Annotation of the results obtained in 2023
All declared work has been carried out. We used a laboratory culture of D. magna for the research. The geomagnetic field (51.7±0.2 µT) and hypomagnetic conditions (0±0.5 µT) were utilized in all experiments. The first corresponds to the usual conditions at the experimental location, and the second simulates changes during the reversal of the Earth's magnetic poles. Magnetic field parameters within the Helmholtz coil system and the geomagnetic field parameters during the experiments were checked daily using a three-component magnetometer. The influence of two combinations of different salinities, oxygen levels, temperatures, and hypomagnetic conditions on D. magna was assessed. Newborn individuals were randomly selected from a synchronized culture and placed in containers with water of different salinity, dissolved oxygen levels, and temperature, with one individual per container. Some of the Daphnia were positioned at the center of the Helmholtz coil system, generating hypomagnetic conditions, while the others remained in the geomagnetic field. Data registered during the experiment included the day of the first brood appearance, the quantity of offspring in the first and the first five broods, the period between broods, the length of newborn daphnids in the first brood, parental mortality, and the body length, carapace width, and caudal spine length of the parental animals by the end of the experiment. The experiment involved selecting the young produced by Daphnia from the second to the fifth broods, freezing them instantly in liquid nitrogen after removing drip-liquid water, and assessing alpha-amylase activity. The experiments assessing the adaptive potential of Daphnia in response to the studied conditions were carried out in two stages. In the first stage, four experimental lines of D. magna were subjected to long-term exposure to the studied factors for eight generations. During the second stage, separate tests were conducted with individuals from these four lines. The second offspring of adult females from the 8th generation of each line (9th generation offspring), no older than 24 hours, were randomly placed in 24 containers. Six containers remained in the same conditions the line had been exposed to for eight generations. Other eighteen containers with Daphnids were exposed to conditions different from those to which the organisms were not pre-adapted. Subsequently, 21-day standard chronic toxicity tests with D. magna were conducted, measuring the day of the first brood appearance, the quantity of offspring in the first and the first five broods, the period between broods, the length of newborn daphnids in the first brood, parental mortality, and the body length, carapace width, and caudal spine length of the parental animals by the end of the experiment. Additionally, the length of newborns from head to tail spine base before the first molt was measured. Throughout the experiments, offspring produced in each generation by Daphnia, including those produced in the second stage of the experiment, were sampled and instantly frozen in liquid nitrogen for subsequent assessment of alpha-amylase activity. Processing of samples obtained in 2022 was carried out using the E-BC-K007-M alpha-amylase activity assay kit (Elabscience, USA) following the manufacturer's protocol. A significant influence of dissolved oxygen level on this parameter was detected (F[2,14]=566.4, p<0.001). In the series of decreasing oxygen levels from 8 to 2 mg/l, enzyme activity increased fivefold, likely associated with increased energy and resource expenditure with decreasing oxygen content in water, aligning with existing literature. Simultaneously, a significant impact of hypomagnetic conditions on alpha-amylase activity in Daphnia whole-body homogenates was established (F[1,14]=215.63, p<0.001). Under hypomagnetic conditions, enzyme activity was lower than in the geomagnetic field. Notably, significant differences between Daphnia exposed to hypomagnetic conditions and the geomagnetic field were observed at an oxygen level of 2 mg/l (alpha-amylase activity in hypomagnetic conditions was approximately 2.3 times lower than in the geomagnetic field), indicating an interaction effect (F[2,14]=146.30, p<0.001). The separate and combined impact of hypomagnetic conditions and varying temperatures on the activity of alpha-amylase in Daphnia whole-body homogenate was examined. Significant temperature influence on this parameter was identified (F[1,12]=17.784, p<0.01). As the temperature increased from 22 to 27 degrees Celsius, enzyme activity rose by one and a half times, associated with increased rates of biochemical reactions. Concurrently, a notable effect of hypomagnetic conditions on alpha-amylase activity in Daphnia body homogenate was established (F[1,14]=215.63, p<0.001). Under the hypomagnetic field, enzyme activity was lower than in the geomagnetic field. The separate and combined influence of hypomagnetic conditions and varying water salinity on the activity of alpha-amylase in Daphnia whole-body homogenate was examined. A significant influence of hypomagnetic conditions on this parameter was discovered (F[1,20]=10.565, p<0.05). Consistent with previous experiments, enzyme activity was significantly lower in hypomagnetic conditions compared to the geomagnetic field. Salinity and the interaction between salinity and magnetic conditions did not affect the alpha-amylase activity in our experiment. Thus, the potential use of alpha-amylase activity as a universal biological marker sensitive to magnetic influence, previously suggested based on experiments with fish, is confirmed. The project's outcomes include the publication of two articles in Russian journals, with translated versions included in the WoS Core Collection, and two more articles are to be published soon. Two oral presentations were reported at conferences based on the project's findings.

 

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Annotation of the results obtained in 2022
All the studies declared in the reporting year have been carried out. The separate and combined influences of hypomagnetic conditions, which may arise due to a reversal of the Earth's magnetic poles, and environmental changes accompanying global climatic processes (increase in temperature and salinity of freshwater environments, decrease in the level of dissolved oxygen) on the morphometric and reproduction traits in Daphnia magna were studied. The weakening of the magnetic background led to a significant decrease in the sizes of parental females, a reduction in the number of offspring produced from the second to sixth broods, and an increase in the body length of the offspring produced in the first brood. An increase in water salinity affected the age of the first offspring production. A trend towards an increase in the length of the caudal spine with increasing salinity was also recorded. Decreased levels of dissolved oxygen led to a decrease in the sizes of parental females, a reduction in the number of produced offspring, and an increase in the period between broods. The interaction of salinity and magnetic conditions influenced the age of the first offspring production and the sizes of parental females. The body lengths of parental females were also affected by the interaction of magnetic conditions and oxygen content and the interaction of magnetic conditions and temperature. In all experiments, additive adverse effects are noticeable as a result of the combined action of the hypomagnetic field and studied environmental changes accompanying global climatic processes. Thus, a decrease in the intensity of the natural geomagnetic field can be an additional factor that aggravates the effects of global climate change. Adaptive changes in daphnia lines in response to the studied treatments will be studied in the second year of the project.

 

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