Grazing impact on the cyanobacterium Microcystis aeruginosa by the heterotrophic flagellate Collodictyon triciliatum in an experimental pond

Yuki Kobayashi, Yoshikuni Hodoki, Kako Ohbayashi, Noboru Okuda, Shin ichi Nakano

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

We estimated the grazing impact of the heterotrophic flagellate Collodictyon triciliatum on the harmful, bloom-forming cyanobacterium Microcystis aeruginosa in an experimental pond during a Microcystis bloom from summer to winter in 2010. For these experiments, we calculated the grazing rates from the digestion rate of C. triciliatum and its food vacuole contents. During the study period, M. aeruginosa exhibited one bloom event with a maximum density of 1. 1 × 105 cells ml-1. The cell density of C. triciliatum fluctuated from below the detection limit to 291 cells ml-1. The number of M. aeruginosa cells ingested by C. triciliatum food vacuoles ranged between 0. 4 and 10. 8 cells flagellate-1, and the digestion rate of C. triciliatum at 25 °C was 0. 73 % cell contents min-1. The grazing rate of C. triciliatum on the M. aeruginosa prey was 0. 2-6. 9 cells flagellate-1 h-1, and its grazing impact was 0. 0-25. 3 % standing stock day-1. The functional response of C. triciliatum to the M. aeruginosa prey followed the Michaelis-Menten model of significance (r2 = 0. 873, p < 0. 001) in our experimental systems, in which the prey concentration varied from 1. 0 × 104 to 2. 1 × 106 cells ml-1. The maximum grazing rate was 6. 2 prey cells grazer-1 h-1, and the half-saturation constant was 1. 2 × 105 cells ml-1. We present evidence that C. triciliatum grazing explained the remarkable decrease in M. aeruginosa cell density in the pond. The present study is the first demonstration of the high potential of protistan grazing on M. aeruginosa to reduce cyanobacterial blooms.

Original languageEnglish
Pages (from-to)43-49
Number of pages7
JournalLimnology
Volume14
Issue number1
DOIs
Publication statusPublished - 2013 Jan 1

Keywords

  • Collodictyon triciliatum
  • Functional response
  • Grazing impact
  • Ingestion
  • Microcystis aeruginosa

ASJC Scopus subject areas

  • Ecology
  • Aquatic Science
  • Water Science and Technology

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