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Algal Bloom Conservation & the Environment

Algal Treatment - Dr Jonathan Newman

In Europe all professional herbicides to treat algae have been banned. Options for control are few but the best include ultrasonic treatment using mixture of low power frequencies, the use of harmless bacteria to compete with algae for nutrient supplies and some shading technologies using dyes.

Lyn Padarn & Algal Bloom ’an ecosystem in decline’

Lyn Padarn is a lake that has suffered, in the past, from the effects of algal bloom, casuing damage to fish wildlfie and the local economy. The effects can be devastating and the possibility of a reoccurance is

always a concern if same conditions happen again. Ultrasonic Treatment

Research work, undertaken at the Centre for Aquatic Plant Management, showed that exposure of Spirogyra and Scenedesmus to ultrasound for less than a week induced changes in the algal cells. The interior of the cell shrunk away from cell wall and the cells died.

Measurements of the chlorophyll content of cells also declined, and exposed cells did not regrow after 3 weeks ofexposure. In outdoor pond tests, algal growth was much lower than in tanks without any treatment, and there were no effects on Daphnia, an invertebrate used as a test organism.

Fish are not effected because the sound level produced is half the required decibels to effect fish. They do not affect submerged plants, water lilies or other desirable aquatic plants, and are highly specific to algae.

Reducing Nutrients

Most aquatic plants need nutrients from the surrounding water or from the sediment in which they are rooted to be able to grow and reproduce. If you take away the nutrient supply the algae die very quickly.

Products are available that reduce nutrient availability for algae by locking it up in bacterial biomass, reducing growth and clearing water bodies.

There are a number of factors to take into account when using this type of product

• Nutrient management techniques work best in static systems, with little or no flow through

• Nutrient management systems work best when applied early in the season, starting no later than March or very early April • Nutrient management techniques need to be applied throughout the growing season to provide continuous control

Shading Technologies

Pond dye is designed to limit the amount of sunlight reaching the lower layers of a pond.

Algae, weeds and plants all require sunlight to thrive; by limiting the sun you naturally reduce algae and plant growth.

Pond dye is also used to improve the appearance of water. For example, Black Onyx lake and pond colorant is a high concentrated colorant that helps create the unique natural look of black water lakes and ponds favoured in golf courses and resort locations.

The 2 images were taken one year apart and demostrate the effectiveness of ultrasonic treatment.

A hydro-acoustic survey recently revealed that the charr population in the lake is extremely low and could potentially disappear from the lake in just 5 to 10 years. Charr reared from fish caught at the lake have been introduced to boost their numbers as well as a back-up population of the Llyn Padarn charr being established at a second north Wales lake.

One issue causing this concern is the possibility of Algal bloom returning, which had a great impact on the lake and the local economy in 2009. The cause, then, was a combination of weather conditions and nutrients such as phosphorous entering the lake, particularly from the nearby sewage treatment works and storm overflow.

An independent study commissioned in 2010, confirmed that the phosphates responsible for the nutrients are found found in shower gel, dishwasher powder and washing machine powder and would have indeed come from the discharges.

These nutrients not but also remove oxygen from the water, which is vital for the fish that live there.

Tailor made solutions for aquatic, riparian and invasive species management.

• • • • •

Aquatic Weed Control Invasive Species Management Algal Control, including ultrasound TopFilm Adjuvant Electromagnetic Water Treatment

‘We will not give up until your weed problem is gone’.

TEL: 0118 972 4041 FAX: 0118 946 4894

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Vines Farm, Crane End, Reading, Berkshire, RG4 9HE 37

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