Now showing items 21-40 of 80
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 ...
Obrador Sala, Biel (Date of defense: 2009-06-03)
Las lagunas litorales son sistemas altamente dinámicos en los que la vegetación sumergida juega un papel estructural y funcional fundamental. En esta tesis se ha realizado una aproximación a la ecología funcional de una ...
Sabaté i Jorba, Santi (Date of defense: 1993-05-21)
L'objectiu general d'aquesta tesi queda emmarcat dins del coneixement del bosc mediterrani i en concret de l'alzinar. El que s'ha pretés és analitzar en el cas de l'alzina (Quercus ilex L.). 1) Com la disponibilitat d'aigua ...
Villamarín Flores, Christian Patricio (Date of defense: 2012-07-09)
En la presente tesis se muestrearon ríos sobre los 2000 msnm (ríos altoandinos tropicales) que se distribuyen en la amplia región de los Andes del Norte (Ecuador) y los Andes Centrales (Perú) en Sudamérica. El muestreo de ...
Martínez-Muñoz, Marco A. (Date of defense: 2012-06-06)
En la presente investigación, se estudió la estructura espacial de las asociaciones de peces demersales que forman parte de la captura incidental de la pesca de camarón, en el ecosistema costero del Golfo de Tehuantepec, ...
Sabater, Sergi (Date of defense: 1987-11-20)
La tesi que es presenta té un doble objectiu: descriure la composició i la dinàmica pigmentària de les poblacions bentòniques, i així mateix descriure les poblacions d'algues que es troben en el riu, analitzant la seva ...
Ballen Segura, Miguel Angel (Date of defense: 2012-09-14)
El comportamiento fagotrófico en especies fitoplanctónicas fue evaluado por medio de técnicas de análisis celular que permiten establecer patrones individuales de cada una de ellas. Primeramente, se calibró el contenido ...
Pretus Real, Joan Lluís (Date of defense: 1991-04-12)
Se ofrece una síntesis actualizada sobre la corología y ecología de los crustáceos epicontinentales (excepto ostrácodos) de las Baleares, y se revisan cuestiones de Biogeografía Ecológica e Histórica.<br/><br/>El tratamiento ...
Aranda Cirerol, Nancy (Date of defense: 2004-06-29)
La calidad del agua costera está siendo alterada por el incremento de los desechos propios de las actividades humanas; los nutrientes nitrógeno y fósforo generados por estas fuentes pueden acrecentar el desarrollo del ...
Soares Cunha, Eugenio Marco (Date of defense: 2005-03-11)
O<br/><br/>A análise da evolução costeira recente da região de Natal (Estado do Rio Grande do Norte - Brasil) é delineada nesta tese de doutorado que tem como objetivo primeiro fornecer subsídios à gestão ambiental desta ...
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 ...
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 ...
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 ...
Gaudes Saez, Ainhoa (Date of defense: 2011-07-07)
This thesis focuses on the study of the meiofaunal community in streams and rivers of the Mediterranean region. It approaches to a community level from a functional point of view, studying their response as a whole to ...
Ejarque Gonzalez, Elisabet (Date of defense: 2014-11-17)
Rivers play a key role in the global biogeochemical functioning, as they link the biogeochemical cycles of the terrestrial and oceanic systems. In the framework of the carbon cycle, streams and rivers receive dissolved ...
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 ...
Sanpera Calbet, Isis (Date of defense: 2014-04-11)
Streams are complex and highly diverse ecosystems. Within the stream network, headwater streams (1st to 3rd order) are highly important. Headwaters represent most of the total length, influence the structure and functioning ...
Romaní i Cornet, Anna M. (Date of defense: 1997-10-21)
Helerotrophic (cetoenzymatic and respiratory activities) and autotrophic (photosynthetic activity) metabolism on epilithic strearn biofilms have been measured, analyzed and studied in this thesis.<br/><br/>The main objective ...
Solà Ortega, Carolina (Date of defense: 2004-07-21)
L'abril de 1998, durant l'accident miner d'Aznalcóllar, més de 6 milions de m3 de llots i aigües àcides altament contaminades amb metalls pesants van ser vessats al riu Guadiamar (Sevilla), destruint els ecosistemes fluvials ...
Vázquez Garcia, Eusebi (Date of defense: 2013-10-11)
The studies presented in this thesis focus on the biogeochemistry of dissolved organic matter (DOM) in an intermittent stream in a Mediterranean climate zone, with great emphasis on extreme hydrologic events: floods and ...