Don't overlook potential threat of 'yellow water' in Lake Erie's western basin, NOAA scientist saysTom HenryThe Blade, Toledo, Ohio

TOLEDO — Here's another reason to keep phosphorous and nitrogen out of Lake Erie: Yellow water.Granted, it's not nearly as common — at least in the western basin — as the blue-green hue of cyanobacteria that people commonly refer to as algae.But Craig Stow of the National Oceanic and Atmospheric Administration's Great Lakes Environmental Research Laboratory in Ann Arbor told journalists Wednesday that more water-treatment plant operators should be on the lookout for stuff that's yellow.Why?Low oxygen in the water column.Stow, a NOAA aquatic ecosystem modeling scientist, explained that when so many nutrients float around in a given portion of the lake, it enters a state of hypoxia, a scientific word for oxygen-deprived.According to the U.S. Environmental Protection Agency, hypoxic conditions exist in pockets of water in which dissolved oxygen concentration falls to only 2 to 3 milligrams per liter.NOAA has determined that when oxygen concentration falls even further, to about 1 mg/l, it causes lake-bottom soil to release manganese, which turns water yellow and causes distinctive rust-like taste and odors.Although water-treatment plants can effectively neutralize heavy manganese releases with chemicals such as potassium permanganate, it takes quick action and the right dosage.Potential manganese releases are now one of the things NOAA is trying to predict more accurately in advance, to give treatment-plant operators more time to react, especially for plants near Cleveland that have had to deal with it at times.Once considered a problem confined mostly to Lake Erie's central basin, hypoxic — or so-called "dead zone" — areas are now believed to be formed somewhere within the western basin in July, then move along the Ohio shoreline to the central basin."September is when the middle of the lake becomes hypoxic," Mr. Stow said during the first day of an annual two-day workshop for Ohio journalists.Manganese releases into the water columns are known as upwellings. Problems exist for water-treatment plants when the water column becomes enriched with manganese, and is drawn into the plants via intakes."If we have a strong, sustained wind, principally out of the northeast, then we'll have upwelling into intakes," Mr. Stow said.Andrew McClure, Toledo's Collins Park Water Treatment Plant administrator, said he's aware of the phenomenon but hasn't seen it occur this far west."We haven't noticed it at the (water-intake) crib," he said.The same is true a little closer to the central basin in Port Clinton, where Ron Wetzel, the Ottawa County Regional Water Plant superintendent, said he's interested in sampling raw water "probably once a month now to get a baseline for next year.""I've seen it in well water. It's pretty distinct," Mr. Wetzel said. "I've not smelled it or seen it at the plant."Also during the workshop's first day, Chris Winslow, the Ohio Sea Grant/Ohio State University Stone Laboratory director, said Lake Erie now has an estimated tourism value of $15.1 billion a year in eight counties along the shoreline, including Lucas, Ottawa, and Erie counties. That's about a third of Ohio's total $40 billion tourism impact. Lake-based tourism also provides about $4 billion in wages, $1.9 billion in tax revenue, and 127,852 jobs, according to his presentation.And Lauren Kinsman-Costello, a Kent State University assistant biology professor, said that although wetlands are accurately described by scientists as the "kidneys of the landscape" because of their filtering ability, many people don't realize some wetlands aren't as effective as others. Some actually release more nutrients than they trap; hence, the need for site-by-site investigations and more soil tests."When you're talking about nutrients, it is way more than acreage volume," she said. "Acreages make a lot of sense for (wildlife) habitat, but not for nutrients."___ (c)2021 The Blade (Toledo, Ohio) Visit The Blade (Toledo, Ohio) at www.toledoblade.com Distributed by Tribune Content Agency, LLC.