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Phosphorus is one of the major nutrients limiting the productivity of terrestrial, wetland and aquatic ecosystems. Over the last decade several research projects were conducted on Florida's ecosystems from state and federal agencies and private industry to address water quality issues, and to develop management practices to control nutrient loads. Phosphorus Biogeochemistry in Sub-Tropical Ecosystems is the first thorough study of the role of phosphorus in ecological health and water quality ever published. Because of its vast and extensively studied ecosystems, Florida has often served as a national laboratory on current and future trends in ecosystem management. The reader will find studies at all levels of biological organization, from the cellular to entire ecological communities. The book is a definitive study of the role and behavior of phosphorus deposition in the upland/wetland/aquatic environment. The papers presented in this book are organized in specific groups: ecological analysis and global issues, biogeochemical transformations, biogeochemical responses, transport processes, phosphorus management, and synthesis. Although Florida's ecosystems are used as a case study, the results presented have global applications.
This Workshop was organized to assess the status of knowledge on the behaviour of phosphorus in sediments and to define gaps and reassess research strategies, particularly with respect to prevalent methodology and future approach; and to define gaps and reassess research strategies for water management measures in aquatic ecosystems, especially in relation to the release of phosphorus from the sediments and its impact on the functioning of the whole system.
Understanding the geochemical controls on how phosphorus (P), a limiting or co-limiting nutrient for plants and microorganisms in many ecosystems, adsorbs to iron (oxyhydr)oxides minerals (henceforth called Fe oxides) is vital to predict the bioavailability of P in a system. Orthophosphate (henceforth called phosphate), the major ion of P utilized by biota, binds strongly to Fe oxides and is removed from solution, decreasing its bioavailability. The ability of Fe oxides to adsorb phosphate and act as a geochemical control on phosphate bioavailability depends on the crystallinity and mineralogy of the Fe oxides. Changes in hydrology and resulting shifts in redox conditions, represented by field measurements of redox potential (Eh), can directly impact phosphate bioavailability by either dissolving Fe oxides and releasing phosphate or precipitating low crystallinity Fe oxides adsorbing phosphate. Additional importance of the interaction of Fe oxides and P is their impact on the stability of soil organic carbon (OC) in Arctic permafrost soils. Permafrost ecosystems store a significant amount (~60%) of the worlds soil OC that are vulnerable to emissions to the atmosphere with increasing permafrost thaw. As such I hypothesize that shifts in soil EH caused by climatic variations such as progressing permafrost thaw and will shift Fe speciation in soil towards low crystallinity Fe oxides, such as ferrihydrite, and increase the capacity of phosphate adsorption and over a longer time period decrease bioavailability of phosphate to microorganism stabilizing soil OC. In this dissertation, I investigate 1) how EH responds to hydrological change, 2) the impact of EH and Fe oxide mineralogy on Fe oxide dissolution and transformation, as well as 3) the resulting impact of changing Fe oxide mineralogy on phosphorus bioavailability to the system, and 4) the impact of thawing permafrost on soil EH and Fe crystallinity and speciation, and the resulting impact on phosphorus sorption to Fe oxides . Methods employed to address the above mentioned research goals included 1) continuous, high resolution measurements of EH with platinum electrodes, 2) sequential extractions to quantify extractable Fe and P in soils and in field-incubated minerals, and 3) x-ray absorption fine structure (XAFS) spectroscopy to evaluate changes in Fe speciation. In Chapter 2, I present research on how soil EH responds to hydrological change in and around a vernal pond . I show how Eh can vary within a small pond temporally and spatially, and how Fe reducing conditions can persist without surface water ponding. In Chapter 3 I describe how Fe oxide speciation evolves over time towards lower crystallinity in contrasting redox conditions at the same vernal pond as in Chapter 2. I also show how Fe oxides can retain phosphate and how freshly precipitated Fe oxides adsorb phosphate potentially reducing bioavailability of P. In Chapter 4 I show how Eh differs along a permafrost gradient in Sweden. I also show how Fe speciation shifts towards the poorly crystalline Fe oxide ferrihydrite as permafrost thaw progresses. Additionally, I show the strong association of P to Fe oxides along the permafrost gradient.
The study of estuaries and coasts has seen enormous growth in recent years, since changes in these areas have a large effect on the food chain, as well as on the physics and chemistry of the ocean. As the coasts and river banks around the world become more densely populated, the pressure on these ecosystems intensifies, putting a new focus on environmental, socio-economic and policy issues. Written by a team of international expert scientists, under the guidance of Chief Editors Eric Wolanski and Donald McClusky, the Treatise on Estuarine and Coastal Science, Ten Volume Set examines topics in depth, and aims to provide a comprehensive scientific resource for all professionals and students in the area of estuarine and coastal science Most up-to-date reference for system-based coastal and estuarine science and management, from the inland watershed to the ocean shelf Chief editors have assembled a world-class team of volume editors and contributing authors Approach focuses on the physical, biological, chemistry, ecosystem, human, ecological and economics processes, to show how to best use multidisciplinary science to ensure earth's sustainability Provides a comprehensive scientific resource for all professionals and students in the area of estuarine and coastal science Features up-to-date chapters covering a full range of topics
Proceedings of a symposium held in Uppsala, Sweden, September 25-28, 1985
Phosphorus in Fresh Water and the Marine Environment investigates sources of phosphorus in fresh water and the marine environment and the problems it causes. The importance of phosphate precipitation as an inbuilt safety device against overproduction of algae in the oceans is discussed, along with the deposition and absorption of phosphates in sediments. The source of the phosphorus in lakes and rivers is considered in relation to population density and distribution. This book is comprised of 26 chapters and begins with a discussion on natural phosphate sources in relation to phosphate budgets, paying particular attention to eutrophication and soil erosion. The significance of man-made sources of phosphorus, such as fertilizers and farming, detergents and sewage, is then examined. Subsequent chapters focus on the role of phosphorus in the growth of plants and animals in rivers, lakes, and the sea; the hydrogeochemical cycling of phosphorus; phosphorus analysis in sea water; and safety evaluation of substitutes for phosphates in detergents. The microbiology of an activated sludge wastewater treatment plant chemically treated for phosphorus removal is also explored. This monograph will be of interest to policymakers concerned with water pollution control.