Producción del carbono del bacteriobentos fotótrofo en las biopelículas sedimentarias de una laguna costera del sur del Golfo de México

Abstract

Abstract. Biofilms of surface sediments from the Sontecomapan coastal lagoon, in the state of Veracruz, Mexico, were studied. The aim was to evaluate the contribution of phototrophic bacteriobenthos and photoautotrophic picobenthos to the production of primary Carbon. Epifluorescence and pigment auto-fluorescence direct counting methods were used for the evaluation. The biomass of these communities were computed by the ‘cell volume:Carbon’ conversion factor. It was observed that the largest ‘new-biomass’ contribution to the benthos was due to the phototrophic bacteriobenthos. The spectrophotometric analysis of chlorophyll a and carotenes present in the phototrophic bacteriobenthos, cultured on regulated oxygen concentration (4 and 5% pO2) were made. The results showed that the syntheses of bacteriochlorophyll-a and carotenes operated under low oxygen concentrations. These results change the belief that pigments syntheses in the red anoxygenic not-sulphured bacteria is inhibited under oxygen presence.