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Almería, Spain

Sanchez-Canete E.P.,EEZA CSIC | Sanchez-Canete E.P.,Centro Andaluz Of Medio Ambiente Ceama | Serrano-Ortiz P.,EEZA CSIC | Serrano-Ortiz P.,Centro Andaluz Of Medio Ambiente Ceama | And 4 more authors.
International Journal of Speleology | Year: 2013

Dynamics and drivers of ventilation in caves are of growing interest for different fields of science. Accumulated CO2 in caves can be exchanged with the atmosphere, modifying the internal CO2 content, affecting stalagmite growth rates, deteriorating rupestrian paintings, or creating new minerals. Current estimates of cave ventilation neglect the role of high CO2 concentrations in determining air density - approximated via the virtual temperature (Tv) -, affecting buoyancy and therefore the release or storage of CO2. Here we try to improve knowledge and understanding of cave ventilation through the use of Tv in CO2-rich air to explain buoyancy for different values of temperature (T) and CO2 content. Also, we show differences between T and Tv for 14 different experimental sites in the vadose zone, demonstrating the importance of using the correct definition of Tv to determine air buoyancy in caves. The calculation of Tv (including CO2 effects) is currently available via internet using an excel template, requiring the input of CO2 (%), air temperature (°C) and relative humidity (%). Source

Martinez-Padilla J.,CSIC - National Museum of Natural Sciences | Mougeot F.,EEZA CSIC | Garcia J.T.,IREC CSIC UCLM JCCM | Arroyo B.,IREC CSIC UCLM JCCM | Bortolotti G.R.,University of Saskatchewan
Journal of Raptor Research | Year: 2013

Most of our understanding of the function of colored traits displayed by birds and the mechanisms that produce or maintain them comes from studies on adults. However, colored traits are often displayed by nestlings from a young age, and these traits may influence parent-offspring interactions or sibling competition. The mechanisms that may mediate the expression of those traits during growth are still fairly unknown in raptors. In this study, we examined a possible mediating effect of corticosterone levels on the expression of carotenoid-pigmented traits in nestlings of Common Buzzards (Buteo buteo), specifically the yellow-orange coloration of their cere and legs. We assayed corticosterone levels deposited in feathers, which can provide a reliable and integrated index of stress responses during growth. Carotenoids can be used to color integuments, or diverted to other physiological processes involved in self-maintenance. We hypothesized that corticosterone levels mediate how carotenoids can be diverted to functions other than coloration. We show that carotenoid and corticosterone levels were positively associated, perhaps because of a higher metabolic activity in more-stressed nestlings. Corticosterone levels were negatively correlated with the coloration of cere and legs in females only. Altogether, our results support the hypothesis that corticosterone may influence how carotenoid pigments are allocated for needs other than coloration, although in a sex-specific manner. We encourage further studies exploring how individuals cope with and respond to stressful conditions, in order to better understand the complex interactions between corticosterone, carotenoids, and coloration during nestling growth. © The Raptor Research Foundation, Inc. Source

Martinez-Padilla J.,CSIC - National Museum of Natural Sciences | Redpath S.M.,University of Aberdeen | Zeineddine M.,University of Aberdeen | Mougeot F.,EEZA CSIC
Journal of Animal Ecology | Year: 2014

Long-term studies have been the backbone of population ecology. The red grouse Lagopus lagopus scoticus is one species that has contributed widely to this field since the 1950s. This paper reviews the trajectory and profound impact that these studies have had. Red grouse research has combined long-term studies of marked individuals with demographic studies over wide geographical areas and replicated individual- and population-level manipulations. A main focus has been on understanding the causes of population cycles in red grouse, and in particular the relative importance of intrinsic (behaviour) and extrinsic (climate, food limitation and parasite) mechanisms. Separate studies conducted in different regions initially proposed either the nematode parasite Trichostrongylus tenuis or changes in male aggressiveness in autumn as drivers of population cycles. More recent experiments suggest that parasites are not a necessary cause for cycles and have highlighted that behavioural and parasite-mediated mechanisms are interrelated. Long-term experiments show that parasites and aggressiveness interact. Two outstanding questions remain to be tested experimentally. First, what intrinsic mechanism causes temporal variation in patterns of male aggressiveness? The current favoured mechanism is related to patterns of kin structuring although there are alternative hypotheses. Second, how do the dual, interacting mechanisms, affect population dynamics? Red grouse studies have had an important impact on the field of population ecology, in particular through highlighting: (1) the impact of parasites on populations; (2) the role of intrinsic mechanisms in cyclic dynamics and (3) the need to consider multiple, interacting mechanisms. © 2013 British Ecological Society. Source

Miralles I.,EEZA CSIC | Piedra-Buena A.,CSIC - National Museum of Natural Sciences | Almendros G.,CSIC - National Museum of Natural Sciences | Gonzalez-Vila F.J.,CSIC - Institute of Natural Resources and Agriculture Biology of Seville | Gonzalez-Perez J.A.,CSIC - Institute of Natural Resources and Agriculture Biology of Seville
Journal of Analytical and Applied Pyrolysis | Year: 2015

Abstract Lignin markers in humic acids (HA, the alkali-soluble, acid-insoluble soil organic matter fraction) molecular features are explored to assess the extent to which plant biomacromolecules are progressively transformed by humification processes leading to stable C-forms in soils. Humic acids extracted from a collection of mountain calcimorphic soils from Sierra María-Los Vélez Natural Park (Southeastern Spain) under different use and management practices were studied in detail by visible and infrared (FT-IR) spectroscopies and analytical pyrolysis (Py-GC/MS). The HAs display a more or less marked lignin pattern defined by characteristic methoxyphenol assemblages released after pyrolysis that are associated to a typical infrared pattern including absorption frequencies bands at 1510, 1460, 1420, 1270, 1230 and 1030 cm-1. This variability in the HA spectroscopic and pyrolytic patterns was used as a source of molecular-level surrogates to establish the balance between complementary mechanisms of soil C sequestration i.e., a selective preservation of lignin associated to raw organic matter and other plant-inherited macromolecules, or alternative mechanisms involving microbial breakdown or plant precursors and its condensation with microbial metabolites. We found that HAs in which the lignin signature was comparatively less marked also show high optical density values suggesting unsubstituted, condensed aromatic units and a chaotic organic structure, pointing to the presence of highly resilient carbon forms. Upon analytical pyrolysis, one group of HAs produced major yields of methoxyl-lacking aromatics (alkylbenzenes and alkylphenols), and poor yields of alkyl compounds, which suggest efficient cleavage of biomacromolecules and the occurrence of active microbial synthesis and condensation processes. In fact, these HAs also displayed broadband IR spectra, and visible spectra showing high optical density and polynuclear quinoid chromophors considered of fungal origin. Other group of HAs yielded upon pyrolysis conspicuous series of methoxyphenols and well-defined alkyl series (alkanes, alkenes and fatty acids). The IR spectra also displayed clear lignin and amide bands, as well as intense 2920 cm-1 band and a low optical density, indicative of a marked aliphatic character. This latter is interpreted as the result of recent diagenetic alteration processes of young organic matter and suggests that C sequestration mechanisms in these soils are mainly based on the stabilization of HAs from plant biomacromolecules and aliphatic structures. These differential lignin alteration patterns indicate that HAs are responsive to soil C sequestration mechanisms, which in the studied soils seem to relay upon microtopographical features rather than to changes in soil use and management. © 2014 Elsevier B.V. Source

Mougeot F.,EEZA CSIC | Martinez-padilla J.,University of Aberdeen | Bortolotti G.R.,University of Saskatchewan | Webster L.M.I.,University of Aberdeen | Piertney S.B.,University of Aberdeen
Journal of Evolutionary Biology | Year: 2010

Vertebrates commonly use carotenoid-based traits as social signals. These can reliably advertise current nutritional status and health because carotenoids must be acquired through the diet and their allocation to ornaments is traded-off against other self-maintenance needs. We propose that the coloration more generally reveals an individual's ability to cope with stressful conditions. We tested this idea by manipulating the nematode parasite infection in free-living red grouse (Lagopus lagopus scoticus) and examining the effects on body mass, carotenoid-based coloration of a main social signal and the amount of corticosterone deposited in feathers grown during the experiment. We show that parasites increase stress and reduce carotenoid-based coloration, and that the impact of parasites on coloration was associated with changes in corticosterone, more than changes in body mass. Carotenoid-based coloration appears linked to physiological stress and could therefore reveal an individual's ability to cope with stressors. © 2009 The Authors. Journal Compilation © 2009 European Society For Evolutionary Biology. Source

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