SFS Annual Meeting

5/23/2019  |   09:00 - 09:15   |  251 DE

MUSSELS AS BIOGEOMORPHIC AGENTS IN STREAMS: PHYSICAL AND BIOGEOCHEMICAL ROLES River form and function depends on the interactions between the living and nonliving world. Biophysical interactions provide information essential to improving predictions of system-scale functions, specifically sediment transport and biogeochemical cycling. We reviewed selected case studies highlighting biogeomorphic agents. We then focused on our studies of unionid freshwater mussels, a highly imperiled faunal group that once dominated the benthic biomass in many streams. Mussels may maintain or transform the physical stability of river bed sediment and alter biogeochemical cycles indirectly by their biogenic structure or directly through processes including biodeposition and bioturbation. We tested the effects of mussels on sediment properties (D50 median grain size and sorting), sediment scour, reach scale bedload transport, and denitrification and annamox activity by deploying 36 enclosures varying in mussel species composition and density in the Sipsey River, Alabama. We found that mussels increase surface layer D50 particle sizes and the degree of sorting, contribute to bed scour, and reduce bedload transport. Further, our results show that mussels positively influence nitrogen removal in streams. Our research suggests that dense, long-lived communities of freshwater mussels can play significant roles as biogeomorphic agents in rivers.

Carla L. Atkinson (Primary Presenter/Author), University of Alabama, carlalatkinson@gmail.com;


Zachary L. Nickerson (Co-Presenter/Co-Author), University of Alabama, znickerson8@gmail.com;


Behzad Mortazavi (Co-Presenter/Co-Author), University of Alabama, bmortazavi@ua.edu ;


Matt Koerner (Co-Presenter/Co-Author), University of Alabama, mrkoerner@crimson.ua.edu;


Lisa Davis (Co-Presenter/Co-Author), University of Alabama, lisa.davis@ua.edu;


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5/23/2019  |   09:15 - 09:30   |  251 DE

ECOHYDROLOGIC FEEDBACKS ON WEATHERING DRIVE KARST SELF-ORGANIZATION In karst landscapes such as Big Cypress National Preserve (BICY) in south Florida (USA), regular patterning of depressional wetlands arises from feedbacks among biota, water movement, and weathering. A new ecohydrologic model of weathering fronts in karst soils indicates that biogenic acidity accelerates weathering twenty-fold, but this biotic amplification depends critically on sustained inundation that slows atmospheric loss of CO2 and promotes transport of carbonic acid to bedrock. Model-derived estimates of an early Holocene initiation of depressions in BICY are supported by several lines of evidence, including contemporary rates of calcium export, accumulation of phosphorus in soils, paleoclimatic and paleoecological records, and radiometric carbon dating of insoluble organic sediment residues. Fine-scale water level dynamics indicate that seasonal surface flow dominates water export, but a model of long-term basin expansion suggests that export limitation does not occur until domes grow considerably larger than their current size. However, even at relatively modest sizes, basin expansion reduces inundation and thus weathering in adjacent uplands, and this feedback inhibits growth and coalescence of neighboring basins. This work illustrates the complex feedbacks that create varied morphologies of karst landscapes.

Jim Heffernan (Primary Presenter/Author), Duke University, james.heffernan@duke.edu;


Matthew Cohen (Co-Presenter/Co-Author), University of Florida, mjc@ufl.edu;


Daniel McLaughlin (Co-Presenter/Co-Author), Virginia Tech, mclaugd@vt.edu;


A Brad Murray (Co-Presenter/Co-Author), Duke University, abmurray@duke.edu;


Jon Martin (Co-Presenter/Co-Author), University of Florida, jbmartin@ufl.edu;


Thomas Bianchi (Co-Presenter/Co-Author), University of Florida, tbianchi@ufl.edu;


Todd Osborne (Co-Presenter/Co-Author), University of Florida, osbornet@ufl.edu;


Xiaoli Dong (Co-Presenter/Co-Author), University of California - Davis, xldong@ucdavis.edu;


Catherine Chamberlin (Co-Presenter/Co-Author), Duke University, catherine.chamberlin@duke.edu;


Nicholas Ward (Co-Presenter/Co-Author), Pacific Northwest National Laboratory, nicholas.ward@pnnl.gov;


Xiaowen Zhang (Co-Presenter/Co-Author), Massachussets Institute of Technology, xzhang15@mit.edu;


Amy Brown (Co-Presenter/Co-Author), Suwannee River Water Management District, ALB@srwmd.org;


Madison Flint (Co-Presenter/Co-Author), University of Florida, mflint@ufl.edu;


Andrea Pain (Co-Presenter/Co-Author), University of Florida, ajpain@ufl.edu;


Carlos Quintero (Co-Presenter/Co-Author), University of Florida, carlosjquintero@ufl.edu;


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5/23/2019  |   09:30 - 09:45   |  251 DE

RIPARIAN FOREST RESTORATION TRANSFORMS STREAM CHANNEL GEOMORPHOLOGY: TIMESCALES AND MECHANISMS OF BIOGEOMORPHIC CHANGE Plants act as effective river ecosystem engineers across spatial scales from individual plants to entire watersheds, through time as biomass changes within the annual growth cycles, over longer?term growth and senescence trajectories, and in response to external climatic, hydrological and geomorphological fluctuations and extreme events. Riparian and in-channel vegetation management is increasingly utilized as a tool in stream restoration and management, yet little is known regarding the timescales of river response to vegetation manipulation. The purpose of this paper is to review the utility of plants as river restoration engineers and present the results of a 40 year riparian reforestation experiment as a case study illustration of the dramatic in-channel geomorphological changes induces by conversion from grass to forest dominated riparian vegetation. Experimental results show widening and shallowing of channel geometry and overall coarsening of the substrate. Channel change accelerates upon delivery of in-channel wood from the maturing riparian forest, suggesting that the engineering potential of vegetation may not be maximized until structural maturity and complex age structures are achieved.

Melinda Daniels (Primary Presenter/Author), Stroud Water Research Center, mdaniels@stroudcenter.org;


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5/23/2019  |   10:00 - 10:15   |  251 DE

THE ROLE OF NESTING MINNOWS FOR MODIFYING THE BENTHOSCAPE Fishes can be important ecosystem engineers in streams. Numerous minnow (Leuciscidae) species modify substrate by constructing nests for spawning. Nocomis chubs carry stones in their months to construct large gravel mounds. Chubs have been documented moving stones up to 25 m each. These nests are unique features on the benthoscape, and are oftentimes the only source of concentrated, unsilted gravel in local habitats. In this study, we aim to quantify (a) the amount of benthic habitat modified by nesting male Bluehead Chubs N. leptocephalus in streams of varying gravel availability, and (b) the role of chubs for upstream and downstream gravel transport. We will measure available and modified substrate throughout the spawning season, and will quantify transport by monitoring marked (painted and PIT-tagged) stones. Preliminary results will be reported.

Brandon K. Peoples (Primary Presenter/Author), Clemson University, peoples@clemson.edu;


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