Characterization of phototrophic pigment composition, metabolic processes and carbon pools in northern chile.

A fluorescence peak occurring within the oxygen minimum layer (OML) of the southeastern Pacific Ocean is sometimes observed. It has been commonly explained as an accumulation of decaying matter.

However, off northern Chile, the peak can be found at shallow enough depths that photosynthesis could be taking place. We therefore hypothesized that this subsurface peak is of phototrophic origin associated with an active microbial community living under suboxic and low light conditions. Work was undertaken on the MinOx cruise, aboard the R/V Vidal Gormaz, off Iquique, March-April 2000, to address this hypothesis.