5/20/2015  |   10:30 - 10:45   |  102C

DISTRIBUTIONS AND FLUXES OF URANIUM IN THE LOWER REACHES OF THE YELLOW RIVER: ANTHROPOGENIC IMPACT (WATER-SEDIMENT REGULATION SCHEME) As one of the most turbid rivers in the world, the Yellow River is also noted with its high dissolved uranium concentration, especially in the middle and lower reaches. Weathering products of the Loess Plateau exert influence on the dissolved U in the Yellow River. Water-Sediment Regulation Scheme (WSRS) is a procedure implemented annually to expel sediments deposited in Xiaolangdi and other large middle-reach reservoirs and to scour the lower reaches of the Yellow River, by controlling water and sediment discharges. This procedure may change the sources, forms, pathway of delivery and fluxes of uranium in the Yellow River. We investigated the different forms of uranium and other relevant parameters in the Yellow River of two representative sites of middle and lower reaches, Xianglangdi and Lijin, respectively. It is shown that the WSRS altered the ratios and sources of water and sediment, as well as the redox environment of the river water, therefore the forms of uranium delivered by the Yellow River water changed correspondingly. The seasonal fluxes of uranium were also changed by the WSRS.

Xueyan Jiang (Primary Presenter/Author), Ocean University of China, jeanjxy@ouc.edu.cn;


Qian Liu (Co-Presenter/Co-Author), Ocean University of China, lqian526@163.com;


Juanjuan Sui (Co-Presenter/Co-Author), Ocean University of China, sjuanjuan1206@126.com;


Zhigang Yu (Co-Presenter/Co-Author), Ocean University of China, zhigangyu@ouc.edu.cn;

5/20/2015  |   10:45 - 11:00   |  102C

ASSESSING THE EFFECTS OF RIVERBANK INDUCEMENT ON GROUNDWATER QUALITY ON A SHALLOW AQUIFER IN SOUTHEASTERN WISCONSIN River bank inducement, the implementation of shallow wells near river systems to induce flow to the aquifer, is being used to augment groundwater supplies in portions of southeastern Wisconsin. However, river bank inducement wells (RBI) are vulnerable to contamination due to their close interaction with the surface water. The vulnerability increases when induced surface waters contain municipally treated waste water. An ideally located, existing monitoring network in Waukesha County, Wisconsin with two RBI wells and a background well are being utilized as the field site for this study. This study intends to determine the recharge mechanisms of the RBI well field, discriminate the source(s) of salt influx seen in the well field, and continue overall geochemistry tracking in order to compile a long-term data base with which to compare future changes. Stable isotope analysis of ?18O and ?2H ratios will be used to define the dynamics of the river and riverine influx into the well field. Major ion analysis of the well field will furnish a continuation of characteristics of the well field and the breakthrough curve associated with pumping.

Laura Fields-Sommers (Primary Presenter/Author), University of Wisconsin- Milwaukee: School of Frehswater Science, fieldss2@uwm.edu;


Timothy Grundl (Co-Presenter/Co-Author), University of Wisconsin Milwaukee- Geosciences and School of Freshwater Science, grundl@uwm.edu;

5/20/2015  |   11:00 - 11:15   |  102C

ANCIENT OUTGASSING AND MODERN FERMENTATION: DUAL SOURCES FOR A METHANE-DRIVEN HYPORHEIC FOOD WEB Thirty years of research on the Nyack floodplain (Middle Fork of the Flathead River, MT) have emphasized speciose and abundant hyporheic macroinvertebrates despite carbon limitation and low rates of productivity in the alluvial aquifer. We investigated the source and role of methane in the food web by radiocarbon dating and 13C and 2H isotopic measurement of hyporheic stonefly biomass, particulate organic matter, and methane. A two end-member mixing model indicated that most stoneflies collected were 70-100% dependent on methane as a carbon source as opposed to particulate organic matter, suggesting that stoneflies might be directly dependent on chemotrophy in the aquifer. Methane concentrations were unusually high, ranging up to 170 µmol/L, and heterogenous in source. While at most sites acetoclastic methanogenesis was the dominant methane source, one site yielded dissolved methane aged at 6900 ± 140 years and stonefly biomass carbon aged at 1300 ± 80 years. We therefore infer an extremely efficient hyporheic food web based on fermentation through the majority of the aquifer, but subsidized by an ancient methane source at specific sites.

Amanda G DelVecchia (Primary Presenter/Author), Flathead Lake Biological Station - University of Montana, amanda.delvecchia@umontana.edu;


Jack A Stanford (Co-Presenter/Co-Author), Flathead Lake Biological Station - University of Montana, jack.stanford@flbs.umt.edu;

5/20/2015  |   11:15 - 11:30   |  102C

WHERE DOES THE SULFATE COME FROM: LINKING ORGANIC SULFUR SPECIATION IN PEATLANDS TO SULFATE RELEASE FOLLOWING DROUGHT Boreal peatlands are often considered to be sinks for atmospherically deposited sulfate. However, episodic pulses of sulfate from these systems have been noted when peatlands are resaturated following drought. Because most of the sulfur in peatlands is bound to the solid phase, and the majority of that sulfur is found in organic forms it has been speculated that the sulfate released following drought represents organic sulfur that has been mineralized to inorganic sulfate. In this study peatland soil samples were collected during wet/saturated and dry/oxidized hydrologic conditions from a peatland in which atmospheric sulfate deposition had been experimentally manipulated. Organically bound sulfur comprised >95% of total sulfur in the soil. Sulfur speciation within the organic sulfur pool was determined at the micron scale in peat samples by X-ray fluorescence mapping and X-ray absorption near-edge spectroscopy. Total and inorganic sulfur concentrations did not vary with hydrologic condition. However, X-ray absorption analyses followed by principal components analysis indicated a shift in speciation among organically bound sulfur groups in wet/saturated soils compared to dry/oxidized soils across sites that had experienced varying sulfate inputs.

Jill Coleman Wasik (Primary Presenter/Author), University of Wisconsin River Falls, jill.colemanwasik@uwrf.edu;


Brandy Toner (Co-Presenter/Co-Author), University of Minnesota, toner@umn.edu;


Daniel Engstrom (Co-Presenter/Co-Author), Science Museum of Minnesota, dre@smm.org;


Paul Drevnick (Co-Presenter/Co-Author), University of Michigan, drevnick@umich.edu;

5/20/2015  |   11:30 - 11:45   |  102C

MEASURING SEDIMENT LOADING AND RETENTION IN A LARGE URBAN HARBOR USING IODINE-131 IN TREATED SEWAGE EFFLUENT Non-point source loading from rivers is a major source of soil, nutrients, and contaminants in receiving water bodies. Material flux estimates to downstream waters are typically derived from watershed or river discharge measurements. Storage of material in the river or river terminus, however, is rarely considered. In this study, we estimate loading and retention of material in the Milwaukee Outer Harbor (area: 4.4 km2) using iodine-131 (half-life: 8 days) – a common radiopharmaceutical found in treated sewage effluent. In July of 2014, sediment loading from the Milwaukee, Menomonee, and Kinnickinnic Rivers (watershed: 2590 km2) was estimated at ~ 200 MT/day. Approximately 40 MT/day (20 %) of the sediment load was at least temporarily retained in the outer harbor. Both iodine-131 derived estimates of sediment loading and retention are consistent with independent estimates of combined river sediment discharge and sediment dredging from the Milwaukee Harbor.

Michael Montenero (Primary Presenter/Author), School of Freshwater Sciences, University of Wisconsin-Milwaukee, montene5@uwm.edu;


James Waples (Co-Presenter/Co-Author), School of Freshwater Sciences, University of Wisconsin-Milwaukee, jwaples@uwm.edu;

5/20/2015  |   11:45 - 12:00   |  102C

IS INCREASING HYPOXIA IN OUR FUTURE? THE EVOLUTION OF GREEN BAY’S DEAD ZONES With a long history of hypereutrophication, summertime bottom water oxygen depletion has been a long standing problem in Green Bay, Lake Michigan, but with little understanding of the dynamics driving it. Monitoring suggests the hypoxic phenomenon is highly variable, a complex result of geographic morphology, wind driven circulation, thermal stratification, water mass exchange with Lake Michigan, and the respiration of labile organic matter rapidly transported to the sediment-water interface. Benthic respiration is the major sink for oxygen in this system, and we are attempting to understand the extent and duration of hypoxia through experimental methods and tracer studies designed to quantify flow patterns, water column mixing and residence times, sediment oxygen demand, short term organic matter deposition, and apparent oxygen utilization rates. Projected warming may extend the stratified period by as much as several weeks, a change that could exacerbate hypoxia and confound management efforts to improve water quality. Models under development will link watershed loading to the biogeochemical and hydro-dynamics of the bay in order to estimate the impact of changing future conditions.

Val Klump (Primary Presenter/Author), School of Freshwater Sciences, University of Wisconsin-Milwaukee, vklump@uwm.edu;


Shelby LaBuhn (Co-Presenter/Co-Author), University of Wisconsin-Milwaukee School of Freshwater Sciences, sllabuhn@uwm.edu;


Dirk Koopmans (Co-Presenter/Co-Author), University of Wisconsin-Milwaukee, School of Freshwater Sciences, koopmans@uwm.edu;


Hector Bravo (Co-Presenter/Co-Author), Univ of Wisconsin-Milwaukee, hrbravo@uwm.edu;


Sajad Hamidi (Co-Presenter/Co-Author), Univ of Wisconsin-Milwaukee, hamidi@uwm.edu;


James Waples (Co-Presenter/Co-Author), School of Freshwater Sciences, University of Wisconsin-Milwaukee, jwaples@uwm.edu;