Browsing by Author "Osses, Pablo"

Now showing 1 - 13 of 13
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    A Case Study on Fog/Low Stratus Occurrence at Las Lomitas, Atacama Desert (Chile) as a Water Source for Biological Soil Crusts
    (2018) Lehnert, Lukas W.; Thies, Boris; Trachte, Katja; Achilles, Sebastian; Osses, Pablo; Baumann, Karen; Schmidt, Jakob; Samolov, Elena; Jung, Patrick; Leinweber, Peter; Karsten, Ulf; Buedel, Burkhard; Bendix, Joerg
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    Los atrapanieblas del Santuario Padre Hurtado y sus proyecciones en el combate a la desertificación.
    (2000) Osses, Pablo; Schemenauer, Robert; Cereceda Troncoso, Pilar; Larrain Barros, Horacio; Correa, Cristobal
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    Biological soil crusts along a climatic gradient in Chile: Richness and imprints of phototrophic microorganisms in phosphorus biogeochemical cycling
    (2018) Baumann, Karen; Jung, Patrick; Samolov, Elena; Lehnert, Lukas W.; Buedel, Burkhard; Karsten, Ulf; Bendix, Joerg; Achilles, Sebastian; Schermer, Michael; Matus, Francisco; Oses, Romulo; Osses, Pablo; Morshedizad, Mohsen; Oehlschlaeger, Claudia
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    Climate and coastal low-cloud dynamic in the hyperarid Atacama fog Desert and the geographic distribution of Tillandsia landbeckii (Bromeliaceae) dune ecosystems
    (Springer, 2021) García B., Juan Luis; Lobos Roco, Felipe Andres; Schween, Jan H.; Río López, Camilo del; Osses, Pablo; Vives Ansted, Raimundo José; Pezoa Jadue, Mariana Ignacia; Siegmund, Alexander; Latorre H., Claudio; Alfaro, Fernando; Koch, Marcus A.; Loehnert, Ulrich
    Despite the extensive area covered by the coastal Atacama fog Desert (18-32 degrees S), there is a lack of understanding of its most notorious characteristics, including fog water potential, frequency of fog presence, spatial fog gradients or fog effect in ecosystems, such as Tillandsia fields. Here we discuss new meteorological data for the foggiest season (July-August-September, JAS) in 2018 and 2019. Our meteorological stations lie between 750 and 1211 m a. s. l. at two sites within the Cordillera de la Costa in the hyperarid Atacama (20 degrees S): Cerro Oyarbide and Alto Patache. The data show steep spatial gradients together with rapid changes in the low atmosphere linked to the advection of contrasting coastal (humid and cold) and continental (dry and warm) air masses. One main implication is that fog presence and fog water yields tend to be negatively related to both distance to the coast and elevation. Strong afternoon SW winds advect moisture inland, which take the form of fog in only about 6% of the JAS at 1211 m a. s. l., but 65% at 750 m a. s. l. on the coastal cliff. Although sporadic, long lasting fog events embrace well-mixed marine boundary layer conditions and thick fog cloud between 750 and 1211 m a. s. l. These fog events are thought to be the main source of water for the Tillandsia ecosystems and relate their geographic distribution to the lowest fog water yields recorded. Future climate trends may leave fog-dependent Tillandsia even less exposed to the already infrequent fog resulting in rapid vegetation decline.
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    La nube estratocúmulo en Tarapacá, Chile : validación de imágenes GOES mediante observación en tiempo real (17 al 26 de junio del año 2002).
    (2005) Osses, Pablo; Barria, Constanza; Farías Salvador, Martín; Cereceda Troncoso, Pilar
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    Pedogenic and microbial interrelations to regional climate and local topography : New insights from a climate gradient (arid to humid) along the coastal Cordillera of Chile
    (2018) Bernhard, Nadine; Moskwa, Lisa Marie; Schmidt, Karsten; Oeser, Ralf A.; Aburto, Felipe; Bader, Maaike Y.; Baumann, Karen; Von Blanckenburg, Friedhelm; Boy, Jens; Osses, Pablo
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    Soil bacterial community structure of fog-dependent Tillandsia landbeckii dunes in the Atacama Desert
    (Springer, 2021) Alfaro, Fernando D.; Manzano, Marlene; Almiray, Cristian; García B., Juan Luis; Osses, Pablo; Río López, Camilo del; Vargas Vásquez, Constanza Giovanna; Latorre H., Claudio; Koch, Marcus A.; Siegmund, Alexander; Abades, Sebastian
    The interplay between plants and soil drives the structure and function of soil microbial communities. In water-limited environments where vascular plants are often absent and only specialized groups of rootless plants grow, this interaction could be mainly asymmetric, with plants supporting nutrients and resources via litter deposition. In this study, we use observational approaches to evaluate the impact of local distribution of Tillandsia landbeckii across elevation on soil bacterial community structure and composition in the Atacama Fog Desert. Tillandsia landbeckii is a plant without functional roots that develops on meter-scale sand dunes and depends mainly on marine fog that transports resources (water and nutrients) from the Pacific Ocean. Our data show that soil bacterial abundance, richness, and diversity were significantly higher beneath T. landbeckii plants relative to bare soils. However, these differences were not significant across T. landbeckii located at different elevations and with different input of marine fog. On the other hand, bacterial community composition was significantly different with T. landbeckii plants across elevations. Further, samples beneath T. landbeckii and bare soils showed significant differences in bacterial community composition. Around 99% of all operational taxonomic units (OTUs) were recorded exclusively beneath T. landbeckii, and only 1% of OTUs were observed in bare soils. These findings suggest that the presence of T. landbeckii promotes significant increases in bacterial abundance and diversity compared with bare soils, although we fail to demonstrate that local-scale changes in elevation can affect patterns of soil bacterial diversity and abundance beneath T. landbeckii.
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    Spatial distribution and interannual variability of coastal fog and low clouds cover in the hyperarid Atacama Desert and implications for past and present Tillandsia landbeckii ecosystems
    (SPRINGER WIEN, 2021) del Rio, Camilo; Lobos Roco, Felipe; Latorre, Claudio; Koch, Marcus A.; Garcia, Juan Luis; Osses, Pablo; Lambert, Fabrice; Alfaro, Fernando; Siegmund, Alexander
    The hyperarid Atacama Desert coast receives scarce moisture inputs mainly from the Pacific Ocean in the form of marine advective fog. The collected moisture supports highly specialized ecosystems, where the bromeliad Tillandsia landbeckii is the dominant species. The fog and low clouds (FLCs) on which these ecosystems depend are affected in their interannual variability and spatial distribution by global phenomena, such as ENSO. Yet, there is a lack of understanding of how ENSO influences recent FLCs spatial changes and their interconnections and how these variations can affect existing Tillandsia stands. In this study, we analyze FLCs occurrence, its trends and the influence of ENSO on the interannual variations of FLCs presence by processing GOES satellite images (1995-2017). Our results show that ENSO exerts a significant influence over FLCs interannual variability in the Atacama at similar to 20 degrees S. Linear regression analyses reveal a relation between ENSO3.4 anomalies and FLCs with opposite seasonal effects depending on the ENSO phase. During summer (winter), the ENSO warm phase is associated with an increase (decrease) of the FLCs occurrence, whereas the opposite occurs during ENSO cool phases. In addition, the ONI Index explains up to similar to 50 and similar to 60% variance of the interannual FLCs presence in the T. landbeckii site during summer and winter, respectively. Finally, weak negative (positive) trends of FLCs presence are observed above (below) 1000 m a. s. l. These results have direct implications for understanding the present and past distribution of Tillandsia ecosystems under the extreme conditions characterizing our study area.
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    The distance to market effect on rural poverty in the Metropolitan Region of Santiago
    (PONTIFICIA UNIV CATOLICA CHILE, INST ESTUDIOS URBANOS TERRITORIALES, 2013) Perez, Rodrigo; Salazar, Alejandro; Foster, William; Osses, Pablo
    The national poverty headcount in Chile has declined considerably since 1990. In 2006, rural poverty rate fell below that of urban areas, due in part to population mobility. Rural areas, however, are still characterized by low educational levels and incomes, explained, in part, by low population density, remoteness to services, and limited access to markets for rural-produced products. This study finds that distance (measured as travel time) of rural populations to urban areas is associated with the incidence of poverty in rural communities after controlling for other factors. Using an econometric model based on geographical and socioeconomic information of the Metropolitan Region of Santiago, the study finds that poverty levels in census tracts increase with distance to Santiago, and, for a given distance, access to transportation reduces poverty, through a mitigation of the distance effect.
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    Understanding Fog and Dew Dynamics for Assessing Non-Rainfall Water Potential Uses in the Atacama
    (2023) Lobos Roco, Felipe Andrés; Suárez Poch, Francisco Ignacio; Aguirre Correa, Francisca; Keim Vera, Klaus Kurt; Aguirre, Ignacio; Vargas Vásquez, Constanza; Abarca Paredes, Francisco Andrés; Ramírez Reyes, Carla; Escobar Moragas, Rodrigo; Osses, Pablo; Río López, Camilo del
    In (semi-)arid regions, harvesting fog and dew can become a complementary solution to traditional water supply. In the Atacama region, a territory of key and water-dependent economic activities, both fog and dew are driven by the advection of marine moisture from the Pacific. Still, little is described regarding the dynamics and water potential of these events. In this study, we analyze the spatiotemporal variability of fog and dew in the Atacama Desert to assess the potential of non-rainfall atmospheric water harvesting. Our research strategy combines three methods to achieve a comprehensive understanding of these phenomena: a satellite-spatial analysis of fog and low cloud frequencies; a thermodynamic characterization of the fog cloud vertical structure; and an observational analysis of fog and dew water collection. Our findings reveal that fog is a regular phenomenon in the area, occurring from 3% to 20% of the year. We estimate that fog cloud reaches 50 km inland and up to ~1100 m ASL, covering a vast territory where it can be harvested. Fog and dew represent 72% and 28% of the total collected atmospheric water (~0.2 L m-2 day-1). Both fog and dew represent a complementary natural water source with multiple uses for local industries.
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    Understanding inland fog and dew dynamics for assessing potential non-rainfall water use in the Atacama
    (2024) Lobos Roco, Felipe Andrés; Suárez Poch, Francisco Ignacio; Aguirre Correa, Francisca; Keim, K.; Aguirre, I.; Vargas Vásquez, Constanza; Abarca, F.; Ramírez Reyes, Carla; Escobar Moragas, Rodrigo; Osses, Pablo; Río López, Camilo del; CEDEUS (Chile)
    In (semi-)arid regions, harvesting fog and dew can become a complementary solution to traditional water supply. In the Atacama region, a territory of key and water-dependent economic activities, both fog and dew are driven by the advection of marine moisture from the Pacific. Still, little is described regarding the dynamics and water potential of these events. In this study, we analyze the spatiotemporal variability of fog and dew in the Atacama Desert to assess the potential of non-rainfall atmospheric water harvesting. Our research strategy combines three methods to achieve a comprehensive understanding of these phenomena: a satellite-spatial analysis of fog and low cloud frequencies; a thermodynamic characterization of the fog cloud vertical structure; and an observational analysis of fog and dew water collection. Our findings reveal that fog is a regular phenomenon in the area, occurring from 3% to 20% of the year. We estimate that fog cloud reaches 50 km inland and up to ∼1100 m ASL, covering a vast territory where it can be harvested. Fog and dew represent 72% and 28% of the total collected atmospheric water (∼0.2 L m−2 day−1). Both fog and dew represent a complementary natural water source with multiple uses for local industries.
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    Vegetation growth and landscape genetics of Tillandsia lomas at their dry limits in the Atacama Desert show fine-scale response to environmental parameters
    (2020) Koch, Marcus A.; Stock, Clara; Kleinpeter, Dorothea; Río López, Camilo del; Osses, Pablo; Merklinger, Felix F.; Quandt, Dietmar; Siegmund, Alexander
    Ecosystem dry limits have been studied in the context of species biology, fitness, and interactions with biotic and abiotic parameters, but the interactive effects of these parameters remain underexplored. Therefore, information on the putative effects of global climate change on these ecosystems is often lacking.", "We analyzed the interplay between fine-scale landscape genetics and biotic and abiotic factors of terrestrial Tillandsia lomas in the hyperarid Atacama Desert, characterized by a fog-dependent vegetation type almost entirely dominated by one single vascular plant species.", "We showed that metapopulations of Tillandsia landbeckii are genetically connected over many hundreds of square kilometers, and despite having a large potential for clonal propagation, genetic diversity is regionally and locally structured. At the landscape level, genetic diversity correlates well with fitness parameters such as growth, flowering, and vegetation density. We also observed fine-scale correlation with a 3-D landscape model indicating a positive feedback with seasonal fog occurrence and availability. The various interactions of biotic and abiotic factors resulted in regular linear banding patterns of vegetation arranged orthogonally toward the landscape slope. Ex situ growth experiments indicated that T. landbeckii grows at optimal rates in this extreme hyperarid environment, and we can extrapolate mean biomass production for this ecosystem.", "Synthesis. Our results suggest that the unique ecosystem of terrestrial Tillandsia lomas in the hyperarid Atacama Desert is an evolutionarily balanced and fine-scaled system. The vegetation itself is composed of long-lived and persistent modules. We developed a descriptive model of the various interacting factors, thereby also highlighting the severe threat caused by global climate change potentially associated with fog disturbance patterns along the Chilean Pacific coast.