Killer Algae, Global Warming, & Mass Extinction

We’ve written before about mass extinction theories that pop up from time to time. See: Cause of Mass Extinctions Discovered? suggesting that solar system “bounces” are to blame; and then there was Constipated Dinosaurs, Abortion, and Darwin, which is too convoluted for a brief summary.

Now we have another theory. At the website of the Geological Society of America, we read Killer algae a key player in mass extinctions. Here are some excerpts, with bold added by us:

Supervolcanoes and cosmic impacts get all the terrible glory for causing mass extinctions, but a new theory suggests lowly algae may be the killer behind the world’s great species annihilations.

Today, just about anywhere there is water, there can be toxic algae. The microscopic plants usually exist in small concentrations, but a sudden warming in the water or an injection of dust or sediment from land can trigger a bloom that kills thousands of fish, poisons shellfish, or even humans.

We wouldn’t want that paragraph to escape your notice. A “sudden warming in the water” might kill us all. Let’s read on:

James Castle and John Rodgers of Clemson University think the same thing happened during the five largest mass extinctions in Earth’s history. Each time a large die off occurred, they found a spike in the number of fossil algae mats called stromatolites strewn around the planet.

Stromatolites are very interesting structures. We continue:

“If you go through theories of mass extinctions, there are always some unanswered questions,” Castle says. “For example, an impact — how does that cause species to go extinct? Is it climate change, dust in the atmosphere? It’s probably not going to kill off all these species on its own.”

But as the nutrient-rich fallout from the disaster lands in the water, it becomes food for algae. They explode in population, releasing chemicals that can act as anything from skin irritants to potent neurotoxins. Plants on land can pick up the compounds in their roots, and pass them on to herbivorous animals.

This is plausible — the problem starts at the bottom of the food chain. Here’s a link to the abstract of the paper by Castle and Rodgers.

One more excerpt:

If the theory is right, it answers a lot of questions about how species died off in the ancient world. It also raises concerns for how today’s algae may damage the ecosystem in a warmer world.

The connection with global warming is conveniently stylish, but it also makes sense. We’ll think about it.

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9 responses to “Killer Algae, Global Warming, & Mass Extinction

  1. Yikes! Killer algae? Almost as scary as killer tomatoes!!!

  2. LRA says: “Yikes! Killer algae?”

    We’re doomed!

  3. Saxitoxin.

  4. Tieing that sort of stuff to global warming is a decent way to get funding, so you can’t blame them for doing that.

    It is something to think about though.

    Makes me wonder though. Blue green algae are normally found in shallow water, e.g. at the edge of dams/lakes, esp where the water is drying up, so it would be more prevalent in a dryer world. Ironically, ice ages tend to be global droughts. A smart (geologist) co-worker of mine told me that a couple of years ago. Just saying thats all… 😉

  5. retiredsciguy

    It makes sense that stromatolites would form after a mass extinction, but not be the cause of an extinction. Stromatolites form when there is nothing around to eat the algae; that’s how the algae mats get to become large formations in the first place. Duh.

    On the other hand, an impact very well could “kill off all these species on its own.” The heat radiated from the plasma resulting from the impact would roast all surface life on half the planet, and the heat radiated from billions of pieces of rock re-entering the atmosphere would roast the rest of the planet. The dust hanging in the atmosphere would block sunlight for a couple years, causing temperatures to plummet worldwide to antarctic conditions.

    Let’s hope we learn from the past and do something to prevent the next impact.

  6. retiredsciguy says: “Let’s hope we learn from the past and do something …”

    I say we make a pre-emptive strike against killer algae before it’s too late! A few good oil spills should teach that algae who’s boss around here. Who’s running this planet — us, or a bunch of pond scum?

  7. retiredsciguy

    Frankly, Curmy, my money’s on the pond scum.

  8. Stromatolites or Tomatolites??? Coincidence… I think not!

  9. retiredsciguy says:
    Frankly, Curmy, my money’s on the pond scum.

    Heh, can’t argue with that one