Recent research indicates that deep oceans are crossing critical boundaries, which jeopardizes their functions of providing food and oxygen to marine life above.
Approximately 66% of the ocean lies deeper than 200 meters (less than 656 feet), and nearly half of those areas are experiencing acidity levels that exceed “safe” thresholds. This information was published in Global Change Biology on Monday.
The reduction in ocean pH poses a significant risk to marine ecosystems and coastal economies, described as a “time bomb” by researchers.
This study received partial funding from the National Oceanic and Atmospheric Administration (NOAA), which has faced funding cuts targeting its climate research activities.
Notably, some of the most drastic changes in deep waters are occurring off the western coast of North America, a region crucial for both crab and salmon fisheries.
Scientists have long warned about this key issue: the ongoing combustion of fossil fuels releases carbon dioxide, which, when dissolved in water, increases ocean acidity. So, technically, the oceans are becoming less basic. This is detrimental, especially for species like corals and clams that are foundational to marine ecosystems.
“Most marine life doesn’t just reside at the surface. The water below hosts various plant and animal species, and due to changes in these deep waters, the consequences of acidification could be more severe than previously thought.”
Five years ago, Findlay’s research suggested that oceans may have surpassed a significant threshold for calcium carbonate levels, a crucial component of limestone and the shells of marine animals, which have fallen over 20% below pre-industrial levels.
According to research from the Potsdam Institute for Climate Impact Research, this shift indicates that we have crossed seven vital “planetary boundaries” necessary for maintaining healthy ecosystems.
Widdicombe from the Marine Research Institute noted, “This means we’re witnessing the loss of essential habitats that numerous marine species rely on.”
“From coral reefs that support tourism to shellfish industries that benefit coastal communities,” he added.
The implications are particularly alarming. The rise or fall of ocean acidity is linked to the absorption of about one-third of all carbon dioxide emitted from fossil fuel combustion.
However, increased carbon dioxide absorption leads to diminished capacity for the ocean to absorb more, resulting in accelerated surface warming.
As noted by NASA, the oceans have absorbed about 90% of the world’s excess heat, which would have otherwise affected the Earth’s surface temperature.
Besides sequestering heat and carbon dioxide, the ocean produces half of the Earth’s oxygen. This vital process is currently jeopardized by warming and acidification incidents threatening marine ecosystems.
As ecosystem degradation continues and fossil fuel usage persists, oxygen levels lower in subsurface waters more rapidly than at the surface.
