Cyanobacteria?

Another water piece that takes place at Cane Bay, St. Croix, US Virgin Islands. Two days ago, while swimming, we noticed this stuff attached to the coral. At first look i thought it was a shredded white plastic bag billowing in the water. It was too far down to retrieve so i kept swimming.

A few strokes later i saw some more of it looking more stringy and wondered what it was. i stopped for a longer look but again thought it was more plastic and kept going. The other swimmers had noticed it by now too and when we reached the first buoy we had seen so much of the stuff that when our heads came out of the water we all said "What iiisssss that stuff?"

Remember, we have been swimming out here three times a week for years. We have watched all sorts of changes and have a real feel for anything out of the ordinary. In 2005 we noticed the brain coral turning this lovely lavender color and then watched in horror as coral bleaching turned the floor of the ocean into a white bone yard. We didn't understand at the time that the beautiful shade of lavender was the corals last gasp.
So that day, when we started discussing it, we were in about 40-50 feet of water. We tried studying this new oddity from the surface. We floated around, looking down, looking up, talking about it. We determined that the material looked completely alien and was definitely not plastic. The more we looked the more we saw.

We couldn't dive down that far so the rest of the swim was spent noting how much of it there was and the area it took up over the live coral. On the way back to shore we agreed one of us needed to go down and get some because it was just too mysterious. We had to wait until we were in about 15 feet of water so we would have enough air to actually scope it out while underwater and collect some.

Two of us dove down and grabbed it off the coral, it came off pretty easily. We brought the samples up to the surface in our fists. It was like nothing we had ever felt before. Rubbery and spongy, stringy and globular and two different colors. One batch was pale pink and the other was pale yellow.

Each of us stuck the stuff between our cap and mask on the backs of our heads so we could swim in without really having to handle it too much. We had no idea if it was harmful so we tried to be cautious.

It was agreed that i would take the stuff home, photograph it and send it off. i did that and soon responses started coming in. Cyanobacteria seemed to be the prevailing answer except the pictures i was sent to look at didn't look like what i had. One scientist said it could possibly be a precursor to more coral bleaching which put me in a terrible mood. i sure hope not...we don't have much coral left.

i left the stuff outside and by mid afternoon it had turned a dark ugly black mess.

Now two days later, after notifying the dive shop and Fish and Wildlife, the stuff is gone. Completely gone, not a bit of it is around. The coral is clear except for the usual algae. We searched everywhere and are completely mystified as to how this unusual growth could have vanished so quickly.

My friend says i should keep the sample i have just in case someone wants to do a chemical analysis. i'm thinking it is too far gone but i've stored it outside just in case.

i'm putting the pictures up on line so if anyone can identify it conclusively let me know. If you double click on the images you will get a larger view.

It is definitely one of those mysteries of nature that we would like to have more answers about.