Date of Completion


Embargo Period



Louise Lewis, Kurt Schwenk, David Wagner

Field of Study

Ecology and Evolutionary Biology


Master of Science

Open Access

Open Access


The green alga Oophila ambystomatus (Chlamydomonadales, Chlorophyceae) is

well known as the symbiotic partner of Ambystoma maculatum, the yellow-spotted

salamander. Recent molecular work has revealed phylogenetic diversity within isolates of

Oophila from New England. Here I investigate physiological properties and genetic

diversity of the algal symbionts representing different evolutionary lineages. In other

well-studied symbiotic systems involving algae, e.g., Chlorella and Hydra, algae and

lichen, or Symbiodinium and Scleractinian corals, the algal symbiont is capable of

multiple trophic modes, thus influencing its capacity as a partner. In this study I

investigated whether genetically differentiated strains of Oophila are capable of

absorbing organic carbon compounds (heterotrophic growth) and hypothesize how this

might play into its symbiotic relationship. A growth study examined each strain’s ability

to grow in light (16:8 L:D; 41 μmol/m2) and in dark (0:24 L:D; 0 μmol/m2) in three

different media types (BBM, BBM+glu, BBM+gal). I determined there is metabolic

variability among the strains that indicates each may provide differential benefits to their


I also reviewed the taxonomic history of Oophila to resolve confusion over its

validity. After a brief recount of its history, I determined that the name is valid, and

suggest a recent collection from the type locality of Middlesex Fells Reservation be

designated as an epitype given that the aged type material lacks diagnostic features and

its DNA is degraded. An epitype will provide future researchers an unambiguous

anchoring specimen and sequence for future taxonomic, molecular and physiological


Major Advisor

Louise Lewis