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Is Human Warming Prodding A Sleeping Methane Monster off Oregon’s Coast?

We’ve talked quite a bit about the Arctic Methane Monster — the potential that a rapidly warming Arctic will force the release of disproportionately large volumes of methane from organic material locked in permafrost and in frozen sea bed hydrates composing volumes of this powerful greenhouse gas large enough to significantly increase the pace of human-forced global warming. But if we consider the globe as a whole, the Arctic isn’t the only place where large methane stores lurk — laying in wait for the heat we’ve already added to the world’s oceans and atmosphere to trigger their release. And a new study out of the University of Washington provides yet another indication that the continental shelf off Oregon and Washington may be one of many emerging methane release hot spots.

For all around the world, and beneath the broad, blue expanse of the world’s seas, rest billions and billions of tons of frozen methane hydrate.

A kind of methane and ice combination, frozen hydrate is one of the world’s most effective natural methods of trapping and sequestering carbon. Over long ages, organic material at the bottom of the oceans decompose into hydrocarbons, often breaking down into methane gas. At high pressure and low temperature, this methane gas can be locked away in a frozen water-ice hydrate lattice, which is then often buried beneath the sea bed where it can safely remain for thousands or even millions of years.

Plume2_nolabels_cropped

(Plume of methane bubbles rising from the sea floor off the Oregon Coast. This image shows methane bubbles originating from the sea bed about 515 meters below the surface before dissolving into the water column at about 180 meters depth. Image source: American Geophysical Union.)

Most of these deposits lay well beneath the sea bed or at extreme ocean depths of one mile or greater. And so far, human forced warming hasn’t been great enough to risk the destabilization of most of these deep ocean carbon stores. But some hydrate deposits rest in the shallower waters of continental slope systems and at depths where current warming may now be causing them to destabilize.

Scientists Think Methane Hydrates May be Destabilizing off Oregon

Enter a new study by University of Washington scientists which found “an unusually high number of bubble plumes at the depth where methane hydrate would decompose if seawater has warmed.” The scientists concluded that these bubble plumes were likely evidence of methane hydrate destabilization due to a human forced warming of the water column in the range of about 500 meters of depth.

The warm waters, ironically, come from a region off Siberia where the deep waters have, over recent decades, been heated to unprecedented temperatures. These waters have, in turn, through ocean current exchange, circulated to the off-shore region of Washington and Oregon where they appear to have gone to work destabilizing methane hydrate in the continental slope zone. A paper published during 2014 hypothesized that these warm waters would have an impact on hydrates. And the new paper is the first potential confirmation of these earlier predictions.

In total about 168 methane plumes are now observed to be bubbling out of the sea bed off the Washington and Oregon coasts. Of these, 14 are located in the 500 meter depth range where ocean warming has pushed temperatures to levels at which hydrate could begin to destabilize. University of Washington researchers noted that the number of plumes at this depth range was disproportionately high, which also served as an indirect indicator that human heating may be causing this methane to release.

PlumesMap

(Locations of methane plumes in the continental slope zone off Washington and Oregon. The location of a disproportionate number of these plumes in a zone now featuring a warming water column is an indication that the human-forced heating of ocean currents is starting to drive some methane hydrate structures to destabilize. Image source: AGU.)

Lead author H. Paul Johnson, a University of Washington professor of oceanography noted in AGU:

“So it is not likely to be just emitted from the sediments; this appears to be coming from the decomposition of methane that has been frozen for thousands of years… What we’re seeing is possible confirmation of what we predicted from the water temperatures: Methane hydrate appears to be decomposing and releasing a lot of gas. If you look systematically, the location on the margin where you’re getting the largest number of methane plumes per square meter, it is right at that critical depth of 500 meters.””

Implications For Ocean Health, Carbon Cycle

Most methane released at this depth never reaches the atmosphere. Instead, it either oxidizes to CO2 in the water column or is converted by ocean bacteria. That said, expanding zones of methane release can rob the surrounding ocean of vital oxygen even as it can saturate the water column with carbon — increasing ocean acidification and reducing the local ocean’s ability to draw carbon out of the atmosphere. Such a response can indirectly increase the volume of heat trapping gasses in the atmosphere by reducing the overall rate of ocean carbon uptake. In more extreme cases, methane bubbles reach the surface where they then vent directly into the atmosphere, proportionately adding to the human-produced greenhouse gasses that have already put the world into a regime of rapid warming.

It has been hypothesized that large methane releases from ocean hydrate stores contributed to past hothouse warming events and related mass extinctions like the Permian and the PETM (See A Deadly Climb From Glaciation to Hothouse). But the more immediate consequences of smaller scale releases are related to declining ocean health.

According to AGU and Dr. Johnson, the study author:

Marine microbes convert the methane into carbon dioxide, producing lower-oxygen, more-acidic conditions in the deeper offshore water, which eventually wells up along the coast and surges into coastal waterways. “Current environmental changes in Washington and Oregon are already impacting local biology and fisheries, and these changes would be amplified by the further release of methane,” Johnson said.

Instances of mass sea life die-off have already occurred at a very high frequency off the Washington and Oregon Coasts. And many of these instances have been associated with a combination of low oxygen content in the near and off shore waters, increasing ocean acidification, increasing dangerous algae blooms, and an overall warming ocean system. It’s important to note that ocean acidification, though often cited in the media, is just one of many threats to ocean life and health. In many cases, low oxygen dead zones and large microbial blooms can be even more deadly. And in the most extreme low oxygen regions, the water column can start to fill up with deadly hydrogen sulfide gas — a toxic substance that, at high enough concentrations, kills off pretty much all oxygen-based life (See Hydrogen Sulfide in the World’s Warming Oceans).

During recent years, mass sea life deaths have been linked to a ‘hot blob’ forming in nearby waters (See Mass Whale Death in Northeast Pacific — Hot Blob’s Record Algae Bloom to Blame?). However, indicators of low oxygen in the waters near Washington and Oregon have been growing in frequency since the early 2000s. Though the paper does not state this explicitly — increasing rates of methane release in the off-shore waters due to hydrate destabilization may already be contributing to declining ocean health in the region.

Slope Collapse, Conditions in Context

A final risk associated with methane hydrate destabilization in the continental slope zone is an increased prevalence of potential slope collapse. As methane hydrate releases, it can deform the sea bed structures within slope systems. Such systems become less stable, increasing the potential for large underwater landslides. Not only could these large landslides displace significant volumes of water or even set off tsunamis, slope collapse events also risk uncovering and exposing more hydrate systems to the warming ocean in a kind of amplifying feedback.

In context, the total volume of methane being released into the off-shore environment is currently estimated to be about 0.1 million metric tons each year. That’s about the same rate of hydrocarbon release seen from the Deepwater Horizon blowout. A locally large release but still rather small in size compared to the whopping 10+ billion tons of carbon being dumped into the atmosphere each year through human fossil fuel burning. However, this release is widespread, uncontrolled, un-cappable and, if scientists are correct in their indications of a human warming influence, likely to continue to increase as the oceans warm further.

Links:

Bubble Plumes off Washington and Oregon Suggest Warmer Ocean May be Releasing Frozen Methane

Geochemistry, Geophysics, Geosystems

Warming Oceans May be Spewing Methane off US West Coast

Concern Over Catastrophic Methane Release

Hydrogen Sulfide in the World’s Warming Oceans

Mass Whale Death in Northeast Pacific — Hot Blob’s Record Algae Bloom to Blame?

A Deadly Climb From Glaciation to Hothouse

Hat tip to Humortra

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Human CO2 Emissions to Drive Key Ocean Bacteria Haywire, Generate Dead Zones, Wreck Nitrogen Web

Trichodesmium. It’s the bacteria that’s solely responsible for the fixation of nearly 50 percent of nitrogen in the world’s oceans. A very important role for this microscopic critter. For without nitrogen fixation — or the process by which environmental nitrogen is converted to forms usable by organisms — most of life on Earth would not exist.

Now, a new study produced by USC and the Massachusetts-based Woods Hole Oceanographic Institution (WHOI), has found that human carbon emissions are set to drive this essential organism haywire. Forcing evolutionary changes in which the bacteria is unable to regulate its growth. Thus generating population explosions and die-offs that will be very disruptive to the fragile web of life in the world’s oceans.

Trichodesmium_bloom,_SW_Pacific

(A Trichodesmium bloom off New Caledonia. Image source: Earth Observatory.)

Trichodesmium — A Mostly Helpful Bacteria Essential to Ocean Life

Trichodesmium is a form of cyanobacteria. It resides in the near surface zone composing the top 200 meters of the water column. Possessing gas vacuoles, the bacteria is able to float and sink through the water column in order to access the nutrients it needs for growth — nitrogen, iron, and phosphorus. A widespread bacteria, it is often found in warm (20 to 34 C), nutrient-poor waters in the Red Sea, the Indian Ocean, the North and South Atlantic, the Caribbean, near Australia, and in the Northeastern Pacific.

Trichodesmium congregates in blooms which are generally a straw-like color. For centuries, this coloration has generated its common name — sea straw. However, in higher concentrations it can turn waters red. The Red Sea, for example, owes its name to this prolific little bacteria. Trichodesmium blooms generate a strata that support mutualistic communities of sea creatures including bacteria, diatoms, dinoflagellates, protozoa, and copepods. These small organisms, in turn, are fed on by a variety of fish — notably herring and sardines.

But Trichodesmium’s chief role in supporting ocean health is through making nitrogen in the air and water available to living organisms. It does this by turning environmental nitrogen into ammonia as part of its cellular metabolism. This ammonia can then be used for growth by a wide variety of creatures on up the food chain. Trichodesmium is an amazing producer of this biologically available nitrogen — perhaps generating as much as 50 percent of organic nitrogen in the world’s oceans (70 to 80 million metric tons) each year.

Human Fossil Fuel Burning is Projected to Drive Trichodesmium Haywire

But now a new study by USC and WHOI shows that atmospheric CO2 concentrations projected to be reached by the end of the 21st Century in the range of 750 ppm CO2 could force Trichodesmium’s nitrogen fixation rate into overdrive and lock it there indefinitely.

Trichodesium Nitrogen Fixation before and after

(Rate of nitrogen fixation in Trichodesmium at 380 ppm CO2 [black and red], at 750 ppm CO2 [pink, yellow and light blue], and when CO2 levels are returned to 380 ppm after five years of exposure to 750 ppm levels [dark blue]. Image source: Nature.)

The study subjected Trichodesmium to atmospheric CO2 concentrations (750 ppm) projected under a somewhat moderate rate of continued fossil fuel burning scenario by 2100 for five years. After this five year period of exposure, Trichodesmium nitrogen fixation rates nearly doubled (see above graphic). But, even worse, after the Trichodesmium bacteria were returned to the more normal ocean and atmospheric conditions under 380 ppm CO2, the rate of nitrogen fixation remained elevated.

In essence, researchers found that Trichodesmium evolved to fix nitrogen more rapidly under higher ocean acidity and atmospheric CO2 states at 750 ppm levels. But when atmospheric levels returned to 380 ppm and when oceans became less acidic, Trichodesmium’s rate of nitrogen fixation remained locked in high gear. For an organism like Trichodesmium to get stuck in a broken rate of higher metabolism and growth is practically unheard of in evolutionary biology. Organisms typically evolve as a response to environmental stresses. Once those triggers are removed, organisms will typically revert to a near match of previous states. Strangely, this was not the case with Trichodesmium.

David Hutchins, professor at the USC Dornsife College of Letters, Arts and Sciences and author of the new study described this alteration to Trichodesium as ‘unprecedented’ stating that:

“Losing the ability to regulate your growth rate is not a healthy thing. The last thing you want is to be stuck with these high growth rates when there aren’t enough nutrients to go around. It’s a losing strategy in the struggle to survive.”

Uncontrolled Blooms, Population Crashes, Biotoxin Production, Dead Zones

Nitrogen is a key component of cellar growth. So Trichodesmium nearly doubling its rate of nitrogen fixation means that the bacteria’s rate of production will greatly increase as atmospheric CO2 levels and ocean acidification continue to rise. Under heightened CO2, the bacteria essentially loses its ability to restrain its population.

La-Jolla-Red-Tide.780

(Large algae/bacterial blooms like this red tide off La Jolla, San Diego are causing the expansion of hypoxic and anoxic dead zones throughout the world’s oceans. A new study has found that one of the ocean’s key microbes goes into growth overdrive as atmospheric and ocean CO2 concentrations rise — which would greatly enhance an already dangerous rate of dead zone expansion in the world ocean system. Image source: Commons.)

As a result, researchers warn that Trichodesmium blooms may run out of control under heightening levels of CO2. Such out of control blooms would rapidly remove scarcer nutrients like phosphorous and iron from the water column. Once these resources are exhausted, Trichodesmium would begin to die off en-masse. As with other large scale bacterial die-offs in the ocean, the decaying dead cellular bodies of Trichodesmium would then rob the nearby waters of oxygen — greatly enhancing an already much amplified rate of anoxic dead zone formation. And we know that anoxic waters can rapidly become home to other, far more dangerous, forms of bacterial life. In addition, large concentrations of Trichodesmium are known to produce biotoxins deadly to copepods, fish, and oysters. Humans are also rarely impacted suffering from an often fatal toxicity response called clupeotoxism when the Trichodesmium produced toxins biomagnify in fish that humans eat. Sadly, more large Trichodesium blooms will enhance opportunities for clupeotoxism to appear in human beings.

Exacerbating this problem of heightened Trichodesmium blooms and potential related dead zone formation is the fact that ocean waters are expected to become more stratified as human-forced warming continues. As a result, more of the nutrients that Trichodesmium relies upon will be forced into a thinner layer near the surface — thus heightening the process of bloom, die-off, and dead zone formation.

Final impacts to ocean health come in the form of either widely available nitrogen, (during Trichodesmium bloom periods) which would tend to enhance the proliferation of other microbial life, or regions of nitrogen desertification (during Trichodesmium die-offs). It’s a kind of ocean nitrogen whip-lash that can be very harmful to the health of life in the seas. One that could easily ripple over to land life as well.

No Return to Normal

But perhaps the most shocking finding of the new research was that alterations in Trichodesmium’s rate of growth and nitrogen fixation may well be permanent after the stress of high CO2 and ocean acidification are removed. Hinting that impacts to ocean health from a rapid CO2 spike would be long-lasting and irreparable over anything but very long time-scales. Yet more evidence that the best thing to do is to avoid a major CO2 spike altogether by cutting human carbon emissions to zero as swiftly as possible.

Links:

Irreversibly Increased Nitrogen Fixation in Trichodesmium in Response to High CO2 Concentrations

Climate Change Will Irreversibly Force Key Ocean Bacteria into Overdrive

Trichodesmium

Earth Observatory

Red Tide Algae Bloom off San Diego

Awakening the Horrors of the Ancient Hothouse

Trichodesmium: A Widespread Marine Cyanobacteria with Unusual Nitrogen Fixation Properties

Nitrogen Fixation

Hat Tip to Colorado Bob

Shades of a Canfield Ocean — Hydrogen Sulfide in Oregon’s Purple Waves?

Are we already starting to awaken some of the horrors of the ancient hothouse ocean? Are dangerous, sea and land life killing, strains of primordial hydrogen sulfide producing bacteria starting to show up in the increasingly warm and oxygen-starved waters of the US West Coast? This week’s disturbing new reports of odd-smelling, purple-colored waves appearing along the Oregon coastline are a sign that it may be starting to happen.

Purple Waves

(Purple waves wash over the Oregon beach of Neskowin on August 15. A form of hydrogen sulfide consuming bacteria is known to color water purple. Is this an indicator that the deadly gas is present in Oregon’s waters? Image source: Jeanine Sbisa and Beach Connection.)

A Dangerous Beauty

Oregon beachgoers and ocean researchers alike are flummoxed. There’s something strange in the water. Something that’s coloring the waves of Oregon’s beaches purple even as the off-shore waters are painted greenish-blue. These puzzling purple waves have been washing up along the Oregon Coastline for the better part of a month. And no-one seems to know exactly what’s causing it.

Eyewitness photographer Jeanine Sbisa described the scene at Neskowin:

“The purple was only on the edge of the water. I did not see any patches in the deeper water. ( in fact the deeper water was a beautiful turquoise, instead of the deep blue that it usually is at Winema). Some of the waves were a deep clear purple. Other waves in other segments were a rich foamy lilac color. The colors were amazing. Very beautiful.”

All up and down Oregon’s coastline similar reports have been surfacing. Oregon State Park Ranger Dane Osis photo documented another incident at Fort Stevens State Park near Astoria. And eyewitnesses at some locations have described a ‘funky smell’ issuing from some of the purple-colored waters.

Initial reports have claimed that there’s no evidence the purple waters are harmful. But such assertions may well be premature.

Purple Sulfur Bacteria

At issue is the fact that the waters off Oregon are increasingly warm. They are increasingly low oxygen or even anoxic. Conditions that are prime for the production of some of the world’s nastiest ancient species of microbes. The rotten-eggs smelling hydrogen sulfide producing varieties. The variety that paint the waters green (or turquoise as described by Jeanine Sbisa above) or even an ugly black. And there is one primordial creature in particular that thrives in warm, low-oxygen, funky-smelling water. An organism that’s well known for coloring bodies of water purple — the purple sulfur bacteria.

Purple Canfield Ocean

(Artist’s rendering of what a Canfield Ocean may have looked like. A Canfield Ocean is a deadly hothouse ocean state implicated in 5 of 6 major mass extinction events. And, perhaps, we see a hint of this deadly ocean along the Oregon coast today. Image source: Biogeochemistry.)

In order for blooms of purple sulfur bacteria to form, waters have to be low in oxygen or anoxic. There has to be hydrogen sulfide gas present in the water. And the water has to be relatively warm. This is because the bacteria is warmth-loving, anaerobic, and it uses the sulfur in hydrogen sulfide gas as part of its energy production process.

In the current day, the purple sulfur bacteria is present in anoxic lakes and geothermal vents. But during ancient times and during times of hothouse extinction, the purple sulfur bacteria are thought to have thrived in the world’s oceans — painting them the strange tell-tale purple we see hints of along the Oregon shoreline today. A purple that was the hallmark color of a life-killing hothouse ocean.

In his ground-breaking book “Under a Green Sky,” Dr. Peter Ward vividly describes what a Canfield Ocean may have looked like:

Finally we look out on the surface of the great sea itself, and as far as the eye can see there is a mirrored flatness, an ocean without whitecaps. Yet that is not the biggest surprise. From shore to the horizon, there is but an unending purple colour – a vast, flat, oily purple, not looking at all like water, not looking anything of our world. No fish break its surface, no birds or any other kind of flying creatures dip down looking for food. The purple colour comes from vast concentrations of floating bacteria, for the oceans of Earth have all become covered with a hundred-foot-thick [30m] veneer of purple and green bacterial soup.

The purple sulfur reducing bacteria, though not dangerous themselves, live in a kind of conjoined relationship with the much more deadly hydrogen sulfide producing bacteria. The purple, is therefore, a tell-tale of the more deadly bacteria’s presence. And hydrogen sulfide producing bacteria may well be the most dangerous organism ever to have existed on the planet — largely responsible for almost all the great extinction events in Earth’s deep history. For hydrogen sulfide itself is directly toxic to both land and ocean-based life. Its deadly effects are increased at higher temperatures. And not only is it directly toxic in both water and air, if it enters the upper atmosphere it also destroys the ozone layer.

(Video shot on July 18 [please excuse the colorful language] showing purple waters and dead jellies, barnacles and mussels on another Pacific Ocean beach. Video source: Gezzart.)

Purple waters are a sign that the little organisms that produce this deadly agent may be starting to bloom in an ocean whose health is increasingly ailing. Tiny tell-tales that we’re on a path toward a hothouse Canfield Ocean state. A path we really don’t want to continue along through the ongoing burning of fossil fuels. For that way leads toward another great dying.

*  *  *  *  *

Pigmented Salps — An Indicator of Bio-Magnification?

UPDATE TUESDAY, SEPTEMBER 1: According to reports from Oregon’s Department of Fish and Wildlife, Oregon’s purple waves are being caused by the large-scale spawning of an oxygen dependent jellyfish-like vertebrate called a salp in the near shore zones along the Oregon coastline. The normally clear salps have apparently developed a purple pigmentation which is coloring the waves in this region a strange hew. The findings, though seemingly reassuring, raise more questions than they do answers.

First, salps do not typically spawn in the near-shore region. However, during recent years, near shore salp spawnings have become more common leading to reports of these jellies washing up all along the U.S. Coastline. Phytoplankton and other bacteria are a typical food source for salps and the jellies are mobile enough to follow this food. So large blooms in the near shore ocean could be one reason for salps coming closer to shore.

Second, salps are typically clear — devoid of any pigmentation. So the question here is how are salps picking up this strange purple color? Since salps are filter-feeders known to eat bacteria, it’s possible that a highly pigmented food source or a source laden with purple sulfur bacteria may be resulting in this odd new coloration for salps. So identifying pigmented salps as the source of the purple coloration does not necessarily eliminate the possibility of sulfur reducing bacteria being present in either the near shore or the off shore waters where salps typically reside and feed. Pigmentation, in this case, may be due to salps bio-magnifying the natural pigmentation in their food source. Given the fact that salp coloration is practically unheard of, it’s somewhat puzzling that marine researchers haven’t investigated this particular mystery a bit further.

Third, the region off the Oregon coastline has been increasingly low in oxygen due to a combination of eutriphication, ocean current change, and ocean warming. This fact of declining ocean health in the off-shore Oregon environment is contrary to assertions circulated in some media sources claiming that large salp blooms are a proof that the environment in the bloom region is healthy. Salp blooms follow bacterial and phytoplankton blooms. And such blooms are well known triggers for dead zone formation. Though salps tend to aid in mitigating these blooms, their presence is not necessarily a sign of healthy waters. Conversely, in the case of very large algae blooms, salps presence may indicate just the opposite. Since salps are oxygen-dependent, it’s possible that the near shore environments where wave mixing tends to oxygenate the water is a drawing these vertebrate jellies closer in due to a loss of an off shore environment healthy enough to sustain them.

As with the freak appearance of pink pigmented salps at Manzanita during 2010, the widespread purple waves off Oregon during 2015 remain somewhat of a mystery. The key question as to why salps, that are known to be a clear-bodied species, are picking up a pigmentation very similar to that possessed by purple sulfur bacteria has not been answered.

Links:

Purple Waves Puzzle Oregon Coastal Scientists

Awakening the Horrors of the Ancient Hothouse — Hydrogen Sulfide in the World’s Warming Oceans

Purple Sulfur Bacteria

Canfield Ocean

Under a Green Sky

Biogeochemistry

Hat Tip to Wharf Rat

Awakening the Horrors of the Ancient Hothouse — Hydrogen Sulfide in the World’s Warming Oceans

“Dead Cthulu waits dreaming…” H.P. Lovecraft

In the 1930s, pulp horror writer H.P. Lovecraft penned tales of ancient monsters called Old Ones that, if awakened, would emerge to devour the world. One of these horrors, Cthulu, lay in death’s sleep in his house called R’lyeh at the bottom of the Baltic Sea (Charles Stross) awaiting some impetus to disturb him from necrotic slumber (ironically, the Baltic sea bed contains one of the world’s highest concentrations of the deadly hydrogen-sulfide producing bacteria that are a focus of this article).

Namibia Hydrogen Sulfide Emission 2007

(2007 Hydrogen Sulfide emission off the coast of Namibia. Such emissions tend to color the surface water green and, in extreme cases, black. Image source: Earth Observatory)

In the imaginary world of H.P. Lovecraft, terrible lore of these horrific Old Ones, among which, Cthulu was the worst, lay stored in ancient tomes. To learn of these mysteries was to risk madness. For the Old Ones were too awful for the human mind to conceive without succumbing to a hopeless darkness.

In researching the terrors that could emerge in a world destabilized by human warming, I am often reminded that human imagination is not without a sense of dramatic irony. But in this case, the irony invoked is that human imagining, in fiction, seems to sometimes possess a broader perception of potential real world risks and their implications for human thought, than the far more defined warning signal coming from the sciences.

Cthulu, in this case, may as well be a metaphor for one of the worst of the world’s ancient climate horrors — the oceanic production of hydrogen sulfide gas that occurred from time to time, during various hothouse events. A production implicated in many of the worst mass extinction events ever to mar the history of life on Earth.

Hydrogen Sulfide — Bi-product of Bacterial Metabolism in the Ancient Oceans

In understanding this ancient horror, we must first take a look at some of the world’s oldest and smallest creatures. Primordial bacteria.

About 3.5 billion years ago, the Earth was a hot, toxic place, bombarded by solar radiation. It was still cooling down after its initial formation. The oceans had spilled out over its surface, but the continents had yet to emerge. Atmospheric levels of CO2 were high and oxygen was virtually nonexistent.

676px-Dvulgaris_micrograph

(Desulfovibrio vulgaris, one of the most well-researched hydrogen sulfide producing bacteria. Image source: Commons)

But, in this world, small microbial organisms thrived. Deprived of oxygen, which is the now typical means of respiration for non plant organisms, the microbes required other sources for their simple cellular metabolism. Sulphate was common in the world’s emerging oceans and reacted well with hydrogen, which was also very common. The result was the emergence of some of the oldest known living organisms — the sulphate reducing bacteria.

Suphate reducing bacteria combined sulphate and hydrogen to produce hydrogen sulfide gas or H2S.

As a result, ancient oceans were cauldrons bubbling over with hydrogen sulfide which was the biproduct of these primordial organisms’ respiration in much the same way that oxygen is a biproduct of plant respiration and CO2 is a biproduct of animal respiration. Such an ocean state, called a Canfield Ocean by today’s scientists, was the common state for the world’s oceans until the emergence of more complex life around 2.5 billion years ago. By about 600 million years ago, the Canfield Ocean state only very rarely came into being and when it did, mass death tended to rapidly follow.

Changes Came With the Emergence of Oxygen

As the Earth system matured and new organisms came into being, CO2 reducing photosynthetic life emerged and began to produce an abundance of oxygen. Toxic to the ancient organisms, the abundance of oxygen pushed the sulphate reducing bacteria into the world’s low-oxygen corners. The deep ocean, or anaerobic mud became a haven for these tiny primordial monsters. Never again would they dominate as they once did. But, from time to time, when priomordial ocean states would infrequently emerge during various hot-house phases in Earth’s climate progression, these life forms would explode, producing prodigious volumes of what, to more complex life, was the very toxic hydrogen sulfide gas.

A Toxic, Volatile Gas

Hydrogen sulfide is directly toxic to most plant and animal based life. Its effects in animals are similar to that of hydrogen cyanide in that it eventually results in cardio-pulminary shock and then death. Lower levels of hydrogen sulfide are associated with loss of smell, blindness, respiratory infections, and loss of neurological and nervous system function. At very low levels, hydrogen sulfide is non toxic and is even produced in cells to perform various functions. Human lethality begins at around 600 parts per million. Smaller mammals with higher respiration rates begin to show lethality at around 450 ppm. Doses in the range of 10-20 parts per million have been known to cause eye irritation and damage over long periods of exposure. Levels over 50 ppm are generally considered harmful if exposure occurs for long durations. Doses between the irritation dose (10 ppm) and the lethality dose (600 ppm) over extended periods are shown to cause the eye damage and degenerative nerve and lung changes listed above.

In the environment, hydrogen sulfide causes numerous other damaging impacts. The gas reacts with hydroxyl and oxygen over the course of about 1 to 3 days to produce sulfur dioxide. Aside from providing a mechanism to draw down local oxygen levels, the sulfur dioxide product can end in the stratosphere where it substantially degrades the protective ozone layer.

Though hydrogen sulfide is slightly heavier than air, tending to pool at lower elevations, it is light enough to be born aloft by winds to various layers of the atmosphere and its even lighter sulfur dioxide products are quite a bit more mobile. At high enough atmospheric concentrations, both it and its sulfur products could begin to seriously degrade the Earth’s protective ozone layer. And evidence exists in the geological record of such events occurring on at least a couple of occasions during the last 250 million years. Notably, during the Permian extinction event, large numbers of fossils have been found with the characteristic UV damage that would occur in a world in which the ozone layer had been greatly degraded.

At high enough concentrations, hydrogen sulfide is volatile enough to burn. A 4.3 percent concentration is immediately combustible, producing a bluish flame. This extraordinarily high concentration would be almost immediately lethal to humans if inhaled and usually only presents a fire risk at highly concentrated sources.

In the current day, high concentrations of hydrogen sulfide gas are often associated with natural gas extraction. Natural gas, by volume, can contain as much as 90 percent hydrogen sulfide. The hydrogen sulfide, in this case, occurs due to catalytic reaction of the hydrocarbon with certain minerals present in the Earth. Though not produced by the same mechanisms as oceanic hydrogen sulfide, the gas in this form is just as dangerous and is a constant concern to workers of the oil and gas industry. Notably, risks of hydrogen sulfide exposure, leaks, and release into the environment have greatly increased with the widespread adoption of hydro-fracking practices that use high pressure liquids to rupture tight gas deposits and chaotically release the substance for its collection at one of the US’s 1 million well sites.

In general, the volatility, danger, and toxicity of the gas is difficult to overestimate. Notably, its lethality resulted in its use as a chemical weapon during World War I.

Culprit of Past Mass Extinctions

High concentrations of hydrogen sulfide, resulting both from its production in a Canfield type ocean state and, possibly, through its release in large methane pulses from the sea bed during catastrophic warming events, has been implicated in numerous mass extinction events both on land and in the ocean. Notably, the Permian-Triassic extinction, the Triassic-Jurassic extinction, and the PETM extinction in the deep oceans all show signs related to ocean anoxia and varying levels of hydrogen sulfide gas production. Earlier mass extinctions such as the Devonian and Ordovician extinctions were also likely caused by anoxia and related hydrogen sulfide production. Lesser extinctions in which ocean anoxia also probably played a part include  the Ireviken, Mulde, Lau, Toarcian and Cenomanian-Turonian events.

Prominent researchers such as Ward and Kump propose that hydrogen sulfide production by sulfate reducing bacteria is a primary extinction mechanism in stratified and anoxic oceans due to their inevitable multiplication in these environments which are, to them, far more favorable than oxygen-rich mixed oceans. In a Canfield Ocean world, large, episodic releases of hydrogen sulfide gas would cause local mass poisonings of land dwelling animals, especially of those living near large ocean-linked bodies of water. The ocean itself would be brimming full and spilling over with this nasty substance. This condition would be highly toxic to most life, requiring extreme adaptation to survive in naturally occurring havens.

Separate depletion of atmospheric oxygen through both the plant killing mechanism of hydrogen sulfide gas and its long-term reaction with oxygen would also make life far more difficult to terrestrial creatures. Finally, the massive amounts of sulfur dioxide produced in such a world would combine with the hydrogen sulfide pulsing into the atmosphere to create an ongoing, long-term degradation of the ozone layer, further harming surface dwelling plants and animals.

During the Permian Extinction, such conditions, together with other impacts of a global hothouse featuring a massive flood basalt, are thought to have wiped out more than 70% of terrestrial organisms and a total of more than 95% of all life on Earth.

Occurrence in Current Seas

Expanding Ocean Anoxia Hydrogen Sulfide in the Baltic Sea

(Expanding bottom anoxia, hypoxia and hydrogen sulfide production since 1960 in the bottom zone of the Baltic Sea. Red indicates region experiencing low or no oxygen content. Black indicates areas where H2S gas is detected. Image source: Baltic Sea Trends)

The world’s oceans, according to recent research, are rapidly becoming more stratified and less oxygen-rich. The result is that mixing between various layers of the ocean is beginning to shut down reducing oxygen content in the deep ocean and spurring the expansion of numerous oceanic dead zones.

Over the past 150 years, the Pacific Ocean was observed to become more stratified at a pace ten times that seen during the end of the last ice age about 12,000 years ago. Such a rapid pace of stratification is putting severe stress on the world’s oceans with numerous regions showing the effects of low oxygen (hypoxia) and some regions succumbing to increasingly anoxic states.

These low oxygen events have been associated with multiplying oceanic dead zones. Very large dead zones have been observed in the Pacific, specifically off the coast of Oregon. Other major dead zones continue to be observed at the mouth of major river systems, such as within the Gulf of Mexico, where the appearance of massive related toxic algae blooms is now an almost annual event. In general, almost all ocean dead zones are expanding leading to the dramatic reduction in habitat size of numerous fish species. And even the most cursory research provides ample evidence that ocean hypoxia is expanding concurrently with a rapidly expanding ocean stratification.

When combined with the jarring effects of rapid ocean warming and expanding acidification, it becomes plainly obvious to almost any ocean ecologist that the world’s ocean system is suffering the heavy bombardment of a new mass extinction event.

It is this kind of low or no oxygen environment that is a prime breeding ground for hydrogen sulfide producing bacteria. In numerous places around the world, such as off the coast of Namibia, in the Black Sea, in the Baltic Sea, in the Gulf of Mexico, in the Chesapeake Bay, and off the coast of Oregon, large and expanding zones of hydrogen sulfide have been observed in deep water environments. In some regions, this hydrogen sulfide occasionally penetrates to the surface layer resulting in major fish kills and a concordant rotten egg smell.

Off the Oregon coast, in perhaps one of the most extreme examples of ongoing ocean hypoxia, one of the world’s largest and most oxygen-starved dead zones continues to expand. The oxygen levels in this region are so low that local fisherman often bring back horrific tales of baby bottom dwelling creatures such as crabs and octopus climbing anchor ropes to escape the dangers of their oxygen-starved environment. In another, possibly related event, masses of starfish perished during 2013 and 2014 as they, over the course of a few weeks, turned to goo. The fact that this sci-fi esque mass death of starfish occurred near one of the world’s largest dead zones should not be lost on those concerned for world ocean health.

But perhaps even more concerning is the fact that this region off the Oregon coast is producing substantial volumes of hydrogen sulfide gas. Volumes high enough in concentration to occasionally cross the ocean-air boundary.

Oregon possesses numerous features that would aid in the transport of this gas to the surface. Primarily, the near Oregon ocean system frequently features strong up-welling currents. These currents can push bottom waters through stratified layers and cause them to contact the surface. If these oxygen starved bottom waters contain hydrogen sulfide gas, as they increasingly do, this harmful gas can be transported into the local atmosphere through mixing.

Such events, thus far, have been limited. However, since the Oregon dead zone’s discovery in 2001, its expansion has been both deeply concerning and well documented, showing a rapid and dangerous growth over the 13 years since its emergence. Despite the documented expansion of deep water hydrogen sulfide in numerous oceanic regions, the only other ocean zone on Earth observed to emit hydrogen sulfide gas to the atmosphere is in the region of coastal Namibia.

In Namibia, huge volumes of organic compounds fall into the sea after being flushed down ocean terminating streams and rivers. These organic compounds rain down into the deep ocean directly off Nambia’s coasts. There, the ocean bottom hosts both an anoxic environment and masses of hydrogen sulfide producing bacteria. As a result, toxic hydrogen sulfide gas periodically erupts from the ocean and into the atmosphere there.

The Very Real Threat That is Oceanic Hydrogen Sulfide Gas Production

There are few limiters to oceanic hydrogen sulfide production in the world’s increasingly stratified and oxygen starved oceans. Sulphate, which the bacteria require for respiration, is one of the most common ocean elements. In the current ocean, it is present in volumes greater than those seen during the Permian Extinction when these tiny monsters are thought to have done their worst.

Iron and manganese in the world ocean system aids in the development of less permeable boundary layers that help keep a lid on deep ocean concentrations of hydrogen sulfide. However, even in the anemic circulation of stratified and Canfield oceans, upwelling will bring the gas to the surface in certain regions. In addition, as the oceans contain greater and greater volumes of the toxic gas, it will push closer and closer to the surface, rendering metals that help reinforce the boundary layer a practically useless prophylactic (such high metal concentrations currently prevent hydrogen sulfide from penetrating the surface layer in the Black and Baltic Seas as well as in the Chesapeake Bay).

In addition, modern industrial farming practices provide extra nutrients upon which these dangerous microbes can feed. High levels of hydrogen sulfide in the deeper regions of the Chesapeake Bay, for example, owes its existence, in part, to massive farm run-off into the Bay and the dumping of mass volumes of nutrients upon which the sulphate reducing bacteria can feed.

It is important to note that we observe heightened levels of hydrogen sulfide gas in the world ocean system now. As hypoxia and anoxia progress with the human-caused warming of the oceans, and as glacial melt interrupts and alters the now strong ocean currents and related mixing, it is certain that hydrogen sulfide production in the deep ocean will continue to increase resulting in elevating levels of harm to ocean dwelling animals and ever more numerous instances of hydrogen sulfide gas contact with coastal and surface waters.

Dead Cthulu Rises

In the context of increasing ocean hypoxia and stratification, we might do well to remember that we are tiny, weak beings at the mercy of great natural forces which we can barely conceive or understand. Forces that we have unwittingly, callously and ignorantly set into motion.

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Long ago, when I was a ten year old child, I was fortunate enough to meet an amazingly kind, adventurous and inquisitive man. The man, whom I will call Rick to keep safe his identity, was a bit of a local paramour in ocean and bay research. He was constantly in contact with both the ocean and adjacent Chesapeake bays, ever venturing out to explore and to conduct research on marine life. In later years, he would be the impetus behind annual summer marine science camps hosted by the Virginia Institutes of Marine Science, Norfolk Academy, and Old Dominion University. But this was later. Now, Rick was helping an elementary school student present on the issue of our then expanding understanding of marine science.

Living so close to the bay and ocean, I was intimately in contact with the living boundary of land and sea. In the more demanding and less stimulating forum that was public education, I seldom had the opportunity to indulge my passion for the oceans. But at age 10 I was given the opportunity to give a broad marine science presentation for my classmates. As part of my project, I constructed posters and models depicting the current state of world ocean research. I graphically illustrated the various known zones of the bathysphere, the light and life filled ones and the more mysterious and far less well understood depths. But Rick was the centerpiece of my presentation. He was my keynote. And he energetically answered all my own and fellow students’ questions, speaking in the kind and intriguing manner that would later draw so many into his charismatic orbit.

In later years, I would attend Rick’s summer marine science camps on two different occasions. In both cases, I observed what appeared to be an increasing concern about both the health of the Chesapeake Bay and the neighboring oceans. In later years, Rick’s attitude, once so full of optimism, bordered on cynicism. The world he loved so deeply was experiencing death on a scale that horrified him. And he harbored a deep sense of betrayal that we weren’t doing more to stop the senseless slaughter of so many of the living things he saw as both beautiful and wondrous.

In the mid 2000s, Rick committed suicide. To me, one of the great ocean pioneers of my developmental years had passed away by taking his own life. And I couldn’t help but wonder if the horrible ways in which the oceans that he so loved were changing was just too much for him. If the commercialization and cheapening of all the things he held most dear along with their subsequent damaging and putting at great risk of terrible harm had robbed his life of beauty and purpose.

Rick was, if anything, a very intelligent and sensitive man. He knew what was happening to the Bay and ocean on a personal level. When the Bay was harmed it was as if it hurt Rick too.

Rick also knew how temperature changes affected the depths. For he was on the front line studying it. He was hauling up the fish and the water samples. He was doing the measuring with his own hands.

Was the awakening of terrible Cthulu, in the form of hypoxia, anoxia and deadly hydrogen sulfide producing bacteria, too much for Rick to continue bearing mute witness? Did his pleas to those working in the marine science community fall only on deaf ears? Was it just too much for this sensitive, feeling, and intelligent man to bear?

*   *   *   *   *

If Rick taught me anything it was that our lives and the life of the ocean are deeply connected. One cannot remain healthy without the other. In contrast to this basic understanding, the damage our continued industrial emission of greenhouse gasses is doing to the world ocean system is a horrific travesty. And the damage we have already caused, have already done to those most sensitive creatures among us, have already set in play for future decades and centuries, is tremendous.

The ocean suffocates, bleeding deadly hydrogen sulfide gas. Cthulu rises from his ancient house in the depths. And yet we still continue down the wretched path in pursuit of more terrible things to come.

Links:

The Earth Observatory

Baltic Sea Trends

Commons

Through the Looking Glass of the Great Dying

Sulphate Reducing Bacteria

Impact From the Deep

Toxicological Profile for Hydrogen Sulfide

Positive Reinforcement, H2S and the Permo-Triassic Extinction

Massive Release of Hydrogen Sulfide to the Surface Ocean and Atmosphere During Intervals of Ocean Anoxia

Expanding Ocean Dead Zones are Shrinking Marlin, Tuna, and Billfish Habitats

Dead Zone Causing Wave of Death off Oregon Coast

Information about Hydrogen Sulfide in the Baltic Sea

Residence time for Hydrogen Sulfide in the Atmosphere

Dramatic Expansion of Ocean Dead Zones

Under a Green Sky

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