title: Algicidal and growth-inhibiting bacteria associated with seagrass and macroalgae beds in Puget Sound, WA, USA.
abstract: The algicidal and growth-inhibiting bacteria associated with seagrasses and macroalgae were characterized during the summer of 2012 and 2013 throughout Puget Sound, WA, USA. In 2012, Heterosigma akashiwo-killing bacteria were observed in concentrations of 2.8×106CFUg-1wet in the outer organic layer (biofilm) on the common eelgrass (Zostera marina) in north Padilla Bay. Bacteria that inhibited the growth of Alexandrium tamarense were detected within the biofilm formed on the eelgrass canopy at Dumas Bay and North Bay at densities of ∼108CFUg-1wet weight. Additionally, up to 4100CFUmL-1of algicidal and growth-inhibiting bacteria affecting both A. tamarense and H. akashiwo were detected in seawater adjacent to seven different eelgrass beds. In 2013, H. akashiwo-killing bacteria were found on Z. marina and Ulva lactuca with the highest densities of ∼108CFUg-1wet weight at Shallow Bay, Sucia Island. Bacteria that inhibited the growth of H. akashiwo and A. tamarense were also detected on Z. marina and Z. japonica at central Padilla Bay. Heterosigma akashiwo cysts were detected at a concentration of 3400cystsg-1wet weight in the sediment from Westcott Bay (northern San Juan Island), a location where eelgrass disappeared in 2002. These findings provide new insights on the ecology of algicidal and growth-inhibiting bacteria, and suggest that seagrass and macroalgae provide an environment that may influence the abundance of harmful algae in this region. This work highlights the importance of protection and restoration of native seagrasses and macroalgae in nearshore environments, in particular those regions where shellfish restoration initiatives are in place to satisfy a growing demand for seafood.
authors.affiliation: Plankton Laboratory, Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido, 041-8611, Japan. Electronic address: n_inaba84@fish.hokudai.ac.jp.
authors.forename: Nobuharu
authors.initials: N
authors.lastname: Inaba
authors.affiliation: Marine Biotoxins Program, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Blvd. E., Seattle, WA, 98112, United States. Electronic address: Vera.L.Trainer@noaa.gov.
authors.forename: Vera L
authors.initials: VL
authors.lastname: Trainer
authors.affiliation: Plankton Laboratory, Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido, 041-8611, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Onishi
authors.affiliation: Division of Environmental Biotechnology, Graduate School of Global Environmental Study, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto, 606-8501, Japan.
authors.forename: Ken-Ichiro
authors.initials: KI
authors.lastname: Ishii
authors.affiliation: Friday Harbor Laboratories, College of the Environment, University of Washington, 620 University Road, Friday Harbor, WA, 98250, United States.
authors.forename: Sandy
authors.initials: S
authors.lastname: Wyllie-Echeverria
authors.affiliation: Plankton Laboratory, Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido, 041-8611, Japan. Electronic address: imai1ro@fish.hokudai.ac.jp.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Imai
mesh_terms: D001419:Bacteria / Q000145:classification / Q000302:isolation & purification; D018407:Bacterial Physiological Phenomena; D004141:Dinoflagellida / Q000502:physiology*; D006540:Herbicides / Q000032:analysis; D010937:Plant Growth Regulators / Q000032:analysis; D012624:Seaweed / Q000382:microbiology; D058009:Stramenopiles / Q000502:physiology*; D044445:Ulva / Q000382:microbiology*; D014861:Washington; D035962:Zosteraceae / Q000382:microbiology*
chemical_list: D006540:Herbicides; D010937:Plant Growth Regulators
keywords: Alexandrium; Algicidal bacteria; Harmful algal blooms (HABs); Heterosigma; Seagrass