Phytoplankton adaptation to marine ecosystems: insights into photophysiological functional diversity

Giovagnetti, Vasco (2011) Phytoplankton adaptation to marine ecosystems: insights into photophysiological functional diversity. [Tesi di dottorato] (Inedito)

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The aim of this study was to investigate the diversity of the photoprotective responses activated by phytoplankton at short temporal scales, i.e. the non-photochemical quenching of Chl a fluorescence (NPQ) associated with the xanthophyll cycle (XC) activity. In this work, we tested the hypothesis that the process of photoprotection, in terms of modulation, extent and efficiency, might be considered as a functional trait in phytoplankton. This ecophysiological work has been performed on four species belonging to the phylum of Stramenopiles. The ecological diversity has been taken into account by studying the photoresponses of species isolated either in surface or deeper water layers, as well as of species adapted to grow either in oceanic or coastal or upwelling ecosystems. Species distinct photoresponses have been also assessed in relation to cell size constraints, using one microplanktonic and three picoplanktonic species. The relation between phytoplankton ecophysiological functional diversity and ecological adaptation has been studied in three picoeukaryotes (< 3.0 μm) isolated from distinct ecosystems, through the analysis of the physiological response curves obtained by plotting a measured variable against a range of a factor (i.e. light) affecting that variable. The photophysiological flexibility as a functional trait has been discussed in relation to niche adaptation. Because of their peculiar set of biological and ecological features, related to their minute cell size, and because of their very narrow size range, picoeukaryotes are interesting model organisms to address (and answer) questions concerning the ecophysiology of algae. The integrative physiological processes (i.e. photoacclimation, photoregulation, photosynthesis, growth), which are in part activated or modified in relation to changing light conditions, have been deeply investigated in the microplanktonic coastal diatom, Pseudo-nitzschia multistriata (Bacillariophyceae). A great plasticity in functioning and regulation has been shown to characterize the photoprotective/photoacclimative processes (XC and NPQ) of this diatom, in agreement with its ecological properties.

Tipologia di documento:Tesi di dottorato
Altre informazioni:Dottorato svolto presso: Stazione Zoologica Anton Dohrn Laboratory of Ecology and Evolution of Plankton Villa comunale - 80121 – Napoli – Italy
Parole chiave:phytoplankton; picoeukaryotes; photoacclimation; xanthophyll cycle
Settori scientifico-disciplinari MIUR:Area 05 Scienze biologiche > BIO/04 FISIOLOGIA VEGETALE
Area 05 Scienze biologiche > BIO/07 ECOLOGIA
Area 05 Scienze biologiche > BIO/09 FISIOLOGIA
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Stato del full text:Accessibile
Data:30 Novembre 2011
Numero di pagine:264
Istituzione:Università di Napoli Federico II
Dipartimento o Struttura:Scienze della Terra
Stato dell'Eprint:Inedito
Scuola di dottorato:Scienze della terra
Denominazione del dottorato:Scienze e ingegneria del mare
Ciclo di dottorato:24
Numero di sistema:8905
Depositato il:14 Dicembre 2011 12:57
Ultima modifica:03 Maggio 2012 11:32

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