Détail de l'auteur
Auteur Ruben Sommaruga |
Documents disponibles écrits par cet auteur (5)
Affiner la rechercheAttenuation of ultraviolet radiation in mountain lakes: Factors controlling the among- and within-lake variability / Isabelle Laurion in Limnology and oceanography, 45 (6) (2000)
Titre : Attenuation of ultraviolet radiation in mountain lakes: Factors controlling the among- and within-lake variability Type de document : Imprimé Auteurs : Isabelle Laurion ; Marc Ventura ; Jordi Catalán ; Roland Psenner (1950-) ; Ruben Sommaruga Année de publication : 2000 Article en page(s) : 1274-1288 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Enjeux de conservation des lacs d'altitude Résumé : High-altitude lakes are exposed to high fluence rates of solar ultraviolet radiation (UVR; 29–400 nm) and contain low concentrations of dissolved organic carbon (DOC). While in most lowland lakes, DOC can be used to predict UV transparency with sufficient accuracy, current models fail to estimate UVR in clear alpine lakes. In these lakes, phytoplankton may contribute significantly to the UV attenuation either as particles or as a source of chromophoric dissolved organic matter (CDOM) with distinctive properties. We investigated a series of 26 lakes in the Alps and Pyrenees, situated at elevations ranging from 422 to 2,799 m above sea level and having DOC concentrations ranging from 0.2 to 3.5 mg L−1. CDOM, as measured by the absorptivity of filtered lake water, explained most of the variability in the attenuation of underwater UVR among lakes (r2 = 0.94, P < 0.001). However, within-lake variation in the UV attenuation revealed a significant contribution from phytoplankton in deeper waters (UV attenuation increasing with chlorophyll a concentration; r2 = 0.97, P = 0.002), only apparent when DOC concentrations were low (∼0.3 mg L−1). The DOC-specific absorptivity (ag*) was also important for characterizing the optical conditions in this series of lakes. Epilimnetic values of ag* were significantly lower in lakes located at high elevations (with low allochthonous CDOM inputs from the catchment), compared to lakes surrounded by trees and meadows. Moreover, ag* was generally lower in surface waters than in deeper water layers, suggesting the influence of photobleaching on UV transparency. The slope S of the exponential regression between CDOM absorptivity and wavelength did not show clear patterns, such as found in marine systems, and often presented lower values in the epilimnetic waters (in association with lower ag*). Collectively, our results suggest that in transparent alpine lakes, the dynamics of the CDOM pool and phytoplankton production will have a strong effect on temporal changes in UV underwater attenuation. Lien pérenne : DOI : 10.4319/lo.2000.45.6.1274 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=150993
in Limnology and oceanography > 45 (6) (2000) . - 1274-1288Laurion, Isabelle, Ventura, Marc, Catalán, Jordi, Psenner, Roland (1950-), Sommaruga, Ruben 2000 Attenuation of ultraviolet radiation in mountain lakes: Factors controlling the among- and within-lake variability. Limnology and oceanography, 45(6): 1274-1288.Documents numériques
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Article (2000)URL
Titre : Climate warming increases vertical and seasonal water temperature differences and inter-annual variability in a mountain lake Type de document : Imprimé Auteurs : Georg H. Nierdrist ; Roland Psenner (1950-) ; Ruben Sommaruga Année de publication : 2018 Article en page(s) : 473-490 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Enjeux de conservation des lacs d'altitude
[LOTERRE-Biodiversité] Changement climatiqueRésumé : Lakes around the world are warming, but not all water layers are warming at the same rate, and some are even cooling. Most studies have focused on summer lake water surface temperatures or analyzed short-time series. Here, we analyze a 44-year time series of water temperature from nine depths in a small mountain lake using dynamic linear models and temporal trend decomposition. We observe a significant long-term warming trend, but this occurred only from August to December in all water layers. The lake warmed ca. twice as fast (0.23 °C decade−1) as the air, but warming of the epilimnion slowed down remarkably (from 0.65 to 0.10 °C per decade) after 1993, a consequence of changing stratification timing. Deeper water layers even cooled thereafter, pointing to a stronger isolation from surface layers, which were still warming over the whole study period. This differential warming of the lake was accompanied by significant shifts of lake freezing and thawing dates leading to shorter ice-cover periods (~ 5 days decade−1). As a result, the thermal Schmidt stability of the water column strengthened, but also temperature variance in the epilimnion increased significantly, together with increasing variance and extremes of local air temperature. Our results show a significant autumn/winter warming effect of lake water together with an increasing intensity of temperature fluctuations in this seasonally ice-covered mountain lake, suggesting that current broad scale estimates of climate change impacts on lakes, based on summer temperature measurements and surface layers, do not fully reflect the effect of climate change. Lien pérenne : DOI : 10.1007/s10584-018-2328-6 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=150995
in Climatic change > 151 (2018) . - 473-490Nierdrist, Georg H., Psenner, Roland (1950-), Sommaruga, Ruben 2018 Climate warming increases vertical and seasonal water temperature differences and inter-annual variability in a mountain lake. Climatic change, 151: 473-490.Documents numériques
Article (2018)URL
Titre : Dust inputs and bacteria infl uence dissolved organic matter in clear alpine lakes Type de document : Imprimé Auteurs : N. Mladenov ; Ruben Sommaruga ; R. Morales-Baquero ; Isabelle Laurion ; Lluis Camarero ; M. C. Diéguez ; A. Camacho ; A. Delgado ; O. Torres ; Z. Chen ; Marisol Felip ; I. Reche Année de publication : 2011 Article en page(s) : 405 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Enjeux de conservation des lacs d'altitude Résumé : Remote lakes are usually unaffected by direct human influence, yet they receive inputs of atmospheric pollutants, dust, and other aerosols, both inorganic and organic. In remote, alpine lakes, these atmospheric inputs may influence the pool of dissolved organic matter, a critical constituent for the biogeochemical functioning of aquatic ecosystems. Here, to assess this influence, we evaluate factors related to aerosol deposition, climate, catchment properties, and microbial constituents in a global dataset of 86 alpine and polar lakes. We show significant latitudinal trends in dissolved organic matter quantity and quality, and uncover new evidence that this geographic pattern is influenced by dust deposition, flux of incident ultraviolet radiation, and bacterial processing. Our results suggest that changes in land use and climate that result in increasing dust flux, ultraviolet radiation, and air temperature may act to shift the optical quality of dissolved organic matter in clear, alpine lakes. Lien pérenne : DOI : 10.1038/ncomms1411 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=150988
in Nature communications > 2 (2011) . - 405Mladenov, N., Sommaruga, Ruben, Morales-Baquero, R., Laurion, Isabelle, Camarero, Lluis, Diéguez, M. C., Camacho, A., Delgado, A., Torres, O., Chen, Z., Felip, Marisol, Reche, I. 2011 Dust inputs and bacteria infl uence dissolved organic matter in clear alpine lakes. Nature communications, 2: 405.Documents numériques
Article (2011)URL
Titre : Lakes as sentinels of climate change Type de document : Imprimé Auteurs : Rita Adrian ; Catherine M. O'Reilly ; Horacio Zagarese ; Stephen B. Baines ; Dag O. Hessen ; Wendel Keller ; David M. Livingstone ; Ruben Sommaruga ; Dietmar Straile ; Ellen Van Donk ; Gesa A. Weyhenmeyer ; Monika Winder Année de publication : 2009 Article en page(s) : 2283-2297 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Enjeux de conservation des lacs d'altitude
[LOTERRE-Biodiversité] Changement climatiqueRésumé : While there is a general sense that lakes can act as sentinels of climate change, their efficacy has not been thoroughly analyzed. We identified the key response variables within a lake that act as indicators of the effects of climate change on both the lake and the catchment. These variables reflect a wide range of physical, chemical, and biological responses to climate. However, the efficacy of the different indicators is affected by regional response to climate change, characteristics of the catchment, and lake mixing regimes. Thus, particular indicators or combinations of indicators are more effective for different lake types and geographic regions. The extraction of climate signals can be further complicated by the influence of other environmental changes, such as eutrophication or acidification, and the equivalent reverse phenomena, in addition to other land-use influences. In many cases, however, confounding factors can be addressed through analytical tools such as detrending or filtering. Lakes are effective sentinels for climate change because they are sensitive to climate, respond rapidly to change, and integrate information about changes in the catchment. Lien pérenne : DOI : 10.4319/lo.2009.54.6_part_2.2283 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=147804
in Limnology and oceanography > 54 (6-2) (November 2009) . - 2283-2297Adrian, Rita, O'Reilly, Catherine M., Zagarese, Horacio, Baines, Stephen B., Hessen, Dag O., Keller, Wendel, Livingstone, David M., Sommaruga, Ruben, Straile, Dietmar, Van Donk, Ellen, Weyhenmeyer, Gesa A., Winder, Monika 2009 Lakes as sentinels of climate change. Limnology and oceanography, 54(6-2): 2283-2297.Documents numériques
Article (2009)URL
Titre : Scientists' warning of threats to mountains Type de document : Imprimé Auteurs : Dirk S. Schmeller ; Davnah Urbach ; Kieran A. Bates ; Jordi Catalán ; Dan Cogălniceanu ; Matthew C. Fisher ; Jan Friesen ; Leopold Füreder ; Veronika Gaube ; Marilen Haver ; Dean Jacobsen ; Gaël Le Roux (1978-) ; Yu-Pin Lin ; Adeline Loyau ; Oliver Machate ; Andreas Mayer ; Ignacio Palomo ; Christoph Plutzar ; Hugo Sentenac ; Ruben Sommaruga ; Rocco Tiberti ; William Ripple Année de publication : 2022 Article en page(s) : 158611 Langues : Anglais (eng) Catégories : [LOTERRE-Biodiversité] Montagne
[LOTERRE-Biodiversité] Changement climatique
[LOTERRE-Biodiversité] Relation homme-environnement
[CBNPMP-Thématique] Enjeux de conservation des lacs d'altitudeRésumé : Mountains are an essential component of the global life-support system. They are characterized by a rugged, heterogenous landscape with rapidly changing environmental conditions providing myriad ecological niches over relatively small spatial scales. Although montane species are well adapted to life at extremes, they are highly vulnerable to human derived ecosystem threats. Here we build on the manifesto ‘World Scientists' Warning to Humanity’, issued by the Alliance of World Scientists, to outline the major threats to mountain ecosystems. We highlight climate change as the greatest threat to mountain ecosystems, which are more impacted than their lowland counterparts. We further discuss the cascade of “knock-on” effects of climate change such as increased UV radiation, altered hydrological cycles, and altered pollution profiles; highlighting the biological and socio-economic consequences. Finally, we present how intensified use of mountains leads to overexploitation and abstraction of water, driving changes in carbon stock, reducing biodiversity, and impacting ecosystem functioning. These perturbations can provide opportunities for invasive species, parasites and pathogens to colonize these fragile habitats, driving further changes and losses of micro- and macro-biodiversity, as well further impacting ecosystem services. Ultimately, imbalances in the normal functioning of mountain ecosystems will lead to changes in vital biological, biochemical, and chemical processes, critically reducing ecosystem health with widespread repercussions for animal and human wellbeing. Developing tools in species/habitat conservation and future restoration is therefore essential if we are to effectively mitigate against the declining health of mountains. Lien pérenne : DOI : 10.1016/j.scitotenv.2022.158611 / HAL : hal-03795426v1
Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=152131
in Science of the total environment > 853 (20 December 2022) . - 158611Schmeller, Dirk S., Urbach, Davnah, Bates, Kieran A., Catalán, Jordi, Cogălniceanu, Dan, Fisher, Matthew C., Friesen, Jan, Füreder, Leopold, Gaube, Veronika, Haver, Marilen, Jacobsen, Dean, Le Roux, Gaël (1978-), Lin, Yu-Pin, Loyau, Adeline, Machate, Oliver, Mayer, Andreas, Palomo, Ignacio, Plutzar, Christoph, Sentenac, Hugo, Sommaruga, Ruben, Tiberti, Rocco, Ripple, William 2022 Scientists' warning of threats to mountains. Science of the total environment, 853: 158611.Documents numériques
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Article (2022)URL
