Influence of Starvation on Respiratory Metabolism and Pyridine Nucleotide Levels in the Marine Dinoflagellate Oxyrrhis marina

Ocean acidification and food availability impacts on the metabolism and grazing in a cosmopolitan herbivorous protist Oxyrrhis marina

“…On the contrary, other studies showed that OA either stimulated respiration (Li and Gao, 2012;Meunier et al, 2017) or did not affect it (Runge et al, 2016) in copepods. For the heterotrophic dinoflagellate O. marina, reduced metabolic cost due to repressed respiration could save energy for it to sustain its growth (Osma et al, 2016). In the present work, the saved energy from the downregulated respiration under elevated pCO 2 could be utilized to sustain cellular acid-base homeostasis.…”

“…It usually experiences fluctuating pCO 2 and pH (Dai et al, 2009;Waldbusser and Salisbury, 2014) as well as phytoplankton food variation (Sherr and Sherr, 2009;Ok et al, 2021). To cope with those stresses, it can adjust cellular components and processes, such as structural proteins (Osma et al, 2016), ion pumps (Bailey et al, 2017), respiration rate and nutritional compositions (this work). Consequently, its robust resilience to acidic stress under future ocean acidification scenarios reflects that the heterotrophic dinoflagellate will be most likely one of the "winners" in future ocean, though the degradation of its nutritional values would influence organisms of high trophic levels, which needs to be explored under impacts of multiple climate change drivers in future studies.…”

Ocean acidification induces distinct metabolic responses in subtropical zooplankton under oligotrophic conditions and after simulated upwelling

“…This is likely associated to the constitutive nature of the ETS and a strategy of cells to short-term fluctuations of a stressor. It has been observed before that under food-shortage (nutrient limitation), conditions that we most probably had during the oligotrophic phase, the response of the ETS is more attenuated as compared to the RO 2 (Osma et al, 2016c), as a strategy to make use of resources once they are available again.…”

“…Since they were first introduced, the enzymatic assays of ETS and GDH have been frequently used as proxies for respiration and ammonium excretion in specific components of marine ecosystems, ranging from bacteria to fishes (Belcher et al, 2020;Finlay et al, 1983;Osma et al, 2016c;Romero-Kutzner et al, 2015;Fernández-Urruzola et al, 2011). These potential rates are usually converted into actual rates by means of empirically determined RO 2 /ETS and RNH 4 + /GDH ratios.…”