Floating in just a single drop of ocean water are thousands, possibly millions of microscopic organisms called plankton. In Greek, 'planktos' means wanderer, which is a pretty good description of these organisms since all they do is float near the surface of the water, completely dependent on the currents to move them along These can further be divided into phytoplankton and zooplankton 'Phyto' also comes from ancient Greek and means plant while 'zoo' comes from the ancient Greek 'xun' meaning animal and these feed on the phytoplankton similar to how animals feed on plants at our scale. Together these two types of plankton form a huge and diverse ecosystem completely invisible to the human eye and yet it was these creatures that have had by far the largest impact on life on earth Seriously, it was around 3 billion years ago when the earth was only about one and a half billion years old that cyanobacteria earth's most Earth's most abundant phytoplankton produced the first gaseous oxygen as part of a chemical reaction we'd later call photosynthesis Now with this highly reactive gas present in the atmosphere new types of chemical processes and therefore organisms could develop Except these ones respired using this toxic byproduct of the plants to fuel the creation of their own organic matter This is known as respiration between these two types of organisms photo synthesizers and respirators An interconnected community or in English the first true ecosystem developed. Essentially, it was these cyanobacteria these phytoplankton that jump-started all other life on Earth But as life became more complicated and widespread it began to have new effects on the planet Occasionally these plankton would die and fall to the bottom of the ocean floor out of the reach of organisms that could consume them and recycle their organic matter in short decomposers could not decompose them eventually this dead Organism would be buried by other Sediments coming from above and all the carbonate took from the atmosphere would become trapped beneath the ocean floor This process is called the biological pump as it takes carbon from the surface and sequester's or pumps it into the subsurface and because earth is more or less a closed system. This has had some gradual but global-scale consequences. Over millions to billions of years atmospheric carbon mostly in the form of carbon dioxide or methane was drained from the atmosphere and stored into sedimentary rocks This constant drain of carbon from the Earth's atmosphere eventually depleted it and what started out as an atmosphere of roughly 30% carbon dioxide 10 percent methane and 60 percent nitrogen Became one with only 0.04% carbon dioxide 0.0002% methane 78% nitrogen and 21% oxygen Oh, yeah, and almost 1% argon But that's not really important because co2 and methane absorb and retain more energy from the sun's rays than either oxygen or nitrogen This change caused to the Earth's atmosphere as a whole to absorb and retain less of the sun's energy Less energy means less heat and over millions of years the earth changed from an extremely hot and humid place into the one we know now, where ice can exist a year-round at the poles and deserts are the prevailing land biome across the planet But in recent years this trend has actually begun to reverse. A little another organism, this one much larger called humans Maybe you've heard of them, have begun to undo the effects of the biological pump You see some of the organic matter that was stored beneath sediments over time became what's known as fossil fuels, an easily available energy source that can be used to power all sorts of really cool things As a result of humans using these fossil fuels carbon that was once a sequestered underground has now been returned into the atmosphere The effects of this trend reversal is a reversal of the previous climate trends or where the earth was becoming colder and more desert this increase in atmospheric carbon works to make the planet warmer and more humid like it once was millions of years ago This isn't really a problem for the planet or even life as they've both survived much worse, like meteors and volcanoes worse The only thing that this really poses a problem for is those humans, as they are the ones that have developed to depend on the Earth being the way it had been so that their crops can grow and their cities remain out of the dangerous reaches of natural disasters Recognizing this some humans have tried to come up with the solution to their problem all sorts of ingenious and creative methods have been laid out to fix this problem of fossil fuel consumption such as not doing as much or promising to hardly do this at all in the future, but doing just as much now But those methods have turned out to not be quite as effective as we had hoped, so scientists have also looked at ways to just undo this issue. To reverse their reversal of the biological pump or in English a way to put carbon back into the ground so it stops changing the weather. Although massive in terms of scale the biological pump is rather slow when compared to how fast humans can recover and expel fossilized carbon but if the rate at which carbon is put back into the subsurface were to be increased to equal or greater than how much we as a society can produce then climate change would essentially be resolved Of course, that's a lot harder than it sounds, or is it? No it is but we're still gonna look at ways to do it. Anyway a couple weeks ago I showed you this map in my Oceans are Deserts video which shows the abundance of chlorophyll a in the ocean This is necessary for photosynthesis to take place and therefore shows how much primary productivity is occurring here Green into red is where there's a high level of production a dark blue to purple is very low levels of production. What we can see is that the majority of the ocean is consumed by these large cells of low productivity with higher productivity only really straddling coastlines and polar waters This is actually why tropical waters are usually so clear as there's hardly any organisms or organic matter in them to block light from passing through While colder waters have much greater amounts of those microscopic plankton that absorb the light for energy making the water more opaque and not to spoil my other video where I talk about this but essentially this distribution of productivity is the result of nutrient distribution across the surface of the ocean where there's more nutrients present there will be more productivity where there's less. Yeah Okay You get at there'd be less productivity after learning this researchers as well as many of my viewers suggested that if we simply add nutrients like nitrogen and phosphorous to these vast areas of deficient ocean We could create huge blooms of phytoplankton which could draw in large amounts of carbon effectively combating the changing composition of the atmosphere reducing climate change. Now, ignoring any effects these blooms might have on other marine ecosystems maybe watch my video on you Eutrophication to understand that a little better. This plan still has some flaws Perhaps the biggest of which is that the production of chemical fertilizers relies on what's known as the haber-bosch process In order to produce ammonia an input of nitrogen from the atmosphere is required as well as hydrogen extracted from natural gas which is already not good, plus the input of energy, which is also derived from fossil fuels. In the end this process consumes a ton of fossil fuels and the use of these fertilizers afterwards would never be able to recoup the atmospheric carbon they produced when created But there's still one last idea that researchers have come up with, but to understand it first we need to go back and talk more about ocean nutrients because when studying phytoplankton populations and different nutrient abundances in the Southern Ocean and the equatorial Pacific researchers made an interesting discovery . In these parts of the ocean neither nitrogen or phosphorous or any other macronutrient was deprived in the water enough to limit growth and yet primary productivity was still low. The next question to ask then is if it's not these nutrients limiting growth, what is? Looking deeper into this the researchers found that there actually was one element in the water that was unusually depleted, iron. It appeared that somehow iron was greatly influencing ocean productivity in certain areas of the ocean further research only supported this idea such as the Vostok ice cores taken in Antarctica. By drilling into the small air bubbles trapped in this ice core we can see what the atmosphere of the earth was like when they first formed, going as far back as 420 thousand years and when comparing airborne iron levels against global climate records It was discovered that for each period of global cooling iron dust concentrations were greater in the air and particle sizes were significantly larger The opposite was also true and warmer times in Earth's history saw a reduction in atmospheric iron concentrations and we can assume that if there was more iron in the atmosphere than there was more in the oceans as well So basically a higher iron abundance in the ocean appears to be linked to lower global temperatures and that link is thought to be through an increase in ocean productivity. Putting everything we've learned together these create a feedback loop where low global temperatures cause less water to evaporate from the ocean making the planet overall less humid, less humidity results in more of the earth becoming desertified More exposed to desert means more sands are blown into the air by the wind leading to an increase in iron deposition in the ocean This increased abundance of iron causes higher productivity in the oceans and with more productivity the biological pump sequester's carbon at a faster rate Less carbon in the form of co2 and methane causes further lowering of global temperatures and allows the cycle to continue Okay, I know that was a lot, but we're not quite done yet So, now we know the role higher in place and affecting global climate But we still don't really know why iron influences productivity in the first place if iron isn't considered a vital nutrient for phytoplankton or really any plant for that matter Why does it appear to be impacting them in such a huge way? Well, as it turns out iron is what you'd call a micronutrient and can play an important role in the very specific functions of different organisms. In humans for example, we need iron for a protein called hemoglobin that makes up a substantial part of our blood functionally it's the iron in the hemoglobin that oxygen attaches to in our lungs where it's then transported to ourselves allowing us to continue on with cellular respiration and you know be alive. As it turns out iron plays an analogous role in many phytoplankton Like cyanobacteria in enzymes like nitrogenase except instead of picking up oxygen the iron found in nitrogenase enables the enzyme to pick up well, yeah you guessed it nitrogen, and as we all should know by now nitrogen is the top nutrient required by essentially all life on Earth So, it's iron that controls the ability of mini phytoplankton to absorb other nutrients and that explains why iron was found depleted in some of these ocean waters while no other nutrient was. They couldn't pick up any other nutrients because there wasn't enough iron I'd also like to point out again where these iron deficiencies were found, in the Southern Ocean and the equatorial Pacific This makes perfect sense because if you remember a second ago I said the only real source of iron in the ocean comes from dusts being blown off from land So yeah, the middle of the Pacific Ocean also known as the furthest place from any major landmass on the planet is exactly where they're likely be the fewest inputs from land. As for the southern ocean while it does surround Antarctica it receives very little iron from the land here as basically all of the continent is covered in ice Therefore trapping any iron that could escape and fall into the ocean, and it was here that all of this was put to the test in experiments like the Southern Ocean iron release experiment or SOIReE for short In this experiment, scientists took powdered iron and dissolved it into diluted sulfuric acid once properly prepared this iron mixture was released in an area over 50 square kilometers in the open ocean south of New Zealand. Initially, about 3800 kilograms of the solution was introduced into the water but on day three five and seven editions of between 1,500 and 50 kilograms and 750 kilograms were added as well. Now, because most phytoplankton can reproduce within a week's time the results were observable almost immediately. The researched crew stayed on location for just 13 days and found the phytoplankton abundance and therefore the primary productivity to have increased by as much as 10 fold in the test area Once the team left the site they continued monitoring it using the seawifs satellite and observed that the resulting phytoplankton bloom created by this experiment remained distinguishable for over 40 days after they left or over 50 days in total Since then several other similar experiments of varying scales have been conducted in the Southern Ocean each time with similar results Basically, yeah, adding even trace amounts of iron can drastically increase ocean productivity in certain areas And this has led a lot of people to wonder if we could potentially use iron instead of other chemical fertilizers to stimulate oceanic productivity Thereby, increasing the input of the biological pump potentially sequestering some of the carbon we've released back into the atmosphere through the burning of fossil fuels, but this is how should I say this and also not a great idea for many different reasons First off, mathematical predictions suggest that even if stimulated with iron to the point where phytoplankton in the Southern Ocean incorporated? 100% of the free nutrients in the water over the next 100 years, at most 15 percent of the carbon released from fossil fuel combustion could be drawn in from the atmosphere and transformed into organic matter So, this already couldn't be the only thing we did. However, just because it has been turned into organic matter doesn't mean this carbon has really been sequestered and most of this carbon would eventually return to the atmosphere through decomposition either fairly soon after the initial bloom or over the next few hundred years if it became mixed with deeper ocean currents Typically the biological pump can only sequester about 0.05 percent to the carbon taken into the ocean by primary production so only about 0.75 percent of our total emissions would be sequestered which means we would have to do this for hundreds possibly thousands of years before its effects became pronounced. Add on to this the fact that extracting and processing iron still requires a large amount of fossil fuel input starting with mining and then transporting it and ending with the refining process Even if we only used recycled iron we'd only be reversing damage done at a less efficient rate than we created it and again would leave a net negative. In short, I do not believe this is a viable method to help tackle climate change but by studying systems and relationships like these we can gain a better understanding of how the earth works and therefore create better models, better predictions and potentially better solutions to the problems we face. If you agree with me on this then maybe you'd also agree that it's important to have people who share and explain these ideas to the general public at no expense to them, so that they can gain public support and possibly even become a reality Unfortunately, sometimes those people need a reliable source of income to support themselves from let's say, a site like Patreon. If you'd like to help support me like all these generous people and get more videos like this one Well, I think you know what to do at this point It really helps me in my channel out and just $1 gets you access to the discord channel I just started. Other than that, seriously, let me know if you liked this video over the course of studying environmental science I've come across several different plans like this to change Earth's climate with varying degrees of plausibility So let me know if you'd like to see more of these kinds of ideas Oh, yeah, and I'm still collecting questions for a Q&A, so hit me up on Twitter, Patreon or even my subreddit to post questions I'll try to read comments, but there's a lot of them So, if you really want me to see it anywhere else is better Of course, subscribe, like this video, follow me on Twitter all that good stuff. I should be back with another soon. Thanks
