Oxygen levels are dropping and ocean waters are acidifying at the fastest rate in at least 300 million years when the greatest marine extinction in earth's history took place according to The State of the Ocean Report 2013 written by an international panel of marine scientists.
Today's explosive increase in human CO2 emissions and warming of the oceans are recreating the conditions of the great Permian extinction 300 million years ago when massive volcanic eruptions in Siberia triggered the release of enormous amounts of stored carbon. A leading theory is that deoxygenation and acidification of the oceans led to the bacterial production of toxic hydrogen sulfide gas which poisoned species dependent on oxygen. By the end of this natural catastrophe 90% to 95% of all marine species were extinct. The biodiversity of the oceans took 30 million years for to recover.
The next mass extinction event may have already begun.
the scale and rate of the present day carbon perturbation, and resulting ocean acidification, is unprecedented in Earth’s known history. Today’s rate of carbon release, at approximately 30Gt of CO2 per year, is at least 10 times faster than that which preceded the last major species extinction (the Paleocene Eocene Thermal Maximum extinction, or PETM, ca. 55 million years ago), while geological records indicate that the current acidification is unparalleled in at least the last 300 million years. We are entering an unknown territory of marine ecosystem change, and exposing organisms to intolerable evolutionary pressure. The next mass extinction event may have already begun.
A "deadly trio” of acidification, warming and deoxygenation
Human CO2 emissions directly cause both global warming and ocean acidification. But that's just the beginning. Mixing tends to decline in warming waters because a warm fresh surface layer is substantially lighter than colder middle and deep water. The surface layer tends to float and not mix. Organic carbon is always falling from the surface to deeper waters. Bacteria oxidize the fallen carbon to CO2. This process reduces oxygen levels and increases the acidity of the water. When the rate of mixing declines the residence time of water in a layer increases, so acidity levels tend to rise and oxygen levels drop in layers below the surface as the climate warms.
Hypoxic - low oxygen - water may be already killing keystone species in the Pacific northwest.
COOS BAY — Something is killing large numbers of a keystone species off the Oregon Coast. Federal researchers say it could spell danger for the region’s other marine life.
Bill Peterson, an oceanographer with the National Oceanic and Atmospheric Administration’s Hatfield Marine Science Center in Newport, said in the past few weeks millions of dead North Pacific krill have washed up on beaches between Newport and Eureka, Calif.
Peterson said it’s the largest die-off he’s aware of in recent history. ...
Joe Tyburczy, a researcher with the California Sea Grant extension office who has been looking into the dead krill with Peterson, said oceanographic cruises along the northern California coast did find lower oxygen levels than usually seen in Pacific Northwest waters.
“If it is hypoxia, there’s a possibility of implications for other species like crab,” he said.
Acidification of sea water in Washington State oyster hatcheries killed the developing oysters. Please watch this outstanding video on ocean acidification.
Oysters started dying by the billions along the Northwest coast in 2005, and have been struggling ever since. When scientists cautiously linked the deaths to plummeting ocean pH in 2008 and 2009, few outside the West Coast’s $110 million industry believed it.
By the time scientists confirmed it early last year, the region’s several hundred oyster growers had become a global harbinger — the first tangible sign anywhere in the world that ocean acidification already was walloping marine life and hurting people.
Richard Feely and a team of scientists from Pacific Marine Environmental Lab were stunned to discover cold, acidic, low-oxygen water welling up to the surface along the northern California coast in 2007. Scientists had not expected acidification to hit the west coast for 50 to 100 years. Dr. Feely published his work and word of it reached oyster farmers who's hatcheries were failing.
The oyster farmers invited Feely to their annual conference.
Feely explained that when north winds blew, deep ocean water was drawn right to the beach, which meant this newly corrosive water probably got sucked into the hatchery. That same water also flowed into the Strait of Juan de Fuca and made its way to Hood Canal.
The oyster industry pleaded with Congress, which supplied money for new equipment. Over several years, the hatcheries tested their water using high-tech pH sensors. When the pH was low, it was very low and baby oysters died within two days. By drawing water only when the pH was normal, shellfish production got back on track.
“They told us it was like turning on headlights on a car — it was so clear what was going on,” Feely said.
Moreover, because processes in the ocean are slow to change this deadly water would continue to affect the Pacific northwest for another 50 years if all human CO2 emissions stopped today. It will take 30 to 50 years for the most acidic water already present along the west coast to well up. This is the beginning of a disaster that we cannot stop. The best we can do is to keep it from growing far larger and far more deadly. The changes happening in the waters of the Pacific northwest are the first stages of a global marine catastrophe if CO2 emissions are not rapidly reduced.
Deadly trio will have cascading consequences for marine biology & humans
It is the simultaneous occurrence of the “deadly trio” of acidification, warming and deoxygenation that is seriously effecting how productive and efficient the ocean is, as temperatures, chemistry, surface stratification, nutrient and oxygen supply are all implicated, meaning that many organisms will find themselves in unsuitable environments.
These impacts will have cascading consequences for marine biology, including altered food web dynamics and the expansion of pathogens. To make matters even worse, this is all happening to marine ecosystems already undermined by other human pressures such as overfishing, eutrophication and pollution.
The adaption of species to these altered conditions is in some cases possible – as is migration, though as warming demands a poleward migration while acidification encourages the movement to warmer more equatorial waters the “green pastures” will become increasingly scarce and competition for them fierce. Mass extinctions happen in the geological equivalent of overnight; we may already have entered into an extinction period and not yet realized it. What is certain is that current carbon perturbations will have huge implications for humans, and may well be the most important challenge faced since the first hominids evolved.
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