Resilience by diversity: Large intraspecific differences in climate change responses of an Arctic diatom

• Published in: Limnology and Oceanography
• Main Authors: Wolf, Klara K. E., Hoppe, Clara J. M., Rost, Björn
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2018
• Subjects: Arctic; Climate change; Phytoplankton
• Online Access: https://epic.awi.de/id/eprint/48036/; https://epic.awi.de/id/eprint/48036/1/Wolf_2018_Resilience_by_diversity.pdf; https://doi.org/10.1002/lno.10639; https://hdl.handle.net/10013/epic.93be5c7b-5d56-4420-aeb3-afe99e6c2935; https://hdl.handle.net/

The potential for adaptation of phytoplankton to future climate is often extrapolated based on single strain responses of a representative species, ignoring variability within and between species. The aim of this study was to approximate the range of strain-specific reaction patterns within an Arctic diatom population, which selection can act upon. In a laboratory experiment, we first incubated natural communities from an Arctic fjord under present and future conditions. In a second step, single strains of the diatom Thalassiosira hyalina were isolated from these selection environments and exposed to a matrix of temperature (38C and 68C) and pCO 2 levels (180 latm, 370 latm, 1000 latm, 1400 latm) to establish reaction norms for growth, production rates, and elemental quotas. The results revealed interactive effects of temperature and pCO 2 as well as wide tolerance ranges. Between strains, however, sensitivities and optima differed greatly. These strain-specific responses corresponded well with their respective selection environments of the previous com- munity incubation. We therefore hypothesize that intraspecific variability and the selection between coexist- ing strains may pose an underestimated source of species’ plasticity. Thus, adaptation of phytoplankton assemblages may also occur by selection within rather than only between species, and species-wide inferences from single strain experiments should be treated with caution.