The failure to mitigate climate change is prompting researchers to look at more drastic approaches, like fertilization of the oceans, to combat the massive excess of carbon dioxide in our air.
Michael Hochella is an Earth scientist at the Pacific Northwest National Laboratory.
We need to decrease CO 2 levels on a global scale. The best chance of cooling the planet is if we use the oceans as a CO 2 sink.
One of the main components of the carbon cycle is the biological pump that takes CO 2 out of the air to store in the ocean's depths.
The tiny organisms need minerals like iron to grow and reproduce, but there's only a fixed amount floating at the surface of the waters with them.
The same help could be offered to the sunlight eaters that float on our seas.
The whales once fed plankton with a huge chunk of natural ocean fertilization. In the past, whales helped remove close to 2 million tonnes of carbon dioxide a year through this process.
We could suck up more CO 2 from the air and carry it with them to their deaths if we added this missingfertilizer. Most of the excess has been released thanks to human activities and the CO 2 is stored in the ocean floor.
It could take hundreds of thousands of years for this carbon to be sequestered as fossils did before them.
The team explained that larger forms of the required nutrients don't linger near the surface for long enough to be used up by the phytoplankton. Natural ocean fertilization can be found in the form of iron oxides and iron OXYhydroxides.
Hochella says the idea is to add new processes. The land has been fertilized by humans for hundreds of years. It is possible to fertilize the oceans in a responsible manner.
Peyman Babakhani and colleagues reviewed 123 studies and found some engineered particles that could be used for fertilization.
Artificial ocean fertilization would need to increase the number of microalgae, but not enough to cause harm.
The team assessed some of the studies and they were able to increase the amount of growth and abundance.
It appears that the nanoparticle's affinity to the cell surface dictates how much is taken up, rather than concentrations, so it could be released at levels equivalent to those already in the sea.
Experiments show that the growth of phytoplankton blooms using ocean fertilization depletes other surrounding resources. Future fertilization might need to incorporate more minerals.
If considerable CO 2 drawdown is achieved by using engineered nanoparticles, this may allow applications of the approach as a carbon dioxide removal technology at smaller scales or specific locations.
With any wide-scale manipulation of the environment, there are risks, like the use of landfertilizer.
Babakhani and colleagues warn that the environmental risks of adding engineered nanoparticles to the ocean need to be assessed.
This idea is still in the early stages, since none of these particles have undergone a focused study in real life.
The long-term impact of the nanoparticles on the biogeochemistry of the oceans is unknown due to their tendency to aggregate over time in marine ecosystems, potentially smothering life below the ocean's surface.
The researchers have a plan to address the issues. Although engineering the correct nanoparticles would be more expensive than using existing materials, it would allow us to tailor them to the needs of specific environments, making them more effective.
Researchers acknowledge that extreme interventions need to be approached with extreme caution because they are becoming more and more likely. We already know how to protect remaining and restore lost and degraded environments.
The research was published in a journal.
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