SPATIAL AND TEMPORAL DISTRIBUTIONS OF MICROPLANKTON DURING THE SUMMERS OF 1992-1993 IN BARKLEY SOUND, BRITISH-COLUMBIA, WITH EMPHASIS ON HARMFUL SPECIES

The microplankton community of an open coastal embayment in British Co lumbia (Barkley Sound) was typical of coastal waters of western North America, but different from that in more sheltered waters of British C olumbia. The spring bloom occurred in May, 1 month later than is usual in the Strait of Georgia and 2 months later than in the coastal fjord s of southwestern British Columbia. In Barkley Sound, the summer plank ton was dominated by diatoms owing to persistent upwelling offshore wi th onshore advection by wind forcing, whereas in other regions dinofla gellates and nanoflagellates usually predominate in the stratified wat ers of summer. Plankton distribution patterns allowed a distinction be tween blooms originating within the system and those advected from off shore. The highest biomass was consistently found in the sheltered nor thern corner of Barkley Sound (Toquart Bay). At least 14 potentially h armful species were present within the Sound. A rise in saxitoxin in t he central island group coincided with an increase of Alexandrium cate nella. A rise in domoic acid in the northwest coincided with an increa se in Pseudo-nitzschia delicatissima and Pseudo-nitzschia pungens. The re was considerable interannual variability, indicating the need for l onger periods of study. Unpublished evidence points to strong dinoflag ellate blooms in the fall.