<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>The growth rates of ciliates estimated under natural conditions with the widely used size fractionation method are much lower than those observed in cultures. However, recent studies performed with a modified dilution method demonstrated that the size fractionation method underestimates the ciliate growth, because it does not remove predators of the same size as the organisms studied. Thus, it is still unresolved whether ciliates are food-limited in different systems and whether their growth rates are indeed lower than those in cultures. This study was conducted in highly eutrophic Lake Gardno using a modified dilution method. Each time, two dilution experiments were performed (around noon and around midnight). Four small, common ciliates from the genera <italic>Rimostrombidium, Tintinnidium, Cyclidium</italic>, and <italic>Urotricha</italic> were studied. The first three ciliates demonstrated very high mean diel growth rates exceeding 0.1 h<sup>-1</sup>, which corresponded well to the highest values reported in the literature for the ciliate growth in cultures at similar temperatures. <italic>Tintinnidium</italic> sp. demonstrated a diel growth rhythm. <italic>Urotricha</italic> sp. was sensitive to the experimental procedure, and measurements of its growth were unsuccessful. Concentrations of food particles were analyzed to check whether organisms studied were food satiated.</p>
</abstract>

The growth rates of ciliates estimated under natural conditions with the widely used size fractionation method are much lower than those observed in cultures. However, recent studies performed with a modified dilution method demonstrated that the size fractionation method underestimates the ciliate growth, because it does not remove predators of the same size as the organisms studied. Thus, it is still unresolved whether ciliates are food-limited in different systems and whether their growth rates are indeed lower than those in cultures. This study was conducted in highly eutrophic Lake Gardno using a modified dilution method. Each time, two dilution experiments were performed (around noon and around midnight). Four small, common ciliates from the genera Rimostrombidium, Tintinnidium, Cyclidium, and Urotricha were studied. The first three ciliates demonstrated very high mean diel growth rates exceeding 0.1 h-1, which corresponded well to the highest values reported in the literature for the ciliate growth in cultures at similar temperatures. Tintinnidium sp. demonstrated a diel growth rhythm. Urotricha sp. was sensitive to the experimental procedure, and measurements of its growth were unsuccessful. Concentrations of food particles were analyzed to check whether organisms studied were food satiated.

Growth rates of common pelagic ciliates in a highly eutrophic lake measured with a modified dilution method

Oceanological and Hydrobiological Studies

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

The growth rates of ciliates estimated under natural conditions with the widely used size fractionation method are much lower than those observed in cultures....

Growth rates of common pelagic ciliates in a highly eutrophic lake measured with a modified dilution method

Article Category: Original research paper

Pubblicato online: 22 giu 2016

Pagine: 216 - 229

Ricevuto: 04 lug 2015

Accettato: 09 ott 2015

DOI: https://doi.org/10.1515/ohs-2016-0020

© Faculty of Oceanography and Geography, University of Gdañsk, Poland. All rights reserved.

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.