Cullman Associate Curator, Cullman Program for Molecular Systematics
Ph.D., University of Maryland
College Park, MD, 2004
Green Algal Systematics and Evolution (Charales)
Systematics of Algae
From microscopic single-celled species to giant seaweeds many meters long, algae are diverse and ancient organisms that can be found in virtually every ecosystem on earth. For millions of years algae have exerted profound effects on our planet. As primary producers algae provide food and shelter for many organisms as well as provide a significant percent of the oxygen we breathe. Algae are locally important water quality indicators and globally important sequesters of carbon dioxide, the major greenhouse gas involved in global climate change. My primary research interest focuses on utilizing several molecular and morphological approaches toward understanding the evolution of green algae in a broad sense, and, more restrictively, the biology, evolution, systematics, and classification of the Characeae.
The Characeae, more commonly know as stoneworts or muskgrasses, are a lineage of fresh-water green algal macrophytes that have a rich fossil record dating to the Late Silurian (~430 million years old). My research group uses modern genomic methods to re-evaluate the taxonomy of the stonworts, which are common in freshwater lakes worldwide and are ecologically important as food and habitat for invertebrates and small fish. Stoneworts have an intricately branched plant body and complex sexual reproduction, and they are considered closely related to the first plants that invaded land some half a million years ago. Stoneworts are also used in habitat remediation and are important model organisms in studies of cell biophysics. As part of a NSF funded project, Phylogeny and Systematics of the Characeae (Charales), we generate DNA sequence data from nuclear, plastid, and mitochondrial genes that are being used to revise the current confused classification of the stoneworts. Our long-term goal is to provide critical data for worldwide studies of diversity and evolution and to produce a robust and stable classification system for this ancient and diverse lineage.
I am also part of a NSF funded Tree of Life project, The Green Algae Tree of Life (GrAToL). This project involves the collaboration of five institutions to understand the evolutionary relationships of all of the major groups of green algae, a diverse group of more than 14,000 photosynthetic species worldwide. Green algae are abundant and play important roles in a wide variety of terrestrial and aquatic habitats, including deserts, extremely salty ponds, and coral reefs, and several species are symbiotic partners with lichens and animals. Thus, green algae are important primary producers in most ecosystems. This project employs gene and organellar genome sequence data to assemble a tree of life reflecting the evolutionary history of the group. This phylogeny will be critical for an improved classification of known species of algae as well as species that are yet to be discovered and will facilitate further studies of green algae genomics and evolution.