TY - JOUR
T1 - Nitrogen and phosphorus fluxes from watersheds of the northeast U.S. from 1930 to 2000
T2 - Role of anthropogenic nutrient inputs, infrastructure, and runoff
AU - Hale, Rebecca L.
AU - Grimm, Nancy
AU - Vörösmarty, Charles J.
AU - Fekete, Balazs
N1 - Publisher Copyright:
©2015. American Geophysical Union. All Rights Reserved.
PY - 2015/3/1
Y1 - 2015/3/1
N2 - An ongoing challenge for society is to harness the benefits of nutrients, nitrogen (N) and phosphorus (P), while minimizing their negative effects on ecosystems. While there is a good understanding of the mechanisms of nutrient delivery at small scales, it is unknown how nutrient transport and processing scale up to larger watersheds and whole regions over long time periods. We used a model that incorporates nutrient inputs to watersheds, hydrology, and infrastructure (sewers, wastewater treatment plants, and reservoirs) to reconstruct historic nutrient yields for the northeastern U.S. from 1930 to 2002. Over the study period, yields of nutrients increased significantly from some watersheds and decreased in others. As a result, at the regional scale, the total yield of N and P from the region did not change significantly. Temporal variation in regional N and P yields was correlated with runoff coefficient, but not with nutrient inputs. Spatial patterns of N and P yields were best predicted by nutrient inputs, but the correlation between inputs and yields across watersheds decreased over the study period. The effect of infrastructure on yields was minimal relative to the importance of soils and rivers. However, infrastructure appeared to alter the relationships between inputs and yields. The role of infrastructure changed over time and was important in creating spatial and temporal heterogeneity in nutrient input-yield relationships.
AB - An ongoing challenge for society is to harness the benefits of nutrients, nitrogen (N) and phosphorus (P), while minimizing their negative effects on ecosystems. While there is a good understanding of the mechanisms of nutrient delivery at small scales, it is unknown how nutrient transport and processing scale up to larger watersheds and whole regions over long time periods. We used a model that incorporates nutrient inputs to watersheds, hydrology, and infrastructure (sewers, wastewater treatment plants, and reservoirs) to reconstruct historic nutrient yields for the northeastern U.S. from 1930 to 2002. Over the study period, yields of nutrients increased significantly from some watersheds and decreased in others. As a result, at the regional scale, the total yield of N and P from the region did not change significantly. Temporal variation in regional N and P yields was correlated with runoff coefficient, but not with nutrient inputs. Spatial patterns of N and P yields were best predicted by nutrient inputs, but the correlation between inputs and yields across watersheds decreased over the study period. The effect of infrastructure on yields was minimal relative to the importance of soils and rivers. However, infrastructure appeared to alter the relationships between inputs and yields. The role of infrastructure changed over time and was important in creating spatial and temporal heterogeneity in nutrient input-yield relationships.
KW - nitrogen
KW - phosphorus
UR - http://www.scopus.com/inward/record.url?scp=84927615262&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84927615262&partnerID=8YFLogxK
U2 - 10.1002/2014GB004909
DO - 10.1002/2014GB004909
M3 - Article
AN - SCOPUS:84927615262
SN - 0886-6236
VL - 29
SP - 341
EP - 356
JO - Global Biogeochemical Cycles
JF - Global Biogeochemical Cycles
IS - 3
ER -