The fluctuation of calcium and magnesium concentrations in the floodwater in the Nemunas and Minija lowlands

Abstract

Calcium (Ca) and magnesium (Mg) are vital elements for the neutralization of soil or water acidity, which is associated with the activity of biota, mobility of heavy metals, phosphorus and other important elements. The current research was aimed to estimate the trends in the fluctuation of calcium and magnesium ions in the floodwater using traditional experimental methods. The studies were carried out during the 1987-2010 period in the Nemunas lowland (upper (Rambynas-Plaškiai) and lower (Girininkai-Smalkai) zones) and in the Minija lowland. In the floodwater of both rivers, the concentration of Ca 2+ was up to three times as high as the mean annual concentration in the river and that of Mg 2+ concentration by up to 1.6 times higher than in the river. A trend towards increasing of these ions concentration in the floodwater was established. In the upper zone of the Nemunas lowland the concentrations of Ca 2+ (159-248 mg l -1 ) and Mg 2+ (14.3-29.3 mg l -1 ) in floodwater were something higher than those in the lower zone -152-240 and 13.5-25.3 mg l -1 , respectively. These differences were significant: Ca 2+ -t act. = 1.75 > t 0.05 = 1.65 and Mg 2+ -t act. = 3.25 > t 0.05 = 1.65. The concentration of these ions with increasing distance from the riverbed decreased and was the lowest in the pre-land part of the floodplain. The strongest correlation between Ca 2+ (r 2 = 0.82, t act. = 7.87 > t 0.05 = 1.75) and Mg 2+ (r 2 = 0.43, t act. = 3.25 > t 0.05 = 1.75) concentrations in the water and soil was determined in the lowest parts of the relief (<0 m), when the floodwater was at more than 1 km distance from the riverbed. The concentrations of the tested ions at the beginning of flood reflect the amount of substances carried from the catchment areas into the rivers. The quality of the water flowing through the valley depended on the relief height, flow velocities and distribution and soil properties.

Exploring the mycobiome and arbuscular mycorrhizal fungi associated with the rizosphere of the genus Inga in the pristine Ecuadorian Amazon

“…In Neotropical forests, other elements like Al, Ca, Mg, K, Fe and Mn have been reported to affect colonization and spore numbers of AM fungi ( Oliveira and Oliveira, 2010 ), which is in line with our metabarcoding results as these soil chemical elements (K, Al, Fe, and Cu) explained the highest amount of variation between the composition of the mycobiome and AMF communities of Inga in terra firme or várzea forest soils (see PCoA showed in Figure 6 ). Ca is known to be a vital element for the neutralization of soil or water acidity after floodings ( Katutis and Rudzianskaite, 2015 ), but is also linked to both AMF richness and diversity ( Guo et al., 2022 ). The beneficial effects of the AMF for host plants are directly related to the fungus’ ability to supply nutrients by extending the effective root absorption surface areas by incorporating its hyphal network.…”

Severe floods in Nemunas River Delta

“…These tendencies lead to discussions about the necessity of adaptation of the Lithuanian rivers to the changing conditions (Kažys et al 2013;Korneev et al 2015) and the preparation of new land management and water management plans (related to the problems caused by long-lasting floods). Some studies (Katutis, Rudzianskaite 2015) suggest that the extended inundation of the lower reaches of the Nemunas River is also able to affect river water quality and the soil chemical composition in the surrounding areas, as well as natural environment conditions within the delta region.…”