Maintenance of terrestrial nutrient loss signatures during in-stream transport
Brookshire, E. N.
Valett, H. M.
MetadataShow full item record
Small streams account for the majority of channel length in river basins worldwide and are the primary conveyors of terrestrial nutrients to rivers and ultimately the oceans. The controls of stream nutrient fluxes, however, are debated. Classical models emphasize that nutrient transport in streams integrates nutrient cycling in the terrestrial watershed while others argue that in-stream processes control nutrient flux. Recent studies have shown that in-stream cycling can be important in determining downstream nutrient fluxes, but results have not been reconciled with mass-balance calculations at the small-watershed scale. Here we use a simple analytical framework to assess nutrient cycling in streams and show that, under most conditions, longitudinally static nutrient concentrations reflect in-stream biotic balance between uptake and regeneration and groundwater inputs. Using measures of nutrient concentrations in small streams across four biomes, we provide evidence for generality of biogeochemical steady state (inputs outputs) in stream ecosystems: overall, longitudinal profiles were. at for nitrogen and phosphorus and were similar in concentration to soil and ground waters. Deviation from. at longitudinal profiles was associated with seasonal or successional biomass growth and small groundwater inputs relative to in-stream sink strength. We conclude that streams tend strongly toward nutrient balance, allowing use of their chemistry as an integrated measure of terrestrial nutrient losses.
Showing items related by title, author, creator and subject.
An analysis of commercial vegetable farms in relation to sustainability in the uplands of Southeast Asia Poudel, D.; Midmore, David; Hargrove, W. (Great Britain: Elsevier Science Ltd., 1998)This paper examines the factors limiting vegetable crop yields in the uplands of Southeast Asia. A survey of farms and soil sampling conducted in the upper Manupali watershed, Mindinao, the Philippines found large differences ...
Delve, R.J. (Academy Science Publishers (ASP), A Division of the African Academy of Sciences (AAS), 2004)A workshop was held 11-16 February 1996 at CMRT, Egerton University to launch the Combating Nutrient Depletion (CND) theme of the Soil, Water, and Nutrient Management Program (SWNMP) of the CGIAR. The meeting at Egerton, ...
Rapid decay of dolichos [Lablab purpureus (L.) Sweet] residue leads to loss of nitrogen benefit to succeeding maize (Zea mays L.) Cheruiyot, E.K.; Mwonga, S.M.; Mumera, L.M.; Macharia, J.K.; Tabu, I.M.; Ngugi, J.G. (CSIRO Publishing, 2007)The legume dolichos [Lablab purpureus (L.) Sweet] has become a popular fallow cover crop in sub-Saharan Africa, intended to supply nitrogen to succeeding cereal crops. The objective of this study is to determine the rate ...