NCAR: Global Temperature Increase To Lower Oxygen Content of Most Ocean Zones by the 2030s

A reduction in the amount of oxygen dissolved in the oceans due to climate change is already discernible in some parts of the world and should be evident across large regions of the oceans between 2030 and 2040. — The National Center for Atmospheric Research in a press release on April 27th.

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Loss of oxygen in the world’s oceans. It’s one of those really, really bad effects of a human-forced warming of our Earth. One of the those climate monsters in the closet that Steve Pacala talks about. The kind of thing we really don’t want to set loose.

Deoxygenated Oceans as Major Killing Mechanism During Hothouse Extinctions

The damage caused by ocean oxygen loss is multi-variant and wide-ranging. The most obvious harm comes in the form of generating environments in which oxygen-dependent life in the oceans can no longer breathe. Any living creature that filters oxygen out of the water for respiration falls under threat due to lowered ocean oxygen levels. A group that includes pretty much all the advanced, multi-cellular life in the seas.

A press statement from the new NCAR study notes:

Scientists know that a warming climate can be expected to gradually sap the ocean of oxygen, leaving fish, crabs, squid, sea stars, and other marine life struggling to breathe.

namibia-hydrogen-sulfide-emission-2007

(Hydrogen sulfide producing bacteria blooms off the coast of Namibia during 2007. Hydrogen sulfide is a highly toxic gas. One that is produced by microbes that live in waters containing little or no oxygen. Image source: Earth Observatory.)

But a second, less immediately obvious hit comes in the form of generating expanding anoxic environments that favor the proliferation of toxin-producing microbes. Called dead zones, these oxygen-poor regions not only provide a suffocation threat to sea life, but they also form areas of water in which environmental toxins can build up. The result is a long-lasting negative impact to the health of life in the ocean and, in the most extreme cases, on land and in the airs as well.

The worst of these toxin-generating microbes are the hydrogen-sulfide producing bacteria. An ancient organism that is incompatible with oxygen-dependent life. A horror out of deep time that has tended to crop up again and again on the list of usual suspects of major hothouse extinction killers. A likely perpetrator of the big ocean and land die offs during pretty much all global warming based extinctions. An organism that dominated the world’s seas and likely vented its deadly gasses into the airs of the world of the Permian — during the worst die-off Earth has ever seen.

In short, hydrogen sulfide is deadly to almost all forms of life that currently dominate the world’s oceans, lands, and airs. And the bacteria that produces hydrogen sulfide requires oxygen-poor environments in which to grow and thrive. A world ocean high in oxygen keeps these little killers hidden away in the deep, dark corners of our Earth. But heat the world ocean up. Deprive it of oxygen. And they start to come out and become a threat (see more in Awakening the Horrors of the Ancient Hothouse).

Oxygen Loss to Become Widespread by the 2030s

Already today we see regions of the world ocean that are experiencing oxygen loss. Some of this oxygen loss is due to a process called eutrophication. In eutrophication, nutrients overload the ecosystems of water-based environments. As nutrient content rises, large bacterial blooms emerge. Eventually, these blooms overpopulate the waters and devour all the food sources. When the microbes then die en masse, their decay robs the surrounding waters of oxygen — generating a dead zone.

Eutrophication has been sapping the world’s oceans of oxygen over wider and wider regions due to both agricultural run-off (fertilizers and top soils flushed into rivers, lakes and oceans that feed large microbial blooms and related dead zones) and due to nitrogen fall out from fossil fuel burning. But human forced global warming also plays a key roll in the loss of oxygen to the world ocean system.

Ocean Deoxygenation Map

(According to a new study from NCAR, ocean oxygen levels are already starting to fall in some regions due to global warming. If warming continues, NCAR finds that most of the world’s oceans will experience some level of oxygen loss due to this warming and due to a related increased stratification of surface waters. Image source: NCAR.)

The new NCAR study provides an excellent description of how warming the world’s surface waters can reduce ocean oxygen levels:

The entire ocean—from the depths to the shallows—gets its oxygen supply from the surface, either directly from the atmosphere or from phytoplankton, which release oxygen into the water through photosynthesis. Warming surface waters, however, absorb less oxygen. And in a double whammy, the oxygen that is absorbed has a more difficult time traveling deeper into the ocean. That’s because as water heats up, it expands, becoming lighter than the water below it and less likely to sink.

Waters that are less likely to sink are less likely to mix. And waters that are less likely to mix transfer less of the atmosphere’s oxygen to the global ocean. It’s a process called ocean stratification. A set of circumstances triggered by warming that can sap the world’s waters of their ability to support life even as it enhances their ability to generate environments favorable to toxin-producing microbes. And in the absolute worst cases, a stratified, oxygen-deprived ocean can transition into a dead, life-on-Earth-threatening Canfield Ocean.

Mobile Ocean Dead Zone

(Mobile ocean dead zones, like this one seen off the West African Coast during 2015, may grow more widespread as the world’s surface waters are depleted of oxygen due to a fossil fuel emission based warming. A new study from NCAR both explains how warming waters can hold less oxygen and notes that loss of oxygen to ocean surface waters becomes very widespread by the 2030s. Image source: Biogeosciences.)

In the NCAR study, which is well worth reading in full, scientists used model runs to determine when and where climate change would start to deprive the world ocean system of oxygen. The study found that regions off the coast of West Africa, regions west of South America, an area to the west of Australia, and a section of the Beaufort Sea were already experiencing lower levels of ocean oxygen due to global warming. West African seas were the first and hardest hit by warming in the models. This is interesting due to the fact that Namibia on the West Coast of Africa is one of the only regions of the world now observed to experience blooms of hydrogen sulfide producing bacteria that extend into the surface waters. West African waters have also generated a number of mobile, low-oxygen dead zones that have spiraled on off into the North Atlantic.

The fact that the NCAR study indicates that global warming has already reduced ocean oxygen levels in a region that is producing both dead zones and, in the case of Nambia, periods during which hydrogen sulfide producing bacteria appear at the surface, is cause for some concern. For by the 2030s, the NCAR model study indicates that global warming will be actively reducing ocean oxygen levels across the vast majority of the North Pacific, a majority of the South Pacific, most of the South Atlantic, and pretty much all of the Indian Ocean region covered in the new research. This raises the risk that open water dead zones like the ones seen off Africa and even hydrogen sulfide producing hot spots like Nambia may begin to creep into other regions of the world ocean — generating further threats to sea life, to fishing industry, and to human beings who depend on healthy oceans for livelihood and for life.

Links:

Widespread Loss of Ocean Oxygen (due to Climate Change) to Become Noticeable by the 2030s

Steve Pacala

Earth Observatory

Awakening the Horrors of the Ancient Hothouse

Biogeosciences

Mobile Ocean Dead Zones

Eutrophication

Ocean Stratification

Canfield Ocean

Hat Tip to Colorado Bob

Hat Tip to June

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Starving Sea Lion Pups and Liquified Starfish — How We’ve Turned the Eastern Pacific into A Death Trap for Marine Species

As of late January, the news reports were coming in hot and heavy. Baby sea lions were dying in droves. More than 15,000 of the pups were already lost due to starvation. And with each passing week, more than 100 of the emaciated, beleaguered, hopeless animals were washing up on California shores.

The pups staggered across beaches, wandered into vacant lots, or tottered, disoriented, along roadways. Refugees all to some unspeakable disaster. Orphans lost or abandoned by parents unable to provide them with even the most basic of sustenance.

Starving Sea Lion Pups

(Starving sea lion pups taken in by the Marine Mammal Center in San Francisco. Image source: WTSP.)

Marine rescue centers, volunteer centers, and even animal shelters were inundated by a flood of desperate, dying animals. Their organs were shutting down. They could barely breathe or walk. The future generation of the more than 300,000 sea lions living along the US West Coast taking a severe blow from a deadly killer lurking in West Coast waters.

By late February more than 1000 sea lion pups had flooded the California Marine Mammal Center. Hundreds more found their way into local and ad-hoc shelters. The number was so great that all support systems for the animals were overwhelmed. Persons finding and seeking help for the dying pups were, more often than not, turned away due to lack of support and rescue resources.

It was like the scene out of some heart-wrenching sci-fi disaster movie. And everyone kept asking the same question — what could cause this?

Mass Sea Lion Deaths for Three Years Running

This most recent spate of sea lion pup deaths and strandings comes after years of the same. News media currently reports the event in isolation — as if 2015 were the only year for such a thing to happen. But the truth is that this crisis has been ongoing now since at least 2013, with an earlier episode in 2009-2010 preceding the current chain of related events.

The 2013 event was so severe that in the end 70 percent of the 50,000 sea lion pups born that year had died. The 2014 event was rather less severe, accounting for ‘only’ twice the normal loss rate. But 2015 has so far been so deadly that even 2013’s staggering number of sea lion pup losses could be exceeded.

The multi-year event represents such a heavy blow to sea lions that marine organizations have declared the entire current young generation under threat of being wiped out.

Adult Sea Lions, Otters, Starfish, Birds and other Marine Creatures Involved

But the story doesn’t stop at young sea lion deaths alone. From May through August of last summer, reports were flooding in of mass adult sea lion, otter, and bird deaths due to what appeared to be exposure to some form of toxin.

The animals would wash up on the beach or drop out of the sky. They would show signs of convulsions. Autopsies of the deceased animals revealed shrunken hippocampus, brain and heart lesions.

The same marine mammal center that is now taking in over 1,000 baby sea lion pups this summer took in 751 adults suffering from these signs of toxic poisoning. Simply put, the adults died this past summer and now the pups are starving.

Further down the food chain, creatures living in bottom water zones were also suffering and dying. Fishermen off Oregon had to go further and further afield to fill nets. Near shore fishing lines came up empty except for crabs scurrying up the lines as if in an attempt to escape from danger below.

And in 2013, thousands upon thousands of starfish began to turn to white clumps. A freakish instance of mass star fish death that continued inexorably through 2015.

A Victim of Sea Star Wasting Syndrome

(A victim of Sea Star Wasting Syndrome. Image source: Crosscut.)

The star fish would succumb to a strange wasting illness. An illness that would ultimately waste whole swaths of multiple starfish species (20 separate starfish species and millions of animals are now thought to be involved). Entire regions saw their starfish populations dwindle to zero. As with the mass sea lion deaths, marine researchers were both stunned and befuddled.

Perhaps even more disturbing is that the various species deaths just keep on coming — with no apparent end in sight.

A Hothouse Serial Killer

Just off shore, a warm wind runs from south to north over the increasingly wasted waters. Warm airs born of warm waters, providing us with clues for the cause of this ongoing mass death event. For the seas off the US West Coast have reached record levels of warmth — a level of ocean surface heat that flared with the most recent El Nino in 2009 and 2010. A warming that has been building steadily ever since mortality events began their incessant march in 2013.

image

(Sea surface temperature anomaly map for February 27, 2015 depicting very large swath of much warmer than average sea surface temperatures running along the West Coast of North America through to the Bering Sea. Such widespread surface warming contributes to numerous detrimental changes to ocean health. Image source: Earth Nullschool. Data Source: Global Forecast System Model.)

Now a broad swath of surface water ranging from 2-5 C above average blankets an entire oceanic zone from Alaska to Mexico.

Such excess heat may seem innocuous at first blush. A little extra warm water may seem pleasant to the casual observer. But what seems pleasant actually conceals a deadly threat.

Warm surface waters spreading over the ocean can serve as a kind of lid. The warm water prevents cooler water from upwelling toward the surface, mixing nutrients and refreshing the water’s oxygen levels. This shut down of overturning is a dangerous oceanic condition called stratification. And it can level a severe blow to almost all creatures along the marine food chain. Plankton become less productive. Low oxygen zones expand, killing the slow-moving bottom creatures all while driving the mobile fish to more productive waters. In the warmer waters, toxic algae blooms become more prevalent. Harmful microbes, which are culled during influxes of cold water, thrive and multiply, posing a disease threat to all marine species. Finally, in the deeper reaches off the coasts of Washington and Oregon, the already oxygen-poor zones, zones rife with methane from hydrate venting, begin producing a deadly seep of hydrogen sulfide gas.

The living sea has now become a killer. And all it took was a little extra added heat to lock west coast waters in an expanding zone of warm water and low oxygen marine mortality.

Low Oxygen Ocean Zones

(The signature of ocean stratification expansion — low oxygen zones. Note the large and expanding region of low oxygen in the Eastern Pacific. For reference, high oxygen is shown in greens, blues and purples, low oxygen shown in oranges, reds and black. Image source: AMOP’s Study of Oxygen Minimum Zones. Image date: 2013.)

As a result we have the proliferation of the sea star wasting illness. An illness that would usually be contained by the seasonal influx of cooler waters. So too do we have instances of sea lion adults consuming fish, mullusks, and shellfish contaminated with domoic acid — a toxin produced by algae blooms in warm waters. And lastly, we have the overall stress on the food chain due to low oxygen and productivity which has driven sea lion food sources so far off shore that females are too exhausted after hunting to feed their pups.

More Dangers to Come

The recent mortality events mirror ocean warming episodes which caused similar die-offs at the end of glacial periods. Then, as now, warming robbed waters of oxygen and productive mixing, causing stress to numerous species.

However, the current pace of human warming is much more rapid than the warming periods that occurred at the ends of the ice ages. In addition, under business as usual human carbon emissions, the deadly, low-oxygen ocean zones are expected to expand, eventually covering the majority of the world ocean system. It’s a transition to a stratified ocean that will make the current west-coast die-off look like a minor prelude by comparison.

Hydrogen Sulfide Eruption off Namibian Coast

(Hydrogen sulfide eruption off Namibian coast on February 15, 2015. In Namibia, anoxic bottom waters host hydrogen sulfide producing bacteria. Runoff rich with organic material feeds these bacteria as they produce more toxic hydrogen sulfide gas. During upwelling events, the hydrogen sulfide is brought to the surface where it is visible as a florescent green or black slick. Under stratified and Canfield Oceans, more and more regions are capable of supporting deadly hydrogen sulfide production. Currently, the Baltic Sea, Offshore Namibia, the Chesapeake Bay, and Offshore Oregon are known to host broad regions of hydrogen sulfide producing bacteria in anoxic dead zones. Only in Nambia do these zones occasionally reach the surface waters, so far. Image source: Earth Observatory/NASA.)

Eventually, if CO2e levels exceed 800-1000 parts per million, a transition to an even more deadly state called a Canfield Ocean is increasingly likely. And a Canfield Ocean is a powerful killing machine. Implicated all the previous hothouse extinctions, this killer, during the Permian Extinction, was likely primarily responsible for the deaths of 95 percent of species in the ocean and 70 percent of species on land. For the oceans eventually filled up with deadly toxins (primarily in the form of hydrogen sulfide gas) which then vented into the atmosphere.

It’s a very deadly ocean state we want to avoid at all costs. And we should view these very troubling instances of ocean species mortality along the North American West Coast as a warning to stop warming to oceans as swiftly as possible.

Links:

 Here’s Why Hundreds of Sea Lion Pups are Washing Ashore in California

Researchers Find Warmer Waters Increase Sea Bed Methane Emissions

Surge in Marine Mammal Strandings on US West Coast

On California Coast, Biotoxins Cause of Deadly Sea Lion Siezures, Seafood Scare

Unprecedented Sea Lion Mortality Along California Coast Associated With Anomalous Ocean Conditions

Pelagic Zone: Commons

Global Warming May Boost Dead Zones in Oceans

Eastern Pacific Oxygen Minimum Research

Starving Sea Lion Pup Rescued on San Fransisco Boulevard

Sea Star Wasting Continues: Will King of the Rock Fall?

Pacific Rocky Intertidal Monitoring: Sea Star Wasting Syndrome

When the Stars all Go Out Along the Coast

Hydrogen Sulfide Eruption: Namibia

Earth Nullschool

Global Forecast System Model

Hat Tips:

Colorado Bob

Lief Thurston

Anoxic Oceans, Biotoxins and Harmful Algae — Missing Links in Mass Dolphin Deaths on US East Coast?

Dolphin Strandings

(East Coast Dolphin Strandings by State and Year. Image source: NOAA)

According to reports from NOAA, as of early October more than 550 dolphins had died and washed up along the US East Coast. The deaths, which NOAA has causally linked to morbillivirus infection, are occurring at a more rapid pace than the massive 1987 die-off which eventually resulted in more than 1100 East Coast dolphin deaths over the course of a 1 year period. By the time the first three months had passed in the 1987 die-off about 350 dolphins had perished. If the current event lasts as long as the 1987 die-off we could possibly see nearly 2000 deaths, setting up the current event as the worst in modern memory.

Morbillivirus — Cause, or Symptom of a More Ominous Problem?

In recent calls to NOAA and the various state institutes of marine science, I continue to receive confirmation that morbillivirus is listed as the primary cause of dolphin deaths. Most of the stranded dolphins have tested positive for morbillivirus and the disease has been implicated in dolphin deaths before. (For reference, morbillivirus is the same disease that causes measles in humans and is similarly virulent in dolphins. )

That said, numerous scientific sources, including The Scientific American and researchers at the NRDC, have questioned whether morbillivirus is the primary cause or just a symptom of a larger problem with ocean health. They point to research showing stranded dolphins with high levels of biotoxins in fatty tissue and individuals that are generally plagued by parasites and other infections. Many of these dolphins display compromised or weakened immune systems as a result of elevated toxicity levels. Meanwhile, a large enough segment of these animals are among the adult population to rule out age as a major secondary cause of mortality.

Algae Blooms as Source of Biotoxins

East Coast Algae Bloom

(Satellite Shot of Green and Brown Tinted Water Indicative of Algae Blooms off the Virginia Coast on Oct 18. Image Source: Lance-Modis)

Sitting on the top of the food chain as one of the oceans’ high-order predators, dolphins consume a large volume of fish. These fish, in turn, are fed by lower food chain sources. As food passes up the chain, any toxin within the food will reach higher levels of concentration, making top order predators, like dolphins, more vulnerable to poisoning.

The biotoxins found in recently deceased dolphins can be linked to harmful forms of algae that tend to develop in low oxygen ocean environments. Some of these toxins can cause various forms of food poisoning in mammals (including humans). Others, like hydrogen sulfide, can build up in adipose tissue to have a number of long-term effects resulting in stresses to major organ systems, neurological and psychological health, and strains on a body’s immunity to disease and infection.

Most of the dead dolphins discovered, thus far, are either males or nursing infants. Both are more vulnerable than females to toxicity due to the fact that males have no means of rapidly shedding biological toxins and infants receive higher doses of harmful substances from toxins concentrating in mother’s milk.

Fasting Dolphins Likely to be More Affected

As toxins build up in the dolphins’ fatty tissues, they come under increased risk of immuno compromise and infection during times when they tap the energy from these stores. Elevated toxicity can happen any time a dolphin may decide to fast rather than forage. As the fats are tapped by the body, the toxins are re-released into the dolphin’s blood stream where they can build up to harmful levels.

Morbillivirus Shouldn’t be So Lethal

Supporting the biotoxin/immuno compromise theory is the fact that morbillivirus shouldn’t carry such a high lethality rate. The virus normally only results in death among the most vulnerable individuals — primarily the very young, the very old, or the already weak or sick. The fact that morbillivirus, in this case, is carrying such a high lethality rate is a direct sign that the virus isn’t the only cause and that a higher portion of the dolphin population is far less healthy than is usual. High biotoxin levels in dead dolphins also point toward a combination of causes.

Dying Oceans and Dying Dolphins

A recent report on the health of the world’s oceans resulted in ominous findings that may also provide further hints as to why so many East Coast dolphins are dying this year. The IPSO 2013 State of the Oceans report found that oceans were experiencing anoxia (loss of oxygen) not just along coastal regions where human nutrient run-off was resulting in massive algae blooms and dead zones, but also in the deep ocean. There, in even the far off-shore waters, ocean oxygen levels were falling. Other high order predators, requiring high oxygen levels to sustain their high metabolisms — like the deep sea marlin — were found to have changed their migratory patterns to avoid deep ocean, oxygen-poor, dead zones forming and expanding throughout the world’s oceans.

The expanding anoxia is both an ocean killer and a direct signal of the changes resulting from human caused climate disruption. Warmer ocean waters hold less oxygen in solution and so they dump more into the atmosphere. In addition, increased fresh water run-off from melting glaciers and more intense rainfall events (due to increases in the world’s hydrological cycle directly caused by warming), result in less mixing of surface waters and deeper waters. Increased run-off also results in more algae blooms which further starve the oceans of oxygen.

These all contribute to increasingly anoxic waters. And once the ocean environment flips to anoxic states, it becomes a host to numerous toxin-producing bacteria. These toxins, in turn, end up in the food chain and directly impact the dolphins and a whole host of other animals.

In other words, a more anoxic ocean is an ocean that produces more harmful bacteria. An ocean full of harmful bacteria is one that increases the risk of dolphin mortality. And when we see spikes in dolphin deaths, as we have on the US east coast this year and on the US gulf coast for every year since 2010, we had better sit up and pay attention. As it’s a clear signal that the oceans, as a whole, are in trouble.

Implications for Both Ocean and Land Dwellers

Because the ocean and the atmosphere are interconnected and because humans greatly rely on the oceans for both foods and livelihoods, it is pure folly to ignore the ongoing plight of the world’s oceans. Toxic fish, mass deaths of ocean animals, and a thinning of the ocean biosphere could result in the loss of enough food to feed upwards of a billion people. Increasing instances of toxic algae blooms will also likely result in higher sickness and mortality rates for those who frequently come into contact with the seas. In the most extreme cases, blooms of hydrogen sulfide producing bacteria could poison the air near toxic algae blooms, resulting in severe hazards for those who live on land.

Transitioning to a stratified, anoxic and/or Canfield ocean state is an outcome of climate change that is all too often ignored. A risk that should be listed among the worst potential outcomes of human greenhouse gas emissions. A risk that has echoes in the great Permian Extinction event in our world’s deep past. It is a danger exists now and the growing risk of its emergence are becoming increasingly apparent.

Signal Received?

The dolphins, our ‘sentinels of ocean health’ are dying. And in their deaths are a message that we should be hearing loud and clear. Will we listen?

Links and Hat Tips:

The State of the Oceans, 2013

Are Dolphins Reaching a Breaking Point?

Are Humans Behind the East Coast Dolphin Die-Off?

Climate Change, Anoxic Waters and Dead Dolphins

Hat Tip to Commenter Steve

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