Fiji/Lau Expedition
May 15–June 3, 2005
Please visit the Ridge 2000 website for additional information.
May 27, 2005
Today we tried again to find the elusive Mussel Valley vent field. We searched with
Jason II in a region just to the north of our target on the previous day. We spent a little more than 6 hours searching and saw lots of rocks and sediments, but no real signs of hydrothermal activity. Again we collected a stalked crinoid, a few sponges and an anemone. Other wise, the pickings were slim.
Over night we are leaving this site and traveling ~160 km northeast to the White Lady site. This area is known to have active vents. In the meantime, Victoria will eagerly await the new samples of bacteria for her genetic studies.
Victoria takes a break from time to time to sing about the glories of
microbiology!
Extracting DNA and RNA
,the genetic material of living organisms, is a fascinating process. First Victoria puts sample of bacteria directly from environmental samples into a small vial and adds buffering solution to keep the molecular compounds, especially DNA and RNA stable. She then freezes the samples until ready to extract. This prevents enzymes found in the tissue samples from breaking up the microorganism's DNA before it can be purified.
When time permits, the samples are thawed and garnet sand and detergent is added. A mechanical agitator shakes this mixture very rapidly for ten minutes. This breaks up the cells and releases the DNA. The samples are then put into a centrifuge, spun for a few minutes and the sand and other solids sink to the bottom. The DNA and other molecules remain in solution.
Victoria uses a pipette to draw up the precious liquid and carefully inserts
the fluid into another vial containing a special solution that causes carbohydrates, proteins, lipids, and contaminating molecules in the sample to solidify and fall out of the solution. The vials are cooled on ice to help solidify the lipids etc. much like bacon grease becomes solid when cooled. Again the samples are agitated then centrifuged. The nucleic acids (DNA and RNA) remain in suspension and the other organic compounds form brownish sediment on the bottom of the vial.
Finally this almost pure DNA/RNA solution is pipeted into another special vial which contains a fine sponge like filter made of glass and a special salt solution and then it is centrifuged. The DNA and RNA will now cling to the structure of the filter. The salts help it hold on. At last, ethyl alcohol is used to wash the sponge filter of any last impurities. The purified DNA holds on to the filter and is removed with purified water. This water/DNA solution is centrifuged and the pure DNA settles on the bottom. Victoria then freezes the DNA for safekeeping. Millions of microorganisms in the sample can then be identified from the DNA by cloning and sequencing.
–Todd Bliss
Kristie took this beautiful sunset over Fiji.
A ratfish (also known as a chimara) swimming over the bottom is a distant relative of sharks and rays.
Here you can see a mobile crinoid lifting off of the bottom and going for a swim. Superficially, these are different from the stalked crinoid that you can see in the logbook from May 25th.
This sea cucumber vacuums the ocean bottom in it's endless search for organic material.