Understanding the Problem of Filamentous Algae in Ponds

There is no denying that spending time in our gardens and yards can bring immense pleasure, more so if you have green fingers. If you have a water feature on your property then there can be certain times of the year when problematic algae species develop. Filamentous algae in ponds are perhaps the most feared situation for any gardener that enjoys spending time caring for their water features.

This type of algae is known to be relentless and quickly reproduces and will cling to any possible surface that is in the pond, for example rocks, pumps, and water filters. Filamentous algae are easy to identify due to their hair like mats. Once it takes hold it can quickly turn your beautiful pond into an ugly mess.

There are actually a number of species of filamentous algae; this includes pithophora, cladophora, and spirogyra. Though they are classified as being unicellular they will group together with other filamentous algae cells with the result that the surface of the water can be obscured completely.

Spirogyra is relatively easy to identify due to its bright neon like green colouring. If you were to examine these algae through a microscope then you will see that it in some way resembles the DNA helix. When in a pond it has a very slimy feel and is most often surrounded by protein bubbles, otherwise referred to as scum.

Cladophora is another all too common species of algae. This variety is often described as having a cotton like appearance. Cladophora frequents the shallow areas of ponds and is often described as having small thin plant like stalks which are undulating and hairy. The third form of filamentous algae is pithophora. This grows in long and thick strands and is sometimes referred to as horse hair algae.

The filamentous form of algae always begins it colonization efforts in the shallower regions of a pond. If your water feature includes ledges or a waterfall then it is here that the algae will first become established. It is worth noting that small populations of filamentous algae are relatively harmless and do not become as prolific as for example planktonic algae. A problem will only occur when the conditions are right; this would normally involve high nitrate levels. Nitrate is the primary energy source for this type of algae.

Once the algae begins to spread to other layers of your pond it will produce a high volume of oxygen. This gets trapped in mats which then float to the surface. If not dealt with the complete surface of the pond can become covered by these mats of algae.

To prevent this problem from occurring you will need to have a quality filtration system set up. Also if you were to allow certain varieties of plants to grow around and in the pond you can reduce the amount of algae which can become a nuisance. Also you can physically remove the mats of algae once they float to the pond's surface. If all else fails then there is also the option of using algaecides, but be warned that this may impact on other aquatic species.

Filamentous Algae are single alage cell thatform long threads or chains and this can cause severe problem with pond owners.