Distribution of phototrophic populations and primary production in a microbial mat from the Ebro Delta, Spain
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Maira Martínez-Alonso [1] ; Joan Mir [1] ; Pierre Caumette [3] ; Núria Gaju [1] ; Ricardo Guerrero [2] ; Isabel Esteve [1]
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[1] Universitat Autònoma de Barcelona
Universitat Autònoma de Barcelona
Barcelona, España
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[2] Universitat de Barcelona
Universitat de Barcelona
Barcelona, España
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[3] Laboratory of Molecular Ecology- UPRES 159, IBEAS-University of Pau, France
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- Localización: International microbiology: official journal of the Spanish Society for Microbiology, ISSN 1139-6709, Vol. 7, Nº. 1, 2004, págs. 19-25
- Idioma: inglés
- Enlaces
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Resumen
Microbial mats arising in the sand flats of the Ebro Delta (Tarragona, Spain) were investigated during the summer season, when the community was highly developed. These mats are composed of three pigmented layers of phototrophic organisms, an upper brown layer mainly composed of Lyngbya aestuarii and diatoms, an intermediate green layer of the cyanobacterium Microcoleus chthonoplastes, and an underlying pink layer of a so-far unidentified purple sulfur bacterium. In the photic zone, oxygenic phototrophs constitute about 58% of total photosynthetic biomass, measured as biovolume, and anoxygenic phototrophs represent 42%. Diatoms constitute 11.8% of the oxygenic biomass, M. chthonoplastes 61.2%, and L. aestuarii and coccoid cyanobacteria 20.6 and 6.4%, respectively. In this laminated community, organic matter has an autochthonous origin, and photosynthesis is the most important source of organic carbon. Oxygen production reaches up to 27.2 mmol O2 m–2 h–1, measured at 1000 μE m–2 s–1 light intensity, whereas oxidation of sulfide in the light has been calculated to be 18.6 mmol S m–2 h–1. This amount represents 26% of the total photosynthetic production in terms of photoassimilated carbon, demonstrating the important role of anoxygenic phototrophs as primary producers in the pink layer of Ebro Delta microbial mats. [Int Microbiol 2004; 7(1):19–25]
