The influence of glucose and peat extract additions on the spring recruitment of Gonyostomum semen from the sediments

Abstract

The effect of two various forms of DOC on the Gonyostomum semen recruitment from sediments was conducted under experimental laboratory conditions. We tested the hypothesis that DOC is a factor enhancing spring recruitment of the species by exposing sediments from a humic lake with a 17-year bloom history, to three various DOC additions (two solutions of glucose and one solution of a peat extract). Sediments and lake water were incubated for 14 days at 16°C, in 14:10 h light:dark cycle, with germling and adult cell abundance ascertained in the water every third day, and water parameters every seventh day. Our important findings were that (1) Gonyostomum recruitment was uneven and the period of germination was relatively short; (2) all treatments significantly affected germling occurrence; however, sugar-derived DOC seemed to suppress the recruitment, whereas peat extract improved it. Due to the additional phosphorus load in peat treatment (against phosphorus-free sugar treatments), it is likely that it played a major role in the observed differences, however, our results did not exclude the potential role of peat-derived DOC forms. In conclusion, we proposed that Gonyostomum expansion is supported by enhanced recruitment from sediment seed banks related to water chemistry alterations, driven by the climate change.