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Fertilizing The Ocean | Earth Wise

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There are a variety of schemes for removing carbon dioxide from the atmosphere.  Some require advanced and generally not-very-well developed technology.  Others, such as planting vast numbers of trees, are nature-based but are daunting with respect to the scale to which they need to take place in order to be truly effective.

Researchers at the Pacific Northwest National Laboratory in Richland, Washington have been examining the scientific evidence for seeding the oceans with iron-rich engineered fertilizer in order to feed phytoplankton.  Phytoplankton are microscopic plants that are a key part of the ocean ecosystem.

Phytoplankton take up carbon dioxide as they grow.  In nature, nutrients from the land end up in the ocean through rivers and from blowing dust.  These nutrients fertilize the plankton.  The idea is to augment these existing processes to increase the growth of phytoplankton.  As they eventually die, they sink deep into the ocean, taking the excess carbon with them.


The researchers argue that engineered nanoparticles could provide highly controlled nutrition that is specifically tuned for different ocean environments.  Surface coatings could help the particles attach to plankton.  Some could be engineered with light-absorbing properties, allowing plankton to consume and use more carbon dioxide.

Analysis of over 100 published studies showed that numerous non-toxic, abundant, and easy-to-create metal-oxygen materials could safely enhance plankton growth.  According to the researchers, the proposed fertilization would simply speed up a natural process that already sequesters carbon in a form that could remove it from the atmosphere for thousands of years.  They argue that given the current trends in the climate, time is of the essence for taking action.

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Fertilizing the Ocean to Store Carbon Dioxide

Photo, posted August 2, 2007, courtesy of Kevin McCarthy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Florida’s Starving Manatees | Earth Wise

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Manatees, also called “sea cows”, have been the victims of farm runoff.  They have starved to death by the hundreds along Florida’s east coast because algae blooms fed by nitrogen-rich fertilizer runoff are proliferating on the ocean surface and blocking sunlight from reaching seagrass below.  Seagrass is the primary source of food for manatees in the winter.  As seagrass dies off, so do the manatees.

Over 1,000 manatees have been found dead so far this year.  It is estimated that fewer than 8,000 remain in Florida waters.  Efforts are underway to restore coastal seagrass in the region as well as clams and oysters, which filter pollutants from water.  Unless the water is cleared up, it will be difficult to regrow the seagrass.  But the current situation is that manatees are so short on food that they are eating seagrass roots, killing the plants and thwarting efforts to help seagrass recovery.

Given this dire situation, the federal governmental has approved a program of feeding manatees.  The starving animals will be fed by hand in Florida, which is a rare wildlife intervention.  Conservation agencies tend to favor leaving wild animals to their own foraging and hunting so that they don’t become dependent on human handouts.

During the trial phase of the program, wildlife experts are likely to feed the animals romaine lettuce and cabbage, which is what manatees in captivity eat.  The hope is to give the animals enough additional food for them to get through the winter.  The trial feeding will begin on private property.  It remains illegal for the public to feed manatees.

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Florida to feed starving manatees in rare conservation move

Photo, posted February 21, 2008, courtesy of Keith Ramos/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Decarbonizing The Most Polluting Heavy Industries | Earth Wise

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The production of steel, cement, and ammonia accounts for about 20% of the carbon dioxide humans pour into the atmosphere.  Modern cities are largely constructed from concrete and steel and most of our food is grown using fertilizer made from ammonia. 

The most widely discussed solutions to decarbonizing these industries are green hydrogen and carbon capture and storage or CCS.

Steel manufacture is responsible for 11% of society’s emissions.  Most production starts by burning coal in a blast furnace. Using CCS could reduce emissions from burning the coal.  But the blast furnace could be eliminated entirely by the use of electrolysis to produce the pure iron needed to make steel.  This would be extremely energy-intensive but using a low-carbon source like green hydrogen could greatly reduce the emissions from making steel.

Ammonia is made by producing hydrogen from natural gas and then combining it with atmospheric nitrogen.  Both the hydrogen production and ammonia synthesis are energy intensive.  Using green hydrogen would eliminate emissions from the hydrogen production itself and new research on catalysts aims at lower-temperature, less-energy intensive ammonia synthesis.

Decarbonizing cement manufacturing is perhaps the toughest challenge.  Cement is made in a high-temperature kiln, typically heated by burning fossil fuels.  The process converts calcium carbonate and clay into a hard solid called clinker.  The main byproduct of that is even more carbon dioxide.  Burning green hydrogen and capturing carbon emission are about the best hope for reducing cement manufacturing emissions.

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Can the World’s Most Polluting Heavy Industries Decarbonize?

Photo, posted June 30, 2009, courtesy of Portland Bolt via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wastewater And Ammonia | Earth Wise

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Ammonia is the second most produced chemical in the world.  More than half of it is used in agriculture to produce various kinds of fertilizer, to produce cotton defoliants that make cotton easier to pick, and to make antifungal agents for fruits.  Globally, ammonia represents more than a $50 billion a year market.

Current methods to make ammonia require enormous amounts of heat – generated by burning fossil fuels – to break apart nitrogen molecules so that they can bind to hydrogen to form the compound. Ammonia production accounts for about 2% of worldwide fossil energy use and generates over 400 million tons of CO2 annually.

Engineers at the University of Illinois Chicago have created a solar-powered electrochemical reaction that uses wastewater to make ammonia and does it with a solar-to-fuel efficiency that is 10 times better than previous comparable technologies.

The process uses nitrate – which is one of the most common groundwater contaminates – to supply nitrogen and uses sunlight to power the reaction.  The system produces nearly 100% ammonia with almost no hydrogen side reactions.  No fossil fuels are needed, and no carbon dioxide or other greenhouse gases are produced.  The new method makes use of a cobalt catalyst that selectively converts nitrate molecules into ammonia.

Not only is the reaction itself carbon-neutral, which is good for the environment, but if it is scaled up for industrial use, it will consume wastewater, thereby actually being good for the environment.  The new process is the subject of a patent filing and the researchers are already collaborating with municipal corporations, wastewater treatment centers, and others in industry to further develop the system.

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Combining sunlight and wastewater nitrate to make the world’s No. 2 chemical

Photo, posted August 29, 2018, courtesy of Montgomery County Planning Commission via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Solar Cell Greenhouses | Earth Wise

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A recent study at North Carolina State University has shown that it can be feasible to use see-through solar panels in greenhouses to generate electricity.  The idea is to use semi-transparent solar panels on greenhouses that allow some of the light to get in for the plants to grow while making the greenhouses energy neutral or even allowing them to generate more power than they use.

The question is how the semi-transparent solar panels might affect greenhouse crops.  To investigate this issue, researchers grew crops of red leaf lettuce from seed to full maturity under a standard set of growing conditions – temperature, water, fertilizer, and CO2 concentration – but varied the light they get. 

A control group was exposed to the full spectrum of white light while three experimental groups were exposed to light through different types of filters that absorbed the particular wavelengths of light that would be absorbed by different types of semitransparent solar cells.

The researchers paid close attention to characteristics of the lettuce that are important to growers, grocers, and consumers:  general appearance, leaf number, leaf size, and weight.  The results were that the lettuce produced using all three kinds of filtered light was essentially identical to that produced in the control group.    Further research is underway looking at how harvesting various wavelengths of light affects biological processes for lettuces, tomatoes, and other crops.

Getting growers to use solar-powered greenhouses would be very difficult if doing so would result in a loss of productivity.  But given these experimental results, it appears as though the decision will boil down to a simple economic argument about whether the investment in new greenhouse technology would be offset by energy production and its resultant savings.

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Study Finds Plants Would Grow Well in Solar Cell Greenhouses

Photo, posted April 8, 2008, courtesy of Brian Boucheron via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Renewable Energy And Green Ammonia | Earth Wise

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Several different clean technology trends may come together on farms across the country where wind turbines could power devices that produce green ammonia for fertilizer and zero emission fuel.

Distributed wind is a kind of renewable energy that doesn’t get much attention.  It refers to turbines that are used to generate electricity for on-site use, as for a factory or a farm.  It typically involves smaller turbines than the behemoths that are used in giant wind farms.

Installing a wind turbine or two on a farm could be quite valuable if the electricity generated could be used to make green ammonia.  Such an application would eliminate the problem of “stranded wind”, which is when a location has lots of wind but lacks access to the electricity transmission infrastructure.

If farmers could utilize wind energy to produce ammonia, they could make their own fertilizer as well as fuel and get relief from price spikes and uncertainties in the commodities market.  Of course, they would also make use of the electricity they generate on site.

Most ammonia is produced using a proven technology called the Haber-Bosch process.   Ammonia contains only nitrogen and hydrogen, both of which can be extracted from the air.  The trick is how to do it efficiently using renewable electricity.   The Department of Energy has a program called the REFUEL Initiative, which aims at deploying renewable energy to produce ammonia.  The University of Minnesota, among other places, has multiple programs dedicated to green ammonia technology. 

There is encouraging progress being made that may ultimately result in a common sight of wind turbines on farms producing fertilizer, fuel, and electricity.

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The Renewable Energy Cows Come Home, Now With Green Ammonia

Photo, posted July 15, 2009, courtesy of Daniel_Bauer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Making Use Of Invasive Seaweed | Earth Wise

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In recent years, millions of tons of brown Sargassum seaweed have formed gigantic blooms stretching all the way across the Atlantic Ocean from West Africa to the Gulf of Mexico.  The seaweed has become a problem for shorelines in the Caribbean, the Gulf of Mexico, and the east coast of Florida.  The massive increase in seaweed populations is related to changes in ocean chemistry resulting from nutrients from fertilizer use entering the water as well as from changes to the climate affecting ocean currents and temperatures.  The seaweed is harming the tourism industry as well as fisheries and ocean ecosystems.

Cleaning up the seaweed that washes ashore is labor-intensive and therefore expensive.  A research team led by two British universities has developed a cheap and simple way to pre-process seaweed to facilitate making it into bulk chemicals and biofuels.  With the new process, cleaning up the seaweed can be both economically and environmentally viable.

Previous techniques for processing seaweed generally required removing it from the saltwater, washing it in fresh water, and drying it – all of which add significant costs.  The new technique makes use of catalysts to release sugars from untreated seaweed that feed a yeast to produce a palm oil substitute.  At the same time, the process creates heat and pressure, turning the residual materials into a bio-oil that can be processed further into fuels, and a high-quality, low-cost fertilizer.

Apart from getting economic value out of the seaweed that is collected, any plastic collected alongside the seaweed can be converted to useful materials as well. 

It appears that the seaweed scourge is here to stay, so finding an economically viable way to deal with it is a welcome development.

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Solve invasive seaweed problem by turning it into biofuels and fertilisers

Photo, posted August 10, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mexico’s Wonder Plant

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In 1979, an American naturalist named Thomas Hallberg visiting a small town in Oaxaca, Mexico was amazed to find a type of local maize – or corn – that grew nearly 20 feet high in poor-quality soil even though the local farmers did not use any fertilizer.

The unique corn plant had aerial roots that grew a mucous-like gel just before harvest season.  It seemed totally implausible, but the plant seemed to be fixing its own nitrogen:  extracting it from the air and somehow making it useful to the plant.

In 1992, Hallberg returned with a group of Mexican scientists and collected samples to study in his lab.  His research showed that the maize indeed received nitrogen from the air through its aerial roots.  It took over 20 years to figure out what was going on in the plants.  It turns out that bacteria that thrive in the low-oxygen environment of the maize’s mucus pulls nitrogen from the air and feeds it to the plant.

Scientists will probably spend years figuring out if a commercial application of this indigenous maize is viable.  It isn’t guaranteed that the self-fertilizing trait of the plant can be bred into a commercial crop.  But if it can, the payoff would be huge.  Farmers spend more than $3 billion a year on corn fertilizer in the US alone.

A vexing problem is who should reap the financial benefits of the maize.  The isolated village where the plant is grown has already signed an agreement to share in any such benefits.   But there are other Oaxacan villages that also grow the plant. 

Mexico’s wonder plant is likely to be caught up in the growing issue of biopiracy, which is the exploitation of indigenous knowledge and biological resources without permission.

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Indigenous Maize: Who Owns the Rights to Mexico’s ‘Wonder’ Plant?

Photo credit: ALLEN VAN DEYNZE/UC DAVIS

Earth Wise is a production of WAMC Northeast Public Radio.

Powering Cars With Cactus Juice

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Back in 2016, a company called Nopalimex, located in Micoacan, central Mexico, built the world’s first cactus-powered energy plant.  The facility utilizes a biodigester to make biogas from nopal, also known as prickly pear cactus.  The nopal plant has been called the ‘Green Gold of Mexico’ and is a staple in Mexican diets, medicine and cosmetics.

Nopalimex is now using the cactus to make biofuel for vehicles.

The fruit of the cactus is pureed, mixed with manure, and then left to decompose, producing methane.  The methane produced – about eight tons a day – fuels the biodigester which powers the company’s corn chip and cactus chip production and is being tested in a fleet of government vehicles.

The biogas will cost just 65 cents per liter, which is about a third cheaper than the cost of regular gasoline.  Using prickly pear as a feedstock for biofuel is attractive because it can be grown in places where traditional energy crops cannot.  One can imagine vast fields of cacti in remote, arid areas of the country where normal crops cannot grow.  It would not suck up the resources or space needed to feed people, which is an ongoing criticism of current bioenergy crops.

As long as the nopals are regularly replanted, the process is almost entirely sustainable, producing only water and nopal waste, which can be used to fertilize other crops.

Finding sustainable ways to produce fuel while doing minimal damage to the environment is an important challenge for countries around the world.  In Mexico, harnessing the power of the prickly pear cactus is a unique and clever solution.

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Mexico’s ‘green gold’: The company powering cars with cactus juice

Photo, posted July 8, 2006, courtesy of Christian Frausto Bernal via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Microplastics In Soil

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Many of us are well aware of the environmental challenge faced because of the proliferation of plastics.  Since plastic does not decompose naturally, most of it remains in our environment. Only 12% has been incinerated and only 9% has been recycled.  A great deal of plastic ends up in the ocean and other bodies of water.  Much of it breaks down into small particles – microplastics – which are now ubiquitous in the oceans.  There are also microplastics that started out that way in the form of little beads used in the cosmetics industry.  Studies have found microplastics in the bodies of 73% of fish from the North Atlantic.

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Tree-Planting Drones

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One of the major causes of the increasing carbon dioxide levels in the atmosphere is deforestation.   We chop down about 15 billion trees each year.  Over time, our activities have reduced the number of trees on earth by about 50%.  We do plant trees – these days, about 9 billion a year.  It is a substantial number, but still leaves a net loss of 6 billion trees annually.

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Small Grains In Corn Country

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Large portions of the Midwest are called the Corn Belt and for good reason.  Overall, about 90 million acres or 140,000 square miles of the United States are planted with corn and about half of that is in Iowa, Illinois, Nebraska and Minnesota.  In most of the Corn Belt, the corn is planted in rotation with soybeans.  Both are warm weather crops and the soil is left barren for nearly half of the year when the two crops are out of season.

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Growing More Food On Less Land

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There are predictions that the world’s population could reach 10 billion by the year 2050.  Whether population growth can be slowed down enough to prevent this remains to be seen.  Regardless, it is clear that we need to figure out how to feed many more people than we have today and we are not even doing that good a job of feeding the current population.

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