Delayed effect of geomagnetic storm simulation on size, mass and activity of digestive glycosidases in roach (Rutilus rutilusLinnaeus, 1758) underyearlings

Abstract

Summary This study aim was finding delayed consequences of the main phase impact and initial recovery period phase of a typical geomagnetic storm (MRGMS) experimentally reproduced in the range of 0–0.001 Hz on roach (Rutilus rutilus L., 1758) embryos. Roe and sperm were collected from four females and eight males caught in the Rybinsk reservoir, to achieve phenetic diversity in the resulting offspring. Mean water temperature during fertilization and embryo incubation was 18.02°C. The embryos were exposed before (1–6 hr post‐fertilization) and after (33–39 hr post‐fertilization) gastrulation to MRGMS with intensities of 100, 300 and 500 nT, which corresponded to the main phase and initial recovery period phase of typical moderate, strong and severe geomagnetic storms. After this exposure, body mass, standard length, mass and length of the intestine, plus activity, temperature and kinetic characteristics of digestive glycosidases were evaluated in four‐month‐old underyearlings (standard length 5.57–8.66 cm, body mass 3.08–12.01 g) developed from exposed embryos. Standard length and mass were lower in fish exposed to different MRGMS following gastrulation. In general, when compared to the controls, the activity of maltase was lower and activity of sucrase higher in fish exposed to different MRGMS before and after gastrulation. Maximal differences between experimental and control groups were caused by an impact of the simulation that corresponded to a moderate geomagnetic storm. After the influence of studied simulations was introduced, adaptive changes in digestive glycosidases were revealed, including an increase of enzymes affinity for the substrate, an enlargement of maltase temperature optimum and a decrease of maltase Eact in the range of environmental temperatures. The magnitude and direction of observed effects depended on the MRGM intensity and the time intervals in embryogenesis when the exposures were carried out.

Delayed consequences of the influence of simulated geomagnetic storms on roach Rutilus rutilus embryos

“…In the experiments utilising 6 h signals to simulate the main phase and the initial period of the recovery phase of a geomagnetic storm as a treatment, only the exposure of roach embryos from the 33rd to 39th hpf led to significant decreases in under‐yearling sizes. At the same time, the L S of under‐yearlings exposed as embryos to these signals during the first 6 hpf did not significantly differ from the control (Golovanova et al ., ). The results of this study are consistent with the hypothesis that there are sensitive intervals to magnetic influence in roach embryogenesis that can significantly affect the growth of fish.…”