PUPCYCLE Day 12 – Building Glass Houses

Tuesday, June 04, 2019 – Cruising offshore from the Oregon coast

PUPCYCLE Log: Day 12 – Building Glass Houses?

Our transit northward continues, supported by the remnants of the R/V Oceanus rock and roll concert from yesterday. By 6:00AM, the scientists were filtering their 48-hour Narrow Shelf incubations and storing them for transfer once the ship arrives back in Newport, Oregon. Beyond the constant activity visible in the make-shift labs onboard the ship, there is so much behind-the-scenes work that must be completed with a research project like

Figure 24 – Olivia prepares to seal a filter for cold storage. After the cruise, Olivia will analyze the nitrogen uptake by the diatoms. [Image credit: Miriam Sutton]
PUPCYCLE 2019 and the bulk of the responsibility for a successful research cruise lies on the shoulders of Chief Scientist, Adrian Marchetti. However, like any successful venture, Adrian must rely on others to facilitate the project’s success. A recent UNC-CH graduate, Olivia Torano, holds one of the key support roles as the Marchetti Lab Manager. Olivia enjoys her multifaceted position at the lab. “I work with so many different scientists doing various types of research,” said Olivia, “and learning more about what they are studying helps me to plan and prepare the lab to better meet their needs.” She confirms the amount of preparation and planning for PUPCYCLE 2019 was mind-boggling. “Not only are you trying to order supplies and materials needed for data collection, but also the other items to prepare the test materials and equipment prior to and after the data is collected.”

Olivia is also conducting research during PUPCYCLE 2019. Her filtration system is set up to capture biogenic silica, which is the silica that diatoms (or other “glass house” organisms) use in the construction of their outer cell wall. In diatoms, this glass wall structure is referred to as a frustule. Each frustule has 2 parts that overlap and connect to form a wall of protection for the single-celled organisms.

Figure 25 – Diatoms are treated with a fluorescent dye that reveals the number of divisions occurring during the incubation experiments Diatom offspring with an “f” indicate new cell growth. [Image source: https://biology-forums.com/index.php?action=gallery;sa=view;id=782; modified by Miriam Sutton]
During reproduction, the cell divides and a new smaller frustule is produced using the silica dissolved in seawater. Olivia is investigating how much silica is being used to produce their shells during the timed incubation period and which species are growing fastest and using the most silica under the various environmental conditions, including: broad vs. narrow; Fe-limited vs. Fe-available; and surface vs. deep water communities. In order to measure the amount of silica being used, Olivia inoculates (or treats) her water samples with a fluorescent dye referred to as PDMPO. (I’ll spare you the long chemical name for this dye.) This treatment occurs 24 hours after their first incubation period. Once inoculated, the samples are returned to the incubation system for an additional 24 hours before Olivia runs her samples through the filters and prepares them for further testing back in Chapel Hill. Any new cell that was formed during the incubation period will fluoresce, or glow, when viewed under her microscope. This allows her to count the number of cell divisions for each species found in the sample.

Whether she’s counting cell divisions as they fluoresce beneath her microscope or the number of 0.2um filter packs needed for the next filtration round, Olivia is supporting PUPCYCLE 2019 on deck and in the shadows.

Olivia Torano was born in Michigan and completed her undergraduate degree in Ecology and Evolutionary Biology from the University of Michigan. She completed her Masters degree in Ecology in December 2019 from the University of North Carolina – Chapel Hill and now works as the Lab Manager for the Marchetti Lab at UNC-CH.

Today’s Certificate Challenge: Diatoms build their cell walls, also known as ___, from silicates found in the ocean.