USC Dana and David Dornsife College of Letters, Arts & Sciences

Although our lab work has been providing us with unexpected results, such as our nitrogen samples forming a precipitate with one reagent and having no reaction with another, we are continuing to analyze our soil. Miller and Alex spent their morning on the 3rd floor finessing the pH meter in the Microbiology Lab. Meanwhile I was running around the lab bothering Lauren Czarnecki, the laboratory manager at the Wrigley Institute, trying to track down a hydrometer, and buckets to dispose of our soil, DI water and Hexamataphospate solution. I couldn’t locate the hydrometer that our advisor, Lisa had brought out, it ended up being on a different lab bench in an narrow box. 

Before we discovered this, Lauren helped me in every way possible to locate a hydrometer.  She guided me to Ellen Kelly, Assistant Director of Education, who let me look through some soil sampling equipment she had in the hope of locating a hydrometer. Meanwhile Lauren contacted main campus, and I called Naomi Martinez from the Environmental studies office and Tony Summers from the CHIRP office of the Catalina Conservancy. Lauren then had the idea to reach out to the Southern California Marine Institute, located on Terminal Island. I called Carrie Wolfe and after a quick check told me there would be a hydrometer on the Miss Christi the following morning. Everyone was so helpful that morning, we are so lucky to be working with these organizations and people.

After some computer work and an e-mail from Lisa letting me know if I looked through the lab I would find a hydrometer in a sea grant box. We started the soil texture analysis by creating a blank with 100 mL of our HMP solution and 900 mL of DI in a 1 L plastic graduated cylinder and mixing one of our samples with 800 mL of DI in a 1 L glass graduated cylinder. We covered the blank with parafilm and inverted the mixture 10 times in order to ensure it was consistent. Once we dropped in the hydrometer we realized that reading a hydrometer that only breaks the surface of the solution by a few inches would be difficult through the opaque plastic. However, we were able to get accurate readings and after taking readings at 30s, 60s and 10 minutes we inverted our soil sample 10 times and started the same process.  The glass made reading the hydrometer much easier which was necessary because the soil, water and HMP mixture foamed slightly from being inverted.

By the end of the afternoon we had recorded the specific gravity and temperature at the previously mentioned intervals and 30, 60, 90 and 120 minutes for both mixtures. We covered both cylinders with parafilm to avoid evaporation or contamination and decided the next day to use the glass graduated cylinder only, due to the ease and accuracy of reading the hydrometer. Working on an island presents certain issues, access to commodities such as lab equipment or groceries are limited. Therefore, I will appreciate the things that USC and being more connected on the mainland provide than ever before. We left the lab organized and ready to return to the following day for our 24 hour readings.

Photos!