Àvila A., Rodà F. (2012) Changes in atmospheric deposition and streamwater chemistry over 25years in undisturbed catchments in a Mediterranean mountain environment. Science of the Total Environment. 434: 18-27.LinkDoi: 10.1016/j.scitotenv.2011.11.062
Surface water chemistry has changed in response to reduced atmospheric deposition of sulphur and acidity in many regions of Europe and North America. Most of these studies come from acidic or low-alkalinity surface waters under high acidic deposition. Mediterranean climates offer a different biogeochemical context, characterised by streamwaters of higher alkalinity and low acid inputs. In this paper, we use surveys of streamwater chemistry conducted in 1981-1984 and again in 2007 in the Montseny natural park (NE Spain) to test whether streamwaters of these well-buffered catchments respond to changes in atmospheric deposition, which has declined for S during the last decades in NE Spain while remaining about stable for nitrogen. The 23 sampled streams drained heathland, beech forests and evergreen oak forests in relatively undisturbed small catchments underlain by silicate bedrock. Bulk deposition of sulphate at Montseny decreased by 54% while nitrate bulk deposition increased (non-significantly) by 30% in this period. Total N deposition is estimated in the range 15-30kg Nha-1y-1 for NE Spain. This is well above threshold values (e.g. 10kg Nha-1y-1) reported as starting nitrogen saturation symptoms in forest ecosystems in Europe. Baseflow sulphate concentrations decreased on average by 47μeqL-1 or 29% of early 1980s concentrations. Baseflow mean nitrate concentrations increased significantly but only from 5.5 to 8.9μeqL-1. Thus, despite decades of high N deposition, these ecosystems appear to be still far from N saturation. Baseflow alkalinity and base cation concentrations increased substantially, probably a combined result of decreased S deposition, enhanced silicate weathering under current higher temperatures, reduced plant cation uptake as vegetation matures, and slightly drier conditions in the survey of 2007. Overall, these well-buffered catchments have shown sizable changes in baseflow chemistry in response to changed atmospheric deposition and other environmental changes. © 2011 Elsevier B.V.
Avila A, Rodà F (2011) Changes in atmospheric deposition and streamwater chemistry over 25 years in undisturbed catchments in a Mediterranean mountain environment. Science of the Total Environment doi: org/10.1016/j.scitotenv.2011.11.062.
Rodrigo A, Avila A, Rodà F (2003) The chemistry of precipitation, throughfall and stemflow in two holm oak (Quercus ilex L.) forests under a contrasted pollution environment in NE Spain. The Science of the Total Environment 305:195-205.
Avila A, Rodrigo A, Rodà F (2002) Nitrogen circulation in a Mediterranean holm oak forest, La Castanya, Montseny, northeastern Spain. Hydrology and Earth System Sciences 6:551-557.
Avila A, Rodà F (2002) Assessing decadal changes in rainwater alkalinity at a rural Mediterranean site in the Montseny Mountains (NE Spain). Atmospheric Environment 36:2881-2890.
Rodà F., Avila A., Rodrigo A. (2002) Nitrogen deposition in Mediterranean forests. Environmental Pollution. 118: 205-213.LinkDoi: 10.1016/S0269-7491(01)00313-X
Atmospheric deposition of inorganic nitrogen was studied at two forested sites in the Montseny mountains (northeast Spain), peripheral to the Barcelona conurbation, and at a nearby lowland town, using bulk deposition, wet-only deposition, throughfall, and dry deposition inferred from branch-washes and surrogate surfaces (metacrylate plates). Bulk deposition inputs of ammonium and nitrate did not show significant temporal trends over a 16-year period. Bulk inputs of inorganic N were moderate, ranging from 6 to 10 kg N ha-1 year-1 depending on the time period considered and the degree of site exposure to polluted air masses from the Barcelona conurbation. Large dry-sedimented particles played a minor role, since wet-only inputs were virtually identical to bulk inputs. On the contrary, branch- and plate-washes indicated substantial dry inputs of N gases and small particles. Total atmospheric deposition was estimated at 15-22 kg N ha-1 year-1, most of it being retained within the studied broadleaved evergreen forests. Ecosystem N availability is thus likely to be increasing in these forests. © 2002 Elsevier Science Ltd. All rights reserved.
Neal C, Avila A, Rodà F (1995) Modelling the long-term impacts of atmospheric pollution deposition and repeated forestry cycles on stream water chemistry for a holm oak forest in northeastern Spain. Journal of Hydrology 168:51-71.
Avila A, Bonilla D, Rodà F, Piñol J, Neal C (1995) Soil water chemistry in a holm oak (Quercus ilex L.) forest: inferences on biogeochemical processes for a montane Mediterranean area. Journal of Hydrology 166:15-35.
Piñol J, Terradas J, Rodà F, Avila A (1995) Using catchments of contrasting hydrological conditions to explore climate change effects on water and nutrient flows in mediterranean forests. In Moreno JM, Oechel WC (eds) Global change and mediterranean-type ecosystems. Springer, Nova York, pp. 371-385.
Rodà F, Bellot J, Avila A, Escarré A, Piñol J, Terradas J (1993) Saharan dust and the atmospheric inputs of elements and alkalinity to Mediterranean ecosystems. Water, Air and Soil Pollution 66:277-288.
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