FeMO2 Dive Cruise 2007
Report Day 03 -- Saturday 13 October 2007 -- Jason, Medea and the Golden Fleece
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FeMO2 Dive Cruise 2007 |
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Jason and Medea had been put in the water shortly after midnight. Medea is a second smaller robot that hangs on the cable between Jason and the ship. In mythology Medea is Jasons's wife and though her magic helps Jason get the Golden Fleece. Medea's purpose for robot Jason is to isolate Jason from the heave of the ship. She also has a camera and thrusters so that she can move if the cable gets too close to Jason or his work area.
Several of us wake up to take our 4 am watches in the Jason control van. The van is dark with 4 video monitors linked to cameras on Jason and Medea and lots of controls and dials and other readouts across the front of the van. Three Jason operators control the movements of the Kilo Moana, Jason, and Medea, the ship's winch, and the navigation of Jason and Medea. The scientist leading the watch sits behind the Jason crew watching the monitors and telling the chief pilot exactly what is needed to fulfill the dive plan.
The chief scientists prepare a dive plan for each dive, in consultation with the on-board scientists. The watch leader in the control van is responsible for making sure that all items in this plan are completed. Whenever possible scientists monitor the progress on monitors throughout the ship or visit with the control room when they need closer interaction with the van crew. In many cases they directly supervise their particular dive tasks.
At the back of the van sit 3 more of the science party. Two of them work recording times, locations and events - "Dive # 307 Oct. 13, 2007, 19:13, scoop sample A taken in microbial mat". They also record the latitude and longitude and the Jason event number. This record allows scientists to map the dive, find the event on the video and reconstruct the sequence of dive tasks. Jason's 3 cameras each feed into a DVD recorder that records everything seen in the van's monitors. Additionally there is a digital video recorder and a still camera for recording specific events. These activities result in dozens of DVD recordings from the three video cameras throughout the dive, high-resolution DV tapes for the science camera, numerous still photographs, and a mountain of navigational data and written records.
During today's dive #307, Jason locates the deepest mat site found on Loihi. These yellowish microbial mats are found at 4984 meters depth at a site that has been dubbed Ula Nui. Ula Nui means "Big Red" in reference to the microbial mats and the volcanic vent that sustains them. Two types of probes measure the temperature of a vent. A solid-state electrochemistry probe is used to determine the chemical changes that occur through the depth of the mat. The microbes produce mats that basically are a puddle of bacteria and oxide minerals about 1 foot deep. Water samples, scoops of the mats and rocks that have been in contact with the bacteria are sampled to understand details of the chemical changes the microbes are causing. Bacterial traps are recovered for genetic analysis of the microbial community. Slurps and scoops are taken to culture the microbes present and determine metabolic rates and details of their metabolic chemistry. A long-term experiment looking at the changes these microbes do to chips of basalt that have been prepared by depleting the chips of specific elements such as iron and manganese. Failure of microbes to colonize chips depleted of one of these elements indicates that the element is necessary for their growth.
The dive ends about 3 pm when Medea and Jason are lifted from the bottom. Medea is brought aboard leaving Jason drifting by its tether just below the waves. The tether is transferred to a crane and Jason lifted aboard. Jason is secured to the deck by straps and the safety rail across the stern replaced before the scientists are allowed to retrieve their samples. The researchers work quickly to prevent samples from drying out or heating up in the afternoon sun. The temperature and electrochemistry probes are opened up to retrieve their data.
While the researchers get busy in their labs and the Jason team services their equipment, the ship turns toward the summit of Loihi for dives in the caldera known as Pele's Pit. The ship will be on station in little more than an hour and a new transponder net will be placed on the bottom and surveyed in. Jason is scheduled for its next dive shortly after midnight.
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