Shell records show climate change is causing California waters to acidify twice as fast as global average in stark warning for ocean health
- Oceans off the coast of California are acidifying twice as fast as global average
- Scientists say that carbon emissions and natural cycles are to blame
- The health of coral reefs and shellfish supplies are both at risk
Scientists have issued a stark new warning about climate change in a study that shows waters off the coast of California are acidifying two times faster than the global average.
The first-of-its-kind study by researchers from the National Oceanic and Atmospheric Administration (NOAA) used thousands of tiny shells called foraminifera pulled from the seafloor outside of Santa Barbara to create a snapshot.
‘By measuring the thickness of the shells, we can provide a very accurate estimate of the ocean’s acidity level when the foraminifera were alive,’ said lead author Emily Osborne.
Pictured above are colorful foraminifera shells taken from mud of core samples and put under a microscope
This image of a foraminifera shell has been magnified 650 times its size by a scanning electron microscope
Scientists say shells examined by researchers were 20 percent thinner than they were a century ago due to lower than usual calcification brought on by increased acidity.
This disconcerting rise in ocean acidity continues to endanger marine life and threaten a vital fishing industry that employs thousands of workers, they say.
Like soil, ocean waters absorb CO2 from the Earth’s atmosphere, and have born the brunt of increased emissions.
According to the New York Times, ocean waters have taken on as much as 27 percent of the carbon produced by humans worldwide.
Once absorbed, rapid changes in acidity and alkalinity come with it. This drastic change in the chemical composition has wreaked havoc on sea life, especially once teeming coral beds which rely on the right acidity to produce their skeletons.
Additionally shellfish commonly eaten by humans like oysters, clams, and sea urchins, soften suffer due to increased acidity and could affect nearly a billion people who rely on ocean-based food as their main source of protein according to the NOAA.
Pictured above is a fisherman off the coast of Santa Barbara, California. The fishing industry is among the potential victims of increased ocean acidfication (stock photo)
Compounding matters off the coast of California is a natural process known as Pacific Decadal Oscillation – a cyclical phenomenon in which ocean currents can drastically drive carbon-rich waters upward and further amplify ocean acidfication.
‘During the cool phases of the Pacific Decadal Oscillation, strengthened winds across the ocean drive carbon dioxide-rich waters upward toward the surface along the West Coast of the U.S.,’ said Osborne.
‘It’s like a double whammy, increasing ocean acidification in this region of the world.’
This confluence of factors is casting doubt on whether ocean life will be able to adapt quickly enough to survive rapidly changing environments according to scientists.
‘We know that evolution works and every creature has some degree of plasticity in them… the environment is changing so fast that we’re probably outstripping the role that it can play,’ Gretchen Hofmann, a marine biologist at the University of California, Santa Barbara,told the New York Times.
WHAT IS CORAL BLEACHING?
Corals have a symbiotic relationship with a tiny marine algae called ‘zooxanthellae’ that live inside and nourish them.
When sea surface temperatures rise, corals expel the colourful algae. The loss of the algae causes them to bleach and turn white.
This bleached states can last for up to six weeks, and while corals can recover if the temperature drops and the algae return, severely bleached corals die, and become covered by algae.
In either case, this makes it hard to distinguish between healthy corals and dead corals from satellite images.
This bleaching recently killed up to 80 per cent of corals in some areas of the Great Barrier Reef.
Bleaching events of this nature are happening worldwide four times more frequently than they used to.
An aerial view of Australia’s Great Barrier Reef. The corals of the Great Barrier Reef have undergone two successive bleaching events, in 2016 and earlier this year, raising experts’ concerns about the capacity for reefs to survive under global-warming