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Start Over Descriptor "allochthony" Journal ecohydrology
3 results on '"allochthony"'

1. Interplay between climate and hydrogeomorphic features and their effect on the seasonal variation of dissolved organic matter in shallow temperate lakes of the Southern Andes (Patagonia, Argentina): a field study based on optical properties.

Author

Soto Cárdenas, Carolina, Gerea, Marina, Garcia, Patricia E., Pérez, Gonzalo L., Diéguez, María C., Rapacioli, Raúl, Reissig, Mariana, and Queimaliños, Claudia

Subjects
GEOLOGY & climate, DISSOLVED organic matter, LAKES -- Environmental aspects, CARBON compound analysis, FIELD research
Abstract

This study analyses the effects of the interplay between climate seasonality and hydrogeomorphic (HGM) lake features on dissolved organic matter (DOM) properties in two neighbouring shallow lakes of Andean Patagonia with different connectivities. The survey was conducted over three years at the end of the wet and dry seasons, assessing the seasonal and interannual variation of dissolved organic carbon (DOC) concentration, whole-lake DOC mass, and DOM quality, through chromophoric and fluorescent DOM (CDOM and FDOM, respectively) properties. During the wet season (fall-winter), precipitation and runoff increased water discharge, water level, and inputs of terrestrial DOM with high aromaticity, humic content, and high molecular weight in both lakes. Contrastingly, during the dry season (spring-summer), in which photodegradation promoted by high irradiance and stagnant conditions drove DOM transformation, nonhumic, low-molecular-weight DOM prevailed. Both lakes displayed synchronicity in their DOC mass and CDOM and FDOM properties, indicative of similar responses to climate forcing, although the overall impact was modulated by their HGM features. Conversely, DOC concentration showed asynchronous responses between lakes, due to the higher intensity of the dilution or evapoconcentration processes in the connected lake, highlighting that DOC concentration is not always sensitive to climate-driven forces. Overall, this study emphasizes the importance of variables other than DOC concentration, like whole-lake DOC mass, DOM quality, and HGM features, to better understand the effect of climate variability on DOM dynamics. Our results allow inferring the potential impact of an environmental scenario characterized by lower precipitation and sustained warming on DOM dynamics in Northern Andean Patagonia. [ABSTRACT FROM AUTHOR]

Published
2017
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2. Trophic resources and emergent food web attributes in rivers of the Lake Victoria Basin: a review with reference to anthropogenic influences.

Author

Masese, Frank O. and McClain, Michael E.

Subjects
FOOD chains, ANTHROPOGENIC effects on nature, RIPARIAN ecology, ENVIRONMENTAL sciences
Abstract

ABSTRACT The ecology of Lake Victoria and rivers draining its 180 000 km2 basin has changed over the past century in response to growing anthropogenic influences that have altered basal resources, trophic status and interactions and river flow regimes. Impacts on the ecology of the lake are well known, but little attention has focused on the ecological status of rivers supplying ecological services to the majority of the basin's over 30 million inhabitants. In this paper, we review existing research on the ecological status of streams and rivers in the Lake Victoria Basin (LVB) and evaluate how they fit into emerging models of riverine ecosystem function in the tropics. Studies to date indicate that allochthonous sources dominate inputs to food webs in forested headwaters and savanna mid-reaches of rivers in the LVB, although transfer pathways vary with position in the river. Although riparian vegetation phenology and hydrologic run-off pathways control the spatial and temporal fluxes of energy inputs in headwater streams; animals play increasingly important roles in savanna mid-reaches. Over the last half century, food web studies have revealed widespread omnivory and a tendency toward increased omnivory among fishes whose diets were more specialized prior to the introduction of Lates niloticus and the ecological changes in the lake. Ecological patterns and processes in LVB rivers generally fit emerging models for the tropics, but studies completed to-date do not find autotrophic energy sources to be important. The findings of this review highlight the importance of specific management actions and needs for future research. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Published
2012
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3. Interplay between climate and hydrogeomorphic features and their effect on the seasonal variation of dissolved organic matter in shallow temperate lakes of the Southern Andes (Patagonia, Argentina): a field study based on optical properties

Author

Raúl Rapacioli, Mariana Reissig, Carolina Soto Cárdenas, Patricia Elizabeth Garcia, Marina Gerea, Gonzalo L. Pérez, Claudia Queimaliños, and María del Carmen Diéguez

Subjects
010504 meteorology & atmospheric sciences, Otras Ciencias Biológicas, ALLOCHTHONY, HYDROLOGICAL CONNECTIVITY, 010501 environmental sciences, Aquatic Science, 01 natural sciences, OPTICAL PROXIES, Ciencias Biológicas, NORTH ANDEAN PATAGONIAN LAKES, Dissolved organic carbon, Dry season, medicine, Temperate climate, Precipitation, Ecology, Evolution, Behavior and Systematics, PHOTODEGRADATION, 0105 earth and related environmental sciences, Earth-Surface Processes, Hydrology, Ecology, Seasonality, medicine.disease, Water level, HYDROGEOMORPHOLOGY, SEASONALITY, DISSOLVED ORGANIC MATTER, Colored dissolved organic matter, Environmental chemistry, Environmental science, Surface runoff, CIENCIAS NATURALES Y EXACTAS
Abstract

This study analyses the effects of the interplay between climate seasonality and hydrogeomorphic (HGM) lake features on dissolved organic matter (DOM) properties in two neighbouring shallow lakes of Andean Patagonia with different connectivities. The survey was conducted over three years at the end of the wet and dry seasons, assessing the seasonal and interannual variation of dissolved organic carbon (DOC) concentration, whole-lake DOC mass, and DOM quality, through chromophoric and fluorescent DOM (CDOM and FDOM, respectively) properties. During the wet season (fall–winter), precipitation and runoff increased water discharge, water level, and inputs of terrestrial DOM with high aromaticity, humic content, and high molecular weight in both lakes. Contrastingly, during the dry season (spring–summer), in which photodegradation promoted by high irradiance and stagnant conditions drove DOM transformation, nonhumic, low-molecular-weight DOM prevailed. Both lakes displayed synchronicity in their DOC mass and CDOM and FDOM properties, indicative of similar responses to climate forcing, although the overall impact was modulated by their HGM features. Conversely, DOC concentration showed asynchronous responses between lakes, due to the higher intensity of the dilution or evapoconcentration processes in the connected lake, highlighting that DOC concentration is not always sensitive to climate-driven forces. Overall, this study emphasizes the importance of variables other than DOC concentration, like whole-lake DOC mass, DOM quality, and HGM features, to better understand the effect of climate variability on DOM dynamics. Our results allow inferring the potential impact of an environmental scenario characterized by lower precipitation and sustained warming on DOM dynamics in Northern Andean Patagonia. Fil: Soto Cárdenas, Estela Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Gerea, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Garcia, Patricia Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Pérez, Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Dieguez, Maria del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Rapacioli, Raúl. Universidad Nacional del Comahue. Facultad de Ingeniería; Argentina Fil: Reissig, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Queimaliños, Claudia Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

Published
2017

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