ALBERT

Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Budy, P., Pennock, C. A., Giblin, A. E., Luecke, C., White, D. L., & Kling, G. W. Understanding the effects of climate change via disturbance on pristine arctic lakes-multitrophic level response and recovery to a 12-yr, low-level fertilization experiment. Limnology and Oceanography. (2021), https://doi.org/10.1002/lno.11893.

Description: Effects of climate change-driven disturbance on lake ecosystems can be subtle; indirect effects include increased nutrient loading that could impact ecosystem function. We designed a low-level fertilization experiment to mimic persistent, climate change-driven disturbances (deeper thaw, greater weathering, or thermokarst failure) delivering nutrients to arctic lakes. We measured responses of pelagic trophic levels over 12 yr in a fertilized deep lake with fish and a shallow fishless lake, compared to paired reference lakes, and monitored recovery for 6 yr. Relative to prefertilization in the deep lake, we observed a maximum pelagic response in chl a (+201%), dissolved oxygen (DO, −43%), and zooplankton biomass (+88%) during the fertilization period (2001–2012). Other responses to fertilization, such as water transparency and fish relative abundance, were delayed, but both ultimately declined. Phyto- and zooplankton biomass and community composition shifted with fertilization. The effects of fertilization were less pronounced in the paired shallow lakes, because of a natural thermokarst failure likely impacting the reference lake. In the deep lake there was (a) moderate resistance to change in ecosystem functions at all trophic levels, (b) eventual responses were often nonlinear, and (c) postfertilization recovery (return) times were most rapid at the base of the food web (2–4 yr) while higher trophic levels failed to recover after 6 yr. The timing and magnitude of responses to fertilization in these arctic lakes were similar to responses in other lakes, suggesting indirect effects of climate change that modify nutrient inputs may affect many lakes in the future.

Description: This research was funded and supported by National Science Foundation grants DEB 1026843, 0423385, 0508570, 1026843, and 1637459, and OPP 9911278, and by the Toolik Field Station, managed by the Institute of Arctic Biology at the University of Alaska Fairbanks with cooperative agreement support from the Division of Arctic Sciences of the Office of Polar Programs at NSF. Additional support was provided by the U.S. Geological Survey, Utah Cooperative Fish and Wildlife Research Unit (in-kind), and The Ecology Center at Utah State University (USU).