NEW RESEARCH SHOWS THAT OCEAN ACIDIFICATION IS MORE ADVANCED THAN PREVIOUSLY THOUGHT

New research shows that ocean acidification is more advanced than previously thought. The findings, that were published ‘Ocean Acidification: Another Planetary Boundary Crossed’ for the journal Global Change Biology, highlight that the threat to marine ecosystems worldwide from ocean acidification is far more extensive than was previously understood.

Until now, ocean acidification had not been deemed to have crossed its ‘planetary boundary’, however, this major new study, led by the UK’s Plymouth Marine Laboratory (PML), the US-based National Oceanic and Atmospheric Administration (NOAA), CIMERS (Oregon State University) and the University of Maryland, has found that this ‘boundary’ was actually reached around five years ago. The study also showed:

• By 2020, the average ocean condition worldwide was already very close to, and in some regions beyond, the “danger zone” for ocean acidification.
• Exploring deeper into the ocean (down to about 200m below the surface), it was discovered that around 60% of these deeper waters had crossed the boundary, compared to 40% of the water at the surface. This increase in ocean acidification has major implications for the survival of many sea creatures, especially those that build shells or skeletons from calcium carbonate.
• The damage is already showing: selected tropical and subtropical coral reefs have lost 43% of their suitable habitats, sea butterflies (pteropods, a key foodweb species) in polar regions have lost up to 61% of their habitat, and coastal shellfish species have lost 13% of their global coastline habitats in which they can sustain their essential biological processes.

PML’s Professor Helen Findlay, Biological Oceanographer and Chair of North East Atlantic Ocean Acidification (NEA-OA) Hub, who led the study explains:

“Looking across different areas of the world, the polar regions show the biggest changes in ocean acidification at the surface. Meanwhile, in deeper waters, the largest changes are happening in areas just outside the poles and in the upwelling regions along the west coast of North America and near the equator.”

“Most ocean life doesn’t just live at the surface – the waters below are home to many more different types of plants and animals. Since these deeper waters are changing so much, the impacts of ocean acidification could be far worse than we thought. This has huge implications for important underwater ecosystems like tropical and even deep-sea coral reefs that provide essential habitats and nursing refuge for many species, in addition to the impacts being felt on bottom-dwelling creatures like crabs, sea stars, and other shellfish such as mussels and oysters”.

PML’s Director of Science, Professor Steve Widdicombe, who is also Co-chair of the Global Ocean Acidification Observing Network (GOA-ON) and the co-focal point for the UN’s Sustainable Development Goal (SDG) 14 Target 3 that aims to minimize and address the impacts of ocean acidification, commented:

“Ocean acidification isn’t just an environmental crisis – it’s a ticking time bomb for marine ecosystems and coastal economies. As our seas increase in acidity, we’re witnessing the loss of critical habitats that countless marine species depend on and this, in turn, has major societal and economic implications.”

“From the coral reefs that support tourism to the shellfish industries that sustain coastal communities, we’re gambling with both biodiversity and billions in economic value every day that action is delayed”.

The full paper can be accessed here

Image credit: Plymouth Marine Laboratory (PML)

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