Phosphorus in Phoenix: a budget and spatial representation of phosphorus in an urban ecosystem.

As urban environments dominate the landscape, we need to examine how limiting nutrients such as phosphorus (P) cycle in these novel ecosystems. Sustainable management of P resources is necessary to ensure global food security and to minimize freshwater pollution. We used a spatially explicit budget to quantify the pools and fluxes of P in the Greater Phoenix Area in Arizona, USA, using the boundaries of the Central Arizona-Phoenix Long-Term Ecological Research site. Inputs were dominated by direct imports of food and fertilizer for local agriculture, while most outputs were small, including water, crops, and material destined for recycling. Internally, fluxes were dominated by transfers of food and feed from local agriculture and the recycling of human and animal excretion. Spatial correction of P dynamics across the city showed that human density and associated infrastructure, especially asphalt, dominated the distribution of P pools across the landscape. Phosphorus fluxes were dominated by agricultural production, with agricultural soils accumulating P. Human features (infrastructure, technology, and waste management decisions) and biophysical characteristics (soil properties, water fluxes, and storage) mediated P dynamics in Phoenix. P cycling was most notably affected by water management practices that conserve and recycle water, preventing the loss of waterborne P from the ecosystem. P is not intentionally managed, and as a result, changes in land use and demographics, particularly increased urbanization and declining agriculture, may lead to increased losses of P from this system. We suggest that city managers should minimize cross-boundary fluxes of P to the city. Reduced P fluxes may be accomplished through more efficient recycling of waste, therefore decreasing dependence on external nonrenewable P resources and minimizing aquatic pollution. Our spatial approach and consideration of both pools and fluxes across a heterogeneous urban ecosystem increases the utility of nutrient budgets for city managers. Our budget explicitly links processes that affect P cycling across space with the management of other resources (e.g., water). A holistic management strategy that deliberately couples the management of P and other resources should be a priority for cities in achieving urban sustainability.

[1]  M. Batty The Size, Scale, and Shape of Cities , 2008, Science.

[2]  Robert D. Brown,et al.  Seasonal Trends in the Chemical Composition of Ten Range Plants in South Texas , 1985 .

[3]  Jessica R. Corman,et al.  Sustainability Challenges of Phosphorus and Food: Solutions from Closing the Human Phosphorus Cycle , 2011 .

[4]  U. Lohm,et al.  The flow of phosphorus in food production and consumption -- Linköping, Sweden, 1870-2000. , 2008, The Science of the total environment.

[5]  N. Grimm,et al.  Atmospheric deposition of carbon and nutrients across an arid metropolitan area. , 2008, The Science of the total environment.

[6]  Wen-Ching Chuang,et al.  Enhanced Classifications of Engineered Paved Surfaces for Urban Systems Modeling , 2009 .

[7]  N. Grimm,et al.  A distinct urban biogeochemistry? , 2006, Trends in ecology & evolution.

[8]  D. Schindler,et al.  Eutrophication science: where do we go from here? , 2009, Trends in ecology & evolution.

[9]  P. Sánchez,et al.  Soil Fertility and Hunger in Africa , 2002, Science.

[10]  D. Cordell,et al.  The story of phosphorus: Global food security and food for thought , 2009 .

[11]  J. Schepers,et al.  Nitrogen Deficiency Detection Using Reflected Shortwave Radiation from Irrigated Corn Canopies , 1996 .

[12]  P. Vitousek,et al.  Changing sources of nutrients during four million years of ecosystem development , 1999, Nature.

[13]  J. Silvertooth,et al.  Comparisons between an Upland and a Pima Cotton Cultivar: II. Nutrient Uptake and Partitioning , 1996 .

[14]  W. Hart,et al.  Watering the sun corridor : managing choices in Arizona's megapolitan area , 2011 .

[15]  Stephen Moore,et al.  Incorporating phosphorus management considerations into wastewater management practice , 2005 .

[16]  N. Grimm,et al.  Global Change and the Ecology of Cities , 2008, Science.

[17]  David Molden,et al.  Saving Water : From Field to Fork Curbing Losses and Wastage in the Food Chain , 2008 .

[18]  K. Nakajima,et al.  A Material Flow Analysis of Phosphorus in Japan , 2009 .

[19]  Erle C. Ellis,et al.  Putting people in the map: anthropogenic biomes of the world , 2008 .

[20]  Xuyong Li,et al.  Net Anthropogenic Phosphorus Accumulation in the Beijing Metropolitan Region , 2011, Ecosystems.

[21]  Jim Nilsson,et al.  A Phosphorus Budget for a Swedish Municipality , 1995 .

[22]  Tammo S. Steenhuis,et al.  MOBILITY AND SOLUBILITY OF TOXIC METALS AND NUTRIENTS IN SOIL FIFTEEN YEARS AFTER SLUDGE APPLICATION , 1997 .

[23]  J. Y. King,et al.  Effect of consumption choices on fluxes of carbon, nitrogen and phosphorus through households , 2007, Urban Ecosystems.

[24]  Nancy B. Grimm,et al.  The Urban Funnel Model and the Spatially Heterogeneous Ecological Footprint , 2001, Ecosystems.

[25]  P. Gober Metropolitan Phoenix: Place Making and Community Building in the Desert , 2005 .

[26]  L. Baker,et al.  Nitrogen Balance for the Central Arizona–Phoenix (CAP) Ecosystem , 2001, Ecosystems.

[27]  R. Antikainen,et al.  Nitrogen and Phosphorus Flows in the Finnish Agricultural and Forest Sectors, 1910–2000 , 2008 .

[28]  J. O. Drangert,et al.  Fighting the urine blindness to provide more sanitation options , 1998 .

[29]  W. Schlesinger,et al.  The Biogeochemistry of Phosphorus Cycling and Phosphorus Availability Along a Desert Soil Chronosequence , 1988 .

[30]  S Uhlenbrook,et al.  Eutrophication and nutrient release in urban areas of sub-Saharan Africa--a review. , 2010, The Science of the total environment.

[31]  S. Carpenter,et al.  Human Impact on Erodable Phosphorus and Eutrophication: A Global Perspective , 2001 .

[32]  H. Paerl,et al.  Controlling Eutrophication: Nitrogen and Phosphorus , 2009, Science.

[33]  Scott Elliott,et al.  ENERGY AND MATERIAL FLOW THROUGH THE URBAN ECOSYSTEM , 2000 .

[34]  Riina Antikainen,et al.  Flows of nitrogen and phosphorus in Finland—the forest industry and use of wood fuels , 2004 .

[35]  Robert J.P. Williams,et al.  The Natural Selection of the Chemical Elements: The Environment and Life's Chemistry , 1997 .

[36]  J. Schröder,et al.  Towards global phosphorus security: a systems framework for phosphorus recovery and reuse options. , 2011, Chemosphere.

[37]  P. Felker,et al.  Influence of phosphorus fertilizer and silviculture treatments on leaf and soil nitrogen and phosphorus concentrations in a matureProsopis glandulosa(mesquite) stand , 1997 .

[38]  Jakob Magid,et al.  Urban nutrient balance for Bangkok , 2001 .

[39]  J. Elser,et al.  Ecological Stoichiometry: The Biology of Elements from Molecules to the Biosphere , 2002 .

[40]  F. Chapin,et al.  Principles of Terrestrial Ecosystem Ecology , 2002, Springer New York.

[41]  David B. Lewis,et al.  Hierarchical regulation of nitrogen export from urban catchments: interactions of storms and landscapes. , 2007, Ecological applications : a publication of the Ecological Society of America.

[42]  Charles Q. Yang,et al.  Durable flame retardant finishing of the nylon/cotton blend fabric using a hydroxyl-functional organophosphorus oligomer , 2005 .

[43]  K. D. Fossum,et al.  Statistical summary of selected physical, chemical, and toxicity characteristics and estimates of annual constituent loads in urban stormwater, Maricopa County, Arizona , 1995 .

[44]  William C. Clark,et al.  1 Evaluating the Influence of Global Environmental Assessments 1 , 2006 .

[45]  C. Gries,et al.  Hierarchical Bayesian scaling of soil properties across urban, agricultural, and desert ecosystems. , 2008, Ecological applications : a publication of the Ecological Society of America.

[46]  J. Overpeck,et al.  Increasing Eolian Dust Deposition in the Western United States Linked to Human Activity , 2008 .

[47]  S. Carpenter,et al.  Global Consequences of Land Use , 2005, Science.

[48]  T. Painter,et al.  The ecology of dust , 2010 .