Phosphorus Mississippi River

But reduced energy use is only part of the story. Synthetic N, P, K are very soluble in water. This makes it easy for plants to use them, but synthetic fertilizer that is not taken up by the plants readily runs off or leaches out of the field into streams or into groundwater. The consequences have been serious. Excess nutrients in lakes and rivers cause algae to multiply and use up all the oxygen, resulting in death of fish and shellfish. Each summer, a 6,000-square-mile dead zone forms at the mouth of Mississippi River due to high levels of nitrogen and phosphorus drained from thousands of acres... 

Figure 11.7 Total particulate phase content of phosphorus [e.g., labile, Fe-P, organic P (Org-P), calcium phosphate (Ca-P), and detrital phosphorus (Detr-p)] in total suspended solids (TSS) (pg g-1 dry wt. TSS) in waters of the lower Mississippi River and inner Louisiana shelf, versus seasonal variability and increasing salinity. (Modified from Sutula et al 2004.)...

Sutula, M., Bianchi, T.S., and McKee, B. (2004) Effect of seasonal sediment storage in the lower Mississippi River on the flux of reactive particulate phosphorus to the Gulf of Mexico. Limnol. Oceanogr. 49, 2223-2235. 

MacRae M., Glover W., Ammerman J., Sada R., and Ruvalcaba B. (1994) Seasonal phosphorus deficiency in the Mississippi River Plume unusually large aerial extent during the record flood of 1993. EOS, Trans., AGU 75, 30. 

James, W. F., J. W. Barko, and H. L. Eakin. 1995. Internal phosphorus loading in Lake Pepin, upper Mississippi River. J. Freshwater Ecol. 10(3) 269-276. 

The range of riverine suspended particulate matter that may be solubilized once it enters the marine realm (e.g., the so-called reactive-F ) is derived from three sources. Colman and Holland (2000) estimate that 45% may be reactive, based on RSPM-P compositional data from a number of rivers and estimated burial efficiency of this material in marine sediments. Bemer and Rao (1994) and Ruttenberg and Canfield (1994) estimate that 35% and 31% of RSPM-P is released upon entering the ocean, based on comparison of RSPM-P and adjacent deltaic surface sediment phosphorus in the Amazon and Mississippi systems, respectively. Lower estimates have been published (8% Ramirez and Rose (1992) 18% Froelich (1988) 18% Compton et al. (2000). Higher estimates have also been published (69% Howarth et al. (1995). 

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