At the University of Wyoming, I work in the Collins Lab as a PhD student in the Ecological Stoichiometry Cooperative. 

I am part of the NSF EPSCoR Track II project to create a database of stoichiometric traits of organisms in their chemical habitats (STOICH) and to conduct related research. This database will be the first of its kind and will enable current and future freshwater scientists to expand the field of ecological stoichiometry and to build upon our understanding of patterns that result from mismatches between available elements and requirements by communities of organisms. Learn more about the Ecological Stoichiometry Cooperative.

A broad-scale shift away from single nutrient limitation toward co-nutrient limitation in U.S. lakes

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There is an ongoing debate about whether N or P is more important in causing eutrophication or which is the main limiting nutrient in freshwaters. However, experiments have demonstrated how both nutrients together have an impact on productivity significantly more than additions of a single nutrient and how stoichiometrically imbalanced resources can have detrimental impacts on aquatic ecology. In this study we challenged the single nutrient viewpoint and evaluated how both N and P contribute to eutrophication and limitation at a continental scale using U.S. Environmental Protection Agency National Lakes Assessment data. Further, we tested the difference between assessing all lakes surveyed during the NLA and lakes that were surveyed in both 2007 and 2017. There are advantages to using full NLA datasets where we might estimate changes broadly, vs resampled lakes where we can learn specific differences, but there is a remaining question of which more accurately describes the broad scale reality, and more research is needed to examine this inquiry further. N correlates more strongly with trophic state in the Western U.S., while P correlates mores strongly in the Eastern U.S., indicating the importance of regional characteristics for understanding drivers of eutrophication. Between 2007 and 2017 lakes across the U.S. are shifting away from single nutrient limitation and toward co-limitation by N and P. And although there was no overall change in trophic state across all surveyed lakes, lakes that were categorized as N- and P-limited showed trends toward eutrophication over the decade. But focusing on a single nutrient may be counterproductive when the goal is eutrophication management. Co-limited lakes can occur either under a lack of nutrients or when an increase in either N or P stoichiometrically balances resources and spurs production. Many lakes across the U.S. could be vacillating between N- and P-limitation. Understanding variation in nutrient limitation and the potential for co-limitation can serve as a starting point for strategizing toward improved water quality. And in addition to controlling excess nutrient export into freshwaters, balancing nutrient stoichiometry may be one way to remediate eutrophic lakes.

Examining climate change-induced disturbances in the Mountain West via stream hydrology and water chemistry​

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At the University of Wyoming, a team of aquatic ecologists, terrestrial ecologists, and hydrologists are working together to reveiw disturbances that have the potential to significantly alter Mountain West stream ecosystem health and services. Sensitive ecosystems of the United States Mountain West are especially vulnerable to alteration due to their low fertility, little vegetation cover, and microclimates. We are focused on pulse and press disturbances that impact Mountain West stream water quality and quantity. Pulse disturbances occur over short time periods and rapidly introduce changes to ecosystem processes and properties, while press disturbances alter ecosystems gradually; e.g., wildfire (pulse), bark beetle (pulse), changes to the hydrological cycle (press), and vegetation community shifts (press). As these four disturbance types increase in severity and frequency and pose a risk to Mountain West streams, it is critical that we develop our understanding of the downstream ramifications on both aquatic and human communities.  

Lakes protect downstream riverine habitats from chloride toxicity

Anthropogenic salt pollution has significantly contributed to the global problem of freshwater salinization, especially in areas where road salt is a commonly used during winter. Here, we examined salt export regimes along a river-lake continuum in a mixed urban and agricultural watershed in the Midwest United States that is experiencing rising salinity. We quantified chloride loads and fluxes through the watershed with the aim of understanding the role of lakes in downstream salt transport. We found that variations in salt export exist based on hydrological, anthropogenic, and seasonal controls in tributaries upstream of lakes and that the lakes diminish those controls on salinity through hydrological and biogeochemical processes.

 Annual patterns, drivers, and balance of chloride in the Upper Yahara River Watershed

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In the Dugan Lab, I studied how chloride is changing freshwater and the impacts of these changes. Check out a day in the life of a scientist studying chloride on the Salt Wise Chloride Monitoring webpage! If you are interested in ways to prevent your salt use from impacting our beautiful lakes and rivers, visit WI Salt Wise for information.
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The goal of my salt research was to track the movement of chloride in the Upper Yahara Watershed and its potential to impact aquatic ecology. This study may also serve to inform management of water quality in the Yahara River Watershed. The Upper Yahara River Watershed is home to Lakes Mendota and Monona. Chloride concentrations have been steadily increasing in these lakes since the 1940s and in recent years, streams in the watershed have been added to the state’s impaired waters list for chloride. With continued urbanization, chloride contamination could quickly become a problem for Dane County’s freshwater ecosystem functions and services. Through my findings, I aimed to improve our understanding of the sources, pathways, and long-term trajectory of chloride in the Yahara River Watershed.