Analysis of decadal time series in wet N concentrations at five rural sites in NE Spain

Avila A., Molowny-Horas R., Gimeno B.S., Peñuelas J. (2010) Analysis of decadal time series in wet N concentrations at five rural sites in NE Spain. Water, Air, and Soil Pollution. 207: 123-138.
Enllaç
Doi: 10.1007/s11270-009-0124-7

Resum:

Nitrogen emissions have grown in Spain during the last 15 years. As precipitation scavenges gases and aerosols from the atmosphere, an effect on rainwater concentrations can be expected. However, time-series studies on wet N concentrations in the Iberian Peninsula are very scarce. This paper aims to fill this gap by analysing weekly rainfall N concentrations at a set of rural sites in Catalonia (NE Spain) from 1995/1996 to 2007 and a forest site monitored from 1983 to 2007. The sites encompass a range of rural environments and climate conditions, from the inland pre-Pyrenees (Sort) to the Mediterranean coast (Begur) and from north (Sort and Begur) to central (Palautordera and La Castanya) and south Catalonia (La Senia). We found a 1-year cycle for concentrations of NH 4 + and NO 3 - whereby higher values were reached at the end of spring-early summer, except at the easternmost coastal site of Begur. Weekly NH 4 + concentrations decreased with time at all sites (except at La Senia) whilst NO 3 - concentrations increased at all sites during the same period. Rainfall SO 4 2- concentrations decreased with time at all sites. The opposite trends in NO 3 - and SO 4 2- concentrations determined a shift in the relative acid contribution of those anions during the 12-13-year period. To interpret the increasing trend, mean annual NO 3 - concentrations were regressed against NO 2 Spanish emissions and to some indicators of local anthropogenic activity. The increase at Sort and Palautordera showed good correlation with local anthropogenic indicators. Wet inorganic N deposition ranged between 4.2 and 6.7 kg ha -1 year -1. When including estimates of dry deposition, total annual deposition rose up to 10-20 kg ha -1 year -1, values that have been found to initiate adverse effects on Mediterranean-type forest ecosystems. © 2009 Springer Science+Business Media B.V.

Llegeix més

Patterns and controls of the variability of radiation use efficiency and primary productivity across terrestrial ecosystems

Garbulsky M.F., Peñuelas J., Papale D., Ardö J., Goulden M.L., Kiely G., Richardson A.D., Rotenberg E., Veenendaal E.M., Filella I. (2010) Patterns and controls of the variability of radiation use efficiency and primary productivity across terrestrial ecosystems. Global Ecology and Biogeography. 19: 253-267.
Enllaç
Doi: 10.1111/j.1466-8238.2009.00504.x

Resum:

Aim: The controls of gross radiation use efficiency (RUE), the ratio between gross primary productivity (GPP) and the radiation intercepted by terrestrial vegetation, and its spatial and temporal variation are not yet fully understood. Our objectives were to analyse and synthesize the spatial variability of GPP and the spatial and temporal variability of RUE and its climatic controls for a wide range of vegetation types. Location: A global range of sites from tundra to rain forest. Methods: We analysed a global dataset on photosynthetic uptake and climatic variables from 35 eddy covariance (EC) flux sites spanning between 100 and 2200 mm mean annual rainfall and between -13 and 26°C mean annual temperature. RUE was calculated from the data provided by EC flux sites and remote sensing (MODIS). Results: Rainfall and actual evapotranspiration (AET) positively influenced the spatial variation of annual GPP, whereas temperature only influenced the GPP of forests. Annual and maximum RUE were also positively controlled primarily by annual rainfall. The main control parameters of the growth season variation of gross RUE varied for each ecosystem type. Overall, the ratio between actual and potential evapotranspiration and a surrogate for the energy balance explained a greater proportion of the seasonal variation of RUE than the vapour pressure deficit (VPD), AET and precipitation. Temperature was important for determining the intra-annual variability of the RUE at the coldest energy-limited sites. Main conclusions: Our analysis supports the idea that the annual functioning of vegetation that is adapted to its local environment is more constrained by water availability than by temperature. The spatial variability of annual and maximum RUE can be largely explained by annual precipitation, more than by vegetation type. The intra-annual variation of RUE was mainly linked to the energy balance and water availability along the climatic gradient. Furthermore, we showed that intra-annual variation of gross RUE is only weakly influenced by VPD and temperature, contrary to what is frequently assumed. Our results provide a better understanding of the spatial and temporal controls of the RUE and thus could lead to a better estimation of ecosystem carbon fixation and better modelling. © 2009 Blackwell Publishing Ltd.

Llegeix més

Yields of SOA formation from oxidation of different BVOC . IAC

Jürgen W, Einhard K, Kiendler-Scharr A, Mentel T, Tillmann R, Hoffmann T, Hohaus T, Llusià J, Dal Maso M, Peñuelas J, Spindler C, Rudich Y, Uerlings R (2010) Yields of SOA formation from oxidation of different BVOC . IAC International Aerosol Conference Heklsinki proceedings.

El rol dels terpens en la competencia entre plantes invasores i natives a Hawai.

Sardans J, llusià J, Niinemets Ü, Owen S, Carnicer J, Rezende E, Peñuelas J (2010) El rol dels terpens en la competencia entre plantes invasores i natives a Hawai. UAB Divulga 05/2010.

Traces de metalls contaminants en biomasses, analitzades espectroscòpicament.

Sardans J, Peñuelas J, Montes F (2010) Traces de metalls contaminants en biomasses, analitzades espectroscòpicament. UAB Divulga 06/2010.

Trazas de metales contaminantes en biomasas, analizadas espectroscópicamente.

Sardans J, Peñuelas J, Montes F (2010) Trazas de metales contaminantes en biomasas, analizadas espectroscópicamente. UAB Divulga 06/2010.

Menys aigua, menys nutrients: el canvi climàtic en els nostres ecosistemes mediterranis.

Sardans J, Peñuelas J, Estiarte M (2010) Menys aigua, menys nutrients: el canvi climàtic en els nostres ecosistemes mediterranis. UAB Divulga 10/2010.

Menos agua, menos nutrientes: el cambio climático en los ecosistemas mediterráneos.

Sardans J, Peñuelas J, Estiarte M (2010) Menos agua, menos nutrientes: el cambio climático en los ecosistemas mediterráneos. UAB Divulga 10/2010.

Effects of AM mycorrhyzal symbiosis on plant isoprenoid prosduction in tomato (Lycopersicon esculentum) plants under drought conditions and fumigation with jasmonic acid. IPGSA Conference.

Asensio D, Rapparini F, Peñuelas J (2010) Effects of AM mycorrhyzal symbiosis on plant isoprenoid prosduction in tomato (Lycopersicon esculentum) plants under drought conditions and fumigation with jasmonic acid. IPGSA Conference. Universitat Rovira I Virgili, Tarragona 28 June-2 July 2010 -proceedings.

Deliciosa lliçó de vida.

Peñuelas J (2010) Deliciosa lliçó de vida. Mètode 67: 39.

Pàgines