Chapter 8Chapter 8

The Phosphorus CycleThe Phosphorus Cycle

© 2013 Elsevier, Inc. All rights reserved.From Fundamentals of Ecosystem Science, Weathers, Strayer, and Likens (eds).

Figure 8.1 An aerial photo of Lake 226 (Ontario, Canada), divided at the narrows by a nylon curtain and treated on one side (right in this photo) with carbon, nitrogen, and phosphorus, and on the other (left in this photo) with only carbon and nitrogen. The photo clearly shows the resulting algal blooms in the side where phosphorus was included in the fertilization mix. (From Schindler 1977.)

© 2013 Elsevier, Inc. All rights reserved.From Fundamentals of Ecosystem Science, Weathers, Strayer, and Likens (eds).

Figure 8.2 Summary of the phosphorus cycle in the modern world. Standing stocks in rocks given in billions of metric tonnes (petagrams); other fluxes and stocks given in millions of metric tonnes (teragrams). (Based on Cordell et al. 2009, MacDonald et al. 2011, and FAO 2007.)

© 2013 Elsevier, Inc. All rights reserved.From Fundamentals of Ecosystem Science, Weathers, Strayer, and Likens (eds).

Figure 8.3 Global distribution of world phosphate rock reserves (in billion metric tons, BMT). Blue indicates the assessment of USGS in 2009 and the purple indicates the adjustment made by Van Kauwenbergh (2010) after comprehensive analysis of available industry and government reports, gray literature, and published studies. It is important to note that a “reserve” is a geological deposit of a material that can be economically and legally extracted or produced at the time of the determination. The USGS has now adopted the new estimates in its official phosphate reports. (Reprinted from Elser and Bennett 2011.)

© 2013 Elsevier, Inc. All rights reserved.From Fundamentals of Ecosystem Science, Weathers, Strayer, and Likens (eds).

Figure 8.4 Phosphorus flows through the global food production and consumption system (in Mt/year). (From Cordell et al. 2009.)

© 2013 Elsevier, Inc. All rights reserved.From Fundamentals of Ecosystem Science, Weathers, Strayer, and Likens (eds).

Figure 8.5 Global map of agronomic P imbalances for the year 2000 expressed per unit of cropland area in each 0.5° grid cell. Inputs to each cell are fertilizers and manures applied. Outputs are crops harvested. The difference between inputs and outputs is the change-in-storage. The P surpluses and deficits shown here are each classified according to quartiles globally (0–25th, 25–50th, 50–75th, and 75–100th percentiles). (Reprinted from MacDonald et al. 2011.)

© 2013 Elsevier, Inc. All rights reserved.From Fundamentals of Ecosystem Science, Weathers, Strayer, and Likens (eds).

Figure 8.6 Reconstructions and projections of anthropogenic P delivered to the oceans. (From Filippelli 2008.)

© 2013 Elsevier, Inc. All rights reserved.From Fundamentals of Ecosystem Science, Weathers, Strayer, and Likens (eds).

Figure 8.7 Shifts in P pools and total quantity of P throughout the course of soil development. (Based on Walker and Syers 1976 and adapted by Vitousek et al. 2010.)

© 2013 Elsevier, Inc. All rights reserved.From Fundamentals of Ecosystem Science, Weathers, Strayer, and Likens (eds).

Figure 8.8 Soil P fractions measured across the Hawaiian archipelago chronosequence provided general support for the Walker and Syers model of the relative shifts in P pools during soil development. PCa = calcium

phosphates and PO = P bound to organic matter. (From Crews et al. 1995.)

© 2013 Elsevier, Inc. All rights reserved.From Fundamentals of Ecosystem Science, Weathers, Strayer, and Likens (eds).