Supplementary Figure 1. Variations in the concentration of GHGs (CH 4 and CO 2 ) in underground air relative to their local atmospheric levels for

Transcription

1 Supplementary Figure 1. Variations in the concentration of GHGs (CH 4 and CO 2 ) in underground air relative to their local atmospheric levels for the set of caves studied. These caves cover a wide latitudinal transect of Iberian Peninsula and with different environmental features. Points and denote cave air samples for each cave and correspond to the atmospheric air samples.

2 Supplementary Figure 2. Variations in carbon dioxide and radon concentrations in underground air from the Ojo Guareña cave system. Time series correspond to the dead-end gallery in the north-eastern sector (see Fig. 5 and the associated text) and are compared to the air temperature difference between the cave air and the exterior. When the temperature gradient is reversed, i.e., the outside air temperature is lower than the cave air temperature, this triggers a renewal process of underground air through advective forces, which causes depletion of both gases. Vertical dashed lines indicate the dates when spot air-samplings were conducted (see Fig. 3).

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4 Supplementary Figure 3. Spatial variation of air temperature, CO 2 concentration and the isotopic signal (δ 13 C[CO 2 ]) in underground air from a dynamically ventilated cave (Ojo Guareña, Spain). Sampling campaign of October 8, Length of scale bars is 50 metres. A: Detailed cross-sections of cave galleries in relation to surface geomorphology and the main entrances to the subterranean system (solid black line represents the studied galleries; the ends of these galleries continue with the rest of the subterranean system, which is not drawn; the dotted lines show the location of other cave levels). Data on air temperature, CO 2 concentration and δ 13 C[CO 2 ] signal in the atmosphere and soil air correspond to the main cave sectors (shaded rectangles). B: Spatial distribution of cave air temperature. C: Spatial distribution of CO 2. D: Spatial distribution of carbon isotopic signal (δ 13 C[CO 2 ]). CO 2 data come from the spot air-sampling during short surveys and the subsequently GHG analyses on lab using the CRDS technique. The spatial maps for each parameter were constructed using a geostatistical gridding based on an ordinary point kriging method, with a linear variogram model and without anisotropy constraints during interpolation (distance between estimated points ranges from 3 to 5 metres). The north-eastern gallery connected with the rest of the subterranean system is shown.

5 Geografic coordinates of cave entrance Morphometric data Climate: average annual data Sampling campaigns Cave latitude longitude altitude (m.a.s.l.) Host-rock Depth of the sampled area Length of the sampled area Total lenght Classification 11 T ( o C) Rain (mm) atmospheric CH 4 (ppb) Cave Soil conditions Cave conditions number samples T ( o C) CO 2 (ppm) δ 13 C-CO 2 ( ) CH 4 (ppb) CO 2 (ppm) δ 13 C-CO 2 ( ) CH 4 (ppb) Rn (Bq m -3 ) Castañar 1,2 39 o 38' 13'' N 5 o 25' 33'' W 590 Shales and greywackes with dolostones 15-55m (average 25 m) 650 m 2315 m Temperate with dry and hot summer 15, , , , Altamira 3,4 43 o 22' 40'' N 4 o 7' 6'' W 159 Dolomitized calcarenitic limestones 3 22 m (average 8 m) 220 m 270 m 13,9 1350, , , , Sidron 5,6 43 o 23'07'' N 5 o 19' 34'' W 167 Carbonate conglomerates and sandstones 5-35 m (average 23 m) 600 m 600 m 13, , , , Ojo Guareña 7 42 o 02' N 3 o 39' W 785 Limestones and dolomitic limestones 30-80m (average 52 m) 2,5 Km 110 Km 11, , , , Rull 8 38 o 48' 40'' N 0 o 10' 39'' W 476 Carbonate conglomerates 9-23 m (average 18 m) 46 m 46 m Temperate with dry or hot summer 15, , , , Ardales 9 36 o 52' 24'' N 4 o 49' 43'' W 565 Dolomite marbles with iron mineralitzations 7-40 m (average 30 m) 390 m 1577 m Temperate with dry or hot summer 17, , , , Pindal 10 43º 23' N 4º 30' W 24 Limestones m (averqage 40 m) 340 m 627 m 12, , , , Supplementary Table 1. Data summary of the main features of the studied caves, including geographic coordinates, host-rock type, dimensions and prevailing climate of surrounding area where caves area located. A detailed description and additional data are found at specific numbered references for each cave.

6 Supplementary references 1. Fernandez-Cortes, A. et al. Characterization of trace gases fluctuations on a low energy cave (Castañar de Ibor, Spain) using techniques of entropy of curves. Int. J. Climatol. 31, (2011). 2. Alonso-Zarza, A.M. et al. Structural and host rock controls on the distribution morphology and mineralogy of speleothems in the Castañar cave (Spain). Geol. Mag. 148, (2011). 3. Saiz-Jimenez, C. et al. Paleolithic art in peril: policy and science collide at Altamira Cave. Science 333, (2011). 4. Cuezva, S. et al. Short-term CO2(g) exchange between a shallow karstic cavity and the external atmosphere during summer: Role of the surface soil layer. Atmos. Environ. 45, (2011). 5. Rosas, A. et al. Paleobiology and comparative morphology of a late Neandertal sample from El Sidron, Asturias, Spain. Proc. Natl. Acad. Sci. USA. 103, (2006). 6. Lalueza-Fox, C. et al. Genetic evidence for patrilocal mating behavior among Neandertal groups. Proc. Natl. Acad. Sci. USA. 108, (2011). 7. Camacho, A.I. et al. Habitat constraints in epikarstic waters of an Iberian Peninsula cave system. Ann. Limnol.-Int. J. Limnol. 42, (2006). 8. De Carvalho, L. et al. Caracterización petrográfica y petrofísica de la roca encajante de la Cueva del Rull (Vall d'ebo, Alicante). Macla 17, (2013). 9. Fernandez-Cortes, A. et al. Detection of human induced environmental disturbances in a show cave. Environ. Sci. Poll. Res. 18, (2011). 10. Moreno, A. et al. A speleothem record of rapid climatic shifts during last glacial period from Northern Iberian Peninsula. Glob. Planet. Change 71, (2010). 11. AEMET-IM. Iberian Climate Atlas. Agencia Estatal de Metereologia (España), Instituto de Metereologia (Portugal). (2011).