Diversity shifts and crude oil transformation in polluted microbial mat microcosms

Abstract

Abstract Diversity shifts linked to crude oil transformation were studied in microbial mats developed under laboratory conditions using a molecular approach and basic biomass determination (protein and predominant pigment content). For this purpose two different microcosms were established, one simulating a four-day black tide and the other trying to reflect the colonisation of contaminated black sediment by the indigenous populations of Ebro Delta microbial mats inoculated over the polluted substrate. The crude oil used as a contaminant was Casablanca, a light oil with low viscosity and low sulphur content similar to Arabian light. In the first microcosm, Microcosm I, neither crude oil degradation nor changes of total and phototrophic biomass were detected. Nevertheless, DGGE profiles showed noticeable changes that suggested a slight increase in the diversity of the bacterial populations, assuming that the number of bands was directly correlated to the diversity of species. Furthermore, when attention is...