Schaefer, S.C. and Alber, M., 2007. Temperature controls a latitudinal gradient in the proportion of watershed nitrogen exported to coastal ecosystems. Biogeochemistry, 85: 333-346.
Schaefer, S.C. and Alber, M.A. 2007. Temporal and spatial trends in nitrogen and phosphorus inputs to the watershed of the Altamaha River, Georgia, USA. Biogeochemistry. 86(3):231-249. (DOI: 10.1007/s10533-007-9155-6)
Schaefer, S.C., Hollibaugh, J.T. and Alber, M., 2009. Watershed nitrogen input and riverine export on the west coast of the U.S. Biogeochemistry, 93(3): 219-233.
Water sampling station in the lower Ogeechee River, Georgia. Inset: GCE-LTER graduate student Sylvia Schaefer processing a water sample.
Riverine N export as a percentage of total input to watersheds of the eastern U.S. as a function of latitude. Calculations for "SCOPE" watersheds (diamonds) were done as part of the International Scope Nitrogen project (Boyer et al. 2002); calculations for southeastern watersheds (circles) were done by GCE investigators (Schaefer and Alber 2007). Solid line at approximately 38 degrees north latitude indicates a potential break point between northern and mid-Atlantic watersheds (blue symbols) and southeastern watersheds (red).
Adapted from Schaefer and Alber 2007