FIG. 1.

Effects of HgCl₂ on Limnothrix planctonica. (A) Growth of cells in control (•), 120-ppb (▴), and 200-ppb (▪) treatments at pH 6.5. (B) Time course for biotransformation of a sublethal application of Hg(II) (120 ppb HgCl₂). Results for total Hg (▪) and acid reduction-detectable Hg (•) are shown. Panel B is adapted from Fig. 1 of a paper by Kelly et al. (24). (C) Biotransformation of 120-ppb and 200-ppb Hg(II) applications after 15 and 30 h. Results for acid-detectable Hg (white), total Hg (gray), and β-HgS (black) are shown. (D) Analysis of French pressed cellular filtrate. Symbols are as defined for panel C (above). Incubation was at 120 ppb Hg(II) for 1 h and extraction as described in Materials and Methods. The particle retention size of the filter is given for each filtrate. All cultures had initial OD₆₆₅s of 0.32. All values are means ± SE for triplicate determinations.