Tesis doctoral de Javier Marco Barba
We undertook a paleolimnological study on the holocene evolution of the albufera de Valencia, the largest coastal oligohaline lake in the iberian peninsula, enclosed in the albufera natural park. The lake has been the focus of many studies during the last century; however, the origin and the evolution of the lake remained unknown. Subfossil ostracod remains preserved in lake sediments were considered as the most suitable bioindicators owing to the significant relationships between the species distribution and shell chemistry (trace elements and isotopes) of ostracods and water physical and chemical variables. The paleolimnology of coastal lakes is a complex and difficult task; hence, prior to this we undertook a study to calibrate the euryhaline ostracod target species cyprideis torosa as a quantitative paleoenvironmental proxy. The results showed that the combination of both shell nodes and d18o provided an accurate quantitative model for salinity reconstruction. On the other hand, c. Torosa shell sr/ca was highly correlated with water sr/ca, allowing the possibility to reconstruct past water sr/ca in a quantitative manner. Additionally, we support the previous findings that d13cdic can be inferred from ostracod shell d13c. These results, together with classical paleoecological analyses and interpretations based on ostracod paleoassemblages and sediment characteristics were applied to study three sedimentary sequences from lake albufera of various lengths (850 cm, 240 cm and 63 cm). The longest two cores provided information about the main transgressive phases occurred during the mid to late holocene. However, a typical marine ostracod fauna was not recorded at a certain unit of the core, suggesting that the lake was not totally open to the sea during this period. The highest resolution of the shorter two cores, allowed to establish that the main desalinization of the albufera took place later than thought before, probably in the last quarter of the xixth century, when an important rice field expansion took place around the lake. The untreated sewage waters and the change of rice cultivation methods from surrounding towns increased the nutrient load onto the lake favoring a drastic eutrophication process during the mid to late xx century. The dense macrophyte cover disappeared from the lake by the end of 1960 resulting in marked sediment differences (disturbed and anoxic sediment layer). Furthermore, the uncontrolled spills from the nearby industries and probably also the increasing hunting activities since the beginning of the xixth century increased the heavy metals load remaining in the sediment.
Datos académicos de la tesis doctoral «Freshwater ostracods ecology and geochemistry as paleoenvironmental indicators in marginal marine ecosystems: a case of study, the albufera de Valencia«
- Título de la tesis: Freshwater ostracods ecology and geochemistry as paleoenvironmental indicators in marginal marine ecosystems: a case of study, the albufera de Valencia
- Autor: Javier Marco Barba
- Universidad: Universitat de valéncia (estudi general)
- Fecha de lectura de la tesis: 23/04/2010
Dirección y tribunal
- Director de la tesis
- María Rosa Miracle Solé
- Tribunal
- Presidente del tribunal: blas Valero garcés
- pere Anadón monzón (vocal)
- eduardo Vicente pedrós (vocal)
- (vocal)