Determining light suppression of mitochondrial respiration for three temperate marine macrophytes using the Kok method

To properly calculate the carbon budgets of coastal marine habitats, potential fluctuations in oxygen consumption due to mitochondrial respiration must be taken into account. As mitochondrial respiration is sometimes inhibited in light, we used the Kok method to estimate whether such suppression occurs in the seagrasses Zostera marina and Ruppia maritima as well as in the macroalga Ulva intestinalis. For Z. marina and U. intestinalis, the respiration rate was clearly downregulated in light, a finding that might be important when determining the impact of respiration on estimated net primary productivity in these marine habitats.