The influence of microbial community structure and function on community-level physiological profiles

Published by Ecoss on

Patterns of carbon source utilization, or community-level physiological profiles (CLPP), produced from direct incubation of environmental samples in BIOLOG microplates can consistently discriminate spatial and temporal gradients within microbial communities. While the resolving power of the assay appears significant, the basis for the differences in the patterns of sole carbon source utilization among communities remains unclear. Carbon source utilization as measured in this assay is a measure of functional potential, rather than in situ activity, since enrichment occurs over the course of incubation, which can range from 24 to 72 hours (or even longer) depending on inoculum density. The functional profile of a community could be an indicator of carbon source availability and concomitant selection for specific functional types of organisms. A more limited view of the profile is as a composite descriptor of the microbial community composition without any ecologically relevant functional information. We manipulated microbial community structure and function in laboratory microcosms to evaluate their influence on CLPP. The structure of rhizosphere communities was controlled by inoculating axenic plants (wheat and potato) with different mixed species (non-gnotobiotic) inocula. Inoculum source influenced CLPP more strongly than plant type, indicating that CLPP primarily reflected differences in microbial community structure than function. In order to more specifically examine the influence of microbial function on CLPP, specific carbon sources in the BIOLOG plates (asparagine and acetate) were added to a continuously stirred tank reactor (CSTR) containing a mixed community of microorganisms degrading plant material. Daily additions of these carbon sources at levels up to 50% of the total respired carbon in the bioreactor caused significant changes in overall CLPP, but caused no, or minor, increases in the specific response of these substrates in the plates. These studies indicate that the functional relevance of CLPP should be interpreted with caution.

Categories:

Related Posts

A CIRCUIT SHOWS HOW CLIMATE WARMING MAY ALTER DIFFERENT ECOLOGICAL LEGACIES IN THE ARCTIC BOREAL FOREST, WHICH THEN FEEDBACK INTO CLIMATE WARMING AND CHANGES TO LANDSCAPE PROCESSES.

NAU-led research team receives $9.6M to study how Alaska’s forests change, adapt to warmer future

Ecological memory stored in a landscape can help an ecosystem recover from disturbances like fire and outbreaks of disease. But what happens when climate warming disrupts that process? How long before ecological memories stored in Read more…

A SCATTERPLOT DEPICTS HOW MUCH CARBON OR OXYGEN ISOTOPE DIFFERENT SOIL BACTERIA TOOK INTO THEIR DNA (A PROXY FOR GROWTH) DURING A 7-DAY EXPERIMENT. SMALL POINTS REPRESENT THE GROWTH OF INDIVIDUAL BACTERIAL STRAINS LINKED BY LINES TO THE AVERAGE GROWTH OF THEIR CLOSEST IDENTIFIED GENUS. COLORS WERE ASSIGNED BY A CLUSTERING ALGORITHM TO GROUP GENERA INTO FAST-GROWING OR SLOW-GROWING LIFESTYLES.

Lifestyles of the fast and slow (bacteria): In the wild, most live in the slow lane

A study led by Northern Arizona University offers new evidence that a common framework to sort bacteria into two lifestyles doesn’t easily apply to bacteria living in wild soil. The findings, published in The ISME Journal, show Read more…

A trio of illustrated panels depicts the soil microbial communities in three treatments of a long-term warming experiment north of Flagstaff, Arizona. The panels are labeled in gray text, left to right: control, short-term warming, long-term warming. The control treatment, far left, depicts bacteria, protists, and other microorganisms identified by sequencing the soil’s metagenome in yellow, orange, green, and blue, along with chains of available nutrients. Soil depicted in the center panel, which has undergone short-term warming, shows an increased abundance and diversity of microbes, some of which are growing, incorporating nutrients, and respiring carbon dioxide. The soil that has undergone long-term warming, imagined in the panel on the right, shows fewer microbial species and competitive relationships that are developing for control of the scarcer nutrients.

Does a warmer future favor microbial friend or foe? Ecoss researchers win $3.4M to study interactions in changing soil

In 2002, the Odyssey probe discovered evidence of past ice on Mars. The U.S. Congress authorized the Iraq War resolution. The Anaheim Angels won the World Series. And in a meadow 15 miles north of Read more…