Sensor buoy on Trout Bog in autumn with the tamaracks in full color in the background

Research – Current Projects

North Temperate Lakes Long Term Ecological Research (NTL-LTER)

NTL-LTER is a collaborative, interdisciplinary program studying the patterns and causes of long-term change in lakes and their landscape. Current NTL-LTER related activities within our group focus on understanding spatial dynamics in NTL-LTER lakes led by David Ortiz (for more information, see below), consequences of changing lake levels (Cassie Ceballos), understanding abrupt ecological change, and lots of other collaborative investigations.

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Lake density across the continental U.S. Graphic from Winslow et al. 2014. Original data set for mapping from the USGS National Hydrography dataset.
Lake density across the continental U.S. Graphic from Winslow et al. 2014. Original data set for mapping from the USGS National Hydrography dataset.

Left-John Crawford and Luke Loken FLAMe-ing on Lake Mendota. The water intake structure can be seen attached to the back of the boat behind Luke’s shoulder. Photo: Nora Casson. Right: a FLAMe generated map of surface water dissovleved in oxygen percent saturation of Trout Lake. Graphic: Luke Loken

Understanding spatial dynamics of lakes: FLAMe studies

Maps are fundamental to our understanding of the world around us, yet for aquatic scientists, the opportunity to see spatial patterns within individual lakes and rivers is extremely limited. Their small size means these ecosystems are often poorly resolved by most remote sensing tools. And even when airborne devices can be tuned to the size of a lake or river, they quantify only a few water quality attributes on cloud-free days.


To overcome these limitations, we use automated environmental sensors to measure multiple water chemistry/quality variables across river and lake surfaces. The Fast Limnology Automated Measurement (FLAMe) platform, developed by John Crawford, Luke Loken, and colleagues (Crawford et al. 2015), was the result of a collaboration between USGS and NTL-LTER, and then improved with support from a UW2020 award. This platform allows us to see spatial patterns in aquatic systems, and ask questions about these patterns, how they change over time, and how they affect and are affected by other ecosystem processes. Luke Loken’s dissertation considered causes and consequences of spatial heterogeneity in both rivers and lakes, and Paul Schramm used the FLAMe to investigate spatial patterns of light extinction within lakes, and how and why the amount of within-lake variation differs among lakes.

We are now using the FLAMe to ask questions about water rapid environmental change in lakes and water quality in rivers. Many abrupt changes within lakes involve development of ‘hot spots’ (e.g., areas of high nutrient or chlorophyll concentrations) and/or transition in spatial patterns leading to the question: How does spatial pattern change for ecosystems near a threshold, and can spatial statistics indicate loss of resilience?

Addressing this question has included (1) a collaborative project with Mike Pace and Steve Carpenter and the Cascade Project to consider the potential for spatial statistics to measure loss of resilience by studying lakes near and far from thresholds for harmful algal blooms (HABs) and (2) examining spatial patterns within Lake Mendota in response to rain events as part of ongoing NTL-LTER research. These efforts are being led by David Ortiz, who is particularly interested in spatial patterns related to algal bloom development.

Studies of water quality in rivers involves a collaboration with USGS colleague Luke Loken. Current work is based on the Mississippi River and uses the FLAMe platform to determine how hydrologic patterns over space and time affect algal distribution in this complex system.

Please visit the FLAMe website for more information and find out where the FLAMe has been!

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Greenhouse gases of streams and rivers

Streams and rivers receive, transport, and transform carbon and nitrogen as water moves from terrestrial to marine environments, and collectively, inland waters ecosystems make larger than expected contributions to global greenhouse gas emissions. These gases are derived from the surrounding environment and/or generated in situ via various respiratory pathways.  We are interested in understanding patterns of methane, carbon dioxide, and nitrous oxide concentrations and fluxes within and among lakes and rivers as well as the controls and consequences of gas production, consumption, and emission.

These studies have involved a combination of both local studies- such as work by grad students John Crawford (Ph.D. 2014), Luke Loken (Ph.D. 2018), Sam Blackburn (M.S. 2019), and Adam Rexroade (M.S. 2022) – and collaborations with colleagues Trina McMahon, Grace Wilkinson, and Hilary Dugan; lab alumni Nora Casson, Luke Loken and Sam Oliver; and other colleagues in the U.S., China, and Sweden including Liwei ZhangGerard Rocher Ros, and Ryan Sponseller– among many others.

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