Life History Response of Daphnia magna to a Mixotrophic Golden Alga, Poterioochromonas sp., at Different Food Levels

Abstract

The toxicity of Poterioochromonas to Daphnia magna was investigated at different food (Scenedesmus acutus) levels. Poterioochromonas alone of 0.4-20 mg C L(-1) was not acutely toxic to D. magna, but did not support D. magna growth, either. When fed mixed diets (2 mg C L(-1) in total), D. magna's survival and reproduction were significantly depressed when Poterioochromonas comprised above 50%, likely due to the inhibition of food ingestion. Large juveniles were less sensitive to poor quality food than neonates. Therefore, Poterioochromonas may affect D. magna living to various extents depending on its concentration, age structure of D. magna populations and availability of other food.

From adverse to beneficial – contrasting dietary effects of freshwater mixotrophs on zooplankton

“…These results are altogether consistent with the findings of Hiltunen et al . (2012) on O. danica and Zhang et al . (2011) on P. malhamensis .…”

“…In the genera Ochromonas and Poterioochromonas , adverse effects on zooplankton were reported in earlier studies (Katechakis et al ., 2005; Zhang et al ., 2011; Hiltunen et al ., 2012). Moreover, toxic compounds produced by members of these genera were also observed (Reich & Spiegelstein, 1964; Halevy, Saliternik & Avivi, 1971).…”

“…CC-BY-NC-ND 4.0 International license made available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is & Porter, 1995;Boxhorn, Holen & Boraas, 1998;Boenigk & Stadler, 2004;Zhang et al, 2011;Hiltunen, Barreiro & Hairston, 2012) as underlying mechanisms. The biochemical food quality profiles of chrysophytes represent a knowledge gap.…”

“…In these ecosystems, mixotrophs can account for a large fraction of bacterivory (Bird & Kalff, 1987;Domaizon, Viboud & Fontvieille, 2003;Hartmann et al, 2012), and thereby play a key role in carbon cycling (Mitra et al, 2014). While a number of recent studies attempted & Porter, 1995;Boxhorn, Holen & Boraas, 1998;Boenigk & Stadler, 2004;Zhang et al, 2011;Hiltunen, Barreiro & Hairston, 2012) as underlying mechanisms. The biochemical food quality profiles of chrysophytes represent a knowledge gap.…”

“…In contrast, surprisingly little is known regarding the dietary effects of chrysophytes on higher trophic levels, despite the fact that they often dominate phytoplankton assemblages. The majority of existing studies reported detrimental effects on zooplankton growth, reproduction and survival suggesting grazing resistance (Vad et al ., 2020) and toxicity (Leeper & Porter, 1995; Boxhorn, Holen & Boraas, 1998; Boenigk & Stadler, 2004; Zhang et al ., 2011; Hiltunen, Barreiro & Hairston, 2012) as underlying mechanisms. The biochemical food quality profiles of chrysophytes represent a knowledge gap.…”