Coevolution of marine phytoplankton and Alteromonas bacteria in response to pCO2 and co-culture.

As a result of human activity, Earth's atmosphere and climate are changing at an unprecedented pace. Models based on short-term experiments predict major changes will occur in marine phytoplankton communities in the future ocean, but rarely consider how evolution or interactions with other microbes may influence these changes. Here we experimentally evolved several phytoplankton in co-culture with a heterotrophic bacterium, Alteromonas sp.

Market forces determine the distribution of a leaky function in a simple microbial community.

Many biological functions are leaky, and organisms that perform them contribute some of their products to a community "marketplace" in which nonperforming individuals may compete for them. Leaky functions are partitioned unequally in microbial communities, and the evolutionary forces determining which species perform them and which become beneficiaries are poorly understood. Here, we demonstrate that the market principle of comparative advantage determines the distribution of a leaky antibiotic resistance gene in an environment occupied by two "species"-strains of growing on mutually exclusive resources and thus occupying separate niches.