Climate-driven disparities among ecological interactions threaten kelp forest persistence

Area of Science:

• Marine ecology
• Climate change biology
• Oceanography

Background:

• Kelp forests face an uncertain future due to ocean warming and acidification.
• These ecosystems are vulnerable to direct climate change impacts and indirect ecological shifts.

Purpose of the Study:

• To investigate the direct effects of ocean warming and acidification on kelp.
• To assess climate-driven indirect effects on kelp forest consumers and competitors.

Main Methods:

• Mesocosm experiments were conducted.
• Direct effects on kelp biomass and photosynthetic health were tested.
• Indirect effects involving urchins, rock lobsters, and algal turf were evaluated.

Main Results:

• Elevated temperatures reduced kelp biomass.
• Ocean acidification promoted the growth of algal turf competitors.
• Warming increased urchin growth and kelp grazing rates.
• Rock lobsters reduced urchin consumption at higher temperatures, intensifying pressure on kelp.

Conclusions:

• Kelp forests at low-latitude margins require adaptation to ocean warming to survive.
• Indirect effects from warming and acidification may impede kelp adaptation.
• Ecological interactions could destabilize kelp forests, leading to shifts towards algal turf dominance.