From Jennifer Marohasy

By jennifer

According to the Bureau of Meteorology, it was going to storm on Sunday.  Instead, the day broke calm and sunny.   And so, Jenn (not me, there is another one) and M-J from Keppel Dive, took a few of us around to the very exposed Wreck Beach facing due east.   This is the beach where you can get properly wrecked on Great Keppel Island – as the story goes.

According to local legends there is gold here, buried somewhere in the sand with a shipwreck, or three.

I found gold by way of a nudibranch, specifically Chromodoris kuiteri.

Most striking when you drop down to the reef at the northern end of the bay is all the bleaching.   It is everywhere at the reefs fringing this island.

What is not bleached seems to be a particularly dark chocolate brown:  it seems much of the coral either has no zooxanthellae or too much.

Can someone explain to me how this works, how does the zooxanthellae become toxic to the coral when the water becomes too warm? What is the physical mechanism?

I’m told that it is not a case of the zooxanthellae dying insitu, rather the coral polyps kick them out.