This looks here like we've got a very small brine pool.
These are highly dense, highly saline waters.
You have a very high degree of dissolved salt in this water,
and so it's much denser than the overlying seawater and it seeks low spots and so you see pools and sometimes we see rivers of moving brine.
I think we're moving up an extinct, what could be a relic brine waterfall here,
where I think that brine fluid moved down slope.
We can now see pretty clearly the shimmering created by the density contrast in the water of that fluid coming out of the seafloor.
It has been a truly spectacular dive today.
To quote Bill Shedd's email, it's days like these, you can't believe you get paid to do this sort of thing.