Factors Controlling the Abundance and Size Distribution of the Phototrophic Ciliate Myrionecta rubra in Open Waters of the North Atlantic |
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| Authors: | DAVID J. S. MONTAGNES JOHN ALLEN LOUISE BROWN CELIA BULIT RUSSELL DAVIDSON CARLOS DÍAZ‐ÁVALOS SOPHIE FIELDING MIKE HEATH NAOMI P. HOLLIDAY JENS RASMUSSEN RICHARD SANDERS JOANNA J. WANIEK DAVID WILSON |
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| Affiliation: | 1. School of Biological Sciences, University of Liverpool, Biosciences Building, Crown Street, Liverpool L69 7ZB, United Kingdom, and
;2. National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH, United Kingdom, and;3. 1Present address: School of Geography and Geosciences, University of St. Andrews, Irvine Building, St. Andrews, Fife KY16 9AL, Scotland.;4. Departamento El Hombre y su Ambiente, Universidad Autónoma Metropolitana‐Xochimilco, Calzada del Hueso 1100, 04960 México DF, México, and;5. Instituto de Investigaciones en Matemáticas Aplicadas y Sistemas, Universidad Nacional Autónoma de México, Apartado Postal 20‐726, 01000 México DF, México, and;6. FRS Marine Laboratory, PO Box 101, 375 Victoria Road, Aberdeen, AB11 9BD, United Kingdom;7. 2Present address: Institut für Ostseeforschung Warnemü?15, D18119 Rostock, Germany |
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| Abstract: | ABSTRACT. Myrionecta rubra, a ubiquitous planktonic ciliate, has received much attention due to its wide distribution, occurrence as a red tide organism, and unusual cryptophyte endosymbiont. Although well studied in coastal waters, M. rubra is poorly examined in the open ocean. In the Irminger Basin, North Atlantic, the abundance of M. rubra was 0–5 cells/ml, which is low compared with that found in coastal areas. Distinct patchiness (100 km) was revealed by geostatistical analysis. Multiple regression indicated there was little relationship between M. rubra abundance and a number of environmental factors, with the exception of temperature and phytoplankton biomass, which influenced abundance in the spring. We also improve on studies that indicate distinct size classes of M. rubra; we statistically recognise four significantly distinct width classes (5–16, 12–23, 18–27, 21–33 μm), which decrease in abundance with increasing size. A multinomial logistic regression revealed the main variable correlated with this size distribution was ambient nitrate concentration. Finally, we propose a hypothesis for the distribution of sizes, involving nutrients, feeding, and dividing of the endosymbiont. |
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| Keywords: | Cell size Mesodinium rubrum microzooplankton plankton protist distribution |
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