This project will substantially advance knowledge of the evolutionary history of the dinoflagellates, an important but understudied group of aquatic microorganisms. Major collaborators include Drs. Wayne Coats (Smithsonian Institution Environmental Research Center), and Senjie Lin (University of Connecticut), as well as international cooperation with Brian Leander (University of British Columbia) and Martin Head (Brock University). The central objective will be to sequence DNA from 100 or more species and to assemble a multi-gene database for comparative analyses to infer their phylogenetic (evolutionary) relationships. A second major objective will be to correlate fossil dinoflagellate cysts with living dinoflagellates that are represented in the molecular dataset. Care will be taken that the dataset includes a roughly proportional representation of both photosynthetic and non-photosynthetic species. To do so will require a combination of techniques, sampling from a wide variety of environments, and application of modern cell-sorting and isolation techniques. Strains studied will be cultured whenever practical, and will be photographed, preserved, and their DNA archived.
Dinoflagellates are environmentally and economically important protists found in both marine and freshwater environments. They include photosynthetic species that serve as an important source of food for plankton and other aquatic life, and are symbiotic with many tropical corals, clams, and other organisms. However, dinoflagellates can also at times be nuisance organisms, causing red tides, toxicity of certain sea-foods, fish kills, and a variety of other environmental and economic problems. They also are an extremely ancient lineage, comparable in age to the plant and animal kingdoms, and occupy an important location in the Tree of Life. An improved understanding of the phylogeny of dinoflagellates will be important to a wide variety of studies in human health, both marine and freshwater environmental science, and in comparative studies of cell biology and evolution. It will also help place the dinoflagellates in the broader context of the eukaryotes, and will make an important contribution toward the long-term goal of a well-resolved phylogeny that samples all groups of living things.
This project will also involve considerable training opportunities at the postdoctoral, graduate and undergraduate student levels, as well as outreach activities with K-12 teachers and students.
Dinoflagellates are typically single-celled eukaryotic microorganisms that live in both marine and freshwater environments (including transient features such as puddles). Some are photosynthetic, while others are predatory or parasitic, and consequently they play diverse ecological roles. They are environmentally and economically important because they influence the base of the aquatic food web, and because they can be nuisance organisms simply by growing to great excess, or by actively producing toxic materials; several forms of seafood poisoning can be traced directly to dinoflagellates. They are also important to geologists as markers of key geological strata. A major deficit in the understanding of dinoflagellate biology is the lack of a clear and well-supported tree of life for all major dinoflagellate lineages. Our project used a combination of structural (morphological) studies and DNA sequence analysis to develop an improved understanding of the relationships among living dinoflagellates. Among its noteworthy broader impacts, the project provided training for six postdoctoral researchers, nine graduate students, twelve undergraduates, one high-school student, and three international visiting scholars. It also engaged nine international institutions in cooperative or collaborative research. In addition to this integral training and human resource development, the project also supported several lectures for the general public (by Coats, Delwiche, Lin, and Bachvaroff), hands-on microscopy activities for high-school students, and tours for the public at the Smithsonian, University of Maryland, and University of Connecticutt. Collection of novel specimens and environmental sampling enhanced publicly available cultures of dinoflagellates and provided a greatly expanded database of mRNA and DNA sequences for phylogenetic analysis. Specimen collection was performed in over 20 locales on the Eastern Seaboard (temperate and subtropical), Gulf of Mexico, and Great Lakes (inland and open freshwater), and at least a dozen locales in the Pacific Northwest (coldwater Eastern Pacific). International collections were performed on collecting trips to South Korea (mesic Western Pacific Ocean), France (Mediterranean). Collaborators provided samples from the North Atlantic, Baltic Sea, Austral Southern Ocean, Sea of Cortez, and tropical Caribbean. Key scientific findings include mRNA-sequence based studies of biological diversity in understudied lineages of dinoflagellates, specifically including photosynthetic, predatory, and parasitic lineages. We also performed DNA-based environmental sampling in several locations, most notably in Connecticut, Florida, and on the Great Barrier Reef of Australia, which demonstrated a great genetic diversity among small and morphologically nondescript dinoflagellates. We also explored the application of emerging high-throughput DNA sequencing technologies combined with flow cytometry to dinoflagellate phylogenetics.
