I’m so Ulva it: Using tufA DNA barcoding for identification and contextualization of Ulva species in Salish Sea

Abstract

Ulva is a genus of green algae, rapidly becoming relevant due to potential uses in the blue economy, in addition to potential biofuel and rare earth element uses. Ulva is characterized by its rapid growth sometimes causing harmful blooms, making it increasingly important to study this algae, particularly the understudied tubular forms. Ulva historically had been difficult to identify based on morphology alone. This project identified Ulva species in the greater San Juan Islands using DNA barcoding, comparing specimen morphological characteristics to what is typically described for the species, as well as using DNA data to contextualize samples into larger clades. From this, key morphological distinctions of identified species and potential distribution patterns relating to environmental and geographic factors are elucidated. In total, 12 species of Ulva were identified from 35 samples, with some samples matching traditional descriptions of named species while some differing from what is expected based on morphology alone. The species found included Ulva compressa, Ulva flexuosa, Ulva expansa, Ulva californica, Ulva fenestrata, Ulva stenophylla, Ulva taeniata, Ulva intestinalis, Ulva prolifera, Ulva australis, Ulva linza, and Ulva torta. In addition, 4 species of Blidingia were identified and treated as an outgroup. Not all of these species however have been tied to a type specimen and more sequencing efforts are needed to accurately quantify diversity of the San Juan region.