Ocean Acidity Reaches Dangerous Levels, Scientists Warn

Ocean acidity is a critical indicator of the planet’s health, as excessive acidification can have catastrophic consequences. A recent study suggests that the world’s oceans are now entering a dangerous zone in terms of acidity.

A team of researchers from the US and UK focused on the planetary boundary for ocean acidification, defined as a 20 percent decrease in average surface aragonite saturation – a vital component for the shells and skeletons of many marine organisms.

By combining computer models with field measurements, the scientists discovered that globally, the oceans are either very close to or have exceeded this boundary. Approximately 60 percent of deeper waters and 40 percent of surface waters have surpassed the threshold.

Based on the observed damage, the team proposes setting the boundary at a 10 percent drop in aragonite saturation, a level that the ocean as a whole surpassed at the beginning of the millennium.

Biological oceanographer Helen Findlay from Plymouth Marine Laboratory (PML) in the UK noted, “The polar regions exhibit the most significant changes in ocean acidification at the surface. In deeper waters, the most substantial alterations occur in regions just outside the poles, along the west coast of North America, and near the equator.”

Although ocean acidification may not be immediately noticeable from the shore, its impact is profound. It harms coral reefs, renders waters inhospitable for shell-forming creatures, and weakens marine life, leading to disruptions in the ecosystem.

This acidification occurs when carbon dioxide is absorbed by the ocean and reacts with water. As greenhouse gas levels increase in the atmosphere, the acidity of the world’s oceans rises.

Helen Findlay emphasizes, “Since these deeper waters are changing significantly, the consequences of ocean acidification could be more severe than anticipated. This poses a significant threat to crucial underwater ecosystems like tropical and deep-sea coral reefs, which serve as essential habitats and nurseries for numerous species.”

Scientists have identified eight planetary boundaries, and six of them have already been breached. Ocean acidification would mark the seventh boundary crossed, underscoring the precarious state of the Earth.

The researchers advocate for prompt action to address the risks, with targeted interventions in the most vulnerable areas to acidification. Protective measures should also be implemented for regions less impacted thus far.

Steve Widdicombe from PML, not part of the study, warns, “Ocean acidification is not just an environmental crisis – it’s a time bomb for marine ecosystems and coastal economies. Delaying action jeopardizes both biodiversity and billions in economic value.”

The study has been published in Global Change Biology.