Abstract
We evaluated nitrogen (N) export for various catchments in the San Pedro River watershed of South-central Chile (39°20′ to 40°12′S) during the dry season (February to March). We measured concentrations and export of the various N species at 16 points from the Andean headwaters to the lowland portion of the watershed: eight main nested points along the main watershed and eight secondary points on tributaries. We expected that, given a downstream increase in pastureland and decrease in native pristine forest cover, inorganic forms of N (DIN) would increase downstream, while conversely, dissolved organic nitrogen (DON) would decrease compared with concentrations in the forested headwaters. Nitrogen concentrations did not show statistically significant differences among the nested catchments. However, there were statistically significant differences in N concentrations associated with land cover among the tributaries. The results suggest that in the presence of base flow, natural landscape properties (barren land, lakes and rivers), explained most of the spatial variation in the N exports, while anthropogenic disturbance was not detectable. There was a negative relationship between DIN export and the coverage of lakes and rivers, suggesting that lakes might be acting as N traps. On the other hand, DIN, DON and total N exports were positively associated to barren land. Total nitrogen export during this 60-day dry season was less than 20 kg km−2 and the annual export was not larger than 100 kg km−2. This study documents the as yet pristine conditions of rivers in southern Chile.
Similar content being viewed by others
References
APHA, AWWA, WEF (1995) Standard methods for the examination of water and wastewater, 19th edn. American Public Health Association, Washington
Biggs T, Dunne T, Martinelli L (2004) Natural controls and human impacts on stream nutrient concentrations in a deforested region of the Brazilian Amazon basin. Biogeochemistry 68:227–257
Borie G, Peirano P, Zunino H, Aguilera S (2002) N-pool in volcanic ash-derived soil in Chile and its changes in deforested sites. Soil Biol Biochem 34:1204–1206
Caraco N, Cole J, Likens G, Lovett G, Weathers K (2003) Variations in NO3− export from flowing waters of vastly different sizes: does one model fit all? Ecosystems 6:344–352
Compton JE, Church MR, Larned ST, Hogsett WE (2003) Nitrogen export from forested watersheds in the Oregon Coast Range: the role of N2-fixing red alder. Ecosystems 6:773–785
CONAF, CONAMA, and BIRF (CORPORACIÓN NACIONAL FORESTAL, COMISIÓN NACIONAL DEL MEDIO AMBIENTE, and BANCO INTERAMERICANO DE RECONSTRUCCIÓN Y FOMENTO) (1999) Proyecto Catastro y evaluación de los recursos vegetacionales nativos de Chile. Informe regional Décima región, 137 pp
Cuevas J, Soto D, Arismendi I, Pino M, Lara A, Oyarzún C (2006) Relating land cover to stream properties in southern Chilean watersheds: trade-off between geographic scale, sample size, and explicative power. Biogeochemistry 81:313–329
Di Castri F, Hajek ER (1976) Bioclimatología de Chile. Vicerrectoría Académica de la Universidad Católica de Chile, Santiago, 160 pp
Donoso C (1981) Tipos forestales de los bosques nativos de Chile. Investigación y Desarrollo Forestal. Documento de trabajo N°38. FAO: DP/CH/76/0003, Santiago, 81 pp
Donoso C (1993) Bosques templados de Chile y Argentina. Variación, Estructura y Dinámica. Ecología Forestal. Editorial Universitaria, Santiago
Galloway J, Aber J, Erisman J, Seitzinger S, Howarth R, Cowling E, Cosby J (2003) The nitrogen cascade. Bioscience 53:341–356
Godoy R, Paulino L, Oyarzún C, Boeckx P (2003) Depositación atmosférica de nitrógeno en el centro y sur de Chile. Un resumen. Gayana Bot 1:47–53
Guevara S, Oyarzún J, Maturana H (2006) Geoquímica de las aguas del río Elqui y de sus tributarios en el período 1975–1995: factores naturales y efecto de las explotaciones mineras en sus contenidos de Fe, Cu y As. Agric Téc 66:57–69
Hedin L, Armesto J, Johnson A (1995) Patterns of nutrient loss from unpolluted, oldgrowth temperate forests: evaluation of biogeochemical theory. Ecology 76:493–509
Hood E, Mark W, Cain N (2003) Landscape controls on organics and inorganic nitrogen leaching across an Alpine/Subalpine Ecotone, Green Lakes Valley, Colorado Front Range. Ecosystems 6:31–45
Lara A, Solari M, Rutherford P, Thiers O, Trecaman R (1999) Cobertura de la vegetación original de la ecoregión de los bosques Valdivianos en Chile hacia 1550. Informe Técnico del Contrato No FB49. Proyecto WWF-Universidad Austral de Chile, Valdivia, 32 pp
Lara A, Wolodarsky-Franke A, Aravena J, Cortés M, Fraver S, Silla F (2003) Fire regimes and forest dynamics in the lake region of south-central Chile. In: Veblen T, Baker W, Montenegro G, Swetnam T (eds) Fire and climatic change in temperate ecosystems of the western Americas (ecological studies). Springer, Berlin, pp 322–342
Lara A, Reyes R, Urrutia R (2006) Bosques Nativos. In: Instituto de Asuntos Públicos, Universidad de Chile (eds) Informe País. Estado del Medio Ambiente en Chile 2006. Ediciones LOM Santiago, Santiago, pp 127–139
Laugenie C (1982) La région des Lacs, Chili meridional. Recherche sur l’évolution géomorphologique d’un piémont glaciaire quaternaire andin, vols. 2. Thése de Doctorat, Université de Bordeaux III, 810 pp
Likens G, Bormann F (1995) Biogeochemistry of a forested ecosystem. 2nd edn. Springer, New York, 159 pp
Lovett G, Weathers K, Sobczak W (2000) Nitrogen saturation and retention in forested watersheds of the Catskill mountains, New York. Ecol Appl 10:73–84
McClain M, Boyer E, Dent L, Gergel S, Grimm N, Groffman P, Hart S, Harvey J, Johnston C, Mayorga E, McDowell W, Pinay G (2003) Biogeochemical hot spots and hot moments at the interface of terrestrial and aquatic ecosystems. Ecosystems 6:301–312
Montgomery D, Buffington J (1998) Channel processes, classification and response, Chapter 2. In: Naiman R, Bilby R (eds) River ecology and management: lessons from the Pacific Coastal Ecoregion. Springer, New York, pp 13–42
Oyarzún C, Huber A (2003) Nitrogen export from forested and agricultural watersheds of southern Chile. Gayana Bot 60:63–68
Oyarzún C, Godoy R, De Schrijver A, Staelens J, Lust N (2004) Water chemistry and nutrient budgets in an undisturbed evergreen rainforest of southern Chile. Biogeochemistry 71:107–123
Perakis S, Hedin L (2001) Fluxes and fates of nitrogen in soil of an unpolluted old-growth temperate forest, southern Chile. Ecology 82:2245–2260
Perakis S, Hedin L (2002) Nitrogen loss from unpolluted South American forests mainly via dissolved organic compounds. Nature 415:416–419
Pérez C, Hedin L, Armesto J (1998) Nitrogen mineralization in two unpolluted old-growth forests of contrasting biodiversity and dynamics. Ecosystems 1:361–373
Pérez C, Carmona M, Armesto J (2003) Non-symbiotic nitrogen fixation, net nitrogen mineralization and denitrification in evergreen forests of Chiloé island, Chile: A comparison with other temperate forests. Gayana Bot 60:25–33
Pezoa L (2003) Recopilación y análisis de la variación de las temperaturas (período 1965–2001) y las precipitaciones (período 1931–2001) a partir de la información de estaciones meteorológicas de Chile entre los 33° y 53° de latitud Sur. Forestry Engineering Thesis, Universidad Austral de Chile, Valdivia
Sokal R, Rohlf F (1995) Biometry, 3rd edn. W.H. Freeman and Company, New York
Soto D, Campos H (1995) Los lagos oligotróficos del bosque templado húmedo del sur de Chile. In: Armesto J, Villagrán C, Arroyo MTK (eds) Ecología de los bosques nativos de Chile. Editorial Universitaria, Santiago, pp 317–334
Strayer D, Beighley R, Thompson L, Brooks S, Nilsson C, Pinay G, Naiman R (2003) Effects of land cover on stream ecosystems: roles of empirical models and scaling issues. Ecosystems 6:407–423
Tosso J (1985) Suelos volcánicos de Chile. Ministerio de Agricultura. 1a edición. Instituto de Investigaciones Agropecuarias (INIA), Santiago, 723 pp
Van Bremen N (2002) Natural organic tendency. Nature 415:381–382
Vitousek P, Aber J, Howarth R, Likens G, Matson P, Schindler D, Schlesinger W, Tilman G (1997) Human alteration of the global N cycle: causes and consequences. Issues Ecol 1:1–16
Weathers K, Likens G (1997) Clouds in southern Chile: an important source of nitrogen to nitrogen-limited ecosystems? Environ Sci Technol 31:210–213
Weathers K, Lovett G, Likens G, Caraco N (2000) Cloudwater inputs of nitrogen to forest ecosystems in southern Chile: forms, fluxes, and sources. Ecosystems 3:590–595
Woelfl S, Villalobos L, Parra O (2003) Trophic parameters and method validation in Lake Riñihue (North Patagonia: Chile) from 1978 through 1997. Rev Chil Hist Nat 76:459–474
Zahradnik P (1981) Methods for chemical analysis of inland waters. Lecture notes for the international graduate training course on limnology. Limnologishes Institut. Österreichische Akademie der Wissenschaften, Vienna, Leaflet, 44 pp
Acknowledgments
We would like to thank the Scientific Millennium Initiative (project P01-057-F and P04-065-F) for funding this research; Gene Likens and Myrna Hall for their comments to this investigation; Eduardo Neira for his support in the preparation of the images and Brooke Penaluna for her support in the translation. We also thank the valuable comments from two anonymous reviewers.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Little, C., Soto, D., Lara, A. et al. Nitrogen exports at multiple-scales in a southern Chilean watershed (Patagonian Lakes district). Biogeochemistry 87, 297–309 (2008). https://doi.org/10.1007/s10533-008-9185-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10533-008-9185-8