Across the seasons, these factors may vary:

• irradiance
• air/water temperature, which is surprisingly colder in spring than in winter
• ice and snow cover on the intertidal rocks where the algae grows
• sea ice in the water, which vary greatly on a daily basis depending on wind and currents.

The varying seasonal conditions become apparent in the coastal intertidal habitat and require fine tuned adaptation mechanisms of the algae to cope with such extreme seasonal differences. As you can see in the fourth picture, the difference can manifest as being encased by a thick drop of frozen seawater during lowtide in spring or winter. Or, lying in the warm sun during summer, when temperatures in the intertidal can frequently reach double digits.

These hostile conditions are challenging not only for the algae, but also for us to sample or even reach sampling spots. When the algae are partly frozen, it becomes much more difficult to select healthy individuals for research. When the coast is covered in ice and snow, it is also more challenging to reach the sampling site.