Effects of temperature and heavy metal pollution on Fucus serratus Søren Laurentius Nielsen Roskilde University

Why bother?

They can form extensive populations They provide food and shelter for animals and substratum for epiphytic algae We know they are affected by temperature and various forms of pollution

But what about germlings? HD Nielsen et al., 2003 They may very well be more susceptible to environmental stressors than adult algae

Questions How will climate change interact with anthropogenic pollution to affect Fucus? Is the effect on germlings more pronounced?

Experimental setup Four temperatures: 6, 12, 17 and 22 °C Copper as a model pollutant –0, 100 and 1000 nM total copper, corresponding to 0, 42 and 422 nM free Cu 2+ –Baltic straits open water and polluted harbor waters respectively A 4x3 setup for with germlings as well as Fucus fronds

Results: Adult Fucus Growth:

Results: Adult Fucus Maximum quantum yield, F v /F m :

Results: Adult Fucus Maximum photosynthesis, ETR max :

Results: Adult Fucus Non-photosynthetis quenching, NPQ:

Results: Fucus germlings Survival:

Results: Fucus germlings Growth:

Results: Fucus germlings Maximum quantum yield, F v /F m :

Results: Fucus germlings Maximum photosynthesis, ETR max :

Results: Fucus germlings Non-photosynthetic quenching, NPQ:

Conclusions: Adult Fucus: –Only the growth is affected and only by temperature –Photosynthetic parameters not affected, so effect on growth must be due to loss processes and/or effect on cell division

Conclusions: Fucus germlings: –Effect on survival, growth and photosynthetic parameters –Effect of both temperature and metal –Survival decreases with increasing temperature, synergistic effect of metal –Temperature has positive effect on growth and photosynthesis, counteracted by metal

Conclusions: Need to include early life stages in assessments of effects of climate change and pollution on fucoid algae Only including adult algae can lead to overloking effects important for population maintainance and survival