Phytoplankton bloom ecology of the Inner Sea of Chiloé, Southern Chile

Abstract

The phytoplankton assemblages studied in the coastal waters of the Inner Sea of Chiloe followed the typical evolution of a spring/autumn diatom bloom alternating with a summer dinoflagellate bloom. The seasonal blooms appeared to be related to light availability and oceanic nutrient-rich waters during spring months. Between 1992 and 2005, periods of relatively high abundance of some potentially harmful diatoms (Chaetoceros convolutus, Leptocylindrus minimus, Leptocylindrus danicus, Pselido-nitzschia spp.) were observed in the coastal waters off Southern Chile. Recurrent harmful algae blooms (HABs) are of considerable concern due to their serious health and ecological impacts. Both the number of HAB events and the magnitude of the algal cell abundance varied considerably from year to year. Although we know little about the factors driving the dynamics of the phytoplankton blooms, integrated in situ biological and environmental data allowed us to test hypotheses on temporal and spatial scales of bloom processes in the coastal waters off Southern Chile.