Jacob Major collecting sediment from Brush Creek for analysis in equilibrium phosphorus concentration (EPC) assays. These assays will shed some light on the process of sediment-phosphorus sorption in agricultural streams in Northwest Arkansas.

Author: Jacob Major | Major: Environmental, Soil, and Water Science | Semester: Spring 2023

Hey! I’m Jacob Major, a junior in the Bumpers College Honors Program majoring in Environmental, Soil, and Water Science. Over the past semester of Spring ’23 I’ve had the privilege of working with Dr. Shannon Speir in her stream biogeochemistry lab to quantify spatiotemporal phosphorus (P) dynamics in two watersheds in Northwest Arkansas dominated by animal agriculture. I was introduced to Dr. Speir and the Honors Program in my first semester in Bumpers by Dr. Kristofer Brye, with whom I was taking Introduction to Water Science. I expressed an interest in the program and in doing research, and by the following semester I was at work in the Speir Lab drafting a successful thesis proposal!

The focus of my research is on agricultural watersheds because of the disproportionate impacts P can have on water quality as the primary limiting nutrient (along with nitrogen) for plant and algal growth. Sources of P are abundant in animal agroecosystems in the forms of livestock manure, chicken litter, animal feed additives, plant matter, and eroded sediment. The Brush Creek and Richland Creek watersheds are both tributaries of Beaver Lake which is the source of drinking water for hundreds of thousands of people in NWA. Excess P loads in fresh surface waters lead to harmful algal blooms, which may host deadly bacteria, in addition to accelerating the process of eutrophication, or the premature aging of lakes which ultimately results in “dead zones” where dissolved oxygen has been depleted below a level adequate to support aquatic life.

The ultimate goal of my research is to inform landowners and policymakers about factors controlling the rate of P loss from agricultural lands into the many streams and tributaries that transect them. With better knowledge of the mechanisms and patterns of how P loads enter and then move throughout freshwater systems, landowners and policymakers can take a better-informed approach to managing our land to maintain soil fertility and conserve Arkansas’ priceless freshwater resources.

Using a synoptic sampling strategy, I will be collecting data for SRP, TP, discharge, DO, conductivity, TSS, and pH at multiple sites distributed longitudinally in each watershed. In addition, sediment samples will be taken at a selection of sites in Brush Creek that will be used in equilibrium phosphorus concentration (EPC) assays, a method used to determine the concentration at which P is neither removed from nor released into the water column by sediment (i.e. is the sediment a net source or sink of P?). These data will be used to analyze concentration-discharge (C-Q) patterns at the outlets which can reveal a lot about how P is mobilized and transported within each watershed (i.e. are sources of P transport-limited, source-limited, or constant?). I will also use this data to determine whether particular subwatersheds are acting as net sources or sinks of P in the watershed, correlating those findings with the results from the EPC assays and upstream land use distribution at each site.

I feel that I’ve learned a lot in the time I’ve spent working on this project—I’ve learned about statistics, coding in R, experimental design, and a whole lot about phosphorus. Perhaps the most valuable things I’ve learned, though, are those things that you don’t find in textbooks. I believe the dialogue and teamwork between student and mentor is among the most valuable things the Honors Program has to offer, along with the opportunity to build professional relationships with other students in the program. When I first considered joining, I was pretty intimidated by the idea of conducting research and completing an Honors thesis project. I had never done anything like that before, and STEM had always been a field I admired, but thought I was poorly suited for. I know now, though, that I’m capable of that and so much more thanks to Dr. Speir and the great group of budding water scientists that I’m so lucky to work with.