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Tesi etd-06262019-110154


Thesis type
Tesi di laurea magistrale
Author
FURIA, MARTA
URN
etd-06262019-110154
Title
CARBON CYCLE IN THE MEDITERRANEAN SEA: THE ROLE OF THE Dissolved Organic Matter
Struttura
BIOLOGIA
Corso di studi
BIOLOGIA MARINA
Commissione
relatore Dott.ssa Santinelli, Chiara
Parole chiave
  • heterotrophic prokaryotes
  • DOM
  • microbial loop
  • PARAFAC
  • parallel multifactorial analysis
  • fluorescence
  • absorption
  • CDOM
  • DOC
  • optical properties
  • thermoaline circulation
  • Mediterranean Sea
  • dissolved organic matter
Data inizio appello
15/07/2019;
Consultabilità
secretata d'ufficio
Data di rilascio
15/07/2022
Riassunto analitico
A different functioning of DOM dynamics and microbial loop has been observed in the western and eastern Mediterranean Sea.
DOM is a complex mixture of organic compounds that passes through a 0.2 μm filter.
A fraction of DOM (CDOM) is capable to absorb light in the visible and UV wavelengths. A fraction of CDOM emits part of the absorbed light in the form of fluorescence. DOM is mostly consumed by heterotrophic prokaryotes, starting the “microbial loop”, that can function as a link or a sink of C to the food web. Biological lability of DOM is defined by the time needed by heterotrophic prokaryotes to use it. Labile DOM compounds are immediately consumed; recalcitrant DOM compounds escape rapid microbial degradation and can therefore accumulate and be transported by water masses circulation.
The main results of these thesis suggested that the different DOM dynamics in the two basins of the Med Sea could be due to a change in DOM quality. DOM quality was investigated through DOM optical properties (absorption and fluorescence), which confirmed a change in DOM pool in the two basins. It has been observed a change in phytoplankton communities, which could be the responsible of the production of DOM with different chemical composition. Physical parameters are also involved in the different DOM dynamics in the two basins. In particular, photodegradation could transform DOM labile compounds into the recalcitrant ones, resulting in DOM accumulation in the eastern basin.
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