Myrionecta rubra (Mesodinium rubrum) bloom initiation in the Columbia River estuary

Lydie Herfort, Tawnya D. Peterson, Victoria Campbell, Sheedra Futrell, Peter Zuber

Research output: Contribution to journalArticle

22 Scopus citations


To better understand the development of the annually recurring late summer red water blooms of the phototrophic ciliate Myrionecta rubra in the Columbia River estuary we examined its standing stocks and measured its growth rates both in the estuary main channels and in Baker Bay, a peripheral embayment situated near the river mouth. Data collected during two summers show a biphasic development of M. rubra blooms, with an initial phase when the protist was only detected in Baker Bay, followed by an established phase when red waters were observed throughout the lower estuary. Ilwaco harbor (Baker Bay's seaward-end) is at least one of the locations where the bloom starts since M. rubra was detected there at concentrations >100scellL-1 before Chinook harbor (Baker Bay's upriver-end) or the estuary main channels. In 2010, this initial phase lasted about 1.5 months, spanning the neap tide of early July to the beginning of the neap tide of mid-August. While high growth rates were measured in Ilwaco harbor during the initial phase (1.2-3.1 d-1) and in the estuary main channels in both surface red (0.7 d-1) and adjacent non-red (1.1 d-1) waters during the established period, growth of the ciliate was not detected in Ilwaco harbor during this second phase. Growth rate data obtained during the established bloom phase also suggest that M. rubra cells in the estuary mostly divide during the daytime and that red water patches might experience self-shading.

Original languageEnglish (US)
Pages (from-to)440-446
Number of pages7
JournalEstuarine, Coastal and Shelf Science
Issue number4
StatePublished - Dec 20 2011


  • Bloom development
  • Columbia River estuary
  • Myrionecta rubra
  • Red water

ASJC Scopus subject areas

  • Oceanography
  • Aquatic Science

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