How Algae Thrives

How Algae Thrives

Understanding Algae

Algae are a diverse group of photosynthetic organisms that are found almost everywhere on Earth! You can find them growing in your aquarium, or you may see it while taking a walk to the local pond. They’re found in both freshwater and saltwater environments, and can thrive in some of the most extreme environments due to their resilience and adaptability. Algae come in many different shapes and sizes, from single-celled organisms to multicellular forms that can grow into massive kelp forests. Let’s dive deeper into all things algae! 

When they aren’t dominating ecosystems, algae thrive as unsung heroes of the planet! They’re important because they produce oxygen through photosynthesis, store carbon dioxide, and provide food for other species. While they do absorb oxygen to respire themselves, algae are still responsible for the production of over half of the oxygen we breathe, and help stabilize Earth’s climate by sequestering carbon dioxide from the atmosphere. Algae are also major components of aquatic ecosystems such as coral reefs and kelp forests.

The types of algae free-floating in freshwater lakes, ponds, and aquariums are called planktonic algae. Planktonic means “floating” and these types lack roots or leaves as single cells that float around water columns. Another kind of algae is benthic, meaning they grow at the bottom of water bodies where they get nutrients from decaying matter, and can grow on rocks, pebbles, plants, and other objects.

Common types of aquarium algae include: 

  • Brown Diatoms – Soft, dusty algae that’s common in new tanks
  • Hair Algae – Look like hair or string in your tank
  • Green Spot Algae – Tiny, hard green spots on plants or glass
  • Black Beard Algae – Gray, bushy clumps
  • Blue-Green ALgae – Often a slimy coating of cyanobacteria 
  • Green water – This is when your water column looks like pea soup (likely planktonic)

How Algae Thrives

Algae are influenced by several factors that can make rapid growth relatively simple if not balanced out. Key contributors in both aquariums and natural ecosystems include:

  • Light – Algae require sunlight for photosynthesis to feed. This is a process of using energy from the sun to convert carbon dioxide into organic compounds for food.
  • Nutrients – Algae require nutrients such as nitrogen and phosphorus to grow.
  • Temperature – Algae thrive in warm temperatures
  • pH – Algae prefer neutral to slightly alkaline pH levels

Algae Thriving in Excess

As we’ve mentioned, algae are amazing for many reasons, but rapid blooms can quickly begin to dominate resources and pose serious risks to ecosystem communities. For instance, sudden algae blooms can reduce water clarity and prevent sunlight from reaching various aquatic life beneath them, while absorbing much of the available oxygen. Algae can be significant contributors to eutrophication because they absorb large amounts of dissolved oxygen from water columns, creating massive nutrient imbalances. This can lead to fish kills or die-offs in other organisms also depending on oxygen.

Algae blooms are already a major problem for coastal communities, and people must be careful to protect themselves and their pets from ingesting and even inhaling toxins from algae blooms.  For example, some types of algal blooms contain red tides and produce domoic acid, a neurotoxin that can cause dizziness, vomiting and diarrhea in people who come into contact with it.

Blooms are of growing global concern as climate change increases favorable conditions for algae blooms to thrive. Between rising temperatures and increased carbon dioxide, accelerating climate change means enhancing conditions for rapid algae growth to take hold. This is important for us to realize as algae blooms have numerous impacts on ecosystems and society.

Negative Impacts of Algae Blooms

On Aquatic Ecosystems: Algae blooms can cause oxygen depletion as they out-compete for resources, which can harm or kill other aquatic life on large scales (depending on size of both the body of water and the bloom)

On Human Health: Certain types of algae produce toxins that can be harmful to humans and pets if ingested or inhaled

Economic Impacts: Algae blooms can have negative impacts on industries such as tourism and fishing due to the impacts explained above


At the end of the day, developing a better understanding of how and why excess algae growth occurs is essential to protecting aquatic ecosystems and human health. As with most environmental problems, there are complex factors involved and identifying their causes can be tricky– especially in your aquarium! 

Taking time to learn about these processes is the best way towards problem prevention, and that’s exactly what led us to plant based Algae Control! Checkout our recent posts to learn more about how Algae Control works and how to use it with your unique, at-home set up!

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