Indiana University-Purdue University Indianapolis (IUPUI) / The shale and mudstone directly superjacent to Desmoinesian coal seams of southern Indiana (Springfield, Houchin Creek, Survant, and Seelyville coals) were initially deposited under marine waters and are shown to exhibit high concentrations of organic carbon, sulfur and redox-sensitive metals (Mo, V, Ni, Fe, and U) that were sequestered during times of benthic anoxia and intermittent to sustained euxinia (anoxic and sulfidic). Strata upsection display geochemical signatures that indicate increasingly oxic and nearshore sedimentation that mirrors cyclothemic sequence stratigraphic trends Carbon source, nearshore and offshore proximity, freshwater and marine influence, and redox conditions of the epeiric sea overlying southern Indiana during the Late Middle Pennsylvanian were identified and tracked throughout the deposition of four drill cores of the Petersburg, Linton and Staunton Formations. Carbon, nitrogen, and sulfur data (total organic carbon [TOC], total nitrogen [TN], and total sulfur [TS]); paleoredox proxies ([Mo/Al], [V/Al], [Th/U], [Fetot/Al]); organic carbon isotopes (δ13Corg); and detrital influx concentrations (Zr) were all used in conjunction with lithological and paleontological interpretations to better understand the mode of deposition in this unique midcontinent ancient epeiric sea. Geochemical results when combined with lithologic and paleontologic interpretations reveal a dynamic environmental system where water column geochemistry varies with the influence of variable magnitudes of epeiric seawater flooding on the extensive peatlands of equatorial Late Middle Pennsylvanian southern Indiana.

Indiana University-Purdue University Indianapolis (IUPUI) / This study explores relationships between temperate stream geochemistry and watershed land cover in two temperate streams, Fishback Creek and School Branch Creek, located in a rapidly urbanizing area on the northwest side of Indianapolis in Eagle Creek Watershed, Indiana. The temporal and spatial patterns of NO3-N, PO4, DOC, SiO2, Cl-, and Na+ were assessed to understand the influence of land cover on the magnitude and timing of water, chemical, and nutrient delivery to streams. Results of the study indicate that the influences of different land cover types on water delivery to streams and in-stream water quality vary seasonally and with respect to flow regime, that urbanization may result in decreased nitrate input, and that phosphate and dissolved organic carbon concentrations will likely remain constant as the watershed is developed. Results also indicate that riparian buffer downstream of intense agriculture lands dilutes high agricultural NO3-N concentrations, but not enough to return in-stream concentrations to natural levels.

Indiana University-Purdue University Indianapolis (IUPUI) / The characterization of the nutrients nitrogen, phosphorus and carbon (NPC) export to streams during storms is an integral part of understanding processes affecting water quality. Despite the fact that excessive levels of these nutrients in the Mississippi River basin adversely affects water quality in the Gulf of Mexico, little research has been conducted on NPC dynamics during storms on larger (>20 km2) agriculturally dominated Midwestern watersheds. This project examined the storm export of nitrate, ammonium, total phosphorus, and dissolved organic carbon (DOC) in the upper Eagle Creek Watershed (UECW) (274 km2) in Central Indiana, USA. Water samples were collected during five winter and spring storms in 2007 and 2008 on the rising and falling limb of the hydrograph, in order to characterize NPC dynamics during storm events. Stream discharge and precipitation was monitored continuously, and major cations were used to examine changes in source water over the duration of the storm and assist in the determination of potential flowpaths. DOC, total P, and TKN (Total Kjeldahl Nitrogen) tended to peak with discharge, while nitrate usually exhibited a slight lag and peaked on the receding limb. Total phosphorus, NH3-, TKN, and DOC appear to be delivered to the stream primarily by overland flow. NO3--N appear to be delivered by a combination of tile drain and macropore flow. Overall UECW displayed smoother nutrient export patterns than smaller previously studied watersheds in the area suggesting that scale may influence nutrient export dynamics. Further research is underway on a 3000 km2 watershed in the area to further examine the role scale may play in nutrient export patterns.