The Pest of the Year: Algae

by Natasha Starkell | 23.12.2013 | pest , algae , environment | 0 comments | Rating: 0 votes




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If we can only choose one pest that made the news this year in dramatic fashion, then it goes without saying that we’ll choose alge. During the summer, the largest ever recorded algal bloom turned the Yellow Sea in China green – over 11,000 square miles of algae was recorded, and more than 19,000 tonnes of growth had to be removed from beaches.

And while we loved the images of people making ‘algae men’, the recent explosion of algae points to a dramatic change and imbalance in the ecosystem (one group of researches believed that it originated from seaweed farms along the coast of Jiangsu Province). Such a huge carpet of algae on the surface of the sea can in turn have a dramatic effect on the environment of the ecosystem underneath. It may block sunlight from entering the ocean and deplete oxygen levels, causing rooted aquatic plants and fish to die.

Algae can also a major problem in garden ponds, causing unattractive discoloured water which affects the aesthetics of the garden, as well as harming aquatic life. There are hundreds of different types, from those that are suspended in water to those that spread across the water as ‘scum’ or blanket weed.

But what can you do in your garden to reduce algal growth? Here are a few ideas.

- If your pond is in a sunny position, grow aquatic plants that provide some shade across at least a third of the surface.

- Use dark pond liners rather than light ones, which may reflect heat.

- Clear the pond if there is too much debris (such as fallen leaves or invasive pond weeds) or sludge on the bottom.

- Use rainwater to top up the pond rather than tap water, and make sure that the depth of the pond is at least 75cm deep.

- Barley straw extract or bags of barley straw can be bought from garden centres to discourage algal growth.

- Install a fountain or water feature to aerate the water.

- Reduce the fish population! Occasionally give some away or move to a different garden pond (but never release into the wild).

And don’t forget – algae isn’t all bad. Professor Keith Davidson, Head of Microbial and Molecular Biology Department at the Scottish Association for Marine Science told us: “Algae are fundamental to all life of earth. Their photosynthesis allows more atmospheric CO2 to be absorbed by seawater. So the algae are fundamental to the global carbon cycle and act to reduce global warming. They also form the bottom of the marine food chain, being eaten by zooplankton, that are in turn eaten by fish.”

It is all good and well, we think, as long as algae stay well away from our ponds.

Photo Credit: Bobby Mckay

Natasha Starkell
Written by Natasha Starkell

Working mum, struggling with gardening chores.

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