Ecological Archives E087-098-A1

Michael J. Vanni, Anna M. Bowling, Elizabeth M. Dickman, R. Scott Hale, Karen A. Higgins, Martin J. Horgan, Lesley B. Knoll, William H. Renwick, and Roy A. Stein. 2006. Nutrient cycling by fish supports relatively more primary production as lake productivity increases. Ecology 87:1696–1709.

Appendix A. Equations used to estimate N and P excretion rates of gizzard shad.

Excretion rates were directly quantified in the lakes in the months indicated, as described in the source references. Pexc = P excretion rate (µg P excreted·fish-1·h-1), Nexc = N excretion rate (µg N excreted·fish-1·h-1), M = fish body mass (g wet mass).

Lake and date

P excretion rate

N excretion rate

Source

       

Burr Oak, July 1999

log Pexc = 1.626 + 0.673log M

log Nexc = 2.393 + 0.647logM

1

Burr Oak, June 2000

log Pexc = 1.573 + 0.675log M

log Nexc = 2.470 + 0.714logM

1

Burr Oak, July 2001

log Pexc = 1.505 + 0.715log M

log Nexc = 2.617 + 0.379logM

1

       

Pleasant Hill, July 1999

log Pexc = 1.502 + 0.687log M

log Nexc = 2.430 + 0.561logM

1

Pleasant Hill, June 2000

log Pexc = 0.902 + 0.971log M

log Nexc = 2.647 + 0.521logM

1

Pleasant Hill, July 2001

log Pexc = 1.317 + 0.747log M

log Nexc = 2.206 + 0.452logM

1

       

Acton, June 1994

log Pexc = 1.358 + 0.816log M

log Nexc = 1.914 + 0.887logM

2

Acton, August 1994

log Pexc = 0.988 + 0.877log M

log Nexc = 1.991 + 0.845logM

2

Acton, July 1999

log Pexc = 1.732 + 0.499log M

log Nexc = 2.173 + 0.675logM

1

Acton, June 2000

log Pexc = 1.384 + 0.689log M

log Nexc = 2.480 + 0.640logM

1

Acton July 2001

log Pexc = 1.164 + 0.905log M

log Nexc = 1.738 + 0.738logM

1

1 Higgins, K. A., M. J. Vanni, and M. J. González. In press. Detritivory and the stoichiometry of nutrient cycling by a dominant fish species in lakes of varying productivity. Oikos.

2 Schaus, M. H., M. J. Vanni, T. E. Wissing, M. T. Bremigan, J. E. Garvey, and R. A. Stein. 1997. Nitrogen and phosphorus excretion by detritivorous gizzard shad in a reservoir ecosystem. Limnology and Oceanography 42:1386–1397.



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