Transit to Mokumanamana: Ship Life and Bioluminescence
Written By Dan Suthers October 12-13, 2004
Tuesday, October 12th
Today is the first day of a two-day transit to Mokumanamana (Necker) Island. Almost everyone slept in. Even Kyle, who usually is up by 0530, slept until 1000. But by the afternoon, everyone seems to be working on organizing their data. Stephani is compiling a database of David and Susan's photographs: stacks of intriguing polaroid proofs sit on the desk next to me.
In the afternoon I saw a backboard outside sickbay and some people inside. It looked like a training session, but who was the volunteer patient? The answer, as you can see, was quite hilarious. We have been assured that the sharks, not us, will eat these patients.
Lobo Thomala gave us a tour of the engine room and associated facilities, including the air conditioning plant, control room, electric motors for the propellors, and the rudder control room. We had to wear hearing protection in the engine room. According to Lobo, the engines aboard (four CAT D398's; one is pictured left) generate 600 kilowatts each or a total of 2.5 megawatts of power: enough electricity to run the town of Ewa. Only three are needed to run the ship: the fourth is a reserve in case of problems. The electricity provides "hotel services" as well as running the electric motors that drive the propellors. All of the equipment is designed to run relatively quietly -- for example, being mounted on rubber pads -- as this vessel was originally designed for surveillance missions: listening to Soviet submarines in the North Pacific under the name "USNS Vindicator". A reassuring note: this means that the ship was also designed to chug through all kinds of bad weather, although we have not needed that capability to date. (That was soon to change ...)
There are a variety of interesting clouds at sunset. Steve Kroening conducted a lesson in "clouds 101".
At night I found some of the the staff relaxing around a hammock on the rear deck, and alerted them to the bioluminescence off the bow (first mentioned in yesterday's article). Darla and I have decided to investigate each evening to see how far south this phenomenon is present.
Wednesday, October 13th
Today people don't sleep in as late, and many of the scientific staff are working on interim reports, to be compiled by Peter. In the morning, the ship pauses in the region of French Frigate Shoals to launch HI-2 so that Scott and Kyle can conduct a comparison of the large ship-based CTD and hand-CTD and radiometry devices from the launch.
Not long after the reports are due, someone in the dry lab looks down the hall and sees smoke coming out of the forward engine room (where a backup engine is located). We call the bridge and report the smoke, and then the bridge announces a fire drill. When the bell rings the crew scramble for their gear while the scientists gather in the dry lab. Since there are no divers in the water during this drill, the lab is crowded. As expected, the fire drill was followed by an abandon ship drill: my 4th, having had the luck to be on board for all of them.
Tonight, David is photographing a coralline algae (Peyssonnelia, species unidentified): some algae makes calciferous structures like coral. David is waiting for the small invertebrates that live in it to start crawling out for their portraints. Darla and I gathered another data point for the crucial question: how far south does the bioluminescence go? The sparkles of light in the foam off the bow seemed decidedly bigger than last night, and lightning could be seen in distant storms.
A little after 2100 we arrived in the region of Mokumanamana and began a TOAD operation (underwater camera). Scott is excited about night operations tonight because this is an area they don't usually get to cover, and it is also an active commercial lobster harvesting area. We saw one Spiny lobster during the TOAD.
After working on an article on fish biomass and predator dominated ecosystems, I looked up "bioluminescence" in an Oceanography textbook, Garrison (2002). I quote:
"I remember as a child walking along a dark California beach where the sand in my footprints glowed after each step. Handfuls of sand thrown out over the wet beach surface burst into fans of blue light strong enough to cast a shadow, and swimmers emerged from the warm water with thousands of glowing points of light clinging to their bodies. The light I saw was caused by dinoflagellates that had multiplied rapidly in the nearshore waters off southern California. In the late 1950s, watewater treatment was not as thorough as it is today, and the effluent was not pumped as far out to sea. The combination of warm, calm water and abundant nutrients often triggered such blooms. These displays are less common today, but on warm September or October nights after the northeast winds have blown the surface water out to sea and upwelling has brought nutrients to the shore, the sand sometimes glows, and waves can flash blue as they break. These dinoflagellates are boluminescent (bios = life, liminis = light). Bioluminescence is the process by which energy from a chemical reaction is transformed into light energy. The imaginatively named compund luciferin is oxidized by the action of the enzyme luciferase, and in the process a blue-green light is emittted. The release of light is very efficient and thus is not accompanied by a release of heat, so the organism does not overheat in the oxydation process." (page 359)
"Some dinoflagellates flash when being attacked by zooplankton. The glow may startle the zooplankter and distract it from feeding. It may also alert larger organisms to the presence of that zooplankter and attract a predator toward the offending grazer. Behavioral studies suggest that dinoflatellate grazers react negatively to a dinoflagellate's blue flash, and perhaps this is why." (page 373)
Often the beauty of nature on a closer look reveals a struggle for survival.