Aquatic hypoxia can be a serious problem, with “dead zones” in lakes or oceans,media New Atlas reported. A new study suggests that a process known as a “falling stream” may help prevent these regions from forming – although this is not a cheap solution.
Lack of oxygen usually occurs when large amounts of nutrients produced by land-based agriculture or other human activities flow into large bodies of water, leading to the proliferation of algae. Too much algae continues to consume large amounts of dissolved oxygen in the water, causing the death of fish and other organisms. Ideally, the formation of “dead zones” can be minimized by changing farming practices, building better wastewater treatment facilities and enabling people to do things differently. But this could be a slow and complex process, so scientists at the Carnegie Institution for Science in Washington, D.C., began working on new ways to prevent oxygen deficiency from existing pollution.
Current methods include using pipes laid at the bottom to soak air through water columns, or using fountains to increase oxygen co-operation on the surface. Because neither method is efficient, scientists at carnegie science research turn to the process of “falling the flow” – which involves pumping more oxygenated water down the surface to disperse oxygen to low oxygen depths.
Tests at the Searsville Reservoir in Woodside, California, have found that underground can increase oxygen saturation by 10 to 30 percent, reportedly enough to prevent many marine life from dying from lack of oxygen. However, the effect was only found a few meters from the water pipe. This means that a wide network of pipes and a large amount of energy will be required to operate the pump to make a significant difference in a typical “dead zone”.
According to the team’s calculations, using the “downstream” process to deal with the annual “dead zone” in the Chesapeake Bay would cost between $4 million and $47 million – a figure that would climb to $26 million to $263 million when it comes to “dead zones” in the Gulf of Mexico.
Nevertheless, it is considered to be much cheaper (and therefore feasible) in the short term compared to radical changes in agriculture, wastewater treatment and other well-developed human activities. In addition, according to computer models, large-scale “drop streams” should be three to 100 times more oxygenated than using bubble tubes and 10,000 to 1 million times more efficient than fountains.
Carnegie atmospheric scientist Ken Caldeira and marine scientist David Koweek led the study. “Reducing nutrient contamination is the only way to permanently eliminate hypoxia, ” says Caldeira. However, our work shows that the drop stream is a technical solution that can develop nutrient management strategies while reducing the risk of hypoxic death zones. “
The paper on the study was recently published in the journal Comprehensive Environmental Science.