5/22/2016  |   10:30 - 10:45   |  307

RESTORATION OF THE UPPER CLARK FORK RIVER, MT: OPPORTUNITIES FOR SYNERGY Restoration of the Upper Clark Fork River, MT represents a landscape-scale effort to address remediation and recovery over 190 km of river. State agencies, including the MT Department of Environmental Quality (DEQ), Natural Resource Damage Program (NRDP), and Fish, Wildlife, and Parks (FWP), have been working closely with the stream ecology lab at the University of Montana to coordinate assessment of a 55 km reach where depauperate fisheries are subject to thermal and nutrient loadings. Abundant phosphorous (SRP, 20-45 ppb) and scare inorganic nitrogen (DIN, 4-8 ppb) suggest nitrogen limitation during summer. In some locations, temperatures exceed thermal tolerance for trout for as much as 20 hr per day during July. Excessive Cladophora blooms (up to 600 mg/m2 as chl a) translate to suspended particulate organic matter concentrations (100 – 500 mg/L) that approach those of the Amazon River. Landscape controls over nitrogen sourcing are being assessed by the joint research team to help prioritize restoration efforts. Coordination between the academic and state agencies may lead to synergistic products enabling research and management objectives as riverscape restoration continues.

H. Maurice Valett (Primary Presenter/Author), University of Montana, Division of Biological Sciences, maury.valett@umontana.edu;


Marc Peipoch ( Co-Presenter/Co-Author), Stroud Water Research Center, mpeipoch@stroudcenter.org;


Nicholas Banish ( Co-Presenter/Co-Author), University of Montana, nicholas.banish@umontana.edu;


Doug Martin ( Co-Presenter/Co-Author), Montana Natural Resource Damage Program, dougmartin@mt.gov;


Beau Downing ( Co-Presenter/Co-Author), Montana Natural Resource Damage Program, beaudowning@mt.gov;


Pat Saffel ( Co-Presenter/Co-Author), Montana Fish Wildlife and Parks, psaffle@mt.gov;


Brad Liermann ( Co-Presenter/Co-Author), Montana Fish Wildlife and Parks, Liermann@blackfoot.net;


Nathan Cooke ( Co-Presenter/Co-Author), Montana Fish Wildlife and Parks, nathan.cook.mt.fwp@gmail.com;


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5/22/2016  |   10:45 - 11:00   |  307

LINKING HABITAT HETEROGENEITY, BIOFILM DIVERSITY, AND ECOSYSTEM METABOLISM IN FLOODPLAIN LANDSCAPES In their natural state, floodplain landscapes exhibit a high degree of biophysical complexity over large scales that results in a plethora of niches at smaller scales. Floodplains are recognized as hotspots of biodiversity and ecosystem processes in large river systems but the mechanisms behind such recognition have been seldom addressed, especially for those involving microbial communities. Using a hierarchical approach, we examined relationships among environmental heterogeneity, biofilm diversity, and primary production across ten riverine floodplains in Montana, US. Results showed significant variation in microbial diversity (H’ = 3.86 – 6.09) and net ecosystem production (-5.7 – 4.7mg O2 m-2 d-1) among characteristic floodplain habitats such as riffles, springbrooks, and ponds. However, individual floodplains themselves served as the dominant landscape filter for species diversity of biofilm communities. River-floodplain systems with more severe N-limiting conditions exhibited up to a 25% relative abundance of N-fixing cyanobacteria in their biofilms, resulting in greater microbial diversity and higher rates of gross primary production at the ecosystem level. Together these findings suggest landscape-scale organization of microbial entities that may translate to diversity-productivity relationships across river-floodplain systems.

Marc Peipoch (Primary Presenter/Author), Stroud Water Research Center, mpeipoch@stroudcenter.org;


H. Maurice Valett ( Co-Presenter/Co-Author), University of Montana, Division of Biological Sciences, maury.valett@umontana.edu;


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5/22/2016  |   11:00 - 11:15   |  307

HYDROLOGIC TRANSPORT-LIMITATIONS DOMINATE WATERSHED ORGANIC CARBON FLUX ACROSS THE UNITED STATES Dissolved organic carbon (DOC) is the dominant form of carbon moving from land to rivers to oceans. This DOC functions as a master variable in aquatic ecosystems, regulating productivity, water chemistry, greenhouse gas production, and basic physical properties. The dynamics of DOC fluxes from terrestrial environments to inland waters is therefore important. Although many physical and biological watershed processes regulate this flux of DOC to inland waters, there is no consensus on how important each process is across watersheds. Thus, we generated and analyzed the watershed DOC export patterns from 1007 watersheds across the United States, include large area, hydroclimatic, land use, and land cover gradients. We reveal that DOC flux is predominantly (79.6% of watersheds) limited by hydrologic transport processes rather than terrestrial source processes. Thus, lateral hydrologic transport of DOC through landscapes to rivers is a key and consistent process. Hence, better representing the hydrologic processes that connect and route terrestrial DOC to inland waters should be a priority for regional and earth system carbon models that currently focus more on biological carbon source mechanisms and soil-atmosphere interactions.

Jay Zarnetske (Primary Presenter/Author), Department of Earth and Environmental Sciences, Michigan State University, jpz@msu.edu;


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5/22/2016  |   11:15 - 11:30   |  307

DOES DENSITY-DRIVEN NOCTURNAL WATER COLUMN MIXING DRIVE REDOX OSCILLATIONS IN FLOCCULENT ORGANIC SEDIMENTS? Thick accumulations of flocculent organic sediments (floc) are common in shallow, calm freshwaters. Floc layers are potentially more influenced by overlying water than relatively consolidated sediments, and may be subject to diel variation in reduction-oxidation (redox) status. The processes driving solute exchange between floc porewaters and overlying waters are unknown. We hypothesized that density-driven advective exchanges associated with nocturnal mixing of the shallow (< 1 meter) water column may extend the redox gradient several cm into floc layers, and thereby eclipse diffusion-driven exchange of oxygen and oxidized solutes as the dominant exchange process. In Fall 2015, we sampled vertical profiles of porewater over diel cycles in six floc settings lacking vegetation. We also measured hydrologic exchange using added bromide and natural heat gradients as conservative tracers. We observed penetration of overlying water with floc porewater up to 10-15 cm into the floc layer, but did not observe simple concomitant shifts in redox profiles expected to occur with the introduction of oxygen and other oxidants. This talk will explore the potential explanations for the absence of evidence for diel redox oscillations.

Dustin Kincaid (Primary Presenter/Author), W.K. Kellogg Biological Station and Department of Integrative Biology, Michigan State University, kincai32@msu.edu;


Stephen K. Hamilton ( Co-Presenter/Co-Author), Michigan State University & Cary Institute of Ecosystem Studies, hamilton@kbs.msu.edu;


Martin Briggs ( Co-Presenter/Co-Author), U. S. Geological Survey, Hydrogeophysics Branch, Storrs, Connecticut, USA, mbriggs@usgs.gov;


Jay Zarnetske ( Co-Presenter/Co-Author), Department of Earth and Environmental Sciences, Michigan State University, jpz@msu.edu;


Mantha Phanikumar ( Co-Presenter/Co-Author), Civil and Environmental Engineering, Michigan State University, phani@egr.msu.edu;


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5/22/2016  |   11:30 - 11:45   |  307

BREAKING AWAY FROM BREAKTHROUGH CURVES - ASSESSING THE HYPORHEIC ZONE IN THREE DIMENSIONS USING GEOPHYSICAL IMAGING The region where subsurface pathways are hydraulically connected to surface flow (hyporheic zone, HZ) plays a large role in nutrient transformation, although it has proven difficult to fully describe its extent. Historically, field experiments have relied on well sampling or inferences made from solute breakthrough curves to describe the HZ. The incorporation of geophysical methods, such as electrical resistivity tomography (ERT), with tracer additions has allowed researchers to directly view the HZ as a 2D plane. We applied ERT in a manner that results in a 3D representation of the HZ to assess hyporheic exchange during and immediately after a constant-rate salt tracer addition in 3 headwater mountain streams with varying sediment type and flow velocities in Wyoming, USA. We found the average depth of solute penetration by ERT to be consistent with hydraulic models based on Reynolds number. However, contrary to our expectations, the HZ responded on the same time scale as surface waters in both reaching equilibrium with enriched conditions and returning to ambient concentrations, suggesting nutrient delivery to the subsurface could be greater than previously thought.

Brady Kohler (Primary Presenter/Author), University of Wyoming, kohlerbrady@gmail.com;


Robert O. Hall ( Co-Presenter/Co-Author), Flathead Lake Biological Station, University of Montana, bob.hall@flbs.umt.edu;


Brad Carr ( Co-Presenter/Co-Author), University of Wyoming, bcarr1@uwyo.edu;


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5/22/2016  |   11:45 - 12:00   |  307

IRON-PHOSPHORUS LINKAGES IN DAPHNIA PULICARIA Stoichiometric theory has advanced with data largely on three elements (C:N:P). Recent studies have revealed widespread physiological adjustments under P-limitation, potentially altering the entire pool of elements encompassing an individual (i.e. the ionome). Transcriptomic studies revealed that under P-limiting conditions, Daphnia differentially express about a third of the genes in its genome. These observations indicate that Daphnia alter the processing of several other elements depending on dietary P-supply. Ionomic analyses revealed that D. pulicaria biomass is made up of 19 elements (+halogens and xenobiotics). P-limited D. pulicaria contained more iron than P-replete counterparts (while containing less Ca, Na, Mg). Growth of D. pulicaria was more sensitive to Fe-limitation than P-limitation. Sensitivity of growth to Fe was more pronounced under P-limitation. Finally, Fe-limited algae grew faster in media that previously contained Daphnia fed a low-P diet, indicating changes in the degree of Fe-limitation due to the physiological state of Daphnia. Strong, correlated shifts in the content of elements other than C,N,P at the base of aquatic foodwebs in response to P-supply may have important ecological ramifications.

Puni Jeyasingh (Primary Presenter/Author), Oklahoma State University, puni.jeyasingh@okstate.edu;


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