Jason's screens go blank and Dive 314 is ended at 4 AM today. Once aboard, the Jason team confirms that the fiber optics in the tether between Jason and Medea have failed. Fortunately they have another, though shorter tether. 

The scientists gather their samples and head to the labs and I begin asking more questions. Rick Davis is working in the radiation lab. He is growing microbes from Lo'ihi in seawater laced with C-14 bicarbonate. Bicarbonate is a carbon atom linked to a hydrogen atom and 3 oxygen atoms: HCO3-. It is the source of carbon from which chemo-synthesizing microbes make organic molecules such as carbohydrates. The process by which organisms make organic molecules from inorganic molecules is called "carbon fixation". Marine organisms fix carbon from HCO3-, plants fix carbon from CO2. Rick is performing carbon fixation experiments to see how much of the HCO3- is converted into organic molecules in the Lo'ihi microbes. In addition to the bicarbonate, Rick is adding things that the microbes need to stay alive - iron and manganese that they can oxidize for energy. When iron is added the microbes that grow using iron will thrive and dominate the enrichment culture. The C-14 will allow the efficiency of carbon fixation to be measured with great sensitivity. If molecules such as lipids are extracted from the enrichment culture, it becomes possible to find out what cellular structures these microbes are putting their energy into.

Suzanna is also interested in the microbes associated with the manganese oxide crusts, so she is developing a technique that allows her to separate these microbes from Lo'ihi samples using magnetism. The magnetic technique is not new, but Suzanna has developed an organic molecule that binds manganese oxide. She coats magnetic beads with this molecule and then puts the beads into a culture tube with the sample. Those microbes bound to manganese oxide, either because they produce it or because they need it as a resource, stick to the beads along with the manganese oxide. She can then place a magnet next to the culture tube to hold the beads and manganese loving microbes to the side of the tube. She then washes out the remainder of the sample. Those microbes not stuck to the beads are washed away leaving a sample enriched in manganese oxide loving microbes. 

Greg is working with nitrogen metabolic processes that are anaerobic - they don't require oxygen so Greg sets up his incubations in a "glove box" (more like a sand blasting cabinet than the glove box in a car) flooded with a mixture of CO2 and Helium. He is looking at nitrogen metabolism in the deep sea so his incubations are spiked with N-15, a stable isotope of nitrogen. Nitrogen is found in the proteins of every living organism and nitrogen gas makes up 79% of the atmosphere. Microbial metabolic pathways convert nitrogen gas to nitrogen in proteins and back again. There are two principal metabolic processes for generating N2 gas, namely "denitrification" and "anammox" (the first uses nitrate and the second uses ammonia to produce N2 gas). Greg is investigating both of these. He appears to be the first to do so on seafloor basalts. The latest geochemical budgets for nitrogen seem to show that the ocean is producing more N2 gas than it is consuming. The excess leaves the ocean for the atmosphere. Greg's research will measure a rate of N2 production for microbes living on Lo'ihi, and determine the relative contribution of denitrification and anammox to the total.