Effects of Lithium on Sediment Microbial Activity
Anthropogenic activities may influence rates of microbial activity through the increased concentrations of pollutants. One relatively understudied pollutant is lithium. In addition to natural sources of lithium, lithium is also derived from a variety of manufactured goods such as pharmaceuticals and electronic devices. Thus, environmental concentrations of lithium are increasing. We studied the effect of lithium on microbial activity measured as respiration, nutrient uptake, and nitrification rates. Homogenized sediment samples were collected from the White River, in central Indiana for in vitro activity assays. Lithium treatments used in assays were representative of the range of lithium concentrations found in natural environments. We found that microbial respiration rates decreased linearly with increasing lithium concentrations. Moreover, no effect of lithium was observed on nitrate and phosphate uptake. These data indicate lithium does influence microbial activity, even at trace concentrations currently measured in natural ecosystems. Lithium contamination in freshwater ecosystems may thus threaten not only microbial communities but also higher organisms. A better understanding of lithium poisoning can lead to the informed development of ways to mitigate harmful effects of lithium in the natural environment.