Tidal freshwater marshes (TFMs) are unique ecosystems that bridge the gap between terrestrial and aquatic ecosystems and are important in the sequestration of soil organic carbon. With the ever changing global climate, TFMs are left vulnerable to downstream effects of rising sea level and salt water intrusion due to increases in flooding by saline waters. These changes often act over large spatial and temporal scales resulting in significant impacts to local and regional environments. This multidisciplinary study assessed the amount and lability of desorbed organic carbon in tidal freshwater marsh soils from the Waccamaw River Marsh, South Carolina and Sweet Hall, a marsh on the Pamunkey River, Virginia. Soils from each marsh were extracted at 0-35 practical salinity units (psu) and the dissolved organic carbon (DOC) concentration, and carbon lability of the leachates were measured. At increasing levels of salinity, soil desorption amounts were higher in the Waccamaw River marsh interior and similar between the Waccamaw River creekbank and Sweet Hall levee. A larger fraction of desorbed DOC was consumed in the more organic soils from the Waccamaw River marsh in comparison to the more mineral soil from Sweet Hall Marsh. Finally, the rate of decay of the desorbed carbon was highest in the Sweet Hall levee soils, indicating more labile desorbed carbon, while the Waccamaw River Marsh soils had lower decay rates indicating less labile desorbed carbon. By understanding how salt water intrusion affects desorption and lability of soil organic carbon, in coastal marshes, we may be able to better understand how increasing sea levels may affect carbon storage in coastal ecosystems.

We quantified U removal and investigated the efficacy of uranium as a quantitative tracer of groundwater discharge in a headwater salt marsh of the Okatee River, Bluffton, SC. Determining the magnitude of U removal is important for advancing U as a tracer of paleo-oceanic conditions. Since salt marsh groundwater is typically enriched in nutrients and other biologically and chemically reactive species, quantifying groundwater discharge from marshes is critical for understanding the ability of salt marshes to modify the chemistry of important species in surface waters. We hypothesized that water-column U(VI) was removed by tidally-induced advection of surface water into permeable, anoxic salt marsh sediments, a process resulting in bacterially-mediated precipitation of insoluble U(IV)O2 and/or sorption of uranium to iron-oxides at the oxic/anoxic sediment interface. Furthermore, we suggested that hydraulic pressure gradients established by marsh-surface tidal inundation and seasonally-variable rainfall promote the discharge of salt-marsh-processed, uranium-depleted groundwater to tidal creeks, producing the surface-water U-removal signal. Groundwater and surface water data revealed non-conservative uranium behavior. We documented extensive uranium removal from shallow marsh groundwater and seasonally variable uranium removal from surface waters. These observations allowed for the calculation of seasonally-dependent salt marsh uranium removal rates. On a yearly basis, our removal rate (58 to 104 mol m-2 year-1) reemphasized the importance of anoxic coastal environments for U removal. High uranium removal, high barium concentration water observed seeping from creek banks at low tide supported our hypothesis that groundwater discharge must contribute to uranium removal documented in tidal surface waters. Average site groundwater provided an analytically reasonable endmember for explaining uranium depletion in surface water. Therefore, we used three endmember mixing models for estimating the fraction of surface water with presumed a groundwater signature. Our discharge estimates of 8 to 37 L m-2 day-1 agreed closely with previously published salt marsh values. Seasonality in discharge rates can be rationalized with appeal to seasonal patterns in observed rainfall, tidal forcing, and marsh surface bioturbation. Although more work is needed, the results of this portion of the study suggest that U may be an effective quantitative tracer of groundwater discharge from salt marshes.

This collection of research examines how changes in the sensory landscape, mediated by both odor and hydrodynamic properties, impact odor-mediated predator-prey interactions in salt marsh communities. I approached this research using an interdisciplinary framework that combined field and laboratory experimentation to address issues of scale and make connections between predator behavior and patterns of predation in the field. I explored a variety of interactions mediated by changes in the sensory landscape including; indirect effects of biotic structure on associated prey, predator responses to patches of prey with differing density and distribution, and dynamic interactions between predators and prey distributions. I found that biotic structure (oyster reefs [Crassostrea virginica]) has negative indirect effects on associated hard clam prey (Mercenaria mercenaria) through the addition of oyster reef odor cues that attract predators (blue crabs [Callinectes sapidus] and knobbed whelks [Busycon carica])and increase foraging success near the structural matrix. Variation in the structure of patch-scale prey odor plumes created by multiple prey results in predator-specific patterns of predation as a function of patch density and distribution which are mediated by differences in predator sensory ability. There is a potential negative feedback loop between blue crab predators and hard clam prey distributions; clam patches assume random within-patch distributions after exposure to blue crab predators, making the detection of patches by future blue crab predators more difficult. Sensory landscapes are also mediated by water flow, which transports prey odor plumes downstream to predators. Characterization of water flow in small-scale estuary systems indicates that values of turbulent flow parameters are highly context specific and depend on both tidal type (spring, neap, normal) and site. Wind and tidal range seem to be good predictors for wave components and turbulent components of fluctuating flow parameters, respectively, although the strength of their predictive ability is dependent on time scale. Modifications of the sensory landscape through changes in structurally-induced turbulence, mixing of individual plumes from multiple prey, and bulk velocity and turbulence characteristics need to be considered when formulating predictions as to the impact of predators on naturally occurring prey populations in the field.

This thesis examines images of women shopping in the art of Kenneth Hayes Miller and Reginald Marsh during the 1920s and 1930s. New York City's Fourteenth Street served Kenneth Hayes Miller and Reginald Marsh, respectively, as a location generating the inspiration to study and visually represent its contemporaneity. Of particular interest to this thesis are relationships between developments in shopping and the images of women shopping in and around Fourteenth Street that populate the paintings of Miller and Marsh. Although, as Ellen Todd Wiley has shown, the emerging notion of the New Woman helped to shape female identity at this time, what remains unstudied are dimensions that geographically specific, historical developments in shopping contributed to the construction of female identity which, this thesis argues, Marsh and Miller related to, by locating in, the department store and bargain store.

No description available.

The Cienega de Santa Clara is a 5600 ha, anthropogenic wetland in the delta of the Colorado River in Mexico. It is the inadvertent creation of the disposal of brackish agricultural waste water from the U.S. into the intertidal zone of the river delta in Mexico, but has become an internationally important wetland for resident and migratory water birds. The marsh is dominated by Typha domengensis with Phragmites australis as a sub-dominant species in shallower marsh areas. The most important factor controlling vegetation density was fire. The second significant (P<0.01) factor controlling NDVI was flow rate of agricultural drain water from the U.S. into the marsh. Reduced summer flows in 2001 due to canal repairs, and in 2010 during the YDP test run, produced the two lowest NDVI values of the time series from 2000 to 2011 (P<0.05). Salinity is a further determinant of vegetation dynamics as determined by greenhouse experiments, but was nearly constant over the period 2000 to 2011, so it was not a significant variable in regression analyses. Evapotranspiration (ET) and other water balance components were measured in Cienega de Santa Clara; we used a remote sensing algorithm to estimate ET from meteorological data and Enhanced Vegetation Index values from the Moderate Resolution Imaging Spectrometer (MODIS) sensors on the Terra satellite. We used Landsat NDVI imagery from 1978-2011 to determine the area and intensity of vegetation and to estimate evapotranspiration (ET) to construct a water balance. Remote sensing data was supplemented with hydrological data, site surveys and literature citations. The vegetated area increased from 1978 to 1995 and has been constant at about 4200 ha since then. The dominant vegetation type is Typha domingensis (southern cattail), and peak summer NDVI since 1995 has been stable at 0.379 (SD = 0.016), about half of NDVI(max). About 30% of the inflow water is consumed in ET, with the remainder exiting the Cienega as outflow water, mainly during winter months when T. domingensis is dormant.

Emergent macrophytes are an integral part of prairie marshes and involved in many of the services that make these ecosystems valuable. Water depth and hydroperiod are two environmental variables that can influence the growth and nutrient content of emergent macrophytes. This study looked at the growth and nutrient content response of hybrid cattail (Typha x glauca) to water depth and hydroperiod in two prairie marshes in southern Manitoba, Canada. Above- and belowground samples of hybrid cattails were collected along a water depth gradient at Oak Hammock Marsh, Canada, and analyzed for biomass, total phosphorus, total nitrogen, total Kjeldahl nitrogen content, shoot height, and density. A second dataset was obtained from the Marsh Ecology Research Program (MERP) experiment, and used to determine the biomass and nutrient content response of the hybrid cattail following one or two years of drawdown. / October 2015

Many recent studies have sought to understand the response of barrier islands and their attendant marshes to sea level rise. The Mississippi River delta plain, specifically the Chandeleur Islands and associated interior wetlands in eastern Louisiana, serves as an excellent natural laboratory for studying these responses. This region is presently undergoing the highest rates of shoreline erosion (> 15 m yr -1) in North America as wetlands are converted to open water in a regime of subsidence-driven rapid relative sea-level rise (~1 cm yr-1). Three conceptual models were developed based on the geomorphic relationships observed in the marsh that describe and predict shoreline processes as the Chandeleur Islands continue to disintegrate and submerge. These models indicate that shells are the dominant shoreline-forming material in the marsh due to the lack of sand-rich strata in the subsurface of the marsh.

There is a demand to reestablish a healthy coastal ecosystem by rebuilding wetlands with river diversion or dredged sediments in coastal Louisiana. Land building projects using dredged sediments from adjacent canals and river beds, can be used to protect the coastal properties and infrastructure systems from flood and storm surges. To predict the sediment’s long term behavior, math models require input parameters based on sediment engineering properties and material characteristics. Proper characterization is critical for accurate design of coastal restoration projects. The dredge material sedimentation characteristics and their effects on the settlement rate of suspended solid particles and underlying foundation soil depend, among other factors, on the grain size distribution of the dredged material, salinity of the composite slurry, and slurry solid particles concentration. This research evaluated the effects of grain size distribution, salinity, and initial solids concentration on the sedimentation characteristics of fine grained dredged sediments in Coastal Louisiana.

As sea levels continue to rise, the projected damage that will ensue presents a great challenge for conservation and management of coastal ecosystems in Florida. Since Juncus roemerianus is a common marsh plant throughout Florida with unique growing characteristics that make it a popular restoration plant, this study implemented a 20 week greenhouse split plot experiment to examine the effects of sea level rise on J. roemerianus and ultimately determine its tolerance ranges to salinity and inundation in a high nutrient environment. Overall, salinity level and the interaction effect of salinity level and water level had the greatest effects on measured growth parameters including average mature height, maximum height, density, basal area, root length, and biomass. An inverse relationship between increasing salinity and the measured growth variables was observed with the greatest growth and survivability in 0 ppt water, survivability and reduced growth in 20 ppt water, survivability and little growth in 30 ppt water, and nearly complete senesce in 40 ppt water. This was the first laboratory study to determine the effect of 40 ppt water on J. roemerianus. Elevated water levels resulted in higher growth variables in the 20 ppt, 30 ppt, and 40 ppt treatments while inundated water levels produced higher growth variables in the 0 ppt treatment despite previous research finding inundation to have completely adverse effects on J. roemerianus. It is likely that the high nutrient environment provided for this study is the cause for this anomaly. The results of this study have major implications for the future of coastal ecosystems that are dominated by stands of J. roemerianus in South Florida and can be used in conjunction with studies on bordering marsh plants to predict shifts in the ecosystems of Florida that are responding to sea level rise scenarios. / Includes bibliography. / Thesis(M.S.)--Florida Atlantic University, 2015 / FAU Electronic Theses and Dissertations Collection