Phytoplankton community growth-limiting nutrients

Within this context, it would be interesting to consider potential interactions between nutrient/substrate limitation and UV-B stress. Nutrient additions have been reported to decrease the sensitivity of bacterioplankton production to UVR [91]. As has been demonstrated [106] a large fraction of the bacterioplankton in marine waters is metabolically inactive as a result of substrate limitation. Phytoplankton may also experience nutrient (N, P, Fe) limitation in the open ocean or in a post-bloom situation. Suboptimal metabolic activity in these cells would hamper DNA repair, and would thereby contribute to rapid accumulation of DNA damage in these cells. In turn, damage accumulation would then decrease viability in this fraction of the community. The low repair rates and residual DNA damage levels (morning samples) in combination with low growth estimates in many bacterioplankton field studies seem to support this hypothesis. 

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