Now showing items 61-80 of 80
Rodríguez Climent, Sílvia (Date of defense: 2014-12-05)
The Ebro Delta represents the most important wetland area in Catalonia, the second most important in Spain (after Doñana National Park) and one of the most important estuarine zones in Europe. Although relatively recently ...
Merbt, Stephanie Nikol (Date of defense: 2015-01-23)
The main goal of this PhD thesis was the study of the ammonium oxidation process in high nutrient loaded urban streams. We aimed to unveil regulating factors and driving mechanisms from the organisms to the ecosystem scales ...
Caballero Solares, Albert (Date of defense: 2015-03-04)
Si vol consolidar-se com a explotació econòmicament i ecològicament sostenible, la piscicultura ha de deslligar-se de la pesca mitjançant la reducció del contingut de farina de peix als pinsos. Aquesta fita pot ser assolida ...
Ribot Bermejo, Miquel (Date of defense: 2015-03-27)
Human activities have increased dissolved inorganic nitrogen (DIN) availability and modified the relative proportion of DIN as NO3- or NH4+ in running waters. Because nitrogen (N) is an essential element for in-stream ...
Roca Carceller, Guillem (Date of defense: 2015-07-06)
Nearshore marine ecosystems like seagrass meadows face a wide range of anthropogenic influences, impacting the system at different spatial and temporal scales. Managing these systems in the face of these pressures requires ...
Farina, Simone (Date of defense: 2015-07-10)
Many nearshore temperate coastal ecosystems are strongly regulated by top-down control. This is particularly true of shallow macrophyte communities, where habitat structuring is heavily dependent on the ability of predators ...
Sperlich, Dominik (Date of defense: 2015-07-24)
The Mediterranean Basin is a climate-change hotspot of the world. Predicted reductions in annual precipitation, increases in mean temperature, and increases in the variability and occurrence of extreme droughts and heat ...
Lupón i Navazo, Anna (Date of defense: 2015-11-16)
Riparian areas are recognized to be natural filters of nitrogen (N) because they can substantially diminish the N delivery from terrestrial to aquatic ecosystems. However, understanding the influence of riparian zones on ...
Arizmendi Mejía, Rosana (Date of defense: 2015-11-25)
Climate change, along with other anthropogenic pressures (e.g. water pollution, overfishing and habitat degradation), is severely impacting oceans around the world, producing important changes in its physical and biological ...
Miró Pastó, Alexandre (Date of defense: 2016-01-08)
Pyrenean high mountain lakes are naturally fishless due to natural barriers that have prevented the natural colonisation of fish species from lower streams. However, there have been numerous trout introductions to such ...
Tomlinson, Benjamin John (Date of defense: 2016-01-20)
The Systems Approach Framework (SAF) is a methodological framework designed to enhance the efficacy of human decision-making processes within social-ecological systems with regard to sustainability. The SAF was applied in ...
Nebra Costas, Alfonso (Date of defense: 2016-01-29)
The Ebro Delta-Estuary complex is one of the largest wetland areas in the western Mediterranean, and it is considered one of the most important estuarine zones in Europe. In 2013, the Ebro watershed, including its deltaic ...
Rodríguez Lozano, Pablo (Date of defense: 2016-01-29)
Wildfires are expected to increase in frequency and intensity because of climate change and changes in land use and management. In last decades, the research on fire effects on aquatic systems has grown, but it has been ...
Castro Català, Núria de (Date of defense: 2016-02-05)
Aquatic systems are under pressure from multiple stressors that affect the structure, the functioning, and the health of species, communities and ecosystems. One of the main human pressures affecting the Earth’s ecosystems ...
Restrepo Ortiz, Claudia Ximena (Date of defense: 2016-02-05)
The annual dynamics of three different ammonia-oxidizing archaea (AOA) ecotypes (amoA gene) and of the SAGMCG-1 (Nitrosotalea-like aquatic Thaumarchaeota) group (16S rRNA gene) were studied by newly designed specific primers ...
Ballesteros Larrotta, Tania Marcela (Date of defense: 2016-02-08)
The Gran Sabana (GS, Northern South America) is a humid savanna region (treeless savanna intermingled with forest patches) with a long history of vegetation changes under fire disturbances. A number of hypotheses seek to ...
Safont Crespo, Elisabet (Date of defense: 2016-02-09)
This thesis is aimed at the study of the flora and vegetation of the Guayana Highlands (GH), a set of -50 table mountains (called tepuis) located in the Guayana Shield of northern South America. Special emphasis is put on ...
Martínez Ricart, Aurora (Date of defense: 2016-04-08)
Habitats commonly occur as more or less interconnected patches constituting spatial heterogeneous mosaics. Connectivity and interactions among habitats can determine their functioning. Therefore, ecological patterns and ...
Gómez Gener, Lluís (Date of defense: 2017-02-10)
Inland waters are active components of the global carbon (C) cycle that transform, store and outgas more than half of the C they receive from adjacent terrestrial ecosystems. However, fundamental uncertainties regarding ...
Nikolakopoulou, Myrto-Georgia (Date of defense: 2021-01-29)
Freshwater degradation has been largely attributed to excess nutrient concentrations of anthropogenic origin. Freshwater degradation in combination with water scarcity are the reason of severe stress on water resources ...