As a senior at San Diego State University, and volunteer with the Edwards lab, I was asked to partner on a project to help identify the invertebrate composition in cores taken in rhodolith and sand (control) samples collected from Catalina Island. Master’s candidate and primary coordinator, Billie Beckley, took the time to introduce me to the project in the early spring of 2018. This project was made possible through the California Sea Grant and Principle Investigator (PI) partnership with Dr. Diana Stellar at Moss Landing Marine Lab. The primary research objective is to ascertain the impacts mooring lines might have on rhodolith beds around Catalina. The data will be used as a baseline for rhodolith ecosystems worldwide in order to study and preserve the complex habitats they provide for other animals.
The initial cores were collected in July of 2018. They were photographed underwater immediately following extraction and preserved in a -80°C freezer until thawed out to be sorted using a microscopic. The pictures were used in identifying anoxic sediment content along with rhodolith composition through the utilization of ImageJ® software. Below is a sample picture that was used in this process:
Although scrutinizing samples multiple hours a week under a microscope may sound monotonous and boring, it was far from it! Every day had its own set of highlights and interesting discoveries. With a sense of curiosity, new organisms were found or different variations of the same order of invertebrates were observed. For example, an interesting mite-like organism popped up a couple times in some of the cores. Below are pictures of both sides of the specimen:
Another notable moment in my sorting process was observing different morphological characteristics between Tanaids found in nearby sand beds verses those in the rhodolith beds. In the sand, Tanaids were a whiteish, opaque color whereas the Tanaids that were living in the rhodolith beds were opaque with darker colored spots on their carapaces. Although this is not explicitly part of the primary research question, it would be interesting to know what factors allow for phenotypic variation between the two taxa.
From January 8-18, 2019, members from both affiliated labs will go back to Catalina to gather more core samples and bring them back to SDSU to sort and analyze. Photosynthetic measurements through the use of Photosynthetic Irradiance (PI) curves will be used the same day they are collected so that we have a better understanding of the overall productivity in these ecosystems. So stay tuned for more updates from the field and the lab!
San Diego State University
B.S. Marine Biology, 2019
California Seagrant Funding R/HCE-04