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Physiological Responses of Mesodinium major to Irradiance, Prey Concentration and Prey Starvation
Author(s) -
Drumm Kirstine,
Norlin Andreas,
Kim Miran,
Altenburger Andreas,
Juel Hansen Per
Publication year - 2021
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/jeu.12854
Subject(s) - predation , biology , mixotroph , photosynthesis , starvation , chloroplast , diel vertical migration , botany , facultative , chlorophyll a , ecology , heterotroph , biochemistry , bacteria , genetics , endocrinology , gene
Ciliates within the Mesodinium rubrum/Mesodinium major species complex harbor chloroplasts and other cell organelles from specific cryptophyte species. Mesodinium major was recently described, and new studies indicate that blooms of M . major are just as common as blooms of M . rubrum . Despite this, the physiology of M . major has never been studied and compared to M . rubrum . In this study, growth, food uptake, chlorophyll a and photosynthesis were measured at six different irradiances, when fed the cryptophyte, Teleaulax amphioxeia . The results show that the light compensation point for growth of M . major was significantly higher than for M . rubrum . Inorganic carbon uptake via photosynthesis contributed by far most of total carbon uptake at most irradiances, similar to M . rubrum . Mesodinium major cells contain ~four times as many chloroplast as M . rubrum leading to up to ~four times higher rates of photosynthesis. The responses of M . major to prey starvation and refeeding were also studied. Mesodinium major was well adapted to prey starvation, and 51 d without prey did not lead to mortality. Mesodinium major quickly recovered from prey starvation when refed, due to high ingestion rates of > 150 prey/predator/d.