Wright State University CORE Scholar Browse all Theses and Dissertations Theses and Dissertations 2018 River biofilm structure and function in a resource landscape modified by agriculture: implications for primary consumers Hannah M. Fazekas Wright State University Follow this and additional works at: https://corescholar.libraries.wright.edu/etd_all Part of the Environmental Sciences Commons Repository Citation Fazekas, Hannah M., "River biofilm structure and function in a resource landscape modified yb agriculture: implications for primary consumers" (2018). Browse all Theses and Dissertations. 2244. https://corescholar.libraries.wright.edu/etd_all/2244 This Dissertation is brought to you for free and open access by the Theses and Dissertations at CORE Scholar. It has been accepted for inclusion in Browse all Theses and Dissertations by an authorized administrator of CORE Scholar. For more information, please contact [email protected]. RIVER BIOFILM STRUCTURE AND FUNCTION IN A RESOURCE LANDSCAPE MODIFIED BY AGRICULTURE: IMPLICATIONS FOR PRIMARY CONSUMERS A Dissertation in partial fulfillment of the requirements for the degree of Doctor of Philosophy by HANNAH M. FAZEKAS B.S., Saginaw Valley State University, MI, 2012 2018 Wright State University COPYRIGHT BY HANNAH M. FAZEKAS 2018 WRIGHT STATE UNIVERSITY GRADUATE SCHOOL July 18, 2018 I HEREBY RECOMMEND THAT THE DISSERTATION PREPARED UNDER MY SUPERVISION BY Hannah M Fazekas ENTITLED River biofilm structure and function in a resource landscape modified by agriculture: implications for primary consumers BE ACCEPTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Doctor of Philosophy. ________________________________ Yvonne Vadeboncoeur, Ph.D. Dissertation Director ________________________________ Donald F. Cippolini, Ph.D. Director, Environmental Sciences Ph.D. Program ________________________________ Barry Milligan, Ph.D. Interim Dean of the Graduate School Committee on Final Examination: ________________________________ Lynn K. Hartzler, Ph.D. ________________________________ John O. Stireman III, Ph.D. ________________________________ Katie Hossler, Ph.D. ________________________________ David L. Strayer, Ph.D. ABSTRACT Fazekas, Hannah M. PhD., Environmental Sciences PhD Program, Wright State University, 2018. River biofilm structure and function in a resource landscape modified by agriculture: implications for primary consumers. Anthropogenic alterations to nitrogen, carbon, and phosphorus bioavailability have increased the flux of these resources into the biosphere and altered stream ecosystem function. Streams modify the transport of these resources to receiving ecosystems through uptake, transformation, and mineralization. Understanding how streams process carbon, nitrogen, and phosphorus can provide insight about how stream ecosystems function in landscapes where human modification is inescapable. I investigated how land use in agricultural regions affect resource availability to primary producers and consumers and the subsequent impact on stream processes. I surveyed headwater streams in three Lake Erie watersheds to determine spatiotemporal nutrient limitation of attached algae. I found that low-order streams exhibit phosphorus limitation and the severity of phosphorus limitation was greatest post-fertilizer application when the imbalance between water column nitrogen: phosphorus concentrations was greatest. These results suggest that biofilm nutrient uptake responded to landscape level influences and attached algae actively sequestered phosphorus from the water column. Agriculture alters the availability of carbon through modification of riparian vegetation. I used genomic techniques to describe longitudinal changes in microbial community iii composition along a stream with headwaters that lacked riparian vegetation due to row crop agriculture but the width of the forested riparian area increased downstream. The relative abundance of the most abundant microbial phyla varied along physical and chemical (light, phosphorus concentration) gradients. Land use affected physical- chemical characteristics of the river, which in turn, influenced sediment microbial community composition. The removal of riparian forested vegetation in agricultural streams leads to an increased availability of light to attached algae. I investigated the effect of attached algal productivity on consumers across an experimental gradient in light intensity. Attached algal productivity and consumer production were coupled across the light gradient. I also studied how land use influenced carbon resource use by common macroinvertebrate functional feeding groups in Midwestern streams. I found that invertebrates consistently used attached algal carbon. This reliance was not affected by riparian vegetation nor the percent of the watershed dedicated to agriculture. Futhermore, food web structure remained similar across the gradient in land use. This work demonstrates that attached assemblages in streams respond to landscape level processes that propagate to consumers. iv TABLE OF CONTENTS Chapter One ........................................................................................................................ 1 Introduction ................................................................................................................... 1 Literature Cited ............................................................................................................. 5 Chapter Two...................................................................................................................... 10 SPATIOTEMPORAL VARIATION IN NUTRIENT LIMITATION OF EPILITHIC BIOFILMS IN LOW-ORDER STREAMS IN THE LAKE ERIE WATERSHED ......... 10 Introduction ................................................................................................................. 10 Methods....................................................................................................................... 14 Site Description ...................................................................................................... 14 Physicochemical characteristics ............................................................................. 16 Nutrient Concentrations ......................................................................................... 16 Biofilm Biomass ..................................................................................................... 17 Biofilm Stoichiometry ............................................................................................ 18 Eco-enzyme activities ............................................................................................. 18 Statistical Analysis ................................................................................................. 19 Nutrient limitation .................................................................................................. 20 Results ......................................................................................................................... 20 Physicochemical Characteristics ............................................................................ 20 Biofilm composition ............................................................................................... 21 Periphyton Stoichiometry and Eco-enzyme Activity ............................................. 22 Drivers of Biofilm Biomass and Enzyme Activities .............................................. 22 Nutrient limitation .................................................................................................. 23 Longitudinal changes in nutrient concentrations .................................................... 24 Discussion ................................................................................................................... 25 Literature Cited ........................................................................................................... 31 Chapter Three.................................................................................................................... 55 v SEDIMENT MICROBIAL ASSEMBLAGE COMPOSITION IN A HETEROGENEOUS RESOURCE LANDSCAPE: LONGITUDINAL TRANSITIONS IN BIOFILM COMMUNITIES ...................................................... 55 Introduction ................................................................................................................. 55 Methods....................................................................................................................... 59 Study site ................................................................................................................ 59 Physicochemical Characteristics ............................................................................ 60 Sediment Particle Size Distribution ....................................................................... 61 Organic Component of Sediment ........................................................................... 62 Sediment Energy Content ....................................................................................... 62 Attached algal biomass and total organic matter content ....................................... 63 Sediment stoichiometry .......................................................................................... 63 Microbial community composition ........................................................................ 63 Microbial community biomass ..............................................................................