TY - JOUR T1 - Carbon and nitrogen stoichiometry and nitrogen cycling rates in streams JF - Oecologia Y1 - 2004 A1 - W. K. Dodds A1 - Marti, E. A1 - Tank, J. A1 - Pontius, J.L. A1 - Hamilton, S.K. A1 - Grimm, N.B. A1 - W.B. Bowden A1 - W.H. McDowell A1 - Peterson, B.J. A1 - Valett, H.M. A1 - Webster, J.R. A1 - Gregory, S. KW - carbon KW - Carbon:Nitrogen ratio KW - nitrogen KW - stoichiometry KW - streams AB - Stoichiometric analyses can be used to investigate the linkages between N and C cycles and how these linkages influence biogeochemistry at many scales, from components of individual ecosystems up to the biosphere. N-specific NH4 + uptake rates were measured in eight streams using short-term 15N tracer additions, and C to N ratios (C:N) were determined from living and non-living organic matter collected from ten streams. These data were also compared to previously published data compiled from studies of lakes, ponds, wetlands, forests, and tundra. There was a significant negative relationship between C:N and N-specific uptake rate; C:N could account for 41% of the variance in N-specific uptake rate across all streams, and the relationship held in five of eight streams. Most of the variation in N-specific uptake rate was contributed by detrital and primary producer compartments with large values of C:N and small values for N-specific uptake rate. In streams, particulate materials are not as likely to move downstream as dissolved N, so if N is cycling in a particulate compartment, N retention is likely to be greater. Together, these data suggest that N retention may depend in part on C:N of living and non-living organic matter in streams. Factors that alter C:N of stream ecosystem compartments, such as removal of riparian vegetation or N fertilization, may influence the amount of retention attributed to these ecosystem compartments by causing shifts in stoichiometry. Our analysis suggests that C:N of ecosystem compartments can be used to link N-cycling models across streams. VL - 140 ER -