Morphological Effects on Gomphonema parvulum Grown Under Different Stressors**


The Environmental Protection Agency (EPA) uses algae as a biological component to monitor bodies of water in the United States. In this study, we will be investigating differing environmental conditions influence on algal, specifically diatom, morphology, characterizing the different morphotypes between laboratory cultures and varying environments to help characterize the dynamics between diatom morphology and environmental conditions. Diatoms are a group of algae characterized rigid glass cell walls which provides a unique life history model. They are typically identified using the morphological species concept and an ever-varying range of sizes may pose challenges in the identification process. There have been attempts to replicate optimal conditions in laboratory settings, however, at a population level, individuals display different morphologies in artificial environments than they do in natural environments. In this research, we investigated the effects of different environments on the morphological responses of the ubiquitous diatom species, Gomphonema parvulum (Kützing) Kützing 1849. G. parvulum is defined as ranging from 17-30 µm long, 5.5-7.5 µm wide with 10-14 striae within 10 µm. Clonal populations of G. parvulum were grown under idealized conditions, with no limiting light or nutrients, from a single cell isolated from Upper Three Runs Creek, South Carolina. DNA analysis confirmed that laboratory samples were monocultures of G. parvulum. G. parvulum was analyzed in archived samples of Upper Three Runs Creek from the years 1956, 2011, and 2018 to compare morphotype variations temporally in the same environments as well as between laboratory environment and natural environments. Morphological variation will be characterized by length and width of diatom frustules, as well as the number of striae within 10 µm of the cell. The goals of this study are to (1) investigate the morphological responses of G. parvulum under optimal conditions and environmental conditions and (2) differentiate morphological responses of G. parvulum temporally in the same habitat.


Georgia College & State University Department of Biological and Environmental Sciences and the Manoylov Phycology Lab

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