title: Molecular characterization ofPseudo-nitzschiacommunity structure and species ecology in a hydrographically complex estuarine system (Puget Sound, Washington, USA).
abstract: Species within the toxic marine diatom genusPseudo-nitzschiacoexist in coastal and estuarine waters globally and are difficult to distinguish by microscopy. Here, we describe a sensitive, high throughput PCR-based Automated Ribosomal Intergenic Spacer Analysis (ARISA) approach to determine the relative abundance ofPseudo-nitzschiaspecies within natural communities over space and time. The method was quantitatively validated using simplified mixtures of DNA or ITS1 standards from isolates ofP. pungens, P. multiseries,andP. delicatissima. Relative abundance calculations based on ARISA profiles from these mixtures reflected input ratios, with minor deviations resulting from intraspecific variability. ARISA was used to identify and quantify at least eight species within Puget Sound and the eastern Strait of Juan de Fuca, Washington, USA:P. americana, P. australis/P. seriata, P. cuspidata, P. delicatissima, P. fraudulenta, P. fryxelliana, P. multiseries,andP. pungens;genotypes corresponding toP. pungensvar.pungensandP. pungensvar.cingulatawere identified by environmental sequencing. The different species were significantly correlated with physical (temperature, salinity), biological (chlorophyllafluorescence, oxygen), and/or chemical (ammonium, nutrient ratios) factors. The ability to determine shifts in the relative abundance ofPseudo-nitzschiaspecies over spatial and temporal scales relevant to dispersion and selection facilitates dissection of the varied mechanisms driving vertical and horizontal species distribution patterns in hydrographically complex systems.
authors.affiliation: Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Saint Petersburg, FL, USA; Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Hubbard
authors.affiliation: School of Aquatic and Fishery Science, University of Washington, Seattle, Washington, USA.
authors.forename: Claire H
authors.initials: CH
authors.lastname: Olson
authors.affiliation: School of Oceanography, University of Washington, Seattle, Washington, USA.
authors.forename: E Virginia
authors.initials: EV
authors.lastname: Armbrust