Slāpekļa un fosfora plūsmu modelēšana Rīgas līča sedimentos
Date
2012
Authors
Lavrinovičs, Aigars
Journal Title
Journal ISSN
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Publisher
Latvijas Universitāte
Abstract
Maģistra darbā „Slāpekļa un fosfora plūsmu modelēšana Rīgas līča sedimentos” apskatīta slāpekļa un fosfora aprite Baltijas jūrā un Rīgas līcī, kā arī šo elementu plūsmu modelēšanā izmantojamie bioģeoķīmiskie modeļi.
Darba izstrādes gaitā modelētas fosfātu, amonija un nitrātu plūsmas, transformācija un zudums Rīgas līča dziļūdens slānī. Minēto procesu modelēšanā izmantotas fosfātu, amonija, nitrātu un skābekļa koncentrācijas, kā arī sāļuma un temperatūras dati, kas iegūti 1993. 1994., 2000., 2001., 2003., 2007. un 2008. gada termālās stratifikācijas periodā Rīgas līča 119. novērojumu stacijā, dziļumā, sākot no 35 m.
Aprēķinātās fosfātu, amonija un nitrātu vidējās plūsmas no sedimentiem ūdens slānī sastāda attiecīgi 122.5, 220.4 un 1081.2 Āmol m-2 d-1. Savukārt biogēno vielu transformācija sastāda -359.6 Āmol m-2 d-1 denitrifikācijas veidā un 52.9 Āmol m-2 d-1 fosfora adsorbcijas veidā.
Atslēgas vārdi: Rīgas līcis, bioģeoķīmiskā modelēšana, biogēno vielu plūsma, sedimenti, dziļūdens slānis.
The masters thesis „Modeling the fluxes of nitrogen and phosphorous in the Gulf of Riga sediments” presents an overview of nitrogen and phosphorus cycles in the Baltic Sea and the Gulf of Riga, as well as an overview of biogeochemical models used for modeling the fluxes of these elements. The thesis focuses on modeling the fluxes, transformations and loss of phosphate, amonia and nitrogen in the deepwater layer of Gulf of Riga. For modeling the proceses mentioned above the concentrations of phosphorous, amonia, nitrogen and oxygen, as well as data on water temperature and salinity have been used. These data were colected during the thermal stratification period below 35 m depths in 1993, 1994, 2000, 2001, 2003, 2007 and 2008 at monitoring station 119 in the central Gulf of Riga. Calculated average fluxes of phosphorous, amonia and nitrogen from sediments to the water column are 122.5, 220.4 and 1081.2 Āmol m-2 y-1 repectively. On average, 359.6 Āmol N m-2 y-1 were lost by denitrification. Phosphate adsorption to the bottom sediments was 52.9 Āmol m-2 d-1. Key words: Gulf of Riga, biogeochemical modeling, nutrient flux, sediments, deepwater layer.
The masters thesis „Modeling the fluxes of nitrogen and phosphorous in the Gulf of Riga sediments” presents an overview of nitrogen and phosphorus cycles in the Baltic Sea and the Gulf of Riga, as well as an overview of biogeochemical models used for modeling the fluxes of these elements. The thesis focuses on modeling the fluxes, transformations and loss of phosphate, amonia and nitrogen in the deepwater layer of Gulf of Riga. For modeling the proceses mentioned above the concentrations of phosphorous, amonia, nitrogen and oxygen, as well as data on water temperature and salinity have been used. These data were colected during the thermal stratification period below 35 m depths in 1993, 1994, 2000, 2001, 2003, 2007 and 2008 at monitoring station 119 in the central Gulf of Riga. Calculated average fluxes of phosphorous, amonia and nitrogen from sediments to the water column are 122.5, 220.4 and 1081.2 Āmol m-2 y-1 repectively. On average, 359.6 Āmol N m-2 y-1 were lost by denitrification. Phosphate adsorption to the bottom sediments was 52.9 Āmol m-2 d-1. Key words: Gulf of Riga, biogeochemical modeling, nutrient flux, sediments, deepwater layer.
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