Florida Bay: Water quality status and trends, historic and emerging algal bloom problems

Florida Bay is a unique subtropical estuary that while historically oligotrophic, has been subjected to both natural and anthropogenic stressors, including hurricanes, coastal eutrophication and other impacts. These stressors have resulted in degradation of water quality in the past several decades, most evidenced by reoccurring blooms of the picocyanobacterium Synechococcus spp. Major nutrient inputs consist of freshwater flows to the eastern region from runoff and regulated canal releases, inputs from the Everglades to the central region via Taylor Slough, exchanges with the Gulf of Mexico, which include intermittent Shark River inputs to the western region, stormwater and wastewater from the Florida Keys, and atmospheric deposition. These nutrient inputs have resulted in a transition from strong phosphorus (P) limitation of phytoplankton in the eastern bay to nitrogen (N) limitation in the western bay. Large blooms of Synechococcus were most pronounced in the central bay region, in the area of transition between P and N limitation, in the mid-1990s. Although non-toxic, these blooms, which have continued intermittently through the early 2000s, resulted in significant sea-grass and benthic organism mortalities. A new suite of stressors in 2005, including the passages of Hurricanes Katrina, Rita, and Wilma, additional canal releases, and the initiation of road construction to widen the main roadway leading to the Keys, were correlated with a large Synechococcus bloom in the previously clear, strongly P- limited, northeastern region of the bay. Sustained for 3 years, this bloom was accompanied by a shift from P limitation to N limitation during its course. Nutrient bioassay experiments suggest that this bloom persisted due to the ability of Synechococcus to access organic N and P sources, microbial and geochemical cycling of organic and inorganic nutrients in the water column and between the water column and sediments (both suspended particles and benthos), and decreased grazing by benthic fauna due to their die-off.

Recent and Historic Drivers of Landscape Change in the Everglades Ridge, Slough, and Tree Island Mosaic

More than half of the original Everglades extent formed a patterned peat mosaic of elevated ridges, lower and more open sloughs, and tree islands aligned parallel to the dominant flow direction. This ecologically important landscape structure remained in a dynamic equilibrium for millennia prior to rapid degradation over the past century in response to human manipulation of the hydrologic system. Restoration of the patterned landscape structure is one of the primary objectives of the Everglades restoration effort. Recent research has revealed that three main drivers regulated feedbacks that initiated and maintained landscape structure: the spatial and temporal distribution of surface water depths, surface and subsurface flow, and phosphorus supply. Causes of recent degradation include but are not limited to perturbations to these historically important controls; shifts in mineral and sulfate supply may have also contributed to degradation. Restoring predrainage hydrologic conditions will likely preserve remaining landscape pattern structure, provided a sufficient supply of surface water with low nutrient and low total dissolved solids content exists to maintain a rainfall-driven water chemistry. However, because of hysteresis in landscape evolution trajectories, restoration of areas with a fully degraded landscape could require additional human intervention.

Historic primary producer communities linked to water quality and hydrologic changes in the northern Everglades

The northern Everglades Water Conservation Areas have experienced recent ecological shifts in primary producer community structure involving marl periphyton mats and dense Typha-dominated macrophyte stands. Multiple investigations have identified phosphorus (P) as a driver of primary producer community structure, but effects of water impoundment beginning in the 1950s and changes in water hardness [e.g., (CaCO3)] have also been identified as a concern. In an effort to understand pre-1950, primary producer community structure and identify community shifts since 1950, we measured pigment proxies on three sediment cores collected in Water Conservation Area-2A (WCA-2A) along a phosphorus enrichment gradient. Photosynthetic pigments, sediment total phosphorus content (TP), organic matter, total organic carbon and nitrogen were used to infer historic primary producer communities and changes in water quality and hydrology regulating those communities. Excess 210Pb was used to establish historic dates for the sediment cores. Results indicate the northern area of WCA-2A increased marl deposition and increased algal abundance ca. 1920. This increase in (presumably) calcareous periphyton before intensive agriculture and impoundment suggest canal-derived calcium inputs and to some extent early drainage effects played a role in initiating this community shift. The northern area community then shifted to Typha dominance around 1965. The areas to the south in WCA-2A experienced increased marl deposition and algal abundance around or just prior to 1950s impoundment, the precise timing limited by core age resolution. Continued increases in algal abundance were evident after 1950, coinciding with impoundment and deepening of canals draining into WCA-2A, both likely increasing water mineral and nutrient concentrations. The intermediate site developed a Typha-dominated community ca. 1995 while the southern-most core site WCA-2A has yet to develop Typha dominance. Numerous studies link sediment TP >650 mg P/kg to marsh habitat degradation into Typha-dominance. The northern and intermediate cores where Typha is currently support this previous research by showing a distinct shift in the sediment record to Typha dominance corresponding to sediment TP between 600 and 700 mg P/kg. These temporal and spatial differences are consistent with modern evidence showing water-column gradients in mineral inputs (including Ca, carbonates, and phosphorus) altering primary producer community structure in WCA-2A, but also suggest hydroperiod has an effect on the mechanisms regulating periphyton development and Typha dominance.

Correspondence of historic salinity fluctuations in Florida Bay, USA, to atmospheric variability and anthropogenic changes

Florida Bay is a highly dynamic estuary that exhibits wide natural fluctuations in salinity due to changes in the balance of precipitation, evaporation and freshwater runoff from the mainland. Rapid and large-scale modification of freshwater flow and construction of transportation conduits throughout the Florida Keys during the late nineteenth and twentieth centuries reshaped water circulation and salinity patterns across the ecosystem. In order to determine long-term patterns in salinity variation across the Florida Bay estuary, we used a diatom-based salinity transfer function to infer salinity within 3.27 ppt root mean square error of prediction from diatom assemblages from four ~130 year old sediment records. Sites were distributed along a gradient of exposure to anthropogenic shifts in the watershed and salinity. Precipitation was found to be the primary driver influencing salinity fluctuations over the entire record, but watershed modifications on the mainland and in the Florida Keys during the late-1800s and 1900s were the most likely cause of significant shifts in baseline salinity. The timing of these shifts in the salinity baseline varies across the Bay: that of the northeastern coring location coincides with the construction of the Florida Overseas Railway (AD 1906–1916), while that of the east-central coring location coincides with the drainage of Lake Okeechobee (AD 1881–1894). Subsequent decreases occurring after the 1960s (east-central region) and early 1980s (southwestern region) correspond to increases in freshwater delivered through water control structures in the 1950s–1970s and again in the 1980s. Concomitant increases in salinity in the northeastern and south-central regions of the Bay in the mid-1960s correspond to an extensive drought period and the occurrence of three major hurricanes, while the drop in the early 1970s could not be related to any natural event. This paper provides information about major factors influencing salinity conditions in Florida Bay in the past and quantitative estimates of the pre- and post-South Florida watershed modification salinity levels in different regions of the Bay. This information should be useful for environmental managers in setting restoration goals for the marine ecosystems in South Florida, especially for Florida Bay.

A Map Through Time – Virtual Historic Cities: New Ways of Exploring Digital Collections

Presentation made by Jamie Rogers and John Nemmers at the Society of Florida Archivists annual meeting in Tallahassee, Florida. Jamie Rogers presented the "Coral Gables - Virtual Historic City" project at Florida International University. John Nemmers presented the "Unearthing St. Augustine’s Colonial Heritage" project at the University of Florida

An incident at sea: The historic combat between U.S. Navy Blimp K-74 and U-Boat 134

This thesis studies the historic encounter between United States Navy airship K-74 and Nazi submarine U-134 in World War II. The Battle of the Atlantic is examined through case study of this one U-boat and its voyage. In all things except her fight with the American blimp, the patrol was perfectly typical. Looked at from start to finish, both her reports and the reports of the Allies encountered, many realities of the war can be studied. U-134 sailed to attack shipping between Florida and Cuba. She was challenged by the attack of United States Navy airship K-74 over the Florida Straits. It is the only documented instance of battle between two such combatants in history. That merits attention. Thesis finding disprove historian William Eliot Morison’s contention that the K-74 airship bombs were not dropped and did not damage the U-boat. Study of this U-boat and its antagonist broadens our understanding of the Battle of the Atlantic. It is a contribution to our knowledge of military, naval, aviation, and local history.

Palm Cottage Garden Historic Preservation

Historic landscapes are vital elements of our nation's cultural continuum and must be protected as a part of living fabric of the community. This thesis addressed the preservation of historic landscape gardens, focusing on design strategies that can make historic time legible in landscape. It proposed a landscape plan for the preservation of Palm Cottage Garden in Gotha, Florida, a significant historic landscape resource. To determine the criteria used to establish how and to what period the estate should be restored, the Secretary of the Interior's Guidelines for the Treatment of Cultural Landscapes was followed. This process involved documenting the current site conditions and evaluating natural and cultural resources. For the garden to continue to keep its historic fabric, rehabilitation was selected. The garden was designed to preserve existing features and make efficient contemporary use of the garden possible. The landscape plan focused on strategies that reveal the site's significant past through new design elements while adapting to current and future needs.

Mountain lake colony pinewood estate garden historic preservation

Pinewood Estate is a significant resource in the history of the theory and practice of landscape architecture. The purpose of this thesis is to provide a landscape plan to restore the Pinewood Estate to its historic integrity in order to retain and reflect its past. In order to determine the criteria used to establish how and to what period the estate should be restored to, the Secretary of the Interior's Guidelines for the Treatment of Cultural Landscapes was followed. This process involved documenting the existing conditions of the estate. Site inventory and analysis and onsite interviews were conducted. Natural and cultural resources were evaluated. As a case study, McKee Botanical Garden was analyzed and evaluated. The comparison of this case study served as a guideline to determine the best practice for the historical preservation of the estate. Despite the changes in the landscape at Pinewood Estate over the past seventy years, the garden today still retains William Lyman Phillips design criteria. For the garden to continue to keep its historic fabric, rehabilitation was selected to allow for improvements that make possible efficient contemporary use of the estate.

Seismic Retrofitting of a Historic Structure with Limited Construction Documentation

Many buildings constructed during the middle of the 20th century were constructed with criteria that fall short of current requirements. Although shortcomings are possible in all aspects of the design, the inadequacies in terms of seismic design present a more pressing issue to human life. This risk has been seen in various earthquakes that have struck Italy recently, and subsequently, the codes have been altered to account for this underestimated danger. Structures built after these changes remain at risk and must be retrofitted depending on their use. This report centers around the Giovanni Michelucci Institute of Mathematics at the University of Bologna and the work required to modify the building so that it can withstand 60% of the current design requirements. The goal of this particular report is to verify the previous reports written in Italian and present an accurate analysis along with intervention suggestions for this particular building. The work began with an investigation into the previous sources and work to find out how the structure had been interpreted. After understanding the building, corrections were made where required, and the failing elements were organized graphically to more easily show where the building needed the most work. Once the critical zones were mapped, remediation techniques were tested on the top floor, and the modeling techniques and effects of the interventions were presented to assist in further work on the structure.

Forging Iconographies and Casting Colonialism: Monuments and Memories in Ontario, 1850-2001

Commemorations are a critical window for exploring the social, political, and cultural trends of a specific time period. Over the past two centuries, the commemorative landscape of Ontario reaffirmed the inclusion/exclusion of particular racial groups. Intended as static markers to the past, monuments in particular visually demonstrated the boundaries of a community and acted as ongoing memorials to existing social structures. Using a specific type of iconography and visual language, the creators of monuments imbued the physical markers of stone and bronze with racialized meanings. As builders were connected with their own time periods and social contexts, the ideas behind these commemorations shifted. Nonetheless, creators were intent on producing a memorial that educated present and future generations on the boundaries of their “imagined communities.” This dissertation considers the carefully chosen iconographies of Ontario’s monuments and how visual symbolism was attached to historical memory. Through the examination of five case studies, this dissertation examines the shifting commemorative landscape of Ontario and how memorials were used to mark the boundaries of communities. By integrating the visual analysis of monuments and related images, it bridges a methodological and theoretical gap between history and art history. This dissertation opens an important dialogue between these fields of study and demonstrates how monuments themselves are critical “documents” of the past.

Source Provenance of Pre-Historic Granitic Grindstones: The Case Study of the Cogotas I Archaeological Site of Arroyo Mucientes/San Lázaro (Castronuño, Valladolid) and a Proposal on the General Methodological Flow Process

The occurrence of hand grindstones at the Cogotas I archaeological sites is considered to be a common feature. Given that a distant-provenance raw material is frequently involved, determination of its source is a basic factor in the search for a better understanding of resource management and for any Political Economy approach. To progress in these directions an overall study should be planned, using selected grindstones with a view to covering diverse sub-zones of the Cogotas I dispersal area, especially because of its considerable distance from the granite basement source. Such a study may today includes diverse analytical procedures combining successive geographic, petrographic, mineralogical and geochemical criteria. To check the plausibility of the proposed methodology, a preliminary test has been carried out on two granite grindstones, obtained at the archaeological excavation at the Castronuño (Valladolid) Cogotian site, which is fifty km away from an inferred source area that was presumably located at Peñausende (Zamora). The result obtained validates the proposed operational process, yielding a generalizable knowledge to other similar situations.

Tourism Impacts of a Portuguese World Heritage Historic Center: Residents’ Perspectives

The World Heritage List (WHL) is widely considered a powerful tool for national tourism campaigns. Sites inscribed on the WHL by the United Nations Educational, Scientific, and Cultural Organization (UNESCO) are commonly treated as catholicons in promoting the tourism industry, which in turn helps to promote economic growth and development. This study analyzes local community perceptions of the importance of the World Heritage Site (WHS) classification of the historic center of the Portuguese city of E ́vora. The research also includes an analysis of the local residents’ perceived tourism impacts on the municipality of E ́ vora. The methodology consists of quan- titative research based on a self-administered survey applied to convenience sam- ples of local residents of the municipality of E ́ vora in the beginning of 2014. The local residents’ perceptions of the level of importance of the WHS classification to the municipality and its impact in the increase of tourists is analyzed. Positive and negative tourism impacts are then ranked and a principal components factor analysis is employed separately to the two groups of impacts in order to identify underlying dimensions associated with residents’ perceptions on tourism develop- ment. Based on the results of the factor analysis, independent sample t-tests are used to investigate differences regarding positive and negative tourism impacts between residents that live near and far from the historic center, and between residents who work/have worked in the tourism sector and residents that work/ have worked in other sectors.

The Mormon Trail: Historic Byway Inventory and Evaluation, 1998

A three-step approach was used to do the study of the Mormon Trail. These involved research, field data collection and evaluation of the project corridors. Step one involved research on the location of the Trail, associated sites and the historic land use near the Trail between 1846 and 1868. The next step involved defining roads to be inventoried and the actual field survey. Step three involved evaluation of the inventoried corridors. This evaluation procedure was based on the methodology currently used by Iowa DOT to evaluate candidate scenic byway routes but involved different evaluation factors. The numeric results of the two analyses can be directly compared. The results of the field survey and evaluation are shown in detail by county. Inventory and evaluation procedures for historic and cultural byways are discussed in Appendix A.

Iowa Historic Property Study of the Thomas A. Graham House (86-00024) : Tama, Iowa, 2002

The purpose of the present recordation project is to provide a documentary record of the Thomas A. Graham House in accordance with the guidelines set forth by the Iowa State Historic Preservation Office regarding historic property studies for houses. Background research for this project was conducted in April 2002. The property was inspected and photographed in November 2001.