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 peatderived 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.

High Iron Requirements for Growth in the Nuisance Alga Gonyostomum semen (Raphidophyceae)

“…2008, Peczula et al. 2015, Hagman et al. 2019), and iron, being able to grow at low light intensities might be G. semen ’s main competitive advantage in brown water lakes.…”

Influence of environmental factors on vertical distribution of zooplankton communities in humic lakes

“…Other common components of phytoplankton were: Peridinium inconspicuum (Dinophyceae), Dinobryon divergens (Chrysophyceae) and Gonyostomum semen (Raphidophyceae) (Grabowska and Górniak, 2004). The last species is a large flagellate (length 36-92 mm, width 23-69 mm) that forms blooms in dystrophic lakes of Poland (Hutorowicz et al, 2006;Pęczuła et al, 2015). Many other studies have shown an increase in the geographical distribution and bloom incidence of G. semen in Northern Europe during recent decades.…”

Germination and colonization success ofGonyostomum semen(Raphidophyceae) cysts after dispersal to new habitats

“…In autumn, sexual reproduction in G. semen occurs through fusion of haploid gametes to a motile planozygote ( Figueroa and Rengefors, 2006 ; Lebret et al , 2012 ; Rengefors et al , 2012 ), which encysts in the water column and sinks to the sediment. The cysts germinate after a dormancy period of at least 11 weeks ( Rengefors et al , 2012 ), but recruitment rates from phytoplankton cysts may vary depending on environmental variables, such as phosphorus and DOC concentrations ( Rengefors et al , 1998 ; Findlay et al , 2005 ; Pęczuła et al , 2014 ). Highest germination rates in G. semen were reported in late spring after 24 weeks of dormancy ( Rengefors et al , 2012 ).…”