• Bryophyte;
  • nutrient response;
  • photosynthesis;
  • sub-Antarctic


N and P, especially when added together, significantly enhanced CO2 assimilation rate in four moss species from a range of habitats on sub-Antarctic Marion Island. NO3 always caused a greater increase in assimilation rate than did NH4+, but this might have been due to Cl added with the NH4+. Possibly for the same reason, K+ addition (as KCl) in some cases depressed CO2 assimilation rate compared with the controls (tapwater addition), as did K + N or K + P compared with N or P alone. The degree to which the mosses were apparently sensitive to Cl was related to their tissue water content and to the soil water content in the habitats in which they occur. The results are discussed in the context of extremely low levels of available soil nutrients in, and small precipitation inputs of nutrients to, plant communities predominated by bryophytes on the island.