• Uli
    link
    fedilink
    arrow-up
    35
    ·
    edit-2
    1 year ago

    All of these things are bad, but the effect on phytoplankton is most frightening of all. Diatoms provide 50-85% of our global oxygen supply. Not only are rising temperatures a problem for them, but ocean acidification also eats away at their silica-based shells. But it does it slowly so by the time they die, they are in deep water where no other diatoms are around to reuse the silica.

    Luckily, there are other ways of recycling diatom remains. The most notable example is the dried lake bed that used to be part of Lake Chad when that lake was far bigger and held many living diatoms. Due to natural changes in climate, the water dried up and that area is now part of the Sahara Desert. About 100 days a year, winds kick the ancient diatom dust high into the atmosphere where it is carried across the Atlantic Ocean and then it settles across South America.

    This is a big reason the Amazon Rainforest is so lush. Diatomaceous fertilizer carried all the way from Africa. And since more plants means more photosynthesis, it causes a lot of water that would have otherwise been locked away in the ground to evaporate through transpiration. All of this excess water is blown westward towards the Andes mountain range. In narrower parts of the Andes, the dense Amazonian clouds overcome the rain shadow effect to precipitate across the west side of the Andes.

    This rainwater causes erosion of quartz, which is ground into fine silica dust. As silt, this dust is washed into the Pacific Ocean, where diatoms absorb the silica and use it to reproduce. In a beautiful global balancing act, as diatom-heavy lakes in Africa dry up, the remains of those diatoms cause a chain reaction that ends up causing a huge increase of diatoms on the opposite side of the globe.

    Great, right? It would be if we weren’t replacing so much of the Amazon Rainforest with monoculture farms which don’t have nearly the same evapotranspiration effect as the flora of the natural ecosystem. So, not only are we baking the diatoms, not only are we dissolving them with acid, we’re also removing one of their most critical reproductive resources.

    It’s like we discovered how resilient the planet is and how hard it is to kill, and humans took that as a challenge.

    Enjoy the oxygen while it’s plentiful.

    • fearout@kbin.social
      link
      fedilink
      arrow-up
      5
      ·
      1 year ago

      That’s a great write up, thanks. Haven’t heard about the connection between the Amazon rainforest and African diatoms, that’s fascinating.

      I thought lake Chad started to dry up mostly in the 60s. I went to read some more about that and I just can’t not mention that the original lake is apparently called Mega-Chad :)

      Anyway, in case anyone else is interested to read about ancient microorganisms fuelling Amazon’s growth, here’s a really interesting paper that describes this system in great detail.

      • Uli
        link
        fedilink
        arrow-up
        2
        ·
        1 year ago

        It’s encouraging, but we shouldn’t rely on it to fix our problems. The good thing is that there are many thousands of varieties of diatoms, each with their own odds of adapting and overcoming the situation we’ve put them in. I have confidence that the planet will survive. But whether enough of these phytoplankton will evolve in time to keep catastrophic extinction events from occurring is still very much in question. We should do everything we can as a species to protect their health.

        • FarFarAway@startrek.website
          link
          fedilink
          arrow-up
          2
          ·
          1 year ago

          No, we cant rely on it to fix our problems. Hell if anything it will adapt and then get exploited later on. Humans just ruin everything…

          I wish we were better and hope that we will do a 180 and try to preserve what is left, but I wouldnt bet on it.

          As much as I’m genuinely fearful of what we are going to endure in the coming years, especially the next generation, part of me feels like we deserve what we get. All we can do is prepare the best we can, cross our fingers, and ride the ride.

          It’s pretty shitty that we’re taking everything else down with us, but it does give me hope that maybe nature will surprise us, and not all will be lost, even if it seems that way.

    • FlowVoid@midwest.social
      link
      fedilink
      arrow-up
      1
      ·
      edit-2
      1 year ago

      The only realistic way to “lose” O2 is to convert it into CO2. And even if enough CO2 were produced to extinguish humanity forever, there would still be plenty of O2 left over. So “running out” of O2 is not a serious concern.

      • Uli
        link
        fedilink
        arrow-up
        2
        ·
        1 year ago

        Yes, in the long term, the planet will be fine. But bear in mind, our entire biology is based on converting O2 into CO2.

        I mean, sure, a couple billion years ago, the global ecosystem had the opposite problem and single-celled archaea was suffocating the planet with too much O2. Those are the conditions that allowed animal life to evolve.

        So, I take your point that the planet will still have O2 long after we flood the atmosphere with the millions of tons of CO2 that used to be buried deep underground. Plankton will have a comeback even if the vast majority of animal life on the planet dies of asphyxiation first. But at that point, the argument of whether we’ve “run out” of O2 is really semantics, right? If we haven’t “run out” of it, but our supply gets low enough that virtually all of us are dead as a result, I don’t place a lot of value in making that distinction.

        • FlowVoid@midwest.social
          link
          fedilink
          arrow-up
          1
          ·
          edit-2
          1 year ago

          I think you missed the point.

          Our atmosphere is 21% O2, and less than 0.05% CO2.

          If that changed by 1% to 20% O2 and 1.05% CO2, we would all die. But not for asphyxiation or lack of O2, because the slight reduction in O2 would be unnoticeable. The drastic increase in CO2, on the other hand, would be catastrophic.