, I got lucky! Those weird knobby bits on the bottom of the ocean are all colonies - large colonies of cyanobacteria. The ocean is hyper saline in this Bay. What is interesting is the diversity of shape of stromatolite. The ones that get exposed at low tide don't have any growth on them. As I got deeper, the stromatolites became covered in all sorts of other algal growth. Fish live amongst the stromatolites, and there are more varieties of fish than expected. As I went deeper still, the stromatolites became more like an algal mat, and then formed a reef-like ridge complete with sea-snake!