Feeding by the Pfiesteria-like heterotrophic dinoflagellate Luciella masanensis.
To explore the feeding ecology of the Pfiesteria-like dinoflagellate (PLD) Luciella masanensis (GenBank Accession no. AM050344, previously Lucy), we investigated the feeding behavior and the kinds of prey species that L. masanensis fed on and determined its growth and ingestion rates of L. masanensis when it fed on the dinoflagellate Amphidinium carterae and an unidentified cryptophyte species (equivalent spherical diam., ESD=5.6 microm), which were the dominant phototrophic species when L. masanensis and similar small heterotrophic dinoflagellates were abundant in Masan Bay, Korea in 2005. Additionally, these parameters were also measured for L. masanensis fed on blood cells of the perch Lateolabrax japonicus and the raphidophyte Heterosigma akashiwo in the laboratory. Luciella masanensis fed on prey cells by using a peduncle after anchoring the prey with tow filament, and was able to feed on diverse prey such as cryptophytes, raphidophytes, diatoms, mixotrophic dinoflagellates, and the blood cells of fish and humans. Among the prey species tested in the present study, perch blood cells were observed to be the optimal prey for L. masanensis. Specific growth rates of L. masanensis feeding on perch blood cells, A. carterae, H. akashiwo, and the cryptophyte, either increased continuously or became saturated with increasing the mean prey concentration. The maximum specific growth rate of L. masanensis feeding on perch blood cells (1.46/day) was much greater than that of A. carterae (0.59/day), the cryptophyte (0.24/day), or H. akashiwo (0.20/day). The maximum ingestion rate of L. masanensis on perch blood cells (2.6 ng C/grazer/day) was also much higher than that of A. carterae (0.32 ng C/grazer/day), the cryptophyte (0.44 ng C/grazer/day), or H. akashiwo (0.16 ng C/grazer/day). The kinds of prey species which L. masanensis is able to feed on were the same as those of Pfiesteria piscicida, but very different from those of another PLD Stoeckeria algicida. However, the maximum growth and ingestion rates of L. masanensis on perch blood cells, A. carterae, H. akashiwo, and the cryptophyte were considerably lower than those of P. piscicida. Therefore, these three dinoflagellates may occupy different ecological niches in marine planktonic communities, even though they have a similar size and shape and the same feeding mechanisms.
Jeong
Hae Jin
HJ
School of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul 151-747, Korea. hjjeong@snu.ac.kr
Ha
Jeong Hyun
JH
Yoo
Yeong Du
YD
Park
Jae Yeon
JY
Kim
Jong Hyeok
JH
Kang
Nam Seon
NS
Kim
Tae Hoon
TH
Kim
Hyung Seop
HS
Yih
Won Ho
WH
D000818:Animals; D001769:Blood; D004141:Dinoflagellida / Q000502:physiology*; D017753:Ecosystem; D005399:Fishes; D007723:Korea; D008386:Marine Biology; D020045:Pfiesteria piscicida / Q000502:physiology; D011235:Predatory Behavior / Q000502:physiology*; D012623:Seawater; D013045:Species Specificity