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| Oyarzún,Carlos E.; Huber,Anton. |
| Measuring nutrients fluxes in watersheds with different landuse is important for evaluating the effects of conversion of native forests to agricultural land, and for establishing guidelines for land management. Nitrogen (N) concentrations and fluxes were studied over a 12-month period in four watersheds in the Lake Rupanco basin in the Andean Cordillera and four watersheds located in the Lake Huillinco basin in the Coastal Cordillera of southern Chile. Two watersheds in either lake basins were covered mainly by native rainforests, and the other two had mixed landuse (livestock pastures, subsistence agriculture and shrub-pasture mixtures). In the Lake Rupanco area, the annual transport of NO3-N from forested and agricultural watersheds was 4.9 and 11.0 kg... |
| Tipo: Journal article |
Palavras-chave: Landuse; Native forest; Nitrogen fluxes; Non-point pollution. |
| Ano: 2003 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-66432003000100010 |
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| Hoch, Thierry. |
| This paper deals with a model of the pelagic ecosystem in the English Channel The model takes into account nitrogen biogeochemical cycle explicitly and indirectly phosphorus, silicon and carbon ones. The pelagic ecosystem is described precisely, on the one hand with the help of three phytoplanktonic compartments, and the other by considering the microbial food web. Primary production appears to be mainly controlled by stratification and turbidity, except in the Bay of Seine where high terrestrial nutrient inputs generate a sharp enrichment. Moreover, the model allows some general ecological conclusions to be drawn. From the simulation, it appears that inorganic nitrogen in the water column is mainly produced by an intense recycling. In accordance with in... |
| Tipo: Text |
Palavras-chave: Nitrogen fluxes; Primary production; Ecological model; English Channel; Flux d'azote; Production primaire; Modèle écologique; Manche. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/1998/publication-841.pdf |
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| Fouilland, Eric; Le Floc'H, Emilie; Brennan, Debra; Bell, Elanor M.; Lordsmith, Sian L.; Mcneill, Sharon; Mitchell, Elaine; Brand, Tim D.; Garcia-martin, E. Elena; Leakey, Raymond J. G.. |
| Recent observations in polar marine waters have shown that a large fraction of primary production may be lost to respiration by planktonic bacteria due to very low bacterial growth efficiencies in cold waters. Here we report that sea temperature may be a key factor influencing the interaction between bacteria and primary production in North Atlantic and Arctic waters, suggesting that low primary production rates could not sustain bacterial carbon demand in the coldest Arctic waters. The use of freshly produced phytoplankton exudate by bacteria in early- and mid-summer was assessed, together with the bacterial uptake of dissolved inorganic nitrogen (DIN = nitrate and ammonium), in surface waters along a latitudinal gradient from the North Sea to the Arctic... |
| Tipo: Text |
Palavras-chave: Carbon coupling; Arctic waters; Phytoplankton and bacteria interactions; Nitrogen fluxes. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00453/56417/58087.pdf |
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