Date

Spring 2020

Document Type

Master's Thesis (Open Access)

Degree Name

Master of Science (M.S.)

Department

Moss Landing Marine Laboratories

Abstract

Environmental DNA (eDNA) is nucleic acids outside of living organisms found in air, soil, water, and ice. It is shed by organisms through waste and other bodily fluids, as well as cells sloughed off the outside of an organism. eDNA breaks down over time, especially when exposed to UV, heat, and bacteria. Scientists can analyze eDNA to identify organisms in an area, though the rates at which it is emanated and decayed seem to vary from organism to organism, complicating interpretation of results. The present study sought to quantify the rates of emanation and decay through a series of in vitro experiments for three species, Mytilus californianus (the California blue mussel), Haliotis rufescens (the red abalone), and Lottia scabra (the rough limpet). Using quantitative PCR (qPCR) to measure eDNA, I found that eDNA emanation rates varied based on species, size, and activity level, and that rates of decay can be influenced by bacterial activity and time under treatment. Small abalone released less eDNA than medium and large abalone over 24 hours, but limpets and mussels released the same amount of eDNA per species despite different wet weights. Similarly, inverted abalone with soft tissue exposed released more eDNA than in their normal posture, but this was not true for limpets or gaping vs non-gaping mussels. Lastly, eDNA degraded over time for all species, mostly in the first 24 hours, and bacteria affected abalone eDNA degradation. In eDNA degradation experiments, nonspecific PCR products decreased reliability of measurements over longer time periods. These data can be used by scientists and managers to interpret eDNA signals of these commercially or ecologically important molluscs to help protect these species and the communities in which they belong.

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