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Nutrient load reduction key to reducing toxins

Okeechobee News - 4/20/2018

"The future is blue-green," Dr. H. Dail Laughinghouse IV told those gathered April 18Chamber of Commerce luncheon in Indian River State College Williamson Center.

Whether that's good or bad depends on your point of view, and on the amount of cyanobacteria present.

Without cyanobacteria, there would be no life on earth. But when cyanobacteria grow too fast or too thick, there is a danger that toxins may be released. The higher the level of toxins, the more dangerous.

Cyanobacteria, also known as blue-green algae, are bacteria that obtain their energy through photosynthesis.

Dr. Laughinghouse, Assistant Professor, Phycology with the University of Florida, has traveled the world to study algae. Where some people might consider the pea green water seen on the Treasure Coast in 2016 to be disgusting, he sees the beauty in cyanobacteria.

People have an attitude problem about algae, he said. They sometimes call it pond scum or frog spittle. "People think ? that is nasty.

"Remember we exist because of cyanobacteria," Dr. Laughinghouse warned. "If you don't like cyanobacteria, hold your breath for five minutes." See what the world would be like without it.

Cyanobacteria is everywhere, he said. It can grow on top of the water, in the water column, under ice, on the ground.

"Anywhere there is a little bit of humidity, there are cyanobacteria," he said.

"They are the primary producers of organic matter, the base of the food chain," he continued. "Everything else exists because of them."

Cyanobacteria has been on the Earth for about 3.8 billion years, he explained. It had nearly 2 billion years of evolution before any grazing animals came on the scene.

Nutrients such as nitrogen and phosphorus cause the blue-green algae to bloom. When it blooms, some cyanobacteria releases toxins. Some species do not produce toxins, he added. Cyanobacteria that can produce toxins does not always do so. There are many factors involved that contribute to a toxic bloom.

Toxins are not just in the water, he continued. Toxins from cyanobacteria can be found in the soil and in the air.

Low levels of the toxins may not be harmful. But when increased nutrient load causes the blue-green algae to bloom, the toxin levels can increase.

The excess nutrients come from human action.

"It's everyone's fault," he said. "Do I want a green lawn? So I put fertilizer on it. Then it rains and some of the fertilizer runs off.

"Agriculture ? we all want to eat," he said. Growing crops and raising livestock can increase the phosphorus levels in runoff.

People also produce waste that goes into sewer systems and septic tanks. "Wastewater treatment does not take all of the nutrients out," he said.

Sources of nutrient load into waterways include fertilizers, pet waste, wildlife, livestock waste, municipal wastewater, septic tanks industrial effluent, detergents and the atmosphere.

A bloom can also increase the nutrient load in the water, he continued. A dense algal bloom increases the pH in the water. When pH is high, phosphorus is released from sediment at the bottom of the lake or waterway. This extra phosphorus continues to feed the bloom.

Microcystins, the toxins released by some cyanobacteria, are found worldwide.

He said algal blooms are documented throughout history, Some researchers have theorized when Moses turned the water as red as blood, it was an algal bloom.

In 1188 bright green and scarlet algal blooms were observed.

In 1853 livestock deaths were attributed to cyanobacteria.

In the 1980s, scientists started to test algal blooms for toxins.

Poisonings reported from microcystins have included everything from humans, fish, cattle, poultry and sheep to giraffes, rhinos and crocodiles.

Researchers believe that some dinosaurs were killed by microcystins.

"Animals such as cattle and horses will not usually drink from a green pond because it tastes bad," he said. "But during a drought, they do." Eagles have been poisoned after eating other birds, which ate snails, which had ingested the toxins, he explained.

Toxins produced by cyanobacteria include neurotoxins which target the central nervous system; hepatotoxins, which can cause tumors and liver failure; and dermatoxins which affect the skin. Microcystins have also been linked to kidney disease, he added.

People who are suffering health ailments related to exposure to these toxins may be misdiagnosed because there has not been enough research in this field, he said.

"I would like physicians to have more training about the different effects of toxins," he said.

What can we do?

Dr. Laughinghouse said there are ways to help reduce the formation of algal blooms that release toxins.

Proactive ways to help reduce algal blooms include reducing the nutrient load into lakes and waterways. Reducing phosphorus is key, he explained. One pound of phosphorus can support 500 pounds of algae.

Nitrogen is also a factor, but some cyanobacteria can "fix" nitrogen from the air, so limiting it is difficult.

Aeration of the water can help reduce algal blooms.

Non-toxic blue dyes can also help control the growth of an algal bloom.

Researchers are studying biological controls, he continued. Some solutions that work in the lab or in a small body of water do not work in a large lake.

Some methods of destroying cyanobacteria cause it to release toxins.

"Don't panic yet," he said. "There might be hope."

More funding is needed for research, he explained.

In Florida, when an algal bloom is reported, the Department of Environmental Protection takes a sample.

"When it blooms, they take a look at it," he said. "We need to see the whole temporal and spatial scale.

"We need constant monitoring.

"We need trained people who know algae," he added.

But the funding is not there.

In 1986, FDEP set limits on phosphorus entering Lake Okeechobee, but aside from the DEP Dairy Rule, there has been little enforcement. Thirty years after the limits were set, the phosphorus loading into Lake Okeechobee is unchanged.

"We need to change our actions," he said. "We have to decrease the nutrients going in.

"People like to point fingers at certain places. Point the finger at yourself," he said.