Under‐ice plankton community response to snow removal experiment in bog lake

Abstract

Although previously overlooked, winter is now seen as a period of significant biological activity in the annual cycle of north‐temperate lakes. Research suggests a future of reduced ice cover duration and altered snow conditions could significantly change the functioning of aquatic ecosystems. This study seeks to explore the possible repercussions of changing ice and snow dynamics on aquatic biological communities, particularly at lower trophic levels. To explore plankton community responses to changing under‐ice light conditions, we performed a whole‐lake manipulation by removing all of the snow from the surface of a north temperate bog lake in northern Wisconsin. Over three winters, samples were collected under ice in the study lake, South Sparkling Bog. The first winter, 2018–2019, served as a reference year during which snow was not removed from the lake and was followed by two subsequent winters of snow removal during 2019–2020 and 2020–2021. Data collected included phytoplankton and zooplankton abundances and taxa, chlorophyll a, dissolved organic carbon, light, Secchi depth, and ice and snow thickness. In our snow removal years, increased light availability in the water column shifted the phytoplankton community from low‐biomass, mixed community of potential mixotrophs, unicellular cyanobacteria and Chlorophytes to dominance by photoautotrophs, and rotifer zooplankton densities increased. Ice condition, specifically the thickness of white ice vs. black ice, was a major driver in the magnitude of change between years. This research improves our understanding of how plankton communities might respond to climate‐change driven shifts in winter dynamics for north temperate systems.

Under‐Ice Oxygen Depletion and Greenhouse Gas Supersaturation in North Temperate Urban Ponds

“…The amount of solar irradiance penetrating the water column depends on the quality of ice and the amount of snow, and therefore affects both mixing potential and under‐ice primary productivity (Jansen et al., 2021). For example, under snow‐free and clear‐ice conditions, surface phytoplankton biomass can be similar to open water concentrations (Pasztaleniec & Lenard, 2008; Twiss et al., 2012; Vörös et al., 2009), while snow and opaque white ice can lead to lower production and fewer phytoplankton (Socha et al., 2023). Additionally, antecedent conditions or seasonal carry‐over can influence under ice conditions (Denfeld et al., 2018; Finlay et al., 2019; Hampton et al., 2022).…”