Ej. Buskey et al., FEEDING, GROWTH AND BIOLUMINESCENCE OF THE HETEROTROPHIC DINOFLAGELLATE PROTOPERIDINIUM-HUBERI, Marine Biology, 121(2), 1994, pp. 373-380
Feeding, growth and bioluminescence of the thecate heterotrophic dinof
lagellate Protoperidinium huberi were measured as a function of food c
oncentration for laboratory cultures grown on the diatom Ditylum brigh
twellii. Ingestion of food increased with food concentration. Maximum
ingestion rates were measured at food concentrations of similar to 600
mu g C l(-1) and were similar to 0.7 mu g C individual(-1) h(-1) (1.8
D. brightwelli cells individual h(-1)). Clearance rates decreased asy
mptotically with increasing food concentration. Maximum clearance rate
s at low food concentration were ca. 23 mu l ind(-1) h(-1), which corr
esponds to a volume-specific clearance rate of 5.9x10(5) h(-1). Cell s
ize of P. huberi was highly variable, with a mean diameter of 42 mu m,
but no clear relationship between cell size and food concentration wa
s evident. Specific growth rates increased with food concentration unt
il maximum growth rates of similar to 0.7 d(-1) were reached at a food
concentration of 400 mu g C l(-1) (similar to 1000 cells ml(-1)). Foo
d concentrations as low as 10 mu g C l(-1) of D. brightwellii (similar
to 25 cells ml(-1)) were able to support growth of P. huberi. The bio
luminescence of P. huberi varied with its nutritional condition and gr
owth rate. Cells held without food lost their bioluminescence capacity
in a matter of days. P. huberi raised at different food concentration
s showed increased bioluminescence capacity, up to food concentrations
that supported maximum growth rates. The bioluminescence of P. huberi
varied over a diel cycle, and these rhythmic changes persisted during
48 h of continuous darkness, indicating that the rhythm was under end
ogenous control.