Tech | January 29, 2012 | 31 comments

Carbon dioxide is driving fish crazy

source: http://www.terradaily.com/reports/Carbon_dioxide_is_driving_fish_crazy_999.html

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JanforGore
Rising human carbon dioxide emissions may be affecting the brains and central nervous system of sea fishes with serious consequences for their survival, an international scientific team has found.

Carbon dioxide concentrations predicted to occur in the ocean by the end of this century will interfere with fishes' ability to hear, smell, turn and evade predators, says Professor Philip Munday of the ARC Centre of Excellence for Coral Reef Studies and James Cook University.

"For several years our team have been testing the performance of baby coral fishes in sea water containing higher levels of dissolved CO2 - and it is now pretty clear that they sustain significant disruption to their central nervous system, which is likely to impair their chances of survival," Prof. Munday says.

In their latest paper, published in the journal Nature Climate Change, Prof. Munday and colleagues report world-first evidence that high CO2 levels in sea water disrupts a key brain receptor in fish, causing marked changes in their behaviour and sensory ability.

"We've found that elevated CO2 in the oceans can directly interfere with fish neurotransmitter functions, which poses a direct and previously unknown threat to sea life," Prof. Munday says.

Prof. Munday and his colleagues began by studying how baby clown and damsel fishes performed alongside their predators in CO2-enriched water. They found that, while the predators were somewhat affected, the baby fish suffered much higher rates of attrition.

"Our early work showed that the sense of smell of baby fish was harmed by higher CO2 in the water - meaning they found it harder to locate a reef to settle on or detect the warning smell of a predator fish. But we suspected there was much more to it than the loss of ability to smell."

The team then examined whether fishes' sense of hearing - used to locate and home in on reefs at night, and avoid them during the day - was affected. "The answer is, yes it was. They were confused and no longer avoided reef sounds during the day. Being attracted to reefs during daylight would make them easy meat for predators."

Other work showed the fish also tended to lose their natural instinct to turn left or right - an important factor in schooling behaviour which also makes them more vulnerable, as lone fish are easily eaten by predators.

"All this led us to suspect it wasn't simply damage to their individual senses that was going on - but rather, that higher levels of carbon dioxide were affecting their whole central nervous system."

The team's latest research shows that high CO2 directly stimulates a receptor in the fish brain called GABA-A, leading to a reversal in its normal function and over-excitement of certain nerve signals.

While most animals with brains have GABA-A receptors, the team considers the effects of elevated CO2 are likely to be most felt by those living in water, as they have lower blood CO2 levels normally. The main impact is likely to be felt by some crustaceans and by most fishes, especially those which use a lot of oxygen.

Prof. Munday said that around 2.3 billion tonnes of human CO2 emissions dissolve into the world's oceans every year, causing changes in the chemical environment of the water in which fish and other species live.

"We've now established it isn't simply the acidification of the oceans that is causing disruption - as is the case with shellfish and plankton with chalky skeletons - but the actual dissolved CO2 itself is damaging the fishes' nervous systems."

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31 comments // Carbon dioxide is driving fish crazy

  • Anonmaly
  • coolplanet
    • +4
      coolplanet  

    • I have two small ponds filled with Black Moor goldfish. For 10 years I have stopped feeding them when the water temp drops below 40f -- usually in November.
      This year I am still feeding them in late January because the water temp has remained near 50 degrees, even when there's a thin coat of ice on the surface.
      It is driving me crazy!

    • 4 months ago
  • circlesquared
    • +1
      circlesquared  
    • coolplanet:

      we are seeing the opposite in FL. When I moved here six years ago we rarely got a frost if ever...now we are guaranteed multiple if not continuous cold far below average for weeks at a time. Last year it was warmer in Canada at my snowbird neighbors house than it was here for most of the winter...they were disappointed they had migrated south

    • 4 months ago
  • coolplanet
  • circlesquared
  • Ambill94
    • +2
      Ambill94  

    • We need some good news on the environment...something besides this...we are clearly reaching the point of no return in some areas...and the dumb-ass right wing assholes just keep digging deeper...pun intended...

    • 4 months ago
  • JanforGore
    • +5
      JanforGore  
    • Ambill94:

      Hmmm good news... we haven't reached the end yet. Which is why we need to know things like this are happening so we can work to try to do something before it is truly too late. But with so many even refusing to admit CO2 is a heat trapping gas and spreading misinformation about this our time is even more limited. I have always thought it was being at the brink of destruction when human willl would spark itself to do what was necessary to survive. I hope I'm right on that.

    • 4 months ago
  • circlesquared
  • Ambill94
  • circlesquared
  • Ambill94
  • circlesquared
    • +1
      circlesquared  
    • Ambill94:

      choice...we have to see and understand wrong before we can choose right and let wrong go. Knowledge IS power and we are stronger than we are ever going to be told...individually, but incredibly so when efforts are combined in right action. It is our choice once we see we do have one how can we let wrong persist?

    • 4 months ago
  • Ambill94
    • +1
      Ambill94  
    • circlesquared:

      I agree with what you say as it applies to rational people, but were are "ruled" by a class of people who follow their paths with the full and certain knowledge that what they do is wrong...but that is a moral crossroads that they routinely ignore as they plow forward toward their short term goals of greed and power...

    • 4 months ago
  • circlesquared
  • Ambill94
  • coolplanet
    • +4
      coolplanet  

    • We are in the midst of the Sixth Great Extinction, this time caused entirely by humans.
      That means, unlike the asteroid that wiped out the dinosaur, we can stop it.
      We finally have the technology to do it within the next ten years. But humans are too preoccupied and self-absorbed to care or understand.

    • 4 months ago
  • JanforGore
  • circlesquared
  • coolplanet
  • circlesquared
  • The_Wanderer_Kansas
    • +3
      The_Wanderer_Kansas  

    • If extended exposure to high CO2 has these effects on fish, there would assumably be similar reactions on dry land. Cognitive disruption, over-excitement of the nervous system, a reversal of standard function with certain receptors... Does this sound to anyone else like it could be a contributing factor to our increase in mental illnesses, learning disabilities and even anti-socical behaviors? Sadly thats the very first thing that popped into my head reading this article.

    • 4 months ago
  • coolplanet
  • JanforGore
  • circlesquared
    • +3
      circlesquared  
    • The_Wanderer_Kansas:

      we know the top of a food chain gets it from both ends as well...bluefin tuna are one of the most highly contaminated fish in the sea. If only it was visible to more people that not only are we breathing chemical laden air, eating chemical laden food, and drinking chemical laden water, but we are being poisoned deliberately by pharmaceutical companies and governments looking for zombies for life. None of the medicines we use need fluoride or aluminum yet you'll find them in almost all of them all the while we are told it is for our personal gain. Now we have radiation, intensified above and beyond what we have ever knowingly experienced before. Much of this could be cut down immediately if people were actually paying attention to the fact that our basic needs are being taken captive and for our survival and that of our children we better do something about it right now.

    • 4 months ago
  • PressCore
    • +3
      PressCore  

    • Trees exist for at least 30 different uses in addition to being beautiful.
      The most immediate reason why a tree exists though is to maintain
      the balance between O2, and CO2 in earths atmosphere close to the
      ground level. The reckless deforestation of the Amazon, and other
      previously left intact rainforrests., is destroying Nature's balance
      whichhas a profound effect on acidifying the oceans, destroying
      the fish. It sadens me to realize I'm part of a species which has
      such a destructive effect on Nature. My instincts are to build, and
      anything but destroy. I regard destruction as malicious. We've come
      this far in our evolution. You'd think that it would be for a better
      purpose than being ignorant predators. Even the smallest form
      of life has it's place in God's design. I would't presume to know
      better than HE what, as they say in Ecclesiastes, what the time &
      place for everything must be.

    • 4 months ago
  • JanforGore
    • +2
      JanforGore  
    • PressCore:

      Our oceans are the smoking gun of our arrogance. We pollute and toxify with abandon not realizing the consequences effect so many different species up the food chain. For those who think CO2 is harmless hopefully this will bring some awareness.

    • 4 months ago
  • The_Wanderer_Kansas
  • JanforGore
    • +4
      JanforGore  
    • The_Wanderer_Kansas:

      Not if you enter freewill into the picture, but I really do not want to make this a thread about religion and God bashing. We are doing this regardless of any other plan and we are responsible for trying to make it right if that is even possible now because as a species we are too busy becoming embroiled in squabbles about differences.

    • 4 months ago
  • circlesquared
  • circlesquared
  • JanforGore
    • +5
      JanforGore  

    • "We've now established it isn't simply the acidification of the oceans that is causing disruption - as is the case with shellfish and plankton with chalky skeletons - but the actual dissolved CO2 itself is damaging the fishes' nervous systems."

      This isn't just about what we are doing to ourselves. Our actions are affecting all species and biospheres.

    • 4 months ago
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