Alexandrium and Scrippsiella cyst viability and cytoplasmic fullness in a 60-cm sediment core from Sequim Bay, WA

Abstract

Many marine protists produce a benthic resting stage during their life history. This non-motile cyst stage can either germinate near the sediment surface to provide the inoculum for subsequent blooms or, be buried by sediment deposits over time and entrained into the sedimentary record.

The long‐term persistence of phytoplankton resting stages in aquatic ‘seed banks’

“…In studies to date, the number of viable cells generally decreases with sediment depth and age; however some deeper layers had higher numbers (and percentages) of viable cells. Thus Feifel et al (2015) found higher germination percentages of Alexandrium and Scrippsiella at 30-50 cm depth (13-42 years old) than in surface samples; Miyazono et al (2012) found higher concentrations of intact Alexandrium tamarense cysts at 22 cm (ca. 50 years old), although the germination percentage fell linearly with depth and exponentially with age.…”

“…Thus Feifel et al . () found higher germination percentages of Alexandrium and Scrippsiella at 30–50 cm depth (13–42 years old) than in surface samples; Miyazono et al . () found higher concentrations of intact Alexandrium tamarense cysts at 22 cm ( ca .…”

“…There are also documented cases of resting stages formed without sexual reproduction (Kremp & Parrow, ). Dinoflagellate cysts have been germinated from sediment layers dated up to approximately 100 years old at 32–63 cm depth in the sediment (Lundholm et al., ; Miyazono et al., ; Feifel et al., ). In many of these studies, deeper (older) sediment layers were screened without successful germinations, indicating that these ages are likely to represent maximum possible viability in these environmental settings.…”

“…The same result was found by McQuoid & Hobson (). The effect of temperature on the potential for long‐term viability in situ has not been systematically investigated, but in marine settings, viability of diatoms and dinoflagellates for up to a century has been reported in cold‐temperate settings in the Baltic (Härnström et al., ; Lundholm et al., ), North Washington state (Feifel et al., ) and northern Japan (Miyazono et al., ). Our own data indicate that the same approximate maximal viability is found in Arctic settings (S. Ribeiro, S. Hardardottir, M. Ellegaard, T. J. Andersen & K. Rengefors, in preparation).…”

“…The dinoflagellate genus Alexandrium includes many toxic species and is one of the groups with extended survival (e.g. Feifel et al., ). Other prominent toxin producers, such as the dinoflagellate Gymnodinium catenatum also produce resistant resting cysts.…”