Gutters teem with inconspicuous life

Scientists from the BOREA Biology of Aquatic Organisms and Ecosystems research unit (CNRS / MNHN / IRD / UPMC / University of Caen / Université des Antilles)—together with a colleague from the Max Planck Institute for Terrestrial Microbiology in Marburg, Germany—have shown that Parisian street gutters are oases of microscopic life, home to microalgae, fungi, sponges, and mollusks.¹ Grouped into communities, these microorganisms may help clean rainwater and urban waste by decomposing solid debris and pollutants such as exhaust fumes and engine oil. A deeper understanding of the role and composition of these communities could help elucidate the services rendered by gutter ecosystems. Published in the ISME Journal on October 13, 2017, the researchers' findings are the first to reveal the unsuspected biodiversity of microscopic life in Paris city streets. Scientists from the BOREA research unit first suspected the presence of microalgae in Paris streets after noting the characteristic green or brown color of gutter water and observing the presence of bubbles, which are the result of photosynthetic activity. The researchers analyzed different samples of non-potable water from the Seine, the Ourcq Canal, curbside water outlets (for street cleaning), and street gutters to identify the microorganisms they harbored.² - The team identified 6,900 potential species³ of eukaryotes⁴ in the hundred or so samples of water and biofilms (consisting of communities of microorganisms) collected from every district of Paris.