Influences of climate, hydrology, and land use on input and export of nitrogen in California watersheds Export

@article{citeulike:4254227, abstract = {Human activities have greatly increased the input of biologically available nitrogen (N) from land-based sources to aquatic ecosystems; yet few studies have examined how human actions influence N export in regions with a strong seasonality in water availability. In this study, we quantified N inputs and outputs for 23 California watersheds and examined how climate, hydrology, and land use practices influenced watershed N export. N inputs ranged from 581 to 11,234 kg N km−2 year−1 among watersheds, with 80\% of total input for the region originating from agriculture (inorganic fertilizer, manure, and legumes). Of the potential N sources examined, mean annual concentrations of dissolved organic N and dissolved inorganic N in study rivers correlated most strongly with manure N input (r 2 = 0.54 and 0.53, respectively). Seasonal N export varied by basin and was correlated with climate, anthropogenic N inputs, and reservoir releases. Fractional export of watershed N inputs by study rivers annually was small (median of 8\%) and scaled exponentially with runoff (r = 0.66). Collectively, our results show that anthropogenic activities have altered both the magnitude and timing of watershed N export in California and suggest that targeted management in specific locations and times of the year could reduce N export to downstream systems in the region.}, author = {Sobota, Daniel J. and Harrison, John A. and Dahlgren, Randy A.}, citeulike-article-id = {4254227}, citeulike-linkout-0 = {http://dx.doi.org/10.1007/s10533-009-9307-y}, citeulike-linkout-1 = {http://www.springerlink.com/content/qvkx1m270704777q}, day = {25}, doi = {10.1007/s10533-009-9307-y}, issn = {1573-515X}, journal = {Biogeochemistry}, keywords = {-, agriculture, budget, california, climate, denitrification, mediterranean, nitrogen, nutrient, watershed}, month = {March}, number = {1}, pages = {43--62}, posted-at = {2009-06-30 12:40:43}, priority = {2}, title = {Influences of climate, hydrology, and land use on input and export of nitrogen in California watersheds}, url = {http://dx.doi.org/10.1007/s10533-009-9307-y}, volume = {94}, year = {2009} }

TY - JOUR ID - citeulike:4254227 L3 - citeulike-article-id:4254227 N2 - Human activities have greatly increased the input of biologically available nitrogen (N) from land-based sources to aquatic ecosystems; yet few studies have examined how human actions influence N export in regions with a strong seasonality in water availability. In this study, we quantified N inputs and outputs for 23 California watersheds and examined how climate, hydrology, and land use practices influenced watershed N export. N inputs ranged from 581 to 11,234 kg N km−2 year−1 among watersheds, with 80% of total input for the region originating from agriculture (inorganic fertilizer, manure, and legumes). Of the potential N sources examined, mean annual concentrations of dissolved organic N and dissolved inorganic N in study rivers correlated most strongly with manure N input (r 2 = 0.54 and 0.53, respectively). Seasonal N export varied by basin and was correlated with climate, anthropogenic N inputs, and reservoir releases. Fractional export of watershed N inputs by study rivers annually was small (median of 8%) and scaled exponentially with runoff (r = 0.66). Collectively, our results show that anthropogenic activities have altered both the magnitude and timing of watershed N export in California and suggest that targeted management in specific locations and times of the year could reduce N export to downstream systems in the region. IS - 1 JF - Biogeochemistry SN - 1573-515X EP - 62 TI - Influences of climate, hydrology, and land use on input and export of nitrogen in California watersheds VL - 94 SP - 43 KW - - KW - agriculture KW - budget KW - california KW - climate KW - denitrification KW - mediterranean KW - nitrogen KW - nutrient KW - watershed AU - Sobota, Daniel AU - Harrison, John AU - Dahlgren, Randy PY - 2009/03/25/ UR - http://dx.doi.org/10.1007/s10533-009-9307-y ER -