Evaluating vertical migration behaviour of harmful raphidophytes in the Delaware Inland Bays utilizing quantitative real-time PCR

Publication Type:
Journal Article
Aquatic Microbial Ecology, 2005, 40 pp. 121 - 132
Issue Date:
Full metadata record
Files in This Item:
Filename Description Size
Thumbnail2005002778.pdf1.09 MB
Adobe PDF
Mixed blooms of 4 species of harmful raphidophytes (Chattonella cf. verruculosa, Chattonella subsalsa, Heterosigma akashiwo, and Fibrocapsa japonica) occur in the shallow (1 ti 2m) Delaware Inland Bays (DIB), USA. Raphidophytes vertically migrate in other deeper water ecosystems to utilise deep nutrient stocks at night, and thus obtain an advantage over non-migrating algae.Anoxic DIB sediments release high levels of bioavailable phosphate, which could potentially be used by vertically migrating flagellates. This study aimed to characterise and understamd the migration oatterns of DIB raphidiphytes, and determine whether benthic phosphate fluxes could provide the cells with P. We demonstrated vertical migration of isolated DIB raphidophyte cultures in the laboratory, where differences inthe response of C. subsalsa and H. akashiwo to light:dark period manipulations suggested possible diffeerneces in external versus endogenous regulation of migration behaviour in the 2 species. Natural blooms in the filed (enclosed in a mesocosm system) also exhibited patterns of diel vertical distributions of each species. Our data suggested that these 2 photoautotrophic species spend daylight hours near the surface and are found directly on the sediment surface at night. However, diel changes in particulate C:P ratios did not support the hypothesis that there is preferential uptake of sedimentary phosphate at night. Our results also suggested that the migration behaviour may have important implications for designing sampling strategies for monitoring programs. QPCR has a number of decisive advantages over traditional microscopic counting methods, making this a poweful tool for fine spatial temporal scale detection and enum,eration of vertically migrating harmful algal species.
Please use this identifier to cite or link to this item: