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Identifier

000305174

Title

Επίδραση της ατμοσφαιρικής εναπόθεσης αζώτου και φωσφόρου στη θαλάσσια παραγωγικότητα : μονοδιάστατη μελέτη του κρητικού πελάγους

Alternative Title

Impact of atmospheric deposition of nitrogen and phosphorius on the ocean productivity in the Cretan sea: A 1-d modelling study

Author

Χριστοδουλάκη, Σύλβια Νικολάου

Thesis advisor

Κανακίδου, Μαρία

Abstract

It has been realized that the atmospheric deposition of trace elements in the marine environment can influence considerably the conditions in oligotrophic seas as the Mediterranean and mainly her Eastern basin. Particular interest presents the deposition of elements such as nitrogen (main as nitrate, ΝΟ₃^-, and ammonium, NH₄⁺) and phosphorous (as phosphate, PO₄^-3), as they are essentially nutritious components for the growth of marine flora and fauna. The present study investigates the contribution of the atmosphere as source nutritious components (nitrogen and phosphor) for the marine ecosystem of the Cretan Sea and consequently the role that the atmosphere plays in the primary marine productivity. For this purpose, atmospheric deposition measurements of nitrogen and phosphorus over Crete Island in the East Mediterranean are coupled with the sea water observations of nutrient availability and chlorophyll-α in the Cretan Sea by the mean of a 1-dimensional ocean biogeochemical model. Firstly, the sensitivity of model is investigated by studying the effect of changing various parameters on the biomass of the pelagic organisms (phytoplankton, zooplankton and bacteria). Taking into account the atmospheric inputs, the 1-dimensional ecosystem model is firstly tuned to simulate the sea water observations in the Cretan sea. Then, the impact of the atmospheric inputs on the ocean productivity is evaluated, by additional sensitivity simulations to these inputs. Further analysis of the underlying biogeochemical dynamics with emphasis on primary production is performed. This analysis demonstrates that nitrogen and phosphorus atmospheric deposition is enhancing the marine primary productivity by 60% and chlorophyll-a by 90% in the Cretan Sea. The results are subject to uncertainties related to the model parameterizations and adopted parameters and the 1-d representation of the oceanic system.

Language

Greek

Subject

Cretan sea

atmospheric deposition

nitrogen

nutrients

ocean productivity

phosporous

Κρητικό πέλαγος

Πανεπιστήμιο Κρήτης. Διατριβές.

Πανεπιστήμιο Κρήτης. Τμήμα Χημείας Μεταπτυχιακές εργασίες.