Food selectivity of Ceriodaphnia quadrangula (O. F. Müller, 1785) (Cladocera) and its impact on competition outcome between two freshwater green algae

Abstract

The present work tested the food selectivity of the cladoceran Ceriodaphnia quadrangula (O. F. Müller, 1785) and its impact on competition outcome between Chlorella vulgaris Beijerinck, 1890 and Chlamydomonas globosa J. W. Snow, 1902. Freshwater green algae, Chlorella, have heavy cell walls and their size usually exceeds the lower limits of hmb size of Ceriodaphnia. According to the optimal foraging theory, it is speculated that Ceriodaphnia would graze on the more exposed and relatively larger Chlamydomonas rather than on Chlorella, and this process would lead to smallsized Chlorella becoming a superior competitor in the presence of Ceriodaphnia. This work used Ceriodaphnia, Chlamydomonas globosa and Chlorella vulgaris to test this hypothesis. The grazing experiment showed that Ceriodaphnia preferred Chi. globosa to Ch. vulgaris, regardless of the concentration and relative abundance of these algae. The decrease in relative abundance of highquality Chlamydomonas in Chlamydomonas-Chlorella assemblages did not diminish the grazing efficiency of Ceriodaphnia on this algal species, but increased the selectivity of small-sized cells of Chlorella. However, when the concentration of Chlamydomonas was extremely high, the grazing of Ceriodaphnia on Chlamydomonas decreased. In competition experiments, it was observed that the presence of Chlamydomonas restrained the growth potential of Chlorella; however, the introduction of Ceriodaphnia into the competing environment weakened this influence and to some extent enhanced the growth ability of Chlorella. The different densities of Ceriodaphnia had an obvious influence on the competition outcome between Chlamydomonas and Chlorella. RÉSUMÉCette étude a testé la sélection de la nourriture par le cladocère Ceriodaphnia quadrangula (O. F. Müller, 1785) et son impact sur les résultats de la compétition entre Chlorella vulgaris Beijerinck, 1890 et Chlamydomonas globosa J. W. Snow, 1902. Les algues vertes d'eau douce Chlorella, ont des parois cellulaires épaisses et leur taille dépasse généralement la taille limite inférieure des appendices de Ceriodaphnia. Selon la "théorie de ravitaillement optimal" ["optimal foraging theory"], il est admis que Ceriodaphnia devrait brouter sur les Chlamydomonas plus exposés et relativement plus grands que sur les Chlorella, et que ce processus devrait conduire les Chlorella de taille plus petite ')

Growth of tropical cladocerans Ceriodaphnia cornuta G.O. Sars, 1885 and Moina micrura Kurz, 1875 fed with different diets

“…Zooplankton forms one of the most important links in aquatic food chain and supports fishery resources in many different inland and marine ecosystems. Zooplankton commonly depends on algae, microbes, and particulate organic matter as its food sources in aquatic ecosystems (Alva-Martinez et al, 2007;Long et al, 2019;Tellioglu, 2013). In aquaculture industry, both phytoplankton and zooplankton function as live foods for commercially important fish and other aquatic organisms because they are easily digestible protein rich diets (Das et al, 2012).…”