Stoichiometry through the seasons: an exploration of high elevation lake chemistry and ecology in southeastern Wyoming, USA

High-elevation watersheds are valuable freshwater resources facing increasing anthropogenic  disturbances and a rapidly changing climate. These compounding impacts cascade through the ecosystem leading to increased water temperatures and nutrients, modified hydrological regimes, and ultimately altered biological processes and biotic communities. Despite their value, little is known about year-round, high-elevation, water body conditions, specifically winter and ice-on conditions. We examined seasonal trends in water chemistry, seston stoichiometry, chlorophyll-A, and zooplankton stoichiometric composition and community structure in seven high elevation lakes (2180-3280 m) in the plains and montane habitats of southeastern Wyoming. Plains and montane lakes show distinct differences in salinity, ice phenology, hydrologic controls, geology, and vegetation, despite their close proximity (53 km radius) and, for some, their hydrologic connectivity. Connected lakes showed diverging water chemistry and seston nutrient composition during phases of hydrologic isolation. The four highest lakes had much longer ice-on periods, and showed that elevation was an important factor associated with surface temperature, specific conductivity, and pH variability. Seston and zooplankton productivity was still evident in most lakes throughout the ice-on period. The examination of seasonal changes in water, seston, and zooplankton stoichiometry has led to a better understanding of the importance of winter lake conditions, and unexpected insights into extreme events that can alter lake function.

Primary Presenter: Casey Brucker, University of Wyoming (cbrucker@uwyo.edu)

Authors:

Casey Brucker, University of Wyoming  (cbrucker@uwyo.edu)

Alyssa Halls, University of Wyoming  (ahalls1@uwyo.edu)

Delsie McCrystal, University of Wyoming  (dmccryst@uwyo.edu)

Amy Krist, University of Wyoming  (krist@uwyo.edu)

Sarah Collins, University of Wyoming  (sarah.collins@uwyo.edu)