Will macroalgae survive the future ocean? – effects of ocean acidification on macroalgal forests

Anthropogenic impacts on marine climate affect salinity, temperature, and pH respectively causing freshening, warming, and ocean acidification (OA). Macroalgal forests, highly productive marine ecosystems and major CO2 sinks, generally respond positively to OA.

Recently, however, I documented the first evidence that OA increases fragility in the habitat-forming brown macroalga, Fucus vesiculosus.

Algae grown under OA were significantly more prone to breakage in the lab and had significantly lower survival when out-planted in the field.This project will investigate the generality of this response in other large, habitat-forming macroalgae.

Using different evolutionary groups of macroalgae, I will study the response to OA throughout the life cycle, if the combined effects of climate change drivers amplify or reduce vulnerability, and if vulnerability depends on environmental history.

Macroalgae, especially large habitat-forming kelps and fucoids, provide complex 3D-habitats providing refuge, shelter, and food for many species of fish and invertebrates.

They are the foundation of near-shore ecosystems providing valuable ecosystem services by supplying food, reducing erosion, and sequestering carbon.

I will investigate macroalgae from nearshore ecosystems in both the Atlantic and Pacific Oceans, and my results will provide a generalized overview of how the resilience and tissue structure of macroalgae are affected by OA in kelp and seaweed forests globally.