Last year, high, turbid waters and a layer of sediment carried into the lake by flooding and rainfall reduced weed growth, explained Cushing. With clear water and low lake levels this summer, those familiar with the bay were expecting more weed growth than they’ve seen, but Cushing believes the sediment may also be helping to suppress weed growth this summer.

SAAWA removes 400 to 500 tons of weeds from the lake each summer with the help of an Aquarius Systems Aquatic Weed Harvester. The weeds contain a lot of water, Cushing explained and once they dry out, 40 to 50 tons of organic matter remains. Removal of the weeds prevents the weeds from dying and decaying in the water where they would release phosphorus and nitrogen, the very nutrients that feed algae blooms.

Currently the weed growth is outstripping our ability to pull them out of the lake, but we are convinced there are benefits to removing as much growth as possible, before it decomposes, spoiling water quality, increasing phosphorus as well as producing conditions for blue green algae growth.

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Aquatic ecologists tend to avoid the term “weeds” when referring to macrophytes – the rooted aquatic plants that many swimmers and boaters disdain. These plants provide food for waterfowl and habitat for fish, but they can also play a critical role in maintaining water clarity.

Many lakes and ponds have two stable states: weedy and clear or devoid of weeds and muddy. This leaves riparian landowners and lake managers with a choice between two undesirable endpoints when nutrient levels are intermediate.

At low nutrient levels, the rooted plants win out because water is clear and plenty of light reaches the bottom of the lake. At high nutrient levels, the algae win out and effectively shade out rooted plants – this means extremely low water clarity and sometimes harmful algal blooms. At intermediate nutrient levels, things get a bit tricky. In this case, lakes can be pushed in one direction or the other – sometimes inadvertently.

When rooted plants are destroyed, mucky bottoms get stirred up and re-suspend nutrients. Competition with algae ceases and foul blooms occur. If plant biomass is not mechanically removed, the rotting vegetation further adds to nutrient availability, turbidity, and algae growth.

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The reservoir has extensive growth of “exotic nuisance aquatic vegetation,” including fanwort and variable-leaf milfoil, according to a report by ESS Group, a firmed hired by the state.

The planned management program calls for herbicide treatments, mechanical harvesting, hand and diver harvesting, and benthic barriers, a method that uses sediment.

“DCR is also seeking approval for the use of algaecide treatments should they be necessary to control algae blooms following the management of aquatic invasive plant species in the reservoir,” the report reads.

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Run off in Cape Coral canals comes from many places. It could be your street, your roof or your lawn. The recycled water used for irrigation is loaded with nitrogen and phosphorous which causes plants to thrive and contributes to algae outbreaks.

Last week Lee County Hyacinth Control cleared out about a miles worth of yellow pond lily from the Shelburne Canal in Cape Coral, Florida. Trapped inside that vegetation, was the equivalent of 10 pounds of fertilizer.

A group of scientists from Johns Hopkins and the University of Nebraska have discovered a new virus that is living in the mouths and throats of people participating in a study. While in itself not so noteworthy, but the fact that it was thought that it could only affect algae makes it interesting.

While conducting a separate experiment, the scientists found the virus living in 40% of a small number of people tested. The virus, called ATCV-1, is a chlorovirus, a family of viruses that infect plants. This virus affects algae in lakes all over the world. As far as researchers knew before this, viruses like this very rarely cross from one kingdom like plants to another, like animals. And even when they do, it’s more likely that they would go from plants to some type of invertebrate, not all the way to a complex animal like a human.

The original study included cognitive tests; the scientists compared the data and saw that people with the virus living in their throats processed visual information about 10% slower than people without the virus. To further test the virus, mice were injected with ATCV-1 and took 10% longer to navigate a maze and spent 20% less time exploring new environments. The infected mice also showed more than 1,000 gene changes in the parts of the brain that are usually considered essential for memory and learning.

While humans cannot be tested for gene mutations, it does raise questions as to the affect algae has on humans and animals.

Interesting note: the group of people tested was from Baltimore.

Read More https://www.science.org/content/article/algal-virus-found-humans-slows-brain-activity

As the human population increases and waterfront development continues, manatees are losing habitat.  The development also damages seagrasses, degrades water quality and reduces the availability of the warm waters that manatees rely upon to survive.  Waters below 68° can prove fatal to manatees.

2013 was the deadliest year on record for the endangered manatee.  With populations of less than 5,000 they have suffered due to boats strikes and algae blooms that not only left many manatees dead, but also destroyed their food supply resulting in even more deaths.

In order to protect the manatees, the U.S. Fish and Wildlife Service will establish a year-round manatee refugee in Kings Bay, its tributaries and adjoining water bodies.  Kings Bay, located at the headwaters of Crystal River and consists of 30 known springs that used to be clear and beautiful.

The once crystal clear water with clean white sand bottoms is now in distress.  Excess nutrients from wastewater, septic tanks and stormwater runoff resulted in declines in water clarity and growth of nuisance aquatic plants.  One such aquatic plant, water hyacinth is now part of an experiment to help restore the Bay and save the manatees.

Water hyacinth once choked the waterways and extensive control measures began in the early 1900’s.  With the water hyacinth under control, filamentous blue-green algae arrived.  A controversial experiment is now under way in Kings Bay to reduce algae populations and remove nutrients by using the ever efficient filtering of the water hyacinth.

Water hyacinth will be placed in containment cages to prevent their spread.  It is believed that the shade from the floating aquatic plants and the nutrients they will remove from the water will make a substantial difference in water clarity in the area.

Kings Bay Restoration