Fig. 1.

Acute exposure to sodium sulfide (Na₂S) increases Ca²⁺ influx in fish acclimated to low-Ca²⁺ concentration ([Ca²⁺]) of water. The effects of Na₂S exposure on Ca²⁺ influx in larval zebrafish [4 days postfertilization (dpf)] acclimated to normal [Ca²⁺] (250 μM; A) or low-[Ca²⁺] (25 μM; B) water for 3 days, beginning at 1 dpf, are shown. Influx of Ca²⁺ was measured in normal [Ca²⁺] water for both experiments. Values are means ± SE; N = 6. ^a,b Different letters represent a statistical difference from each other (one-way ANOVA, followed by a Holm-Sidak post hoc test; P < 0.05).