Abstract
Phytoplankton acclimates to irradiance by regulating the cellular content of light-harvesting complexes, which are nitrogen (N) rich and phosphorus (P) poor. Irradiance is thus hypothesised to influence the cellular N : P ratio and the N : P defining the threshold between N and P limitation (the ‘optimal’ N : P). We tested this hypothesis by first addressing the response of the optimal N : P to irradiance in a controlled experiment with Chlamydomonas reinhardtii. Then, we did a meta-analysis of experimental data on optimal and cellular N : P ratios across light gradients to test the generality of an N : P to light response within species. In both the experiment and the meta-analysis, N : P ratios decreased with irradiance, indicating that factors affecting underwater irradiance, like depth and the composition of the water, may influence the relative N : P requirement. The effect of irradiance did not differ between optimal and cellular N : P ratios, but observations of optimal N : P were on average 2.8 times higher than observations of cellular N : P.
| Original language | English |
|---|---|
| Pages (from-to) | 880-888 |
| Number of pages | 9 |
| Journal | Ecology Letters |
| Volume | 19 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - 1 Aug 2016 |
| Externally published | Yes |
Bibliographical note
Copyright the Author(s) 2016. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.Keywords
- Chlamydomonas
- reinhardtii
- ecological stoichiometry
- irradiance
- light
- N : P ratio
- nitrogen
- optimal N : P
- phosphorus
- Redfield ratio