Why Would Algae Grow in a Lake?

It is normal for different plants to grow within and inside the lake, because of conducive growth conditions present in the lake environment. Algae, in this case, is no exception, and they are heavily present across different lakes. Algae is a group of organisms capable of manifesting the photosynthesis process. 

It lacks roots, leaves, or even stems and is only categorized by the size which can either be unicellular group or multicellular. Algae are capable of growing in freshwater and saltwater lakes and any other moist environment and you might need lake cleaning services. Being primary producers, they form an integral part of the aquatic food chain.

Algae can reproduce either sexually or asexually or through both processes; with favorable environmental stimuli for reproduction present, algae can fill up the entire lake. However, there are several reasons why algae would grow in a lake, types of algae, and any benefits or shortcomings of these organisms to their immediate environment covered below.

Why Would Algae Grow in a Lake?

Before determining why algae would grow in a lake, let’s first talk about the different types of algae. There are plenty of algae species in lakes around the world. 

Algae can be free-floating in lakes, which are referred to as phytoplankton; there are some species of algae attached to rocks, docks, and aquatic plants referred to as periphyton. However, algae are mainly categorized into the following three groups; 

Chlorophyta (Green Algae)

Green algae fall under this group; they grow mostly in freshwater lakes though there are few instances where green algae can be found in oceans. Chlorophyta contains chloroplasts, making them capable of carrying the photosynthesis process, they are also reproduced and mostly grow in a multicellular form.

Chrysophyta (Golden-brown Algae)

Chrysophyta comprises diatoms and mostly unicellular algae, which thrive in both fresh and salty lakes. This group of algae is considered less toxic to humans and aquatic life.

Cyanobacteria (Blue-Green Algae)

The third group of algae is the blue-green algae though not so close to the green algae type; blue-green algae thrive under warm temperatures and an adequate supply of nutrients. Just like green algae, they are likely to cause an algal bloom, which extends to cover a bigger part of the lake. 

Conditions that favor algae growth

The three groups of algae mentioned above, including several other small groups, grow in either fresh or salty lakes when the following conditions discussed below are present.

Adequate Amount of Sunlight

Lakes normally receive a significant amount of sunlight given that there are few to no trees blocking direct sunlight. Algae thrive through the photosynthesis process, being able to produce food and play a vital role in the aquatic food chain. 

Therefore, the sunlight present within a lake is enough to foster the growth of algae in a lake. When sunlight and the right temperature requirements are combined, algae are more likely to thrive and grow into large size or multicellular within a short amount of time.

There is adequate sunlight and favorable temperatures during spring and early summer, it is why algae tend to grow tremendously during this season. By mid-summer, there is likely a decline in growth due to a reduction in nutrients.

Stagnant Water

Some lakes though not all have stagnating water, especially man-made lakes at the park. These lakes experience less movement of water. Making them vulnerable to algal growth. 

Stagnant water allows for excessive penetration of sunlight and room for particles to settle with less disturbance. Therefore, low turbidity due to less running water, allows algae to thrive. When algae’s growth is fully manifested, turbidity rate significantly reduces further.

Maintaining a high turbidity level for a lake is an advantage because it rids off any breeding ground for algae making the conditions unsupportive of their growth.

Presence of Nutrients

Agricultural activities which occur in homes built near a lake contribute immensely to the presence of nutrients in a lake. Algae grow well when the following nutrients find their way into a lake; Nitrogen, Potassium, and Phosphorous. 

Backyard gardens or lawns which are fertilized to improve growth and productivity ends up being a donor of nutrients to a lake nearby.

The occurrence of run-off or leaching due to excessive rains drains these nutrients into a lake and subsequently creates optimal conditions for the growth of algae. There is a need to reduce the use of chemical fertilizers in lawns and back yard gardens and replace this with organic farming techniques. 

The downside of these chemicals being channeled to the lake is not only algae growth but they are also harmful to aquatic life and generally, it compromises the quality of water in a lake.

Problems Associated with Algae Growth in Lakes

Algae contribute immensely to the aquatic life cycle, by the merit of being a primary producer. This process contributes to the effective circulation of oxygen necessary for the well-being of aquatic life. 

Additionally, some aquatic animals use algae as their food, creating a balance within the aquatic ecosystem.

Despite being beneficial, algae can be detrimental once it grows extensively to cover an entire lake. Blue-green algae, for instance, can cover a large area because they cannot be consumed by zooplankton due to their toxic nature.

 The ability of blue-green algae to avoid being destroyed by zooplanktons leads to the formation of a green mat likely to destroy the beauty of the lake and the general outlook and quality of the water therein.


Algae is indeed useful to some greater extent in the aquatic environment but some other groups like blue-green algae can cause problems. Increased growth of algae within a lake is an indication that there are plenty of nutrients in such a lake, especially Nitrogen. To curb this problem, there is a need to cut down on chemical fertilizer usage, especially for lawns or gardens which are likely to drain such nutrients to a lake. Organic farming methods could be an ideal way to cut down on more nutrients finding their way into a lake.