If you own a pond or dam, you’ve likely seen at least a couple of different types of algae appear in your water. But what exact types of algae are out there? Well, there are thousands of different species of algae, but pretty much all of them can be placed into a few key types. We dive into these common types below. But before we do, let’s first examine what exactly algae is.
What is Algae?
Algae is a wide-ranging form of photosynthetic organisms that live in various ecosystems. They are most commonly associated with water, though they can live and grow in soil and snow, or any other place where water is commonly accessed. Most species of algae are microscopic, though you can find much larger types such as giant kelp. They can be single-celled or multi-celled, with some forms having more complicated structures that closely resemble bacteria.
While algae can be a nuisance, most common species are not toxic to humans or livestock. However, uncontrolled growth can still put fish and other forms of aquatic life at risk.
How Does Algae Form?
Algae forms in nutrient-rich, aquatic environments where there are ample levels of light and a warm temperature. It originates from nutrients such as phosphorus and nitrogen, which enter the water through things such as agricultural runoff and fertilizers. This leads to rapid growth and algae blooms appearing.
5 Most Common Types of Algae
While all forms of algae originate in similar ways, the number of individual species of algae is actually very high. Each type that we are about to discuss requires slightly different conditions in order to appear and thrive, such as nutrient levels, oxygen levels, and water temperature.
The five most common types found in Australian ponds and dams are:
- Green algae
- Diatoms
- Euglenoids
- Dinoflagellates
- Blue green algae
Let’s go into each of these in a little more detail.
1. Green Algae
When you think of algae, the first colour you’re likely to associate with it is green. That’s because it is the most commonly found type of algae in Australian water systems. Within the broad range of green algae (chlorophyta), there are a number of sub-species that are particularly prevalent, including:
- Filamentous green algae: This form of floating algae appears across a water surface. They generally have the appearance of long, stringy, or slimy green mats that attach to rocks or dam wall surfaces. You’ll usually find them in the shallow areas of your water system.
- Planktonic green algae: This tiny form of algae suspends itself in water and has the impact of turning water into a pea-green colour, in much the same way as green dust algae. It is harmless but does affect the overall appearance of a water system. Volvox is a common form of planktonic algae.
- Colonial green algae: There is some crossover with planktonic green algae here, with many species (such as Volvox) fitting into both categories. However, what defines colonial green algae is that it forms as grouped cells rather than unicellular.
Green algae thrives in warm, nutrient-rich waters that are still or slow-moving. They can often cause deoxygenation at night and clogged irrigation systems, as well as looking quite unappealing.
2. Diatoms
Diatoms are microscopic organisms, so it’s not immediately obvious that they are present within a water system. However, when enough of them appear together, they can present the appearance of brown algae. They are defined by their glass-like shells made from silica and come in two main shapes; pennate (elongated) or centric (round or radial).
Unlike other algae, diatoms do have notable benefits to a water system. They are vital in instigating aquatic food webs and are a great producer of oxygen. They’re also used by scientists to help monitor water quality as they are very susceptible to change. However, as with most algae, too much can create poor aesthetics within a waterway.
Diatoms prefer cooler water temperatures and benefit from more turbulent water.
3. Euglenoids
Euglenoids are a form of flagellated, unicellular algae that are easily identifiable by their whip-like tails and ability to move freely within water bodies. They carry out photosynthesis but they can also feed on organic material, making a useful addition to aquatic environments in small numbers.
Euglenoids are normally green; however, they can present with a reddish or orange hue depending on the environments they’ve developed in.
Euglenoids will normally appear in stagnant, warm water where aeration hasn’t been allowed to take place. They can also comfortably manage in low-oxygen zones.
4. Dinoflagellates
This form of algae can be found in both fresh and marine waters and is often denoted as a form of red algae when allowed to cluster in large numbers. As they are microscopic, their presence is not apparent straight away. Their cell walls are made of plates made of theca, and they are generally round or oval-shaped.
Unlike most forms of algae, dinoflagellates can produce mild toxins which can be harmful to humans and other lifeforms. However, this is a rare occurrence and they don’t usually grow in numbers large enough (within freshwater environments) to produce the necessary level of toxins.
They are also excellent nutrient recyclers and can process by-products such as nitrogen and phosphorus.
5. Blue-Green Algae
This final form of aquatic plant is slightly misleading – it’s not actually a form of algae. Rather, it is a type of cyanobacteria that shares certain characteristics with plant cells, including the ability to photosynthesise. However, for a long time it was considered a form of algae, and so the name has stuck.
It’s still an apt description. Blue green algae can bloom much like true algae species and thrive in warm, clear, stratified waters. It can still dominate waterways if allowed to go unchecked. And unlike most forms of algae, it can quickly turn waters into very toxic areas for humans and other organisms.
As such, blue green algal outbreaks are subject to local and national alerts during the Australian summer.
Buy blue-green algae test kits
How to Keep Algae Under Control
To clear algae from underwater rock surfaces, jetties etc, you can try AlgaeLift which is a peroxide-based water treatment. It isn’t an algaecide, but rather it lifts algae away, giving beneficial bacteria and other aquatic organisms better access to digest and remove the algae. Because it’s based on peroxide, AlgaeLift naturally breaks down into hydrogen, oxygen, and water, leaving no harsh residues behind. When used as directed, it’s safe for fish, plants, and other aquatic life.
However, for long-term management of algae, and for improving your water quality in general, we recommend a combination of Biostim and aeration. Biostim is our all-natural probiotic solution to help curb the nutrient levels that feed algae blooms. They essentially feed the good bacteria and microbes and allow native plants to grow without the risk of being dominated. And with these good microbes benefiting from the increased oxygenation that aeration brings, you can quickly bring your algae populations under control in no time.
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