Chemical ecology

The importance of chemical ecology

Chemical ecology, has helped to understand terrestrial ecosystems. How bees pollinate flowers, how birds find their nests and human attractiveness to a partner are some of the many examples of interactions which are mediated by chemicals. It is not difficult to imagine the catastrophic consequences of the absence of such crucial relationships. Imagine a similar scenario without chemical interactions in the marine environment. Species would no longer be able to identify their food, locate their pray, recognize mates,... . Species-specific chemicals can shape community processes such as seasonal succession, niche structure, selective feeding and population dynamics.

The [www.marBEF.org MarBEF] ROSEMEB (Role of Secondary Metabolites in Ecosystem Biodiversity) project has provided a better understanding of the roles of these chemicals in maintaining marine biodiversity and driving ecosystem functionality.

Chemical ecology and microbes

Microbes sense their environment via cell-associated and diffusible molecules such as AHL (N-acylhomoserine lactones). Such molecules are constantly produced by many bacteria and diffuse through membranes into the surrounding environment.

When a certain cell density (a threshold or quorum) of the bacterial population and a corresponding concentration of AHL is reached, the expression of certain target genes is initiated. These may include the proteins for light emission in luminous bacteria or pathogenic factors that cause disease.

This quorum-sensing typically controls processes, such as swarming (coordinated movement), virulence (coordinated attack) or conjugation (gene transfer between cells), which require high cell densities for success and that are essential for the survival of the organisms which produce the molecules.