Gustaaf M. Hallegraeff, JA Marshall, John F. Valentine, Sean Hardiman
Tóm tắt
Cyst beds of Alexandrium catenella (a causative organism
of Paralytic Shellfish Poisoning) are widespread in New South Wales coastal
and estuarine waters (temperature range 13–25˚C). Cysts produced by
cultured isolates exhibited dormancy periods at 17˚C as short as
28–55 days. This contrasts with the usually longer dormancy requirements
of temperate populations of A. catenella from Japan (97
days at 23˚C) and of A. tamarense from Cape Cod or
British Columbia. With some Australian cysts, a 1-h temperature increase from
17˚ to 25˚C (equivalent to summer heating of shallow estuaries)
improved germination success (up to 100% germination achieved after 98
days), but cold–dark storage did not produce the lengthened dormancy
requirements that have been reported overseas for overwintering temperate cyst
populations. The significance of this finding is that different geographic
isolates of the same dinoflagellate taxon can have different cyst dormancy
requirements which play different ecological roles (overwintering strategy
v. rapid cycling between benthos and plankton).
