Evolutionary legacy response observed in algae and bryophytes following hydrogen sulfide administration

Even though sulfur is an essential macronutrient required for growth and productivity, there are toxic compounds of this element that exert detrimental effects and produce physiological stress. It is speculated that the accumulation of H 2 S, a lethal gas, may have been a major contributing factor in past mass extinction events, where the environment was fairly anoxic with fluctuating temperatures.

The potential of this toxic compound to exist as an environmental stressor suggests that certain organisms may have adapted to survive these periods of mass extinctions. It is hypothesized that due to the abundant presence of H 2 S in the past, ancient land plants may have an adaptive advantage that allowed them to survive and thrive. In this study, species of bryophytes and algae were exposed to specific concentrations of aqueous H 2 S over a seven-day period and measured their photosynthetic capacity at timed intervals using a FluorCam.