The Damaging Effects of Fertilizers on the Marine Ecosystem

The dramatic increase in the use of synthetic fertilizers Nitrogen, Phosphorus and Potassium (NPK) since the early 1900’s has resulted in the depletion of naturally occurring minerals in soils. The Earth Summit concluded in 1992 that “There is deep concern over continuing major declines in the mineral values in farm and range soils throughout the world.” This was based on data showing a decline in nutrient levels over the last 100 years: Europe – 72% decline. Asia – 76% decline, North America – 85% decline. Nanotechnology has the potential to revolutionize the agricultural and food industry with new tools for the molecular treatment of diseases, rapid disease detection, enhancing the ability of plants to absorb nutrients etc.

Farmlands worldwide have steadily been depleted of trace minerals. One may surf the net and see literally thousands of academic articles on this subject. Although we can still produce abundant food volume (tons per acre) using chemical fertilizers on our farmlands, the quality of the produce has declined significantly over time.

Consider a study from the US Department of Agriculture presented to the United States Senate in 1936. It concluded:

“ . . . the alarming fact is that foods (fruits, vegetables, and grains) now being raised on millions of acres of land that no longer contains enough of certain minerals are starving us – no matter how much we eat.”

That was over 80 years ago! It has gotten even worse today. We use more than double the amount-per-acre of chemical fertilizers than we did in 1936 and our crop quality and mineral content is worse than it was in 1936.

In recent years, agencies of the federal government have emphasized the need to diminish America’s reliance on chemical fertilizers. Scientists at the USDA’s Agriculture Research Service in Texas, conduct online seminars and travel the country teaching farmers how to create healthy soil. Their message is simple:

“Although the United States has some of the richest soils in the world, decades of agricultural abuse have taken their toll, depleting the dirt of essential nutrients and killing off bacteria and fungi that create organic material essential to plants.“

Worldwide, agriculture is the second-largest source of climate change pollution—and both the manufacturing and application of fertilizer has a heavy emissions toll. Synthetic nitrogen fertilizers (derived from fossil gas) and pesticides (derived from fossil gas and crude oil) both contribute to global warming, biodiversity collapse, and toxic pollution. From a manufacturing perspective, the production of the key component of synthetic nitrogen fertilizers is Ammonia (NH₃) which contributes between 1 and 2% of worldwide carbon dioxide emissions. Ammonia has to be made at a high pressure under high temperatures—meaning it takes a lot of energy to manufacture. Most of that energy comes from burning fossil fuels like coal and methane gas, which give off the greenhouse gas carbon dioxide, the main cause of climate change.

From an application perspective, synthetic NPK fertilizers also produce greenhouse gases after farmers apply them to their fields. Crops only take up, on average, about half of the nitrogen they get from synthetic fertilizers.

NPK fertilizer applied to crops release an estimated 450 million tons of carbon dioxide (CO2) per year as a result of only half of the fertilizer being absorbed by crops — equivalent to the total energy system emissions of South Africa. Much of the applied fertilizer runs off into waterways, or gets broken down by microbes in the soil, releasing the potent greenhouse gas nitrous oxide into the atmosphere. Although nitrous oxide accounts for only a small fraction of worldwide greenhouse gas emissions, pound for pound, nitrous oxide warms the planet 300 times as much as carbon dioxide. Agriculture accounts for roughly two-thirds of global emissions of nitrous oxide (N2O).

Waste by-products are also an issue with NPK fertilizers. Potassium and Phosphorus are both mined ores. Phosphate production generates huge amounts of phosphogypsum wastes, nearly 48 million MTs in 1988 alone. Industry estimates that 5.2 tons of phosphogypsum is produced for every ton of phosphoric acid. Phosphorus processing also produces high quantities of naturally occurring radioactive materials. The environmental impact of potash mining is generally localized to the mine site, and may include the disruption of vegetation and wildlife, as well as large-volume water consumption and contamination. Then all three components have to be processed together. This quadruple production process has massive negative impacts on the immediate environment and broader climate change impacts.

Fertilizers contain high concentrations of nitrogen, phosphorus, and other nutrients that are essential for plant growth. When applied in excess, these nutrients can seep into waterways and eventually make their way into the ocean. This process, known as nutrient pollution, can lead to harmful algal blooms, fish kills, and other negative impacts on marine life.