Growth, toxicity and oxidative stress of a cultured cyanobacterium (Dolichospermum sp.) under different CO₂/pH and temperature conditions

Abstract

SUMMARYCyanobacteria blooms are a worldwide nuisance in fresh, brackish and marine waters. Changing environmental conditions due to upwelling, changed mixing conditions or climate change are likely to influence cyanobacteria growth and toxicity. In this study, the response of the toxic cyanobacterium Dolichospermum sp. to lowered pH (−0.4 units by adding CO2) and elevated temperature (+4°C) in an experimental set-up was examined. Growth rate, microcystin concentration and oxidative stress were measured. The growth rate and intracellular toxin concentration increased significantly as a response to temperature. When Dolichospermum was exposed to the combination of elevated temperature and high CO2/low pH, lipid peroxidation increased and antioxidant levels decreased. Microcystin concentrations were significantly correlated with growth rates. Our results show, although oxidative stress increases when exposed to a combination of high CO2/low pH and high temperature, that growth and toxicity increase at high temperature, suggesting that the cyanobacterium in general seems to be fairly tolerant to changes in pH and temperature. Further progress in identifying biological responses and predicting climate change consequences in estuaries experiencing cyanobacteria blooms requires a better understanding of the interplay between stressors such as pH and temperature.

Physiological and Biochemical Analyses Shed Light on the Response of Sargassum vulgare to Ocean Acidification at Different Time Scales

“…It should be kept in mind that, apart from constituting a benefit for autotrophs, the increase in aqueous CO 2 causes seawater acidification which has the potential to affect metabolism and cellular homeostasis, thereby impairing cellular function or increasing energy demand, as it has been found in cyanobacteria and phytoplankton (Taylor et al, 2012; Brutemark et al, 2015). Indeed, we found higher activities of oxidative metabolizing enzymes in response to short-term transplants from the control to the acidified site; these higher values were maintained in natural populations under long-term conditions of acidification.…”

“…Elevated CO 2 can induce oxidative stress in marine organisms by increasing ROS production either directly by increased formation of free radicals, due to the interaction of CO 2 with other ROS, and/or indirectly by enhancing Fenton reaction at lower pH (Tomanek et al, 2011; Hu et al, 2015). The possible induction of oxidative stress in autotrophs by OA has been poorly investigated and mostly limited to phytoplankton, where CO 2 /lowered pH has been shown to induce oxidative stress (Brutemark et al, 2015; Yangüez et al, 2015). Elevated CO 2 has been also shown to alleviate high PAR and UV stress in the unicellular chlorophyte Dunaliella tertiolecta (Garcia-Gomez et al, 2014).…”

Влияние щелочности, сверхнизкой концентрации диоксида углерода и интенсивности излучения на спектральные свойства, фитобилисомы, фотосинтез, фотосистемы и функциональные группы нативной цианобактерии Calothrix sp. ISC 65

“…The growth rate and intracellular toxin concentration increased significantly as a response to temperature. When Dolichospermum was exposed to the combination of elevated temperature and high CO 2 /low pH, lipid peroxidation increased and antioxidant levels decreased (Brutemark et al, 2015).…”

Technical Note: A minimally invasive experimental system for <i>p</i>CO<sub>2</sub> manipulation in plankton cultures using passive gas exchange (atmospheric carbon control simulator)

“…Many studies of planktonic organisms (particularly autotrophs) employ dilute batch culture, where seawater media pre-conditioned to the appropriate chemistry is inoculated at a low density, sealed, and allowed to grow for a limited period of time (e.g., Eberlein et al, 2016;Hoins et al, 2016;Wilcox-Freeburg et al, 2013;Zhang et al, 2015). Changes in water chemistry can exceed 1 pH unit and 15 % of DIC during the course of the batch culture when biomass is high or duration is long (Brutemark et al, 2015). Dilute batch culture systems are not well suited for zooplankton studies because cultures are subject to gas exchange each time they are opened for feeding, and dilute cultures of prey can cause encounter rates to limit growth and grazing rates of zooplankton.…”