Lucy Roussa
Eastern Washington University
Research Mentor: Julie Keister
Project: Measuring From the Sky: Methods to Quantify Moon Jellyfish Aggregations Using Areal Photographs
Hello! My name is Lucy, and I am a dual biology and environmental science major at Eastern Washington University in Cheney, Washington. This summer I had the pleasure of working with Julie Keister for a remote internship investigating Moon jellyfish aggregations in Puget Sound.
Moon jellyfish, Aurelia labiata, are a dominant component of the marine ecosystem of Puget Sound. The aggregations are huge; they can easily be seen from aerial surveys and can be composed of thousands of jellyfish. Aggregations this large can have an impact on the surrounding marine community. The jellyfish compete with forage fish for zooplankton, which are microscopic animals that they both feed on. Moon Jellyfish also can alter the chemistry of the water by increasing dissolved nitrogen and decreasing the dissolved oxygen.
My part in this project was to develop a protocol for image processing which is used to construct a photo that can allow us to measure the area of these jellyfish aggregations in square meters. I started my work by sorting images of Budd Inlet from the Washington state DOE into usable and unusable images: the minimum criterion for a usable image is the presence of two shorelines and visible jellyfish aggregations. Next, ground control points (GCPs) were added to the images in ImageJ by identifying known structures (i.e., buildings, buoys, docks) which were marked in Google Earth Pro. Once GCPs were identified, the ImageJ was used to locate X, Y pixel coordinates of the marked locations of GCPs and unique jellyfish aggregations. By using the X, Y pixel location, and latitude and longitude of the GCPs, the images are then processed in MATLAB. This creates an orthorectified photo that is uniform in pixel dimensions and suited for measuring jellyfish aggregations. The orthorectified photo is then analyzed again in ImageJ where the final version of the image contains only jellyfish aggregations as pixels. This method of image analysis is proving to be a useful tool in quantitatively measuring jellyfish abundance.
While most of my research was conducted remotely, I was able to visit Seattle and present my research in person for CICOES faculty and mentors. Due to good timing and a great mentor, I was also able to participate in marine field work for this project on University of Washington’s research vessel – Rachel Carson. On this cruise we used ring nets to catch Aurelia and obtain size measurements. A CTD, a device used to measure conductivity, temperature, and depth, was deployed to gather water samples. We used the water taken from this device for chlorophyll, nutrients, and phytoplankton analysis. All the data collected on this cruise will be used in graduate level research as well as the project that I took part in during this internship.
I am so grateful for my acceptance into this program. It was really an unforgettable experience that I would suggest for any aspiring scientist. On top of learning new skill sets I have met so many amazing people along the way. CICOES is not only a wonderful REU, but a lasting network of support and encouragement from other interns and faculty. This experience has given me the confidence I need to excel in my future endeavors as a scientist.
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