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

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

Something lurking in the Northeastern Pacific is killing off the graceful giants of the world’s oceans. For since May of 2015 30 large whales have been discovered dead — their bloated and decaying bodies washed up on Alaskan shores. It’s an unusual mortality event featuring a death rate of nearly 400 percent above the average. So far, scientists don’t yet have a culprit. But there is a prime suspect and it’s one that’s linked to climate change.

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Bears consuming whale carcass

(Bears consume the carcass of a beached finback whale on the Alaskan coastline. Image source: NOAA.)

This month the US government declared an ‘unusual mortality event’ after it was confirmed that 30 large whales including 11 finback whales, 14 humpback whales, one gray whale and four other whales so bad off it that spotters where unable to identify the bodies by type were found dead. For large whales, whose numbers tend to be low due to size, low birth rates, and dietary requirements, that’s a very rapid mortality rate. As a comparison, all of 2014 only featured four large whale deaths in the Gulf of Alaska.

According to an official statement from NOAA:

“NOAA Fisheries scientists and partners are very concerned about the large number of whales stranding in the western Gulf of Alaska in recent months… To date, this brings the large whale strandings for this region to almost three times the historical average.”

Hot Blob’s Record Algae Bloom Suspected

Starting an official investigation of this odd large marine mammal mortality event shows that scientists are somewhat baffled about what could have caused the tragic deaths of these majestic creatures. But the scientists’ investigation is not absent a suspect. For the emergence of extraordinarily warm ocean water in a region where these whales live has been linked to a number of mass sea creature die offs.

This area — an expansive zone of 1 to 5 degree Celsius hotter than average surface waters — has been implicated in the mass death of starfish, in dolphin mortality events, in sea lion mortality and orphaning events, in sea otter deaths, in salmon deaths, and in the mass death of crabs and shellfish (see “Starving Sea Lion Pups and Liquified Starfish” and “Hot Pacific Ocean Runs Bloody“).

Hot Blob

(A combination of factors related to human-caused climate change have forced the Northeastern Pacific into a period of record warmth. First, sea ice recession in the Arctic has enabled the formation of warm ridges in the Jet Stream over this region. Second, ocean waters are globally hotter than they’ve been in at least 135 years. Third, a switch to positive PDO and El Nino in the Pacific has unlocked an unprecedented degree of ocean heat forced into Pacific waters by record strong trade winds throughout the 2000s. As a result, the typical positive PDO signal is amplified. In other words, as Dr. Kevin Trenberth has warned time and again, deep ocean warming is coming back to haunt us. Image source: NOAA/ESRL.)

Abnormally warm waters fertilized by the particulate fallout from fossil fuel based industry and climate change driven wildfires can create a host of problems for sea life. First, the warmer waters contain lower levels of oxygen — which reduces the range in which fish and crustaceans can live. Hotter, lower oxygen and zero oxygen waters also create zones and regions in which toxic microbial life thrive. We’ve talked a lot about the deadly hydrogen sulfide producing bacteria. But the expansive algae blooms of a warming, nutrient enriched ocean surface can produce a host of other toxins. Microcystins, Nodularins, Anatoxin-a, Cylindrospermopsins, Lyngbyatoxin-a, Saxitoxin, Lipopolysaccharides, Aplysiatoxins, BMAA, Hydrogen Sulfide Gas and Domoic Acid are just some of the toxins produced by algae and bacteria that thrive in warming waters, in low oxygen waters, or in waters that have been subject to high nutrient loading from increasing run-off and the fallout of nitrogen and particulates due to fossil fuel burning.

In particular, this year’s record red tide has resulted in an extreme outbreak of the kind of algae that produce the deadly neurotoxin — domoic acid.  And it’s this domoic acid poisoning that many are pointing to as a possible cause of excessive whale deaths.

Whale stranding locations

(Whale stranding locations along an abnormally warm Gulf of Alaska. Strandings may be associated to a global warming-tied blob of hot water in the Northeastern Pacific together with a related red tide algae bloom impacting the region. Image source: NOAA.)

The massive algae bloom impacting regions of the Northeast Pacific threatens whales in a number of ways. First, the whales swim in the algae-filled waters. So the toxin is a part of their environment. It thus becomes unavoidable. The toxin concentrates in the bodies of the tiny sea creatures upon which the whales feed — planktonic life forms that, in their turn, feed on the toxin-laden algae. As domoic acid moves up the food chain, it bio-magnifies — becoming more concentrated. And since whales must consume prodigious volumes of small sea life to survive, the opportunity for biomagnification of toxins in whales is great.

Biomagnification of domoic acid is also a threat to human beings. And it is for this reason that the US Fisheries Services have curtailed the consumption of West Coast shellfish, which can contain high concentrations of domoic acid from 2015’s record red tide.

Conditions in Context — Deadly Waters

Mass whale deaths and strandings along the Alaskan coastline have, over recent weeks, garnered a great deal of attention from the public. However, these strandings and deaths do not occur in isolation. The tragic and freakish mortality events are happening in a region of abnormally hot water. A region of hot water that scientists have linked to human-forced climate change. An area in which numerous other mass sea creature deaths have occurred.

The region features low oxygen waters. Waters infected by deadly microbes that have liquified starfish, crabs, and sea cucumbers. And waters that now feature the largest red tide — a massive bloom of toxic algae — on record. It should be very clear from all these related events occurring within the same region of abnormally hot water that a warming ocean is an increasingly deadly ocean. And if we are to have any hope of halting these events, we should look to cessation of fossil fuel burning and related human forced warming of the Earth System as rapidly as possible.

Links:

NOAA: Alaska Fisheries

NOAA/ESRL

Scientists Baffled by Mass Whale Death

Whales are Mysteriously Dying in Northeastern Pacific

Starving Sea Lion Pups and Liquified Starfish

Hot Pacific Ocean Runs Bloody

Hat Tip to Colorado Bob

Hat Tip to Andy in San Diego

(Please support public, non-special interest based, science like the fantastic efforts conducted by the fisheries and ocean researchers at NOAA.)

 

 

Hot Pacific Ocean Runs Bloody — Blob Now Features Record Red Tide

Red Tide. It’s what happens when massive algae blooms cover vast regions of ocean.

The biological density of the blooms is so great that they can paint the waters affected a shade of brown or red. A bloody color indicative of clouds of dangerous microbes just beneath the surface. And today, a massive Red Tide — perhaps the largest ever recorded — now stretches from California to Alaska along a vast stretch of the North American West Coast already reeling under the ongoing and dangerous impact of a massive ocean heating event that researchers have called ‘The Blob.’

Red Tide

(A Red Tide can paint the ocean in bloody shades as seen in the image above. It’s also bad news for many marine species — first due to production of deadly biotoxins and second due to its ability to rob ocean waters of oxygen as the bloom dies off and decays. Image source: Wind’s Sustainability Blog.)

A Red Tide has numerous impacts to both marine life and human industry. Microbes within the tide produce biotoxins that are deadly to marine species. Domoic acid, PSP and DSP are all toxins that have been identified during the current Red Tide event. The toxins primarily affect fish and marine mammals — risking mass fish and dolphin, sea lion, seal, otter, and whale deaths during widespread blooms. The toxins concentrate as they move up the food chain, making them most dangerous to top predators. Primary effects of the most lethal toxins are convulsions and paralysis. Other toxins cause nausea, cramps and diarrhea.

Human beings are also at risk and for this reason crab and shellfish fisheries all up and down the US West Coast are being closed. Impacts are so widespread marine ecologists like Vera Trainer, manager of the Marine Microbes and Toxins Programs at the Northwest Fisheries Science Center in Seattle, are calling the event unpredented:

“The fact that we’re seeing multiple toxins at the same time, we’re seeing high levels of domoic acid, and we’re seeing a coastwide bloom — those are indications that this is unprecedented.”

Global Warming, Hot Blob — Prime Suspects

Scientists currently suspect extreme Northeastern Pacific Ocean heat led to the sudden appearance of Red Tide this week — a combination of warm and nutrient rich waters are well known to be the key ingredients for Red Tide formation. Ingredients that are increasingly prevalent due to human fossil fuel burning. Ingredients that are increasingly evident in the Northeastern Pacific. In short the burning of fossil fuels both warms the atmosphere and ocean even as it seeds the surface water with nitrogen. The warm water is a preferred environment for the microbes that form the Red Tide and the nitrogen — both as a constant rain from the sky due to fossil fuel emission and as effluent from streams due to farm runoff — essentially fertilizes the bloom.

It is for these reasons that many scientists suspect the hot Blob of water in the Northeastern Pacific has played a role in the formation of the current unprecedented Red Tide.

image

(The Northeastern Pacific hot Blob now features a dangerous Red Tide — perhaps the largest and most toxin laden Red Tide ever seen. Image source: Earth Nullschool.)

Warming the world ocean through human carbon emissions is thus a very dangerous consequence. Now, more and more regions are featuring hot zones that are increasingly deadly to sea life. This region of the Northeast Pacific in particular has seen a number of instances of mass ocean creature death due to impacts associated with warming waters. The recent Red Tide being the last of a long chain including a mass starfish die-off, fish kills, bird kills, and marine mammal deaths and disruption — including a winter and spring emergence of crowds of starving sea lion pups along California beaches.

Next Step — Anoxia, Possible Hydrogen Sulfide Issue

This particular Red Tide is still in its early stages. It could last for weeks. But as it reaches its last days, the mass production of microbial life will rob the ocean surface of the nutrients necessary to sustain it. As this happens, the microbes will experience a sudden die-off. The mass of dead microbes will then sink and decay. This decay will further rob already de-oxygenated waters, particularly off Washington and Seattle, of still more oxygen. So the final act of this particular Red Tide will be to make a bad ocean water oxygen situation in many of the affected regions even worse (in the worst case potentially setting some zones up for an ugly deep water hydrogen sulfide production).

Links:

Toxic Algae Bloom May be the Largest Ever

Huge Bloom of Toxic Algae Hits US West Coast

NOAA (Please Support!)

Sea Lion Sickness

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

Starving Sea Lion Pups and Liquified Starfish How Human Warming is Turning The Eastern Pacific Into a Death Trap for Marine Species

Hat Tip to Andy in San Diego

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