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Feeding by the Heterotrophic Dinoflagellate Oxyrrhis marina on the Red‐Tide Raphidophyte Heterosigma akashiwo : a Potential Biological Method to Control Red Tides Using Mass‐Cultured Grazers
Author(s) -
JEONG HAE JIN,
KIM JAE SEONG,
YOO YEONG DU,
KIM SEONG TAEK,
KIM TAE HOON,
PARK MYUNG GIL,
LEE CHANG HOON,
SEONG KYEONG AH,
RANG NAM SEON,
SHIM JAE HYUNG
Publication year - 2003
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.2003.tb00134.x
Subject(s) - heterosigma akashiwo , red tide , dinoflagellate , biology , mesocosm , incubation , heterotroph , clearance rate , algal bloom , botany , ecology , phytoplankton , bacteria , biochemistry , nutrient , genetics , endocrinology
. As part of the development of a method to control the outbreak and persistence of red tides using mass‐cultured heterotrophic protist grazers, we measured the growth and ingestion rates of cultured Oxyrrhis marina (a heterotrophic dinoflagellate) on cultured Heterosigma akashiwo (a raphidophyte) in bottles in the laboratory and in mesocosms (ca. 60 liter) in nature, and those of the cultured grazer on natural populations of the red‐tide organism in mesocosms set up in nature. In the bottle incubation, specific growth rates of O. marina increased rapidly with increasing concentration of cultured prey up to ca. 950 ng C ml −1 (equivalent to 9,500 cells ml −1 ), but were saturated at higher concentrations. Maximum specific growth rate (μ max ), K GR (prey concentration sustaining 0.5 μ max ) and threshold prey concentration of O. marina on H. akashiwo were 1.43 d −1 , 104 ng C ml −1 , and 8.0 ng C ml −1 , respectively. Maximum ingestion and clearance rates of O. marina were 1.27 ng C grazer −1 d −1 and 0.3 μ1 grazer −1 h −1 , respectively. Cultured O. marina grew well effectively reducing cultured and natural populations of H. akashiwo down to a very low concentration within 3 d in the mesocosms. The growth and ingestion rates of cultured O. marina on natural populations of H. akashiwo in the mesocosms were 39% and 40%, respectively, of those calculated based on the results from the bottle incubation in the laboratory, while growth and ingestion rates of cultured O. marina on cultured H. akashiwo in the mesocosms were 55% and 36%, respectively. Calculated grazing impact by O. marina on natural populations of H. akashiwo suggests that O. marina cultured on a large scale could be used for controlling red tides by H. akashiwo near aquaculture farms that are located in small ponds, lagoons, semi‐enclosed bays, and large land‐aqua tanks to which fresh seawater should be frequently supplied.