Sediment size distribution and composition in a reservoir affected by severe water level fluctuations

  • The reservoir sediments are important sinks for organic carbon (OC), the OC burial being dependent on two opposite processes, deposition and mineralization. Hence factors such as severe water level fluctuations are expected to influence the rate of OC accumulation as they may affect both deposition and mineralization. The Barasona Reservoir has been historically threatened by siltation, whilst the use of water for irrigation involves a drastic decrease of the water level. In this context, we have studied the physical and chemical characteristics (grain size, major and minor elemental compositions, organic and inorganic carbon, and nitrogen) of the recent sediments of the Barasona Reservoir and the relationships among them in order to: a) elucidate the main processes governing OC accumulation, b) evaluate the rate of OC mineralization and c) approach the effect of drought on the sediment characteristics in this system. Our results indicated that Barasona sediments were dominated by fine silts (>60%) and clays (>20%), the mean particleThe reservoir sediments are important sinks for organic carbon (OC), the OC burial being dependent on two opposite processes, deposition and mineralization. Hence factors such as severe water level fluctuations are expected to influence the rate of OC accumulation as they may affect both deposition and mineralization. The Barasona Reservoir has been historically threatened by siltation, whilst the use of water for irrigation involves a drastic decrease of the water level. In this context, we have studied the physical and chemical characteristics (grain size, major and minor elemental compositions, organic and inorganic carbon, and nitrogen) of the recent sediments of the Barasona Reservoir and the relationships among them in order to: a) elucidate the main processes governing OC accumulation, b) evaluate the rate of OC mineralization and c) approach the effect of drought on the sediment characteristics in this system. Our results indicated that Barasona sediments were dominated by fine silts (>60%) and clays (>20%), the mean particle size decreasing from tail to dam. Desiccation increased particle sorting and size distribution became bimodal, but no effect on average size was observed. Attending to the composition, Barasona sediments were very homogeneous with low concentrations of nitrogen (TN) and phosphorus (<12 g kg(-1) dw and <0.6 g kg(-1) dw, respectively) and high concentration of OC (approximate to 36 kg(-1) dw). TN was negatively related to dry weight Sediment mixing due to drastic changes in water level may have favoured the observed homogeneity of Barasona sediments affecting carbon, major ions and grain size. The high amount of OC deposited in Barasona sediment suggested that the adsorption of OC onto fine particles was more important than in boreal lakes. The rate of oxygen consumption by wet sediment ranged from 2.26 to 3.15 mg O-2 m(-2) day(-1), values close to those compiled for Mediterranean running waters. (C) 2015 Elsevier B.V. All rights reserved.show moreshow less

Export metadata

Additional Services

Share in Twitter Search Google Scholar Statistics
Metadaten
Author:Pilar Lopez, José Andrés López-Tarazón, Joan P. Casas-Ruiz, Marcelo Pompeo, Jaime Ordonez, Isabel Munoz
DOI:https://doi.org/10.1016/j.scitotenv.2015.06.033
ISSN:0048-9697
ISSN:1879-1026
Pubmed Id:http://www.ncbi.nlm.nih.gov/pubmed?term=26105704
Parent Title (English):The science of the total environment : an international journal for scientific research into the environment and its relationship with man
Publisher:Elsevier
Place of publication:Amsterdam
Document Type:Article
Language:English
Year of first Publication:2016
Year of Completion:2016
Release Date:2020/03/22
Tag:Barasona reservoir; Drought; Grain-size; Organic carbon; Respiration rate; Sediment
Volume:540
Pagenumber:10
First Page:158
Last Page:167
Funder:Spanish Ministry of Economy and Competitiveness [2010 CSD2009 00065]; Secretary for Universities and Research of the Department of the Economy and Knowledge of the Autonomous Government of Catalonia; FPI predoctoral grant [BES-2012-059655]; Ebro Water Authorities
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Erd- und Umweltwissenschaften
Peer Review:Referiert