Nitrogen along with phosphorus are natural nutrients that are a regular part of aquatic ecosystems. Both contribute to the growth of aquatic plants and algae, which support food and habitat for marine life. But an excess of Nitrogen in the atmosphere is polluting the air and water and the price we are paying is serious human health and environmental issues, and impacting the economy.
Nitrogen is also the most abundant element in the air we breathe. But too much nitrogen and phosphorus has entered our environment and affected many streams, lakes, rivers, and coastal waters for the past several decades, and we have already begun to pay a high price for it.
Nitrogen And Phosphorus: Excessive Nutrients Harming Aquatic Life
The presence of excess nitrogen and phosphorus is upsetting the delicate balance in the environment. It causes algae to grow uncontrollably fast, quicker than the capacity of the ecosystem to handle. This increase affects the quality of water, habitat, and food resources. It also leads to the decrease of oxygen levels in the water that is vital for the survival of marine life.
Algae blooms are leading to an increase in oceanic dead zones. these are immense oxygen-free zones in the oceans, which doesn’t allow ocean life to survive. The problem is getting worse due to mega-storms and climate change, which is worsening the problem.
Nitrogen and phosphorus are together responsible for the human ability to produce so much food. The elements are indispensable building blocks for crops and plants. As they are also building blocks for the manufacture of synthetic fertilizers, they are thus vital to the mass production of food.
But both nitrogen and phosphorus are also leading to the most severe ecological catastrophe the world has known, though the extent of it is yet to be recognized. This destabilization of the natural cycles of phosphorous and nitrogen has been aggravated by the rampant use of artificial fertilizers to boost crop yield which began in the 20th century.
While mono-crop production has gone through the roof, it has done immense harm as agricultural runoff has leaked into water bodies, ultimately ending up in the oceans. Thousands of square kilometers of dead zones, such as the one in the Gulf of Mexico have killed fishing in these areas.
The matter has worsened with the increase in frequency and intensity of storms. This coupled with higher sea and surface temperatures due to climate change is aggravating the problem.
These dead zones and algae blooms are interlinked and unless the world acts now to repay them immediately, the dead areas will keep increasing each year.
The imbalance caused by the overload of phosphorus and nitrogen into the atmosphere is threatening the biodiversity of regions around the world. It is moving humans from space where they can operate safely.
Fixing Nitrogen And The Green Revolution
Man has long strived to ‘fix’ nitrogen and phosphorus to the soil as it meant bountiful crops. Crops wither away in the absence of these two components. Though nitrogen makes up close to four-fifths of the planet’s atmosphere, plants cannot use it as long it isn’t converted into a reactive form.
Early agricultural societies used the ‘slash-and-burn’ technique where unknowingly phosphorus and nitrogen were released from the burnt plants and transferred to the soil.
Farmers subsequently realized that rotating certain crops restored the balance in the soil. They found that combining clover with legumes including soybeans helped in nitrogen fixation as soybeans are among several rare crops that have the ability to fix nitrogen on their own.
Subsequently, people moved to the use of organic manure. This supplied both phosphorus and nitrogen and proved better than the burning technique. These innovations increased agricultural production immensely and supported a huge population.
The Advent Of Artificial Nitrogen And Phosphorus
An alchemist in Germany was the first to discover that the human body contained phosphorus. In the middle of the 17th century, he accidentally discovered this while boiling huge quantities of urine in search of the ‘philosopher’s stone.’ Human bones were now added to organic manure to be used as fertilizer.
But humans still lacked a huge source of nutrients that could increase agriculture on a large scale. In the middle of the 19th century, the colonial nations in the Americas and Europe came to know of a process used by native communities in Peru. They fertilized their harvests with the accumulated droppings of seabirds.
Called guano, it is a hugely effective fertilizer with a high content of nitrogen, potassium, and phosphate, all key nutrients essential for all types of crops.
The discovery of guano by the colonial powers led to their introduction to modern farming techniques. The guano trade was an important milestone in the development of modern farming using the input-intensive method.
A pan-Atlantic trade involving seabird guano boomed in the 19th century and even led to war between Chile, Peru, and Bolivia for control of islands that were the source of the droppings.
They began to be exported in huge quantities to the US and Europe till another development led to its decline.
At around the same time, scientists in the US found soluble phosphorus in natural rock deposits.
The Discovery Of Artificial Way To Fix Nitrogen
German chemists Carl Bosch and Fritz Haber discovered in the early 20th century that altered the progression of human history. The discovery of the Haber-Bosch method of nitrogen-fixing created an explosion in the production of synthetic fertilizers.
They developed a technique through which atmospheric hydrogen and nitrogen could be converted into ammonia using heat and pressure. It led to the creation of artificial fertilizers and also explosives used in WW I.
These discoveries along with the development of pesticides for mass use led to the production of food in quantities that were inconceivable in the past. With a mere increase in 30% of agricultural land, the world was able to feed a population that increased from 1.6B to 6B in the 20th century.
It was a stupendous effort, but people gradually realized the severe drawbacks of the indiscriminate use of artificial fertilizers. The biosphere was piled with billions of tons of artificial fertilizers.
From 15M tons of biologically active nitrogen sourced from rice and legumes in the 1890s, we are now utilizing 200M tons of nitrogen every year along with 47M tons of phosphorus each year.
The technological marvel that was modern agriculture came at a high price.
The Movement Of Nitrogen Across The Biosphere
The nitrogen movement across the biosphere was stable and controlled before the introduction of artificial fertilizers. The ‘nitrogen cycle’ was relatively simple back then.
Nitrogen movement was confined to the plants and animals released into the soil through manure and decay of dead animals. Some of it escaped through the conversion of bacteria or trickled down into the waterways.
The nitrogen cycle remained stable for ages and was the basis of life on the planet. It helped nourish and sustain both plant and animal life equally in an equilibrium of atomic movement.
The Artificial Boost Up Of Nitrogen Production
The coming of the industrial age and the introduction of technology into agriculture upset the balance. Fertilizers based on nitrogen and containing phosphorus help support over 50% of the planet’s population. But the indiscriminate use of artificial fertilizers has led to a deluge that has inundated water bodies and uses the balance of nitrogen and phosphorus in them.
Companies flooded the marketplace with cheap nutrients with the help of the Haber-Bosch technique, and the government subsidized their use to farmers to ramp up the production of crops.
This massive introduction of phosphorus and nitrogen soon began polluting the atmosphere, permeating the ecosystem in considerable quantities, more than the planet could safely absorb.
An even more worrying piece of news is that over 80% of the nitrogen that is introduced to the atmosphere through artificial fertilizer escapes through runoff, soil erosion, atmospheric conversion, plus various other forms. studies have shown that a mere 14% of the nitrogen introduced through artificial fertilizers ends up as food. The rest end up polluting the atmosphere.
This saturation of phosphorus and nitrogen is wreaking havoc with the ecosystem. And the effect has been gradual and unseen until recently. Sewage and fertilizers containing nutrients that have been consumed by humans enter groundwater as runoff. These nutrients lead to an explosion of the growth of algae and cyanobacteria in water bodies.
The abundance of nutrients leads to massive growth or blooms. The abundance is also referred to as red tides due to the color. The explosive growth of algae leads to anoxia or the total depletion of oxygen which kills the algae. They float to the top as rotting scum, toxic, and are red or green. This process is known as eutrophication and is common throughout the world, especially at the mouth of rivers and at times even in the deep ocean.
This condition uses up oxygen and kills almost all forms of marine life. It has affected rivers in the US, in China, and India areas that have the maximum concentration of nutrients.
The Disturbance Of 9 Planetary Boundaries
The excessive use of phosphorus and nitrogen is one of the 9 planetary boundaries which we are disrupting. We have pushed the boundaries of safe confines of human activities that have disrupted the natural systems of the planet and put our very existence at risk.
The concept was developed by the Stockholm Resilience Center and the bio-geochemical flow of phosphorus and nitrogen is defined as one of them.
Nitrogen Overload And The ‘Dead Zones’
The water bodies of the planet are the worst sufferers due to the pollution caused by excess nitrogen and phosphorus in the environment. The Gulf of Mexico is the biggest dead-zones on earth. Massive agricultural runoff from the US through the Mississippi River is causing damage worth $2.4B each year. but the costs are much more than the loss of the fish in those zones.
Other dead zones are present in the Chesapeake Bay and off the Oregon coast. There are similar dead zones in East Asia and Northern Europe. Such zones have been increasing in size and duration due to climate change. They are starting much earlier each year and ending later.
The Gulf of Mexico dead-zone is getting bigger and covered 6,334 sq. m. (16,400 sq. km.). Almost all fish plus other forms of aquatic life are absent during this period. And it has been expanding for over 3 decades and growing in size each year.
The problem of such nutrient overload was recognized 50 years ago. Regulations were imposed in many regions, but the political will was lacking to implement them. For instance, no politicians had the guts to take on the agricultural and livestock lobby in the Midwest. But scientists have proved that actions have led to results. But they say that they are mostly tokenism and lack the drive needed for a long-term solution.
The danger line has already been crossed in the case of nitrogen. ‘smashed’ is the time used by researchers. While climate change continues to grab headlines, nutrient runoff, called biogeochemical flows by scientists is just as dangerous to the planet’s ecosystem. And things have already spiraled out of control.
Action to curb the menace is still at a discussion stage. Scientists are highlighting the issue, but the policy is still at a nascent stage. The problem has yet to be clearly defined before any policy response in the matter.
Addressing The Issues
Efforts to address the issue of nitrogen pollution are a victim of what scientists call ‘fragmented’ efforts. Nitrogen is getting pushed into the biosphere in ways other than agricultural runoff. The burning of fossil fuels releases nitric oxide. Nitrous oxide is also released from agricultural lands. They are greenhouse gases and the latter is 300 times more potent than CO2 in contributing to climate change as a greenhouse gas.
Scientists say that the nutrient pollution issue is a victim of ineffective and incoherent control. Nitrogen use is still advocated for its agricultural use rather than seen as a danger that needs to be addressed. Policymakers need to ensure food security with the danger it poses to the environment, especially the oceans.
An immediate reduction in the use of fertilizers would lead to food insecurity. Instead, scientists believe that a more practical strategy is to limit waste. $200B worth of nitrogen is wasted annually. The use of cover crops to hold nutrients to the soil is one solution. Other methods that could be propagated include improving the storage of manure, introducing the methods of inter-cropping of nitrogen-fixing legumes, and planting buffer zones. Saving even 50% of the wastage would mean saving $100B.
We need to take note that the major biodiversity extinctions, the Late Ordovician, and the End-Permian events were preceded by anoxia, or the total depletion of oxygen, in the oceans of the planet. It led to the destruction of 90% of all species.