Microbial Community Metabolic Responses to Variable Environmental Conditions Measured by the Adenylate Energy System

Abstract:

The adenylate energy system provides a holistic view of the energy metabolism of microbial communities through measurements of the primary energy trafficking molecule adenosine triphosphate (ATP), and its dephosphorylated metabolites adenosine diphosphate (ADP) and adenosine monophosphate (AMP). The production and turnover rates of ATP are direct measures of metabolic energy turnover in microbes while the production and turnover rates of AMP are direct measures of microbial growth rates. We measured ATP, ADP, and AMP concentrations, phosphorylation rates, and turnover rates in marine microbes using high pressure liquid chromatography and incubations with radiolabeled 32P-phosphate. These measurements were conducted on natural marine microbial communities under various nutrient and environmental conditions, using samples from coastal and offshore sites in the North Atlantic. We sampled depth profiles in the Florida Straits using a CTD and conducted multi-day nutrient incubations with seawater from Biscayne Bay, off the coast of Miami, Florida. Through these analyses we were able to show the connections between the metabolic state of the microbial communities and the environmental conditions they were experiencing.