The benthic resting cyst: A key actor in harmful dinoflagellate blooms - A review

Abstract

Resting cysts (RC) constitute a coupling between benthic and pelagic stages and influence the bloom development in a number of bloom forming dinoflagellate species. Encystment capability coupled with high vegetative cell density (> one million cells 1-1) contribute to the formation of an accumulation zone: "the cyst bank", which is directly linked to the success of bloom initiation and its recurrence. The survival time of benthic RCs (few weeks to several years), their viability which could be negatively affected by predation, and their mandatory dormancy period (few days to several months) are variable and influence the seeding potential of the population significantly. Excystment rate, mainly controlled by temperature and oxygen level, and the germling cells' viability determine the inoculum size. Many biological processes in RCs have been shown to be controlled by endogenous and environmental factors, and vary between species and within the same species as a function of geographic strains.