This is a guest blog post by Christina Albright-Mundy
The effects of urbanization and industrialization can be felt worldwide, from the air we breathe to the water we drink. Our rapid shift from an agrarian world to a highly developed one has had major environmental impacts, such as smog-filled skies, rapid resource depletion and polluted waterways. For water enthusiasts, this damage is becoming more apparent every day, and one of the most severe effects of this environmental degradation is eutrophication.
Eutrophication is defined according to Merriam-Webster “the process by which a body of water becomes enriched in dissolved nutrients (as phosphates) that stimulate the growth of aquatic plant life, usually resulting in the depletion of dissolved oxygen.” Nitrogen and phosphorus are two of the main eutrophicating nutrients. Both are vital for terrestrial and aquatic plant life; their presence a limiting factor in growth.
When these nutrients are present in unnatural quantities, the polluted area will experience a rapid growth of algae and plants . As these plants start to die and decompose, the amount of dissolved oxygen available in the water column decreases, as decomposition requires a large input of oxygen. The area will become hypoxic and the animals living here will either leave or they will die. The area, now void of life, will be referred to as a “dead zone.”
It’s no mystery that these excess nutrients are coming from wastewater runoff, which carries them directly into our waterways. The two main sources of these excess nutrients are fertilizers and agriculture runoff. Excess nutrients in soil substrate will filter into groundwater, also eventually leaching into our waterways.
Animal manure is responsible for the largest introduction of nutrients into our waterways, with factory farms being the worst offenders. Animal feces deposit nutrients into the soil, and the excess goes into the groundwater. Rainwater and excessive irrigation wash manure on the soil’s surface into streams and rivers. Fertilizers behave in the same manner.
Impervious surface cover is another area of concern. When water flows downhill towards a streambed under natural conditions, most of it will be absorbed by the soil substrate. By reducing the amount of water immediately entering our waterways, the soil can filter it and utilize nutrients from the runoff. There is no absorption when wastewater runoff flows over cement surfaces, thus the water flows unimpeded towards our waterways.
The takeaway for divers means poor diving conditions. Visibility in these polluted areas will be poor (think pea soup); the plant life will be choking; the wildlife will be sparse. Unless your intention was to practice search and recovery skills, these conditions are recreationally useless. But of more pressing concern, eutrophication is environmentally devastating.
And though the problem is global, we can help lessen the effects of eutrophication on a personal level by adopting some or all of the following practices in both our own gardens and with our consumer choices.
- Avoid the use of fertilizers, synthetic or organic.
- Maintain as much native vegetation as possible.
- Avoid bare soil.
- If you must water the lawn, use only the water needed to moisten the grass, producing no runoff.
- Utilize rain barrels to collect rainwater for future lawn care and to prevent wastewater runoff.
- Plant a rain garden.
- Remove fallen leaves from gutters and dispose of them as green waste.
- Lessen (or eliminate) your consumption of animal products.
When it comes to reversing the effects of eutrophication, there is a lot of work to be done. There are substantial dead zones in the Black Sea, the Baltic Sea, Chesapeake Bay, Long Island Sound and the Mississippi River Delta, where the dead zone is roughly the size of New Jersey. Unless we drastically reduce the volume of nutrients entering our waterways, these areas, and more like them, will appear. As stewards of our world’s water, we must do our part and prevent the further destruction of aquatic ecosystems through eutrophication.