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

Leave a comment


  1. steve

     /  October 18, 2013

    You mentioned the possibility of an increase in bacteria in a more anoxic ocean. Are you concerned with the flesh eating bacteria cases in Louisiana and Florida just the beginning of this type of outbreak? Related to oil spill and efforts from trying to treat it?

    • Anaerobic bacteria proliferate.

      I’d seen the reports of incidents of flesh eating bacteria in Florida and along the Gulf Coast. I don’t yet have enough info to provide what I feel is an accurate assessment.

      That said, these kinds of bacteria proliferate in warmer, less oxygen rich, waters. So they should be a concern. I’ll keep an eye on it. Hopefully, there will be more info soon.

      In general, as the oceans warm they tend to host more and more of this managerie of toxic microbes. The primordial microbes come back and they, in general, tend to be deadly to more recent forms of life. Primarily, it’s only oxygen that keeps them in check. So the lower the levels of oxygen, the greater the hazard.

  2. Tom

     /  October 18, 2013

    Yeah, we’re in big trouble, and bug trouble. With U.S. moose populations undergoing the same fate – being devoured by ticks and disease (winters used to kill them off), the sardine population disappearance off of Nova Scotia last week and the article I read talking about starfish turning to goo off the coast of Vancouver, we’ll see not only increased rates of this, but it’ll get “closer to home” rapidly too.
    It’s just a matter of time before some pathogenic virus comes along and starts wiping us out.

  3. Is it possible that the increase in autoimmune diseases in humans is also the result of this as we are after all on the top of the food chain. Anything below us surely has an impact no matter how we see it. And I guess we have basically treated the ocean as a big garbage bin for a very long time now as if it had a fantastic way of swallowing whatever we put into it. But I guess its also a lot like the atmosphere. For us the sky seems endless, but when you look at how thin the atmosphere “sliver” is on the earth when you look at it from space you realize how fragile it all is. I believe the oceans will prove to be the same…

    A good short movie about “The Overview Effect” explaining this realization of how important it is to look back at earth:

    • JCL –
      Add to that “endocrine disruptors”, many of our modern compounds mimic estrogen once they break down, and enter the food web of the oceans. This attacks the males of species , making them hermaphrodites. This is at work from the bottom of the food chain to the top.

      • Another big mess.

        I wonder if anyone has done a comprehensive study of toxins in human adipose? Not likely that we would see the same degree of exposure to ocean bio toxins. But it might be worthwhile to look at populations that consume high volumes of seafood.

  4. Lot’s of news about the oceans this year. None of it good . But I would add one more thing to the list of it’s ills. That it’s turning into a plastic soup along with it’s other problems. I am reminded of the forecast for Midway Island , that it’s beaches will be the first to be made of tiny grains of plastic in the very near future.

    Nothing says Anthropocene like a beach made of made of embrittled Bic lighters, and tooth brushes.

  5. The Yellow Sea on Oct 12, 2013 –

  6. Tom

     /  October 20, 2013

    Colorado Bob: didn’t someone just complete a documentary about the plastic debris and birds (maybe fish and turtles too)? I recall seeing something about it.

  7. Yachtsman describes horror at ‘dead’, rubbish strewn Pacific Ocean

    Ivan MacFadyen says he was shocked by absence of sea life during his 37,000km voyage between Australia and Japan

    • Steve

       /  October 23, 2013

      That is really sad and disturbing. It hit Yahoo today with the title “The Ocean is Broken!”. Time will tell how quickly we really start suffering badly from this. It seems like most things in nature have a tipping point. I wonder how many have already been reached in our oceans.

  8. Study shows unprecedented warmth in Arctic.

    ( —The heat is on, at least in the Arctic. Average summer temperatures in the Eastern Canadian Arctic during the last 100 years are higher now than during any century in the past 44,000 years and perhaps as long ago as 120,000 years, says a new University of Colorado Boulder study.

    Read more at:

  9. Nuclear Waste Lurks Beneath Arctic Ice

    Large-scale Soviet nuclear tests, dumping of spent fuel and two scuttled nuclear-powered submarines are a major source of pollution in the Arctic ocean, a Russian research institute has said.

    There are 17,000 containers and 19 vessels holding radioactive waste submerged in the Kara Sea, as well as 14 nuclear reactors, said a report passed by Russia to the Norwegian authorities in 2012, according to Bellona, an environmental group that acquired a copy of document.

    Read more:
    The Moscow Times

  10. Climate Change Aids Toxic Slime’s Advance

    Sewage and fertilizer runoff into China’s Lake Taihu have fed a nasty bloom: an annual explosion of frothy cyanobacteria, which release neurotoxins into the lake. Hans Paerl, a marine and environmental scientist who studies Lake Taihu, says the warmer temperatures brought by climate change only contribute to the slime’s advance.

    • “They have been on Earth for about two billion years. They were the first organisms that figured out how to split water and produce oxygen by photosynthesis. And they’ve seen lots of changes that have occurred on Earth, including, you know, the advent of oxygen itself but warming, cooling, glacial periods, etc. They have a playbook that is very, very sophisticated.

      And they are now taking advantage of many of the changes that we’re imposing on the environment, including too many nutrients, climate change, particularly warming, hydrologic modifications – building dams, for example, to slow down the water coming into our ecosystems. So, you know, we’re playing into their playbook, basically.”

  11. New “Tipping Points” episode, “Dangerous Rise of Oceans”, airs Saturday at 9 pm EDT/8 pm CDT.

    ““Tipping Points”, a landmark 6-part TV series that began last Saturday on The Weather Channel, airs for the second time on Saturday night, October 26, at 9 pm EDT. The new episode, “Dangerous Rise of Oceans”, goes on an expedition from the Great Southern Ocean to the Great Barrier Reef and Tuvalu, to explore the changing currents and oceans that are driving extreme storms, sea surge and changing the landscape of many small South Pacific communities. The series is hosted by polar explorer and climate journalist Bernice Notenboom, the first woman to climb Mt. Everest and walk to the North and South Poles. In each episode, Notenboom heads off to a far corner of the world to find scientists in the field undertaking vital climate research to try to understand how the climate system is changing and how long we have to make significant changes before we reach a tipping point–a point of no return when our climate system will be changed irreversibly.

  12. Steve

     /  October 30, 2013

    Unrecorded weather in Alaska taking place now. High temp 2 days ago was 30 degrees above normal.

  13. More bad news from the oceans –

    Marine scientists are scrambling to determine the extent and cause of a disease that is killing starfish along the West Coast, including Sonoma County.

    The affliction, called sea star wasting disease, has killed up to 95 percent of the stars in some tide pool populations ranging from southeast Alaska to Santa Barbara in a manner similar to scenes from a horror movie.

    “They essentially melt in front of you,” said Pete Raimondi, chairman of the Department of Ecology and Evolutionary Biology at UC Santa Cruz’s Long Marine Lab.

  14. It would be really great if you post something . You write all these great posts , and then go dark ?

    You sound like me.

    • I think I suffer from manic depression, like Hendrix. Energy levels coming back up, though. Hey, and it takes a lot of effort to put those things together.

      In any case, wish granted. Best to you Bob, I’m enjoying your comments everywhere (Think Progress et all).

  15. I currently have both all posts and all comments posted to this blog emailed to me. I rarely do that. Thank you.


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