CTD and niskin rosette.
Aloha! Today is Saturday 6.15.2013, day 5 of our research cruise. It has been an exciting week of science! Due to slow/inconsistent internet it has been difficult to update this blog and we have done a lot so I have tons to write about! On Wednesday 6.12.2013 my student group ("The Kraken", self-named:) worked on analyzing water samples collected at multiple depths between the surface of the water down to 1000 meters using the niskin sampling tubes on the CTD rosette (see picture). We took samples to measure important basic water quality parameters such as dissolved inorganic nutrients, dissolved oxygen, particulate carbon, nitrogen and phosphorous, and ATP. The ATP analysis was particularly interesting. ATP (Adenosine-5' triphosphate), is a coenzyme that transports energy within cells for metabolism. It can be thought of as the "molecular unit of currency". Since ATP is found in and around all living organisms, measuring the total concentration (amount per volume) of ATP in our water samples provides a measure of total microbial biomass. The analysis for quantifying ATP is super cool...After filtering our water sample onto a small filter, we place it into a tube filled with a boiling base solution. This step breaks up the cells and extracts the ATP. After the extraction we add "firefly dust" which contains an enzyme (luciferase) and subtrate (luciferin) extracted from fireflies! The reaction produces light and the amount of light produced is directly proportional to the amount of ATP and therefore the amount of living organisms in the sample! The reaction is catalyzed by the enzyme (luciferase) simplified to this:
luciferin + ATP --> oxyluciferin + AMP + light
Sarah Q. Foster
Sarah is a 2nd year Ph.D. student in the Fulweiler Lab. This blog documents her experience taking a summer course "Microbial Oceanography: From genome to biome" at C-MORE at the University of Hawai'i at Manoa.