. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. \ Oxygen-sulfide interface Oxygen-sulfide interface Sulfide-rich zone 0 100 200 300 400 500 H2S 7 8 9 PH Figure 2. Depth gradients in O2 oxygenic photosynthesis, sulfide, pH, and microbiota. (a) At left is a schematic vertical section of the topmost 2 mm of subtidal mat dominated by Microcoleus chthonoplastes cyanobacteria. Letters along the right margin indicate the following: A: diatoms; B: Spirulina spp. cyanobacteria; C: Oscillaloria spp. cyanobacteria; D; Microcoleus chthonoplastes
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. \ Oxygen-sulfide interface Oxygen-sulfide interface Sulfide-rich zone 0 100 200 300 400 500 H2S 7 8 9 PH Figure 2. Depth gradients in O2 oxygenic photosynthesis, sulfide, pH, and microbiota. (a) At left is a schematic vertical section of the topmost 2 mm of subtidal mat dominated by Microcoleus chthonoplastes cyanobacteria. Letters along the right margin indicate the following: A: diatoms; B: Spirulina spp. cyanobacteria; C: Oscillaloria spp. cyanobacteria; D; Microcoleus chthonoplastes cyanobacteria; E; nonphotosynthetic bacteria; F: unicellular cyanobacteria; G: fragments of bacterial mucilage; H: green nonsulfur bacteria; I: Beggiatoa spp.; J: metazoans (, nematodes); K: abandoned cyanobacterial sheaths. Also shown are depth profiles for key chemical constituents in the Pond 5 mat, as follows: photosynthetic O2 production rates (horizontal barsl, and concentrations of O: and sulfide, and pH (data from J0rgensen and Des Marais, 1986). each partner. Virtually every member of the anaerobic com- munity is subject to such effects (Schink, 1988; Zinder, 1993); therefore, the participation of cyanobacteria in the cycling of hydrogen and organic acids could substantially affect biogeochemical function and community composition (Hoehler et 2001). Similarly, anaerobes consume these thermodynamically sensitive end products and thus can provide an important feedback on fermentation and nitrogen fixation by cyanobacteria at the levels of both enzyme and gene regulation. Carbon, oxygen, and sulfur budgets Several general observations can be made about the cycling of carbon, oxygen, and sulfur (Canfield and Des Marais, 1993; Des Marais et al., 2002b). During the day, most of the O-> produced is recycled within the mat by O2 respiration and some sulfide oxidation. At night, CK is consumed principally by sulfide oxidation near the mat- water interface. Microbia
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
