University of Zagreb. Faculty of Science. Department of Biology.
Abstract
Autotrofni organizmi mogu iz anorganskih tvari primljenih iz okoliša sintetizirati organske spojeve koristeći se svjetlosnom energijom (fototrofi) ili kemijskom energijom oslobođenom u različitim kemijskim reakcijama (kemoautotrofi). Kemoautotrofni organizmi su sumporne, nitrifikacijske, željezne, manganske, metanske, ugljik monoksidne bakterije i bakterije praskavog plina. Sumporne bakterije žive u sedimentima stajačica i u sumpornim vrelima, gdje transformiraju velike količine sumporovodika. Mogu oksidirati sumporovodik koji nastaje pri razgradnji organskog materijala ili pri redukciji sulfata. Tu reakciju provode Beggiatoa i Thiotrix. Vrste roda Thiobacillus mogu osim sumporovodika, sulfida i sumpora do sulfata oksidirati i druge sumporne spojeve, dok Desulfovibrio koristi sulfat kao akceptor elektrona tijekom oksidajice uz različite donore elektrona. Publicirani istraživački rad u talogu gipsa pokazuje vertikalnu raspodjelu sumpornih bakterija pomoću mikrosenzora za ispitivanje kisika, pH i sulfida, čime je utvrđen sastav i aktivnost sulfat reducirajućih bakterija.Autotrophic organisms are receiving inorganic substances from the environment to synthesize organic compounds using light energy (phototrophic) or by chemical energy released in various chemical reactions (chemoautotrophic). Chemoautotrophic organisms transform sulfur, nitrogen, iron, manganese and carbon. Sulfur bacteria live on the muddy bottom of sediments, in sulfur springs, generally in places where they transform hydrogen sulphide. They can oxidize compounds containing sulfur, such as hydrogen sulfide, which occurs during decomposition of organic material or the reduction of sulfate. This reaction is carried out by Beggiatoa and Thiothrix. Thiobacillus can oxidize hydrogen, sulfide, sulfate and other sulfur compounds, while Desulfovibrio is a sulfate-reducing bacteria using sulfate as an electron acceptor during oxidation of different electron donors. The published case study int he gypsum crust, vertical distribution of phototrophic, sulfate reducers and methanogens in salinities of 156 and 206 g/L was examined using microsensors for oxygen, pH and sulfide. Community of sulfate reducing bacteria varied with the depth of the crust and their diversity was lower as the salinity increased
