The Summer of Algae

At the start of my work this summer, the intent was for me to work with cleaning algal samples with hydrogen peroxide and determining a method for thinly spacing the cleaned frustules for imaging with a scanning electron microscope (SEM).  I was able to take some pictures of the frustules using the Phenom SEM at the Applied Research Center (ARC) but the samples were too congested with debris and other frustules for the images to be of any use other than my learning.  Because the frustules are very small with complex, intricate features, the SEM can distort the images of these objects.  So to get around this, lots of images need to be taken at different times to avoid the phenomenon known as charging up as I discussed in an earlier post.  For this to happen, I must be able to return to the same frustule many times, hard to do when there are thousands of similar looking ones and sediments.  However, because of constraints with supplies, the majority of my time was focused on constructing a craft that would contain screens for algae growth.  This required using the machine shop to create features for this craft to hold as well as raise these screens out of the water.  We are working in the York River, so this makes for a challenging environment.  Because of the salt water, many commonly used materials cannot be used as they will corrode, such as steel (stainless is great though).  Our main challenge this summer was creating a pulley system for raising the screens out of the water.  This might not sound like such of an issue but these screens will have algae growing on them (hopefully).  Algae is mostly water, so its decently heavy when wet.  Our first design for a cross-plate to hold the screens was a quarter inch thick aluminum plate.  This significantly bowed under the weight of screens and a small amount of growth the first time we tried to raise them.  So we switched to a type of reinforced aluminum bar which held up much better.  The junction between the poles that supported the pulley system and the crossbar holding the screens was a problem area.  The crossbar would twist and bind on the pole so that it would only move up a foot or two if we were lucky in the beginning.  We redesigned this region to reduce the amount of contact between the poles and the crossbar to a bare minimum. It works ok now, the weight is still an issue though.  On the very last day of our research experience, we were able to take the craft out to its mooring location in the York River.  It had previously been sitting in the boat basin at VIMS.  However, the combination of strong current and choppy waters made it so that we were not able to reinstall the screens which had been removed for transport.