Growth of Photosynthetic Biofilms and Fe, Pb, Cu, and Zn Speciation in Unsaturated Columns with Calcareous Mine Tailings from Arid Zones

Table 3

Relative abundance of the sulfur-oxidizing bacteria (SOB) and of the sulfate reducing bacteria (SRB) before the assay (𝑡₀) and in the columns after the wet (𝑡_𝑤) and dry (𝑡_𝑑) seasons, per stratum.

	Aerobic SOB (pH 8.5)			Anaerobic SRB (pH 8.0)
	𝑡0	𝑡𝑤	𝑡𝑑	𝑡0	𝑡𝑤	𝑡𝑑
E1	+	++	++	++	+++	+++
E2	+	+++	++	+++	+++	+++
E3	−	+	++	++	++	++
E4	++	+++	++	++	++	+++
E5	+	++	++	++	+++	+++
E6	−	+	−	+	++	+++

Note: number of cells in each of the 10 visual fields: −: 0; +: ≤10; ++: ≤20; +++: ≤40.