Phosphorus, nitrogen and potassium are nutrients of the plant world. With just the right amounts we get a bountiful harvest. However, as the old wives’ tale goes, too much of a good thing can be bad and in this case, it is disastrous.
These helpful nutrients can make parts of lakes or oceans dead by producing toxic ‘algal blooms’ in bodies of water. However the term, algal, for algae, is a misnomer. What is occurring in Lake Erie is actually an overproduction of bacteria—namely, cyanobacteria.
Cyanobacteria are a species of photosynthetic bacteria. The Lake Erie bacteria are known to produce colorful ‘blooms’ or scum that resemble algae, which is why we call them algal blooms.
Algal Blooms: Nature Correcting Itself?
Because all natural bodies of water contain a multitude of bacteria, many see the blooms as nature correcting itself. However, the occurrence in Lake Erie is not natural – this bloom is the result of an over-abundance of fertilizers that came as run-off from farms.
Inorganic phosphates (PO4), and nitrogenous fertilizers (urea, for instance) disproportionately feed bacteria over other life. Fish, algae, and other microorganisms are literally choked from the lake by an over-production of cyanobacteria.
Through the unwanted addition of fertilizer into the water, too many available nutrients results in an overgrowth of bacteria in a process called eutrophication. The result is a lack of oxygen in the body of water.
Lake Erie’s Toxic Blooms
Like all natural bodies of water, Lake Erie supports a multitude of life that includes bacteria. Lake Erie has produced toxic blooms since the middle of the last century when phosphates from detergent production fed the phenomenon. Among the different species of bacteria in Lake Erie, the cyanobacteria species of interest, Microcystis spp. produces a seven-peptide (amino acid) toxin that has rendered water in parts of Lake Erie non-potable and dangerous. In fact, those areas are not just undrinkable, they’re dead zones.
What is a Water Dead Zone?
Areas in which there is less dissolved oxygen are known as ‘dead zones’ due to a lower level of marine life; life requires oxygen to continue. Environmentalists first acknowledged dead zones at the height of the ‘Ecology Movement’ of the 1970s—spurred by the work of the late Rachel Carson. The dead zones in Lake Erie receded at the end of the 1980s, but farm run-off has re-ignited the problem. So, the question must be asked, how can we re-mediate the dead-zones of Lake Erie (or any natural body of water)?
The initial efforts to re-mediate Lake Erie centered on curtailing phosphate usage, however the present rise in temperature has contributed to the prevalence of dead zones throughout the world as well. So, the presence of a dead zone in Lake Erie may be viewed as a test case for other sensitive bodies of water in the world. But, present efforts of the country’s scientific technology centers on observing and understanding the toxic blooms.
However, an intriguing case of water remediation comes from the rivers and watershed areas of India; rivers like the Ganges have been a source of fresh water for parts of India for many years. Since India is the second most populous country with the least amount of fresh water per person, the methods of successful remediation of India’s water resources could provide a potential solution for Lake Erie as well.
Like the problem spots in the west, contamination occurs near urban and farmland areas, but in parts of India, remediation efforts are moving forward. The efforts may be grouped in the following manner:
1. Extensive and exhaustive monitoring for toxins is in place (to assure prevention of contamination).
2. Extensive water treatment facilities throughout the country.
3. Encouragement of self-sufficiency through rain-water harvesting.
4. Water-reuse technology: remediation of ‘gray water’ followed by its re-use.
Preventing Algal Blooms and Toxic Water
Although none of the technologies sounds revolutionary and are also in use in the U.S., the scope by which the U.S. remediates water for re-use is far less encompassing. It should be noted the nature of the U.S. economy encourages independent business-people to seize the moment and develop re-mediation technology.