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Researchers from Sweden extrapolated the laboratory results from data collected from mineral weathering rates in the laboratory and in the field, with the field data having lower rates. Data from the Aitik site in northern Sweden was used as a model to investigate the scale-dependence of weathering rates.

Eutrophication problems in coastal and marine waters worldwide emphasize the significance, for the scientific community as well as the whole society, of relevant quantification of catchment-scale nitrogen transport from land to coast. Different catchment-scale nitrogen budget models use, and base management recommendations on, quite different process representations of and spatial resolution approaches to in-stream nitrogen attenuation. We compare three different spatial resolution approaches to modeling nitrogen loss rates in streams of the same drainage basin. Results show that commonly used spatial model aggregation may lead to artificial decrease of calibrated nitrogen loss rates with increasing stream depth (or flow), in addition to any such dependences that may prevail in independently measurable reality. Coastal nitrogen impact predictions and practical management implications of large-scale model aggregation of nitrogen attenuation rates may further differ considerably from those based on rates from finer resolution modeling or independent measurements. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the comment made by Richard B. Alexander and colleagues on the article "In-Stream Nitrogen Attenuation: Model-Aggregation Effects and Implications for Coastal Nitrogen Impacts," by A. Darracq and G. Destouni in a 2005 issue.