Richardson, C.J., and S. Qian. 1996. Long-term phosphorus assimilative capacity in freshwater wetlands:  A new paradigm for sustaining ecosystem structure and function. Environmental Science & Technology 33 (10):1545-1551.


Abstract.  Statistical analysis of a North American Wetland Database (NAWDB) allowed us to develop a mass loading model that was used to separate P assimilative capacity (defined as P absorption with no significant ecosystem change and no elevated P output) from storage capacity (Maximum storage) in wetlands.   Our analysis indicates that, given ample supplies of other nutrients, average P assimilative capacity (PAC) in North American wetlands is near 1 g m-2 yr-1.   From this analysis, we proposed a "One Gram Assimilative Capacity Rule" for P loadings within natural freshwater wetlands if long-term storage of P, maintenance of community structure and function, and low P effluent concentrations are required.   an Everglades test site supports our hypothesis that natural wetlands will lose native species, become P saturated in a few years, and export unacceptable amounts of phosphate when phosphorus loading exceeds PAC.  Moreover, our findings clearly demonstrate that even P-limited wetlands have the capacity to assimilate low levels of P loadings without significant changes in ecosystem structure and function.

Reproduced with permission from Environ. Sci. Technol. 1999, 33(10):1545-1551. 1999 American Chemical Society.

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