Thesis Watch: Jordan Jenckes

By Zeke Shomler

February 16, 2023, Geoscientist Jordan Jenckes successfully defended his dissertation entitled “Variability of Hydrogeochemistry and Chemical Weathering Regimes in High Latitude Glacierized Coastal Catchments.” This is the culmination of four years of research, including field work and data analysis, in the Gulf of Alaska watershed. 

Hydrogeochemistry is the study of the chemical systems of ground and surface water, including the interaction between physical geology and the movement of minerals and sediment (small dissolved particles) in water. In particular, Jenckes’ work focuses on the effects of receding glaciers on the chemical makeup of the water entering the Gulf, taking in factors like seasonal weather patterns and elevation. 

This research was part of a larger five-year project called “Fire and Ice” as part of EPSCoR: the Established Program to Stimulate Competitive Research, which is funded by the National Science Foundation. This allows Jenckes’ work to gain even greater significance in conversation with research from many other fields, such as biology and geography. The University of Alaska received EPSCoR funding for this project to better understand water systems in Alaska and the effects of rising temperatures. Jenckes is the lead graduate researcher for what’s referred to as the “Stream Team”; as part of the project’s science puzzle, Jenckes’ work makes up the piece related to the chemistry of the watershed. 

The field work for this research took him to five different testing sites across Kachemak Bay, where he collected monthly water samples. These were then prepared and sent to labs to be tested and analyzed for substances like organic carbon, calcium, and magnesium. He also incorporated data from over 150 stream sites across the Gulf of Alaska watershed, where sensors took measurements such as water temperature and electrical conductivity up to four times per hour. 

While field work is an indispensable part of the research process, much of Jenckes’ work gets done back in Anchorage where he analyzes the data. He makes comparisons and calculations that factor in large data sets from other sources, such as the US Geological Survey, to get a comprehensive view of the interactions between the physical landscape, the changing climate and glacial patterns, and the chemical makeup of the water systems of Southeast Alaska.

This research determined that glacier coverage has a strong impact on the solute concentration of the watershed. As global temperatures rise and glaciers recede, the amount of chemical weathering will increase, sending more dissolved materials into the Gulf. He also paid attention to regional variations, finding patterns such as greater susceptibility to weathering in Lynn Canal than Kachemak Bay. 

The chemical makeup of the water systems that Jenckes studies has important implications for the entire Gulf ecosystem. He explains how biologists, for example, are working in intertidal communities as part of this EPSCoR project to understand the effects of changing water chemistry on creatures like mussels, kelp, and phytoplankton. This ecosystem and its life, aside from being important in its own right, are important for Alaska both culturally and economically.

Jenckes, born and raised in Alaska, started his academic career with a BA in History before getting his BS in Geological Sciences from UAA. Then he started connecting with his advisor, Dr. Lee Ann Munk, while working as a geospatial data analyst and software engineer. Once the EPSCoR project started, he was able to begin his PhD research alongside Dr. Munk, publishing numerous articles along the way in journals such as Geophysical Research Letters and Earth’s Future. 

Jenckes will be using his skills and knowledge in geoscience and data analysis to start post-doctoral research at UAA this summer. Alongside Dr. Munk, he will be working in a lab studying electrification, which has implications for the production of products like electric vehicles. 

He gives special thanks to his wife Monica and his son Leopold for supporting him in pursuit of this important geoscientific research.