ena-STUDY-JYU-03-02-2015-12:12:23:672-12
Effects of iron on the bioavailability of natural dissolved organic matter
Mineralization of dissolved organic matter (DOM) plays an important role in the global carbon cycle. The biodegradation of DOM can be altered by complexing with iron (Fe) or adsorbing on inorganic minerals. In order to study the effects of Fe on the biodegradation of natural DOM, we performed a set of laboratory incubation experiments using extracted DOM and enriched bacteria originating from a highly humic lake water. We tested two ways of Fe introduction and priming effect by another labile carbon substrate (glycerophosphate, GlyC), and then followed bacterial growth and respiration over 25 days. Priming of the DOM degradation with GlyC led to the highest cell numbers, biomass, and respiration, which was . associated to growth of Caulobacter using the next-generation sequencing. Complexation of DOM by Fe decreased bacterial growth compared to DOM alone treatment, but the priming by GlyC reversed the situation. Bacterial growth efficiency (BGE) was also reduced in the DOM-Fe complex treatment. This study showed that even if Fe is needed for bacterial growth, it can significantly reduce the bioavailability of natural DOM, but other labile substrates (e.g., GlyC) may prime the mineralization of DOM-Fe complexes
Mineralization of dissolved organic matter (DOM) plays an important role in the global carbon cycle. The biodegradation of DOM can be altered by complexing with iron (Fe) or adsorbing on inorganic minerals. In order to study the effects of Fe on the biodegradation of natural DOM, we performed a set of laboratory incubation experiments using extracted DOM and enriched bacteria originating from a highly humic lake water. We tested two ways of Fe introduction and priming effect by another labile carbon substrate (glycerophosphate, GlyC), and then followed bacterial growth and respiration over 25 days. Priming of the DOM degradation with GlyC led to the highest cell numbers, biomass, and respiration, which was . associated to growth of Caulobacter using the next-generation sequencing. Complexation of DOM by Fe decreased bacterial growth compared to DOM alone treatment, but the priming by GlyC reversed the situation. Bacterial growth efficiency (BGE) was also reduced in the DOM-Fe complex treatment. This study showed that even if Fe is needed for bacterial growth, it can significantly reduce the bioavailability of natural DOM, but other labile substrates (e.g., GlyC) may prime the mineralization of DOM-Fe complexes