Thesis (M.S.)--Indiana University, 2007. / Department of Earth Sciences, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Philippe G. Vidon, Lenore P. Tedesco, Kathy J. Licht. Includes vitae. Includes bibliographical references (leaves 110-114).

Eutrophication is an increasing global concern as human effluent saturates lakes with an over abundance of nutrients. Phosphorus, generally being the limiting nutrient, is often the most impactful, allowing cyanobacteria populations to grow out of control leading to harmful blooms that can produce cyanotoxins, anoxic lake conditions, and mass fish kills. Utah Lake, a shallow highly eutrophic fresh water lake located in central Utah Valley, has experienced these harmful algal blooms for the last several years. The internal phosphorus cycle is a significant driver in Utah Lake's eutrophication, as the sediments act as both a sink and a source for phosphorus. Most of the phosphorus originates from external sources, gets captured by the sediment, and then through several physiochemical and biological process, gets released back into the surface water as a self sustaining eutrophication system. To determine the effects of the different physiochemical processes that drive the internal phosphorus system, we incubated 72 total sediment cores taken from two locations, chosen to best represent the lake's chemical and spatial variability, under aerobic, anaerobic, pH=9.5 and pH=7 conditions with various P concentrations (ambient, 0.5X, 2X, 4X) taking water samples at 0, 12, 24, and 72 hours. Dissolved oxygen (DO), pH, soluble reactive phosphorus (SRP), total dissolved phosphorus (TDP), and other major ions were measured for each sample. The highest P sediment release occurred under aerobic conditions, while the highest P sediment uptake occurred under anaerobic conditions. While pH did appear to have a mild effect on P flux, our study showed the lake has a remarkably stable bicarbonate buffer system making it unlikely that pH would contribute significantly under natural settings. Under all conditions the 2X and 4X cores experienced the highest P uptake, but final elevated P concentrations were still higher than initial ambient concentrations, indicating a probable delayed recovery time after external reductions occur.

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Indiana University-Purdue University Indianapolis (IUPUI) / This study investigated nutrient export during three spring storm events in two different land use watersheds (agricultural and mixed land use) in a glacial till landscape of the Midwestern, USA. The objectives of the study were: (1) to determine how land use affects water, nitrate, soluble reactive phosphorus (SRP) and dissolved organic carbon (DOC) delivery (timing, amount) to streams during spring storms in two central Indiana watersheds with contrasting land use; and (2) to determine nitrate, SRP and DOC flow pathways to streams during spring storms. High frequency stream sampling of nutrients and cations, coupled with hydrograph separations using δ18O, was used to identify water flow pathways and event and pre-event water contributions to the streams. Data indicate land use and storm characteristics play a role in the export of water and nutrients. In the agricultural watershed (Watershed A), the storm hydrograph is dominated by pre-event water, whereas the mixed land use watershed (Watershed M) storm hydrograph is more event water dominated. Watershed A also contains higher nutrient concentrations, especially nitrate. High bulk precipitation and greater maximum intensity export more nitrate, SRP, and DOC to the streams. Results also indicate nitrate, DOC, and SRP concentrations display distinct temporal patterns during spring storm events. DOC concentration increased with stormflow and peaked on the rising limb/with maximum discharge regardless of land use or storm event. In Watershed A, SRP concentration followed a similar pattern to DOC during small storms; therefore they are believed to be exported together with flushing of saturated near-surface soil waters via macropores/overland flow. However, SRP likely has multiple flowpaths, one dominated over another depending on the storm. Nitrate concentrations matched Ca2+, Mg2+, and Na+ trajectories and decreased with stormflow, suggesting a tile drain/subsurface flowpath. Nitrate and SRP peak concentrations are delayed relative to DOC in Watershed M. The wet retention ponds in the headwaters are believed to delay the stormflow response, and therefore, the delivery of nutrients to the stream.

The aim of this diploma thesis was to clarify the differences among three different ponds (Bolevecký, Třemošenský, Šídlovský) situated in Pilsen. All of the above mentioned ponds are recreational areas where Bolevecký pond is best known for his water quality improvements since 2006 (after application of Fe and Al - colagulants and also fish - stock changes). The main difference was based on the growth of submersed water plants. The macrophytes were growing slowly or not at all in Bolevecký pond. There was a huge expansion of macrophytes (mainly Myriophyllum spicatum species) in Třemošenský and Šídlovský ponds therefore the water plants must be regulated during summer seasons by mechanical harvesting. The water in all three ponds proves the same qualities but the differences may be found in the nutrient composition of sediments. The fractionation analysis (the founders Psenner and Puczsko) confirmed the fact that all localities are poor in phosphorus however the differences were found in content of iron. The increased content of iron was observed in sediments of Šídlovksý and Třemošenský ponds (mainly in BD fraction - the iron was unstable under redox potential changes). The result of this analysis proves that phosphorus is potentially more available for macrophytes in sediments of Třemošenský and Šídlovský...

Eutrophic Utah Lake receives a large nutrient load from a variety of sources, includingtreated wastewater discharges, runoff and tributaries, recycling from bottom sediments andAtmospheric Deposition (AD). AD was the focus of this study and was comprised of twocomplementary parts. First was a study of nitrogen and phosphorus depositions from theatmosphere, and second was a study of phosphorous as contained in soils near Utah Lake viafractionation methods.The soil samples were found to contain approximately 1,000 mg-P/kg soil for totalphosphorus (TP). A separate phosphorus (P) fractionation gave slightly higher values, excludingthe residual P, we are 95% confident that one gram of sample soil contains between 2.2 and 4.3percent water soluble P, 0.6 to 1.1 percent loosely-bound P, 2.5 to 4.4 percent aluminum andiron-bound P, and 90.7 to 94.2 percent calcium-bound P.AD results indicate that during the period from April 1 to Nov 17, 2018, Utah Lakereceived approximately 58 tons of soluble reactive P, 153 tons of TP, 118 tons of nitrogen (N)from nitrate, and 387 tons of N from ammonium via AD.Nutrient quantities from AD are very large compared to the 17 ton/yr of P needed for aeutrophic loading to the lake. Because of the very large overall nutrient loading to Utah Lake, itis likely that some other limiting growth factors are controlling algal growth.

Total phosphorus concentrations in the open waters of the Laurentian Great Lakes are currently at or beneath target concentrations set by international agreement. Despite the success of phosphorus loading controls in remediating nearshore eutrophication problems in the past, nuisance growth of Cladophora has recently returned to the lower Great Lakes. This thesis examines soluble reactive phosphorus (SRP) in a northwestern segment of Lake Ontario to assess whether allochthonous or autochthonous sources of phosphate lead to localized areas of PO43- enrichment that may help to explain the seemingly paradoxical resurgence of Cladophora. As SRP is often an overestimate of PO43- in P-limited waters, measures of SRP made with the standard method were compared with measures of SRP made with modified methods (i.e., using dialysis and magnesium-induced co-precipitation) designed to more accurately measure phosphate when it was expected to be at low concentrations. Measures of SRP made with standard and modified methods did not differ, however, SRP was 1 to 3 orders of magnitude higher than a more sensitive steady-state radiobioassay for PO43- used for comparison in offshore waters. Although the utility of SRP is limited when phosphate concentrations are very low, SRP is useful to measure localized areas of phosphate enrichment, and its relative concentrations can be compared in time and space. To quantify the degree to which allochthonous inputs and dreissenids contribute to PO43- concentrations that permit Cladophora growth, intensive sampling for SRP was carried out prior to, during and following the Cladophora growing season. SRP was higher in the nearshore than offshore and near the mouth of a large tributary and a treated wastewater outfall than in samples from other locations along the shoreline, but only in the spring and autumn. Phosphate turnover times indicated lower P-limitation in the nearshore and near local inputs versus the offshore. Higher concentrations of SRP were measured in samples taken 15 cm and 50 cm above dreissenid mussel-beds than in those obtained at corresponding depths over other substrata and from higher up in the water column through the Cladophora growing season, while Chl a concentrations displayed the reverse trend. These results suggest that PO43- excreted by dreissenids could be more important in time and space than external inputs in supporting nuisance Cladophora growth in the current nearshore environment. Continued research and monitoring of P dynamics in the nearshore combined with model approaches should better predict whether more stringent P controls would be effective in managing Cladophora growth.

Total phosphorus concentrations in the open waters of the Laurentian Great Lakes are currently at or beneath target concentrations set by international agreement. Despite the success of phosphorus loading controls in remediating nearshore eutrophication problems in the past, nuisance growth of Cladophora has recently returned to the lower Great Lakes. This thesis examines soluble reactive phosphorus (SRP) in a northwestern segment of Lake Ontario to assess whether allochthonous or autochthonous sources of phosphate lead to localized areas of PO43- enrichment that may help to explain the seemingly paradoxical resurgence of Cladophora. As SRP is often an overestimate of PO43- in P-limited waters, measures of SRP made with the standard method were compared with measures of SRP made with modified methods (i.e., using dialysis and magnesium-induced co-precipitation) designed to more accurately measure phosphate when it was expected to be at low concentrations. Measures of SRP made with standard and modified methods did not differ, however, SRP was 1 to 3 orders of magnitude higher than a more sensitive steady-state radiobioassay for PO43- used for comparison in offshore waters. Although the utility of SRP is limited when phosphate concentrations are very low, SRP is useful to measure localized areas of phosphate enrichment, and its relative concentrations can be compared in time and space. To quantify the degree to which allochthonous inputs and dreissenids contribute to PO43- concentrations that permit Cladophora growth, intensive sampling for SRP was carried out prior to, during and following the Cladophora growing season. SRP was higher in the nearshore than offshore and near the mouth of a large tributary and a treated wastewater outfall than in samples from other locations along the shoreline, but only in the spring and autumn. Phosphate turnover times indicated lower P-limitation in the nearshore and near local inputs versus the offshore. Higher concentrations of SRP were measured in samples taken 15 cm and 50 cm above dreissenid mussel-beds than in those obtained at corresponding depths over other substrata and from higher up in the water column through the Cladophora growing season, while Chl a concentrations displayed the reverse trend. These results suggest that PO43- excreted by dreissenids could be more important in time and space than external inputs in supporting nuisance Cladophora growth in the current nearshore environment. Continued research and monitoring of P dynamics in the nearshore combined with model approaches should better predict whether more stringent P controls would be effective in managing Cladophora growth.