Sedimentation Patterns of Photosynthetic Bacteria Based on Pigment Markers in Meromictic Lake La Cruz (Spain): Paleolimnological Implications

摘要: Sedimentation fluxes of photosynthetic pigments and their derivatives, focused on the anoxygenic bacteria populations, were determined in meromictic Lake La Cruz over a three-year period using sediment traps. Bacterial settling occurs pulses response to lake dynamics. Two main annual events affect particle Cruz: (1) Following an event massive calcium precipitation summer that caused water whiting, maximum flux chlorophyll derivatives towards was registered. Although whiting is accompanied by phytoplankton biomass sinking, it not followed concomitant bacterial sinking. (2) In contrast, disruption chemocline contact populations with oxygenated waters during autumn overturn provoked destruction sulfur plate, causing mass mortality, registered material as from phototrophic bacteria. Among bacteriochlorophyll oxidation products, bacterioviridin (bvir) detected high relative abundance settled collected The much increased bvir after thermal overturn, associated mortality purple bacterium, Amoebobacter purpureus, confirms suitability this molecule useful paleoindicator degree oxygen exposure experienced population.