Tag Archives: wetlands

The Fight Against Toxic Algae

Signs posted around the Grand Lake, Ohio read: “Danger: Avoid all contact with the water.”  When dangerously high levels of toxins from blue-green algae in Grand Lake, Ohiio were publicized in 2009, many residents and tourists stopped using the 13,000-acre lake in northwest Ohio. Hotel revenue and home values sank for several years as algae bloomed in the state’s largest inland lake.

Greenish water still laps at Grand Lake’s shores, but recent water samples show that the amount of algae-feeding nutrients entering the lake is down significantly. State, federal and private donations covered more than $10 million in projects aimed at improving water quality. More people are boating on the lake again. Grand Lake could now serve as an example for communities with algae problems across the nation, experts say.

Algal blooms are on the rise, from Lake Erie to the Florida Everglades. In August 2019, the Environmental Protection Agency listed algae-related beach closures or health advisories in 23 states, and it said other blooms may not have been reported. In 2010, the EPA found that 20% of 50,000 lakes surveyed had been affected by phosphorous and nitrogen pollution, which feeds algae.e  Cleaning up bodies of water choked with toxic algae has proved difficult. The project to repair Grand Lake, once one of the most polluted by algae in the nation, is one of the clearest successes. It shows cleanup is possible, but also expensive and time-consuming.

“It’s not restored yet, but it’s on the road to recovery,” said Stephen Jacquemin, an associate professor of biology at Wright State University-Lake Campus in Celina.  Beginning in 2012, wetlands areas were built around the lake, which was hand dug in the 1830s. The thick stands of bulrushes and other plants have reduced phosphorous and nitrogen levels in water entering the wetlands before reaching the lake by as much as 90%, Dr. Jacquemin said.  Three wetland areas, which cost a total of about $6 million to build, are constructed as a series of interconnected pools that allow particulates to settle out and plants and microbes to remove nutrients.

Areal View of Artificial Wetlands, Great Lake Ohio

 The state’s Department of Natural Resources has also dredged the lake bottom to remove nutrient-loaded sediment, and tried to clean up one of Grand Lake’s beaches near St. Marys by building a rock jetty and installing aerators and a curtain to filter water. Recent water tests there showed levels below 6 parts per billion of the toxin microcystin, under Ohio’s threshold of 20 parts per billion for avoiding contact with water.

As Green Algae Forces Beaches to Close, Ohio Lake Offers Hope, WSJ, Sept. 18, 2019

Waterbird Habitats Lacking

The spring of 2017 50 million waterbirds will move from their winter homes in South-East Asia, Australia and New Zealand to their breeding grounds in Russia, Mongolia, northern China, the Korean peninsula, Japan and even Alaska. They rely on intertidal flats teeming with nourishing molluscs, worms and crustaceans, as well as plants, to supply the food that fuels their journeys.  Of the eight big flyways, the East Asian-Australasian is also the one displaying the sharpest decline in the number of birds. Of its 155-odd waterbird species, at least 24 are now globally threatened. They include the diminutive spoon-billed sandpiper, a wader whose numbers are down to fewer than 200 pairs.

Transiting one of the world’s most dynamic industrial regions is clearly taking a toll. Asia’s migratory waterbirds face immense pressures, from hunting, pollution, ingested plastic and competition from aquaculture. But the biggest disaster is the destruction of coastal way-stations. Since 1950 China has lost over half its coastal wetlands to “reclamation”. According to the International Union for Conservation of Nature (IUCN), the Yellow Sea, into which the Yellow River flows, has lost over 35% of intertidal habitat since the early 1980s. An especially destructive moment was the run-up to the Beijing Olympics of 2008, for which a lot of heavy industry was moved from the capital to the coast.

Xianji Wen, who works for the WWF, describes the Yellow Sea as a “bottleneck” for the whole flyway: so many waders pass through it that the loss of habitat there is particularly consequential. Four-fifths of Asia’s red knots, having wintered in Australasia, stop on their way north at one spot, Luannan, east of Beijing. The bar-tailed godwit flies non-stop from New Zealand to the Yellow Sea—over 6,000km. After recovering there, the species flies non-stop again to its breeding grounds in the extreme north of Russia.  Populations of both species have crashed by over a third, probably because of coastal development…..

There is a silver lining, however. The vast middle class created by the region’s breakneck growth is becoming interested in conservation…In China several hundred birdwatchers gather for the spring migration by the Yellow Sea near the North Korean border. And Mr Wen says that local governments in China increasingly take pride in the acclaim they win for conservation schemes—several work with the WWF. In 2016 China and New Zealand even signed an agreement—an “air bridge” between the two countries—to protect the habitat of the bar-tailed godwits, whose annual departure, Maori mythology holds, is for the homeland of the ancestors who first colonised New Zealand.

South Korea’s conservation movement is feeble. But the government of North Korea, by failing to develop the country, has inadvertently preserved a greater share of valuable waterbird habitats. It recently agreed to designate one as a protected site under the “Ramsar” international convention on wetlands….

Excerpt from Canaries in the Coal Fumes, Economist, Apr. 22, 2017