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Identifier

000430839

Title

Διαχρονική μεταβολή οργανικού και ανόργανου φωσφόρου σε υγρή και ξηρή εναπόθεση στην Ανατολική Μεσόγειο

Alternative Title

Temporal variability of organic and inorganic phosphorus in wet and dry deposition in the Eastern Mediterranean

Author

Στάντσιου, Μαριθέα Ι.

Thesis advisor

Μιχαλόπουλος, Νικόλαος

Reviewer

Κανακίδου, Μαρία
Περγαντής, Σπυρίδων

Abstract

Atmospheric deposition is one of the most important sources of nutrients, especially in oligotrophic areas, such as the Mediterranean Sea. Τhe deposition of elements such as nitrogen (N), phosphorus (P) and iron (Fe), is of particular interest for the environment as these elements are necessary for the development of oceanic flora and fauna. As a result of this, it has been found that atmospheric deposition of trace elements can be an important factor that affects the productivity of oligotrophic seas, such as the Mediterranean Sea and especially its Eastern basin, which has been shown to have a limited amount of P. In order to observe the temporal variation of atmospheric soluble phosphorus deposition, measurements of total soluble phosphorus (TDP) and soluble inorganic phosphorus (DIP) were performed on samples of wet and dry deposition through spectrophotometric determination. The results enabled also the determination of the percentage contribution of soluble organic phosphorus (DOP) to TDP, which has been shown to be of importance for the bioavailabilit y of the element to the ecosystems and consequently for the productivity of the Mediterranean Sea. The sampling took place at Finokalia (Prefecture of Lasithi, Crete), a remote coastal area a nd in Heraklion (Crete), a large urban center in the Eastern Mediterranean Basin. It is noticeable that the analysis of the results has attributed a very large fraction of TDP to DOP during this specific study, suggesting that the main forms of phosphorus are organic. Therefore, unknown sources of organic phosphorus possibly exist, as suggested in a previous study, which supports the biological origin of the majority of phosphorus. In the present study, the factors that can affect the monthly variation of the concentrations and the fluxes of phosphorus in each region were discussed. Furthermore, of particular interest was the observation that the solubility of phosphorus increases with decreasing on rain water pH. Finally, the mechanisms of deposition of DIP are studied and the dominant deposition mechanism, which is dry deposition, is presented. As for the deposition of DOP, both deposition mechanisms (wet and dry) are equally important. Also, was presented the similar spatial variability in two sampling areas (Heraklion and Finokalia), which is prooved by data comparison.

Language

Greek

Subject

DIP

DOP

Phosphorus

Spectrophotometric determination method

TDP

Temporal variation

Διαχρονική διακύμανση

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