We measured oxygen isotope ratios (delta18O) of xylem sap, phloem sap, leaves, wood and bark of Eucalyptus globulus Labill. growing in southwestern Australia. Carbon isotope ratios (delta13C) were measured in the dry matter of phloem sap, leaves and wood. Results were used to test several aspects of a mechanistic model of 18O enrichment and provided insights into post-photosynthetic variations ...

azotobacter vinelandii, a gamma-proteobacterium, is an obligate aerobic free-living gram-negative soil bacterium capable of fixing nitrogen. oxygen transfer rate into the cell is reduced by the increase of alginate concentrations during the course of a. vinelandii cultivation. this phenomenon provides a low intracellular oxygen concentration needed for nitrogenase activity. the aim of this stud...

Irrigated rice field soil is subjected to frequent changes in oxygen status due to the water regime by agricultural management. In this study, the community response of microeukaryotes in rice field soil to the oxygen status was explored in a microcosm experiment under defined conditions. Water-saturated soil was incubated under a two-level factorial design of oxygen and organic enrichment with...

A reduct ion in dissolved oxygen concentrat ion is one of the most important direct effects of nutrient over-enrichment of coastal waters on fishes. Because hypoxia can cause nlortality~ reduced growth rates, and altered distributions and behaviors o f fishes, as wel l as changes in the relative importance o f organisms andpathways of carbon f low within f o o d webs, hypoxia and anoxia can lea...