Soil Lake Inundation Moat Experiment (SLIME): Continuous environmental measurements from the North Shore Lake Fryxell (NFRX) Active Layer and Moat Monitoring Station (ALMMS), McMurdo Dry Valleys, Antarctica (2018-2022, ongoing)

The Soil Lake Inundation Moat Experiment (SLIME) was developed by the McMurdo Valleys LTER project to investigate the ecological function of lake moats in Antarctica. These moats form during the austral summer when the edges of permanently ice-covered, closed-basin lakes melt, creating open-water zones, or ‘moats,’ between the shoreline and the thick (3-5 m) perennial ice cover. Extensive microbial mats are found across these moatbeds, yet their ecological dynamics remain poorly understood. To study these habitats, we established sampling transects on the north and south shores of Lake Fryxell and the East Lobe of Lake Bonney. At each transect, we manually sample soils, sediments, microbial mats, and the water column during the austral summer. To complement these efforts, Active Layer and Moat Monitoring Stations (ALMMS) continuously measure key environmental variables, including moatbed temperatures, incoming and underwater photosynthetically active radiation (PAR and UW-PAR), subsurface temperatures, soil volumetric water content, and soil electrical conductivity across a moisture gradient from wet (near the lake shore) to dry (further inland). These measurements help us understand environmental and ecological changes as shoreline soils transition between aquatic and terrestrial habitats, whether through inundation from rising lake levels or drying as moatbeds are exposed. The North Shore Lake Fryxell SLIME transect is located approximately 500 m west of the Lake Fryxell Camp. Sensor deployments along the transect follow a wet-to-dry gradient, capturing environmental transitions in real time.