Questions of the Day: Microbes in the Western Pacific Ocean

11Jan2007

Left: Jeremy and Ryan haul in the CTD rosette. Right: Filters containing organisms collected from different depths in the water column.

Question of Day: Do you scoop [organisms] up with a micro-fine net or do you suck them up or what? (Liz Z., Michigan)

Answer (Part II): Yesterday we showed you a device called a plankton net that is used to collect some pretty small members of the planktonic community, but not the smallest! In order to collect the really small organisms (bacteria and viruses) we use what is called a CTD rosette. CTD stands for Conductivity-Temperature and Depth. These parameters are measured by electronics in the center of the package. This piece of equipment also has 24 bottles that surround the electronics and are initially cocked open. We can position the CTD at any depth in the water column using a crane and close the bottles using a computer on deck. This traps water from that depth within the closed bottles. We can then bring the water to the surface and filter the bacteria and viruses out of it. The second picture above shows 4 different filters with organisms from 3 different depths in the water column. The first filter on the left is brand new and does not have any organisms on it. The second filter from the left has organismsfound in water collected at 5 meters. The third filter from the left has organisms from 75 meters and the filter on the right has organisms from 200 meters depth. Note the differences in the color of the filters!

 

10Jan2007

Question of Day: Do you scoop [organisms] up with a micro-fine net or do you suck them up or what? (Liz Z., Michigan)

Left: Copepod collected in plankton net viewed under a light microscope. Right: Dreux (left) and Annette (right) remove specimens from plankton net.

Answer: We use multiple techniques to collect different organisms of interest. Larger organisms like copepods are collected using a plankton net. This net is similar to a butterfly net and is dragged behind the ship to collect specimens. Things caught in the net are funneled down into a plastic jar that can be removed and brought back to the lab on the ship (Dreux is holding the plastic jar in her hands). Really small organisms like bacteria are too tiny to be caught by this type of device. Tomorrow we'll show you how we collect these microbes.

Question of Day: Why does the Kilo Moana have a funny shape (two hulls)? (Hokulani Elementary School)

Answer: The R/V Kilo Moana is from a class of ships referred to as swath vessels. The twin (two) hull design allows the ship to be more stable and move more efficiently through the water. In fact, the R/V Kilo Moana is so advanced that it was recently called one of ten "Super Ships" in the world by the Discovery Channel (Zackary Johnson, Chief Scientist, University of Hawaii).

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