One of the discerning lessons in geography at secondary school level is the knowledge that about 71 percent of the Earth’s surface is water-covered, and the oceans hold about 96.5 percent of all Earth’s water. Water also exists in the air as water vapor, in rivers and lakes, in icecaps and glaciers, in the ground as soil moisture and in aquifers as ground water, and even in all living things, animals and plants.
Volume of water in the 29 percent of the non-oceanic part of Earth, the land where we dwell contains less than five percent of the water on Earth. In fact, there is enough water to cover the whole Earth completely to a depth of 2.6 kilometer, if the earth was made spherically uniform like a ball. This is because there is an estimated 1.34 billion cubic kilometers of water in the oceans while the surface area of Earth is estimated to be 510 million square kilometers. It is the topography of the world that keeps the continents above water while soil erosion is constantly bringing down the high-elevated areas like mountains. It is very clear that there is so much water on the earth occupying closed to three – quarter of the earth surface.
In the slightly above one – quarter of the earth, people can only dwell in a fraction as forestry occupies 34 percent, Barren land especially desert has 14 percent while inland water bodies, snow and glaciers occupy 4 percent. About the 50 percent of the habitable land is being used for agricultural purposes. This means that there will be pressure on agricultural land as the population increases when more food is required to supply the ever-expanding population of the world.
To give a vivid picture of the likely pressure on agricultural land, it is pertinent to present a trend of population explosion of the world from the slightly over 100 years ago (1900 to 2018). Records from http://www.worldometers.info/world-population/world-population-by-year/ show that by the year, 1900, the world population was estimated to be 1.6 billion, with an average yearly increase of 1.9 percent, the population moved to 3.03 billion by 1960. The figure moved to 4.458 billion by 1980, then moved to 6.145 billion by the year 2000, again moved to 6.958 by the year 2010 and then finally to 7.633 billion by June, this year 2018. This means that the world population decupled from 1.6 to 7.6 billion within a period of 118 years.
With this trend, the population estimated to be 9.8 billion by 2050 and 11.2 billion by 2100. Will the land surface be adequate to supply foods that can meet the dietary needs of the population in 50, 70 and 100 years to come? More land can be brought into cultivation by clearing the forest, adapting innovative farming methods and increasing farms in vertical direction to increase food production. Can humanity considers using the 71 percent fraction of the earth occupied by ocean for farming activities? If more lands are cleared, what is the environmental implication of bringing more land into cultivation? Will it increase the greenhouse emission? These are questions and challenges attracting the attention of the innovators and researchers. One of the identifiable solutions to these challenges is “Ocean Farming”
Ocean farming involves growing of food in the ocean as one may discerningly observe that sea vegetable exit flourishing within and under the ocean. Are these vegetable edible?Imagine crops growing in the ocean without fertilizer application, no air, no soil, no fresh water, no only seawater and sunlight. Weeding, tillage practices and protection of crops against pests and diseases are practically not required in ocean farming thereby saving costs commonly incurred from such operations. Ocean farming is “zero-input food production” — it requires no additional fresh water, fertilizer, pesticides, feed or soil to grow. As the price of fertilizer, herbicide, insecticide, water, and feed goes up, zero-input farming will naturally be the most affordable food on the planet. It receives everything it needs from the sun and the sea, plant grows super-fast —can grow 2 – 2.5 cm a day as stated by an expert of ocean farming. Some of these inputs are hugely energy-intensive and huge climate risks to both freshwater and soil. Ocean farming can be so exciting in addition to its profitability compared to land farming.
The technique of ocean farming or “3D ocean farming” consists of horizontal ropes on the water’s surface, anchored to hurricane-proof floats that connect to lines underwater supporting seaweed crops and interspersed with hanging net enclosures to grow scallops and mussels. Clam and oyster cages, also connected to the surface ropes, sit on the seafloor. The major crop in ocean farming is seaweed, which is known to improve the marine environment by absorbing dissolved nitrogen and phosphorus. These are two pollutants that end up in the ocean through agricultural runoff, and carbon dioxide, which drives ocean acidification and global warming. Oyster, another major sea vegetable is also another good nitrogen remover from water. Seaweed is highly nutritious addition to human diets and contains protein, vitamin C and calcium.Seaweeds contain more vitamin C than orange juice, more calcium than milk, and more protein than soybeans, are the major feeds of fish, which made them highly nutritious. “By eating the plants fish eat, we get the same benefits while reducing pressure on fish stocks. So it’s time that we eat like fish” as posited by an ocean farmer. In addition, seaweed can be used as a potent soil fertilizer and animal feed.
On environmental implication of ocean farming, it is not only environmentally friendly but actually revitalizes degraded or dying ecosystems by creating seaweed groves that become nurseries and sanctuaries for many marine species.The kelp recaptures some of the nitrogen and phosphorus released from wastes that escape from the aquaculture pens, helping make salmon farming — whose high concentration of fish produce large amounts of fecal material — measurably cleaner. It’s a pro-active approach to conservation, which goes beyond the growing movement to create no-fishing reserves. Therefore, in this era of climate change, serious consideration should be accorded to preservation of the world’s oceans so that they continue to serve humanity without becoming destructive. Consequently, there should be strategy of restoration of oceans within the conservation efforts of environmentalists. Questions asked by enthusiastic ocean farmer capture the environmental friendliness of the ocean farming “It’s not just about: How can we save the oceans? How can we protect the sea animals? It is also about how can the oceans save us? How can it provide food, jobs, safety, and a sustainable way of life? I’m convinced the answer is ocean conservation with symbiotic green farms.,” which is successfully being provided by Ocean farming.
The profitability of ocean farming is the result of prolific nature of ocean greens such as kelps, which are not only small boutique crops but can grow incredible amounts of food in small areas. Kelps can produce 25 tons of greens and 250,000 shellfish per acre in five months. Additionally, Seaweeds could be a powerful source of zero-input biofuel.
Feasibility studies from a research station indicated that 2,000 gallons of ethanol per acre could be produced from seaweeds — that’s a 30 times higher yield than soybeans and five times more than corn can produce. The kelp will grow eight to twelve feet in a five-month period. And the whole food column is nourishing. The oysters, mussels, and scallops provide low-fat protein and all sorts of important vitamins: selenium, zinc, magnesium, iron, B vitamins, and omega-3s. The sea vegetables are analyzed — different forms of algae like kelp — and they create lots of vitamins and minerals and nine different amino acids, plus omega-3s.
Ocean farming is most efficient way of growing food, environmentally sustainable way possible — vertically. And it grows quickly. Can Nigeria farmers start to think of ocean farming? Well, in Nigeria, we are yet to cultivate fifty percent of our arable land, and thus, ocean farming is more theoretical than practical, however, this option is still available for our future needs.
Professor Othman is the Executive Director of National Agricultural Extension and Research Liaison Services (NAERLS), ABU Zaria.