Seeding the Oceans
Virtually every part of our planet has felt the effects of climate change: including rising seas, extreme weather, drought and loss of species. We humans have contributed to the problem by burning fossil fuels which create gasses like carbon dioxide which trap heat in our atmosphere like a giant greenhouse. There are many strategies for reducing our output of these gasses and now a plan is in place to reduce the Carbon dioxide that is already in our atmosphere. I’m Jim Metzner and this is the Planet.
Michael Hochella: The oceans are already doing this. In fact, before humans even existed on the planet, there were oceans that were taking down CO2 out of the atmosphere. And certainly today, we can actually measure directly that of all the gigatons we put in the atmosphere of CO2 every year, the oceans already take up like a super sponge, about 1/3 of that.
Michael Hochella is a laboratory fellow and senior advisor at the Pacific Northwest National Laboratory and a University Distinguished Professor Emeritus at Virginia Tech. he’s been working in the fields of nanoscience and technology for over 25 years.
Michael Hochella: How about if I told you there are photosynthetic organisms in the oceans that take out even more CO2 from the atmosphere than all the green things on continents. Well, it happens with these organisms we call phytoplankton. They’re very small, so small that if you were looking at a single phytoplankton organism, you need a microscope to see it. But they use the same, generally speaking, they use the same kind of photosynthesis as a green plant on land. Meaning it’ll take up CO2 that’s dissolved in the water. Where does this carbon dioxide in the ocean water come from? It comes from the atmosphere. So you pump CO2 into the atmosphere, and some of that CO2 will come out of the atmosphere and dissolve into the seawater. And that’s what the phytoplankton are using for their CO2 source. And just like a plant on land, they’ll take that CO2 and turn it into biomass, which makes that organism grow.
What happens naturally is that organic mass that is sinking in the ocean, And if it keeps going down, um, hundreds of meters, thousands of meters into the ocean, the deeper it gets, hundreds, thousands of meters. The deeper it gets, the longer it’ll stay down there. And sometimes, and this happens naturally, that biomass that’s sinking gets all the way to the ocean floor. And there it’s, it’s stored on, on the ocean floor for long, long periods of time, many thousands to hundreds of thousands of years. So that really gets rid of CO2 that used to be in the atmosphere. So nature does that and we would want to do that by ocean fertilization.
Jim Metzner: What areas in the ocean might we begin to fertilize
Michael Hochella: 35:55 Ocean fertilization is basically going to the parts of the ocean that don’t have all the nutrients that phytoplankton need to reproduce. These are parts of the ocean that are sort of like deserts. There, there is life there, but not much. So if you want to fertilize the oceans, it makes a lot of sense to go to these areas that are missing nutrients, that phytoplankton need to grow into a reasonable size population to take down a reasonable amount of CO2 and add that nutrient.
Jim Metzner: What would be an example of an area that you’re talking about – a desert in the ocean.
There are a couple oceans, um, the most well-known and most studied for this process of ocean, ocean fertilization, where there are zones that have very little life because of lack of nutrients is the southern ocean. A lot of people have never heard of the southern ocean, but it’s a globally important ocean that surrounds Antarctica, and that’s the southern ocean. So a lot of ocean fertilization experiments have actually already happened in our southern ocean. An ocean that many people would be very familiar with – the Pacific Ocean, the world’s largest ocean; there are parts of the Equatorial Pacific Ocean, that means the Pacific Ocean that are between, say, South America and Asia along the equator that also are very underpopulated with phytoplankton.
In the oceans, the one thing that phytoplankton mostly misses is iron. And so the number one fertilizer for the oceans in places where we want more phytoplankton to grow, to take down more CO2 from the atmosphere, happens to be a micronutrient – iron, depending on what part of the ocean you’re in, everything else might be there already. It’s just lacking iron.
So where in this process does nanotechnology fit in?
Nanotechnology is a new idea in terms of this fertilization. The idea was sort of borrowed from land-based fertilizers. Fertilizers go back thousands of years. In the 21st centuries, we’re growing food on the planet to feed right now, just short of 8 billion people very successfully because of fertilizers. Fertilizers have become more and more sophisticated; fertilizers can be very damaging to land. You can over-fertilize, which brings, things like phosphorus and nitrogen coming off the farmland into rivers and streams and estuaries and lakes and ponds, which causes real problems for the bio biosystems in water.
It’s worth noting that nanoparticles are extremely small. They’re on the scale of atoms. And they have unique properties, properties which scientists are putting to good use.
MIchael Hochella :
One thing they’ve done on land is they’ve starting to develop nanofertilizers. So these are fertilizers where each particle of the fertilizer is nano size, and they’re very specifically tailored to work with very specific plants for exactly what that plant needs. So the nano part allows you to very precisely target and tailor that fertilizer for that particular plant. The new idea (is) making nano fertilizers for ocean water for phytoplankton, specifically for phytoplankton.
This will be tried in the real world starting, we hope in the next five to 10 years. And it will be at the scale of tens to hundreds of square kilometers in the ocean to start with. And these, these experiments will be done very carefully and very selectively, very carefully monitored, where we can report the data to governments and the general public to look at the health of the phytoplankton populations to make sure we’re not upsetting the ecology of the surface of the ocean. Because if we are, even a little bit, we would go back to the drawing board and fix it. And we think we can, with ocean going experiments and then back in the lab to refine the distribution of the fertilizers exactly what’s in the fertilizers, how quickly they will release to the phytoplankton, and then verify that the phytoplankton population is growing and then upon their death they’re aggregating and sinking quickly so that the CO2 is stored deep in the oceans for at least hundreds, a hundred years or more, hopefully thousands of years.
There’s always downside risks. You talked about the risks of over fertilization on land. What are some of the risks that could be involved and what can we do to avoid anything bad happening out of this very promising idea?
There are always risks. And you go into this at your own peril if you do not take into account those risks. We hope we’re smart enough in the 21st century where we’re not taking that big of a risk in doing this. With any form of energy or with any form of cleaning up what’s left over – the mess the energy leaves behind. There are always risks. There are always good sides and bad sides. There’s no exception to that. The thing we have to with any form of energy or with any form of clean up – in this case, bringing CO2 down to its normal levels for giving us our normal climate. We have to minimize the risk and maximize the benefits. And if we minimize the risk, meaning that presumably there are still risks, we make those risks so minor that they’re inconsequential compared to the benefit of what we’re doing in the long run.
MH 49:50 The bottom line message is that we can’t afford to wait any longer. And governments around the world and their funding agencies and including philanthropists are realizing the speed at which we have to correct this problem. And the effort now around the world is growing really rapidly and it’s become tremendous. And we’re hoping that by 2040, 2050, we’ll be in much, much better shape and maybe see the light at the end of the tunnel by that time.
Oceans cover 70 percent of our planet and may hold the key for our survival in the future, as scientists weigh the potential risks against the consequences of not doing enough to alleviate climate change. My thanks to Michael Hochella. Pulse of the Planet is made possible in part by the Center for Earth and Environmental Nanotechnology and the National Science Foundation. I’m Jim Metzner.