Gamma Radiation Induced Changes in the Biochemical Composition of Aquatic Primary Producers and Their Effect on Grazers

Abstract

Changes in the biochemical composition of primary producers can alter their food quality, influencing their consumers and further propagating through the food web. Gamma (È) radiation is an environmentally important type of ionizing radiation as it can damage macromolecules such as DNA, proteins, and lipids due to its high frequency, short wavelength, and high energy photons. Here, we investigate whether short-term È-radiation changes the biochemical composition of primary producers and if radiation-induced changes affect higher trophic levels. Two phytoplankton species were exposed to two doses of È-radiation and compared to a control. The metabolic profile and total protein content of the algae were measured at five time points within 24 h. Additionally, we measured carbon incorporation rates of Daphnia magna fed with the exposed algae. Gamma radiation had a significant effect on phytoplankton biochemical composition, although these effects were species-specific. The changes in phytoplankton biochemical composition indicate that È-radiation induced the production of reactive oxygen species (ROS). D. magna incorporated more carbon when fed with algae previously exposed to È-radiation; this could be due to radiation-induced changes in nutritional quality, algal anti-grazing defenses, or chemical feeding stimuli.

Effect of nutrients and gamma radiation on growth and lipid accumulation of Chlorella vulgaris for biodiesel production

“…Nitrogen starvation (Rehman & Anal, 2019), phosphate limitation (Yu et al, 2016), magnesium supplementation (Esakkimuthu, Krishnamurthy, Govindarajan, & Swaminathan, 2016;Goh et al, 2019), carbon source (Raeisossadati, Ahmadzadeh, McHenry, & Moheimani, 2014), iron content of the culture medium (Chandra, Amit & Ghosh, 2019), high salinity (Ji et al, 2018), and high light intensities (He, Yang, & Hu, 2018) can enhance the lipid content. Gamma radiation had a significant effect on the biochemical composition of phytoplankton, although these effects were species-specific (Golz & Bradshaw, 2019). The growth density of Chlorella pyrenoidosa mutated by 500 Gy of 60 Co irradiation increased by 53.1% (Cheng et al, 2013).…”

Effect of gamma irradiation on the growth and lipid productivity of green microalgae

“…This enzyme can stimulate the accumulation of lipids within the cytoplasm and chloroplast, which might improve the tolerance to oxidative stress and resistance of the microalga (Garay et al 2014;Zhu et al 2016). As obtained by Golz and Bradshaw (2019), that the growth of Spirulina platensis has significantly increased at lower gamma irradiation doses (less than 500 Gy) while at higher doses, its growth was inhibited by 30 %. Although, exposing the microalgal cells to gamma irradiation might also lead to biomass loss Effect of gamma irradiation on growth and lipid productivity of green microalgae Another study by Abomohra et al (2016) revealed that even though the gamma irradiation had an adverse impact on the biomass production of Spirulina platensis, a significant rise in the carbohydrates, lipids, and pigments amounts was observed in biomass extracts, unlike the protein levels.…”

Impact of Culture Media Composition, Nutrients Stress and Gamma Radiation on Biomass and Lipid of the Green Microalga, Dictyochloropsis splendida as a Potential Feedstock for Biodiesel Production

“…Little information is available on the effect of γradiation on the physiological mechanism and biochemical composition of microalgae 10,11 . The objectives of this study were to investigate the effect of culture media composition, nutrients concentration (nitrogen, phosphorous, magnesium, and carbonate) as well as the dosage of γradiation on both algal growth and lipid parameters of microalga, Dictyochloropsis splendida…”