🌊 EPOCA Project Summary: The European Project on Ocean Acidification
The European Project on Ocean Acidification (EPOCA) was the first major international research effort dedicated to understanding the biological, ecological, biogeochemical, and societal implications of ocean acidification (OA). OA is caused by the ocean absorbing massive amounts of human-made carbon dioxide, leading to a reduction in pH and carbonate ion concentration.
🎯 Overall Objectives and Research Themes
Launched in May 2008, EPOCA involved over 160 scientists from 32 institutions in 10 European countries. Its overall goal was to fill critical knowledge gaps and predict the future impact of OA on marine life and the Earth system.
The research was structured around four core themes:
Theme 1: Changes in Ocean Chemistry and Biogeography
- Objective: Document past and present spatial and temporal fluctuations in ocean carbonate chemistry and the distribution of marine species.
- Methods: Used paleo-reconstruction (e.g., on deep-sea corals and foraminifera) to assess past variability and continuous sampling at time-series stations (e.g., in the Arctic) for present-day observations.
Theme 2: Biological Responses
- Objective: Quantify the impact of OA on marine organisms and ecosystems, including the potential for acclimation and adaptation.
- Methods: Conducted extensive laboratory and field perturbation experiments (mesocosms and natural $\text{CO}_2$ venting sites) on key organisms across various taxonomic groups (e.g., calcifiers, plankton).
Theme 3: Biogeochemical Impacts and Feedbacks
- Objective: Integrate chemical and biological findings into models to project how OA will alter ocean biogeochemistry over the next 200 years and how these changes will feedback on climate.
- Methods: Used Earth System Models (ESMs), forced global/regional ocean models, and a sediment model to investigate impacts on the carbon, nitrogen, sulfur, and iron cycles.
Theme 4: Synthesis, Dissemination, and Outreach
- Objective: Synthesize results from the other themes, assess uncertainties, risks, and critical thresholds (‘tipping points’), and communicate these findings to policymakers and the public.
- Method: Formed the EPOCA Reference User Group (RUG) to ensure scientific accuracy and effective dissemination through policy guides, media, and educational materials.
💡 Major Scientific Results
EPOCA generated over 200 publications and significantly advanced the understanding of ocean acidification.
Key Findings by Theme
| Theme | Major Scientific Highlights |
| Theme 1: Chemistry and Biogeography | OA is faster than expected in the Arctic near Iceland, with surface pH dropping 50% faster than average subtropical rates. Synergistic effects were found, with global warming and thawing permafrost exacerbating OA in the coastal Arctic. |
| Theme 2: Biological Responses | Adverse effects on calcifying organisms are robustly confirmed, especially in early life stages (e.g., bivalves, echinoderms). Variability in sensitivity exists, reflecting genetic diversity or regional differences. Studies highlighted the importance of long-term exposure for acclimation and synergistic effects, where OA narrows the thermal tolerance of many organisms. |
| Theme 3: Modeling and Feedbacks | Models projected that $\sim\mathbf{10\%}$ of Arctic surface waters would become undersaturated within 10 years during summer. Regional models showed high vulnerability in areas like the Northwestern European Shelf Seas and Eastern Boundary Upwelling Systems (EBUS), where local factors like river input and upwelling exacerbate acidification. |
Legacy and Outreach
- Data Archiving: Maintained two critical databases: one for EPOCA’s observational/experimental data and another—the EPOCA/EUR-OCEANS data compilation—archiving all published data on biological responses to OA, ensuring long-term accessibility.
- Standards and Best Practices: Led the community-reviewed ‘Guide to best practices in ocean acidification research and data reporting,’ which has been widely distributed to standardize research protocols.
- Policy Impact: Played a significant role in raising global awareness, contributing to major policy activities (e.g., IPCC AR5) and producing multilingual guides for policymakers.
- Educational Content: Produced award-winning outreach materials, including the animation ‘The other CO2 problem and the movie ‘Tipping point’.
