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We devised a simple and rapid technique for establishing axenic cultures of centric diatoms by sieving and washing resting stage cells. This technique is an effective means for establishing the axenic cultures of species that have endogenous resting spores. The primary advantage of this method is in the isolation of cells when the target species is absent from the water column. [ABSTRACT FROM AUTHOR]

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 × 10 6 CFU g −1 wet 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 ∼10 8 CFU g −1 wet weight. Additionally, up to 4100 CFU mL −1 of 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 ∼10 8 CFU g −1 wet 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 3400 cysts g −1 wet 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. [ABSTRACT FROM AUTHOR]