Divergent ecosystem responses within a benthic marine community to ocean acidification

Area of Science:

• Marine Biology
• Ecosystem Ecology
• Oceanography

Background:

• Ocean acidification poses a significant threat to marine organisms and ecosystems globally.
• Predicting ecosystem-level impacts is challenging due to diverse species-specific responses to changing ocean pH.
• Shallow water CO(2) vents offer a natural laboratory to study ocean acidification effects.

Purpose of the Study:

• To investigate emergent ecosystem responses to ocean acidification in Mediterranean rocky reef communities.
• To assess the impact of varying pH levels on benthic invertebrate communities.
• To understand how ocean acidification influences marine biodiversity, biomass, and trophic structure.

Main Methods:

• Utilized natural CO(2) vents in the Mediterranean Sea as a model system.
• Assessed in situ benthic invertebrate communities across a gradient of ambient, low, and extreme low pH zones.
• Analyzed data on taxa richness, taxonomic evenness, biomass, individual abundance, and trophic structure.

Main Results:

• Extreme low pH zones exhibited fewer taxa, reduced taxonomic evenness, and lower biomass.
• Total individual abundance remained consistent, indicating density compensation by tolerant species.
• Trophic structure shifted towards fewer groups and dominance by generalists in low pH environments.

Conclusions:

• Ocean acidification decreases marine biodiversity, biomass, and trophic complexity in benthic communities.
• Despite varied species responses, ecosystem functions are negatively impacted by ocean acidification.
• Extreme acidification scenarios may lead to significant biodiversity loss and impaired ecosystem function.