Dormancy cycles in A. catenella cysts are driven by year-round temperature conditioning. New statistical models will characterize the distribution of cycling rates for assessments of the adaptability of different cyst populations to changing bottom water conditions. Large variance in dormancy cycle timing is anticipated across GOM cyst beds due to differences in temperature seasonality across this expansive habitat. Refined models of dormancy cycling will be validated through sediment incubations and used for assessment of likely changes to bloom source locations from changing bottom water temperatures. The extent to which dormancy cycles also limit the duration of inshore blooms will be assessed through studies in Nauset Marsh (NM) and Lombos Hole (LH).

Use of automated sensor systems in the study of localized NM blooms has shown that termination there is overwhelmingly driven by new cyst production and dispersal. Mass sexual induction in NM is exclusively associated with exceptionally high and ephemeral cell concentrations that are only efficiently detected through continuous observing. Accordingly, the applicability of NM-type dynamics to the GOM will be explored through deployment of automated systems that provide continuous, high frequency observations of phytoplankton communities, water column structure, and thin layers of enhanced biomass. Real-time data telemetry will guide adaptive sample collection from ships and regular sediment sampling will determine the timing and intensity of new cyst production within overlying waters. Parallel sampling will assess grazing pressure and nutrient limitation as alternative factors that may induce gametogenesis and/or drive GOM A. catenella bloom termination.

Pseudo-nitzschia occur year-round in the GOM. Bloom and toxin dynamics are driven by large-scale hydrographic and environmental forcings as well as life-history transitions that renew bloom populations. The latter will be explored through combined IFCB and automated ribosomal intergenic spacer analysis (ARISA) to track cell size changes within individual Pseudo-nitzschia spp. Abrupt size increases can indicate recent and widespread sexual renewal. In parallel, a series of metatransciptomic studies will leverage continuous IFCB and ESP observing to determine drivers of P. australis growth and toxin dynamics along the Maine coast.