Jordan Stirrat answers a reader’s question on how aquatic plants grow in the wild without optimal conditions.
How come plants can grow in suboptimal conditions in the wild?
It is widely accepted that as you increase the amount of light in a planted aquarium, you have to also increase the CO2 (and other nutrients) levels to prevent algae. However, I often wonder how nature achieves an algae-free ecosystem in the wild. I have seen many still water habitats in the wild where algae is not a problem. These have sometimes been shallow and receive a considerable amount of daylight. The levels of CO2 in these habitats are not stable and never reach those levels recommended for a planted aquarium. Other nutrients, such as iron, are also present in much smaller quantities than recommended. Yet plants in these environments thrive. I’d welcome any feedback you can give me on this.
JOHN ANUSAS
Photo by Tai Strietman
Jordan says: This is a fascinating subject, highlighting the many ways nature creates stable environments for ecosystems to thrive and the contrast to what can be achieved in a home aquarium. Firstly, natural ecosystems are typically more diverse than our planted aquariums at home. They include various aquatic plants, organisms that feed on algae and microorganisms that compete with algae for nutrients. In nature, cycles of growth and decomposition occur that are supported by organisms which feed on decaying matter, creating a functioning ecosystem. This decomposition produces nutrients for plants in a balanced manner, preventing the system from becoming overwhelmed – most of the time, anyway.
Regarding CO2 levels, some bodies of water can have high CO2 concentrations, while others may have very low levels. Nonetheless, plants can thrive in both conditions, depending on specific species and their adaptations. Marginal plants even utilise CO2 from the air.
In some areas habitats go through periods of flooding followed by drought, which the plants adapt to. Natural environments have endured over time because they can adapt. Both plants and algae develop traits that allow them to coexist without one overpowering the other.
In contrast, aquariums are closed systems with fewer external factors. Aquarists often aim for plant growth and algae control that exceed natural levels. Advances in technology and knowledge have made this possible. While plants can survive in less ideal conditions, hobbyists often strive for perfection, which may not truly align with the goal of replicating natural environments in our homes. Ultimately, it’s fostering a connection with nature remains the main goal and that’s a huge pulling factor for many in the hobby.
Did you know: Some aquatic plants can gain inorganic carbon from bicarbonate ions (HCO3-) that are in the water. This can help a plant compete where CO2 is a limiting factor in hardwater areas environments. Common plant species like Ceratophyllum demersum and Vallisneria spp. have been shown to do
Photo by Shutterstock
This was originally published in the December 2024 issue of the magazine. Check out our latest digital subscription offers here!