Even though I’m technically a field scientist, I have yet to sprout my sea legs as our first trip will begin June 19th as a 10-day sampling cruise with Dr. Stan Locker on the Weatherbird II. The objective of the research cruise is to study bathymetry and geomorphology in the area of DeSoto Canyon, following the Deepwater Horizo oil spill. We will be tagging along and gathering filter samples along the way at multiple depths. Whilst in the lab with Dr. Nienow, my coworkers and I have worked to prepare earlier samples from gulf cruises in both December 2013 and May/June 2014.
|Above and below: My coworker Courtney Bryller and I prepare to acid boil some plankton net samples.|
In order to view diatoms in plankton net samples under the microscope or the SEM (Scanning Electron Microscopy) machine, we must first boil them in acid, such as nitric acid and oxidize them with a really potent oxidizer such as potassium dichromate. This allows us to get rid of organic matter and any calcium carbonate-containing tests of microorganisms and view only the silicious frustules of the diatoms we are concerned with. We then dry them out, incubate them, and prepare them for slides or mount them on SEM stubs.
Here are several diatoms, listed at the genera level as seen under a light microscope:
|Pleurosigma (100x objective)|
Amphora (100x objective)
Diploneis (40x objective)
Paralia (looks like gothic architecture with flying buttresses! – 100x objective)
This picture I took while I was learning to use the SEM:
|I still have no idea what it is.|
|Christopher Horruitiner, Valdosta State University|