By Stephen Palumbi, PhD.
Being a micromanaging monster takes a lot of energy, and the brain of our stress tanks sucks down more power than I thought.

Coral reefs are dying off around the world. To further his work on the issue, Dr. Stephen Palumbi, director of Stanford’s Hopkins Marine Station, Pew Fellow in Marine Conservation, and OWOO Science Advisor is in American Samoa and the Cook Islands in search of the corals most likely to survive. This is the fifth in a series of special reports from the field that will continue throughout his team’s three-week expedition.

Part 1    Part 2    Part 3    Part 4    Part 6    Part 7


The stress tank is not happy. Sitting in a perfect spot in our little house on Aitutaki, it will not run correctly. It is driving me crazy. The tank’s brain is basically a micromanager, the worst boss you could think of, wanting to know every second exactly what is going on and telling its subordinates (a chiller and a heater) minute by minute what to do. It turns out that being a micromanaging monster takes a lot of energy, and the brain of our stress tanks sucks down more power than I thought. So much that the voltage converter we got for it, that turns 240 volt Cook Island power into 120 v power needed by the stress tank, is barely enough. It can run the brain, but much to my dismay it doesn’t have enough wattage left over to run the heaters, chillers, pumps and lights.

Our guest house on Aitutaki.

Mary, a researcher, snorkeling in the lagoon.

Now what? Until I get an extra converter, we bump to plan B.

First, I give up on the lights I brought…they are special LED bulbs and draw a lot of power. I replace my LEDs with 60 watt bulbs, which double as heaters, since regular bulbs put out a lot of warmth. This is good, since I can’t get the heater to function at all.  The recirculating water pump is the only thing that the main brain will power. Enough is working for a test.

In go the corals, collected for this pilot run at a stunning back reef beach near the end of the old Aitutaki runway. Scattered mounds of Porites corals and a variety of branching corals grow in clumps just a few yards off the beach. Swimming out from there to the reef, perhaps a 300 yards away, we pass gardens of corals and small fish, interspersed with sand channels and old reef rock. I can find all the species I want here – the same ones I had tested in Ofu last week. Four little branches of each coral come back to the beach in a plastic ice cream container. I nestle it into the storage bin of a rented motor scooter, strap a 5-gallon carboy of seawater to the back, and within an hour of leaving the house, I’m back with the makings of our first coral stress test.

A garden of branching corals at the Airport Runway Beach destined to share a small fragment with the stress tank.

The coral stress tank, working with one bulb and no laptop on Aitutaki in the garage of our beach house. Not ideal conditions.

I run it at 33 C (91.4), quite a bit higher than the Aitutaki back reef temperature of 26 C (78.8 F). This should tell me if these corals are heat resistant: Ofu corals take this temperature easily. But the tank does not cooperate. It heats up too fast and too much, and the brain can’t deliver enough power to the chiller. So, I have to turn the chiller on when the tank heats up and turn it off when it is too cool. Though I have a microprocessor in the tank brain and another in a laptop connected to the tank, I spend the day plugging the chiller in and out, in and out.

The tank cycles from 33 degrees to 34 and back again. I can’t stabilize the temperature much better than that manually. But I complete the experiment, running the corals for 4 hours, taking out one branch from each species every hour and adjusting them slowly to normal temperature. The results: …unusable. Between the odd light bulbs and the irregular temperature, all I can tell from this experiment is that these corals are unhappy. I can’t compare the results to Ofu, which is the purpose of this expedition.

Back to the drawing board. I have to fix the lights and get the brain enough power. Nowhere on Aitutaki is there another voltage converter – I’ve looked in the only hardware store. I will have to go diving instead, and wait to get back to Rarotonga, where there is a guy who may have the right thing.



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