Justin’s Log 16-8-99

First an explanation of the images. They are - with lights on and with ‘black-light’ only. These show coral fluorescence – one of the methods we are using to monitor coral health and search for ways to spot early warning signs of reef death. This produced some very exciting results! Two additional pictures include a lab setup for monitoring coral flourscence, under natural light and under UV. Note the small coral in the container: it lights up under UV illumination.

Now the log……

Day 7, or is it 8, into the mission and we are all very tired. Despite the constant wonder of living underwater I think we are all looking forward to that first beer and being able to walk a few more than 5 yards – I am certainly!

Before that however, we have some fascinating experiments ahead of us. Roy Caldwell and Hutch, our ever cheerful Habitat Technician, went to the deep NE site this morning to look for mantis shrimps. They was a population there 4 years ago when we were last here, but they seem to have moved on or disappeared. We are not sure if this indicates anything about the health of the reef but study continues in that direction. We are worried.

Tom (our fearless leader) and Nadav, now known as ‘Newt’ for his ability to spend limitless time underwater, are yelling at each other on the wet-porch.

“South-east.”
“What?”
“SOUTH-EAST”
“OK – West”
“NO! SOUTH-EAST”
“With the sock?”
“Roger that!”

They are measuring polarized light underwater, a facet of light we can’t see at all, but many marine creatures, including mantis shrimps, can. They may use it for navigation and ‘secret-signaling’ to each other.

This ‘language of the reef’ is what fascinates me. As well as polarized light, many reef fish and crustaceans us color to say things to their neighbors, and it is this communication with color that I am trying to understand. So every day – out to the reef to measure fish colors. We have to measure them using special equipment, as our color vision is very different to these animals. In other words, the way they see themselves is very different to the way we see them. As a result our eyes are unreliable for quantifying this.

The sock, by the way, is actually a ladies stocking (heaven knows what it is doing down here) that Tom and Nadav are using to prevent too much light entering their sensor. There is a joke in there about “daylight robbery” but I’m too tired to work it out!

This afternoon we will be glued to our coral work. All of us know from previous work here, and from work on other reefs that the world’s reefs are now in serious danger. Much of Conch Reef has died over the last 4 years and we are desperate to find ways to reverse this trend and stop it reaching the rest of the world.

One way to assess coral health is using their natural fluorescence. This bright light signal, actually similar to that used in fluorescent marker pens, may give us a way to monitor the state of coral reefs. The accompanying images show this ghostly green light coming from a lettuce-coral.

Now it’s time to get out there and see what the reef will tell us today about how to look after it in the future.