In July 2013, I posted a blog entitled “The Blob that Ate Cleveland! Yikes!” That blog talked about Harmful Algal Blooms (HABs) returning to the Western Basin of Lake Erie. The HABs were moderate that year.
However, in Summer 2014, the City of Toledo’s water system was shut down for 3 days – a result of the proliferation HABs in the Western Basin.
Approximately 500,000 people were without safe drinking water over that period of time, people were deprived of the Lake’s recreational opportunities – and, of course, aquatic life was deleteriously affected.
In short, water quality has been deteriorating in the Western Basin due to huge industrialized farming practices in Northwestern Ohio’s Maumee River watershed. Now, that deterioration is starting to affect Cuyahoga County by way of “Dead Zones” in the Lake’s Central Basin – in other words, you and me.
Last Wednesday, 25 July, cleveland.com posted an article entitled “Lake Erie Dead Zone Threatens Cleveland Drinking Water.” It noted that Lake Erie’s HABs “typically spend the summer in the Western Basin, but as the lake warms and winds from the west blow the blooms eastward, they merge with a separate, less toxic bloom of a different type of algae in the Central Basin.”
Apparently, this combination “develops into tons of algae that from August to the end of September sinks to the bottom of the lake where it decomposes and consumes oxygen until the lowest 10 feet is nearly entirely depleted.”
This "Dead Zone" in the deep, frigid water about 15 miles north of Cleveland – and ranging as far east as Ashtabula – turns the water yellow, smelly and distasteful. It threatens the drinking water for millions of Northeastern Ohioans and forces fish and other aquatic creatures to leave the contaminated area or die from lack of oxygen.
According to Jeff Reutter, the retired director of Ohio State's Sea Grant and Stone Lab, "The danger comes because there's no good easy way to get oxygen into the cold bottom layer… The demand for oxygen by microorganisms is so great that there's none left for the fish and critters."
According to the website of the Cleveland Division of Water (CWD), “during the late summer, Lake Erie can form a ‘Dead Zone.’ The Dead Zone is a large area of low-oxygen water located in Lake Erie’s Central Basin – approximately 45-55 feet below the surface. No fish can live without oxygen; thus the term Dead Zone. This water is colder and has a low pH. These conditions can also cause the water to absorb manganese from the bottom of the Lake, which is not harmful to drink but can cause water discoloration.”
The website attributes the Dead Zone in the Central Basin to the growth of HABs in the Western Basin – noting that “Changes in farming practices, especially in western Ohio and eastern Indiana, have caused increasing amounts of phosphorus to enter Lake Erie...”
The website explains that, as algae die, the detritus sinks to the bottom of the Western Basin of Lake Erie. Under the right weather conditions, Dead Zone water can then shift vertically and horizontally – and migrating from the Western Basin to the Central Basin. Once here, it can reach one of CWD’s 4 intakes.
The above-cited cleveland.com article also reported that monitoring and tracking the dead zone as it develops is the responsibility of Scott Moegling, (CWD’s) Water Quality Manager. "We have buoys in the lake and satellite imagery to help us understand the hypoxia," the scientific definition for oxygen deprivation in the water, Moegling said.
Moegling has helped create a color-schemed hypoxia map that is updated daily and posted online – for use by public water systems, fisheries and power industries. "To the best of our knowledge, it's the only real-time hypoxia monitoring device being used by any water system on the Great Lakes," Moegling said. "We've learned how to treat" the Dead Zone water, "we just have to know when it's coming so we don't have to wait until it's on us to react."
To be fair, Dead Zones have developed in the Central Basin of Lake Erie for more than 100 years due to phosphates and raw sewage that were dumped into the lake prior to passage of the Clean Water Act in 1972. The Dead Zones disappeared for a while, but became a concern for water treatment plants again after they returned about a decade ago with the emergence of HABs in the Western Basin.
The Dead Zone of the Central Basin eventually dissipates during the fall when the warm, oxygenated upper levels of the lake water mixes with the cold, oxygen-depleted lower levels, returning the lake water to normal until the next year.
Wait until next year? Yikes!!
Z
