PAM Fluorometry and Spectroscopy
I use pulse-amplitude-modulated (PAM) fluorometry extensively in my work to measure photosynthetic performance of algae, corals, and even kleptoplastic sacoglossan sea slugs. Rapid light curves (RLCs) induce photosynthesis at several steps of increasing light and allow us to analyze several important photosynthetic parameters in these taxa. Details on best practices for RLC data processing and analysis are outlined in a recent publication.
Reflectance measurements taken with an Ocean Optics modular spectrometer were key to determining the importance of parapodia in Plakobranchus ocellatus sea slugs.
Confocal Laser Scanning Microscopy (LSM)
I’ve used confocal LSM for analysis of coral host and sacoglossan kleptoplast pigments, specifically, green, cyan, and red fluorescent proteins (FPs). Confocal LSM is a powerful tool to visualize three-dimensional structures in corals and invertebrates without the need to sacrifice the animals.
From the images below: Leptastraea purpurea harbors several fluorescent proteins in its relatively large polyps (left), whereas these FPs were only occasionally found in Montipora flabellata tentacles, (middle). LSM of the kleptoplasts in the internal digestive tubules of Plakobranchus ocellatus shows the great density of these undigested organelles that still show some functionality (right).
I’ve been trained in coral histology and histopathology and have processed tissue and stained slides for analysis with light microscopy. Histology is one of the best methods to determine pathological responses in tissue samples. My master’s thesis describes an acute bacterial challenge experiment and the response of two coral genotypes. One major discovery from this work was the lack of outward signs of disease when histological samples showed advanced progression of deterioration.
Fieldwork, particularly on SCUBA, is one of my favorite parts of the job. Whether for data collection along transects or for collecting specimens, I find my time underwater so important as this is also a time to observe. Depending on the nature of the research, however, snorkeling and/or surveying the intertidal zone also present opportunities for discovery. I’ve conducted transect surveys for coral ID, disease, structure from motion (SfM), and for long-term monitoring projects. I am always looking for more reasons to get into the water to better understand how my research can help repair our damaged marine ecosystems.