Assessment of littoral algal diversity from the northern Gulf of Mexico using environmental DNA metabarcoding.

Traditional methods for algal biodiversity monitoring are costly and time inefficient because they rely on high-level taxonomic expertise to address species identity problems involving phenotypic plasticity and morphological convergence. These problems are exacerbated in regions such as the Gulf of Mexico, that has a limited history of phycological exploration, but that are economically important or threatened by numerous anthropogenic stressors. Given the high pace of disturbance to natural systems, there is a critical need for expedient and cost-effective tools for the study of benthic algal communities.

Molecular and morphological diversity of Narragansett Bay (RI, USA) Ulva (Ulvales, Chlorophyta) populations.

Macroalgal bloom-forming species occur in coastal systems worldwide. However, due to overlapping morphologies in some taxa, accurate taxonomic assessment and classification of these species can be quite challenging. We investigated the molecular and morphological characteristics of 153 specimens of bloom-forming Ulva located in and around Narragansett Bay, RI, USA.

DNA taxonomy in morphologically plastic taxa: algorithmic species delimitation in the Boodlea complex (Chlorophyta: Cladophorales).

DNA-based taxonomy provides a convenient and reliable tool for species delimitation, especially in organisms in which morphological discrimination is difficult or impossible, such as many algal taxa. A group with a long history of confusing species circumscriptions is the morphologically plastic Boodlea complex, comprising the marine green algal genera Boodlea, Cladophoropsis, Phyllodictyon and Struveopsis. In this study, we elucidate species boundaries in the Boodlea complex by analysing nrDNA internal transcribed spacer sequences from 175 specimens collected from a wide geographical range.