Heterosigma akashiwo as a potential source of prey for the toxic dinoflagellate, Dinophysis acuminata
Date
2020
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
Dinophysis acuminata is a toxic dinoflagellate that is found worldwide in coastal regions, including the Delaware Inland Bays (DIBs). It produces the toxin, okadaic acid, and has the potential to cause diarrhetic shellfish poisoning. Previous studies demonstrated that lab cultures of D. acuminata acquire plastids from its prey, the ciliate, Mesodinium rubrum, which, in turn, acquired plastids from the cryptophyte, Teleaulax amphioxeia. Reports of D. acuminata from field samples, however, have found plastids of the raphidophyte, Heterosigma akashiwo within D. acuminata cells, which suggests a broader range of prey than originally thought. This project seeks to better understand prey selection by D. acuminata in laboratory culture and wild populations found in the DIBs. There are three goals for this project: (1) evaluate the relationship between co-occurring blooms of D. acuminata and H. akashiwo in the DIBs, (2) determine if H. akashiwo is a source of prey for either D. acuminata or M. rubrum, and (3) design a dual excitation ratiometric approach using fluorescence microscopy to identify species-specific pigments in chloroplasts retained by D. acuminata. Our results show that in Torquay Canal, blooms of D. acuminata do not occur in response to the presence of H. akashiwo D. acuminata does not prey on or retain plastids from H. akashiwo. A better understanding of biotic and abiotic factors that contribute to blooms of D. acuminata, such as nutrients, temperature, and prey availability, will help in forecasting blooms and monitoring for toxicity.
Description
Keywords
Delaware inland bays, Dinophysis acuminata, Harmful algae, Heterosigma akashiwo, Ratiometric method, Torquay Canal