The nitrogen cycle is a multi-step process that breaks down waste in the pond into usable components for plants to use as food and is the backbone of the whole ecosystem.
Without the nitrogen cycle, ammonia levels would constantly increase, leading to issues with water quality and fish health.
It sounds impressive on first read, but it’s actually very logical and easy to understand. We firmly believe it’s vital to take the time to learn how it works so you can more easily care for your pond and troubleshoot when it’s out of balance.
For those keen beans who want to dig a little deeper into the technical (but not too technical), let’s look at each of the steps in the nitrogen cycle for a deeper understanding of what’s going on.
1. Organic Material
The process begins with the breakdown of organic material in the pond. Organic material includes plant debris, fish waste, uneaten fish food, dead bacteria, dead fish. As each of these break down, they produce ammonia as a by-product.
There is a common misconception that fish keep a pond clean, they don’t. They add more waste (and nutrient load) to the water and don’t provide a net increase in the cleanliness of the water. But, they are great to have in your pond!
2. Conversion of ammonia to nitrite
Ammonia and nitrite are poisonous to life in your pond, but different forms of bacteria that live in your pond convert ammonia into nitrite.
This stage of the process utilises an ‘ammonia-oxidising’ beneficial bacteria called nitrosomonas that converts ammonia into nitrite by using ammonia as an energy source.
3. Conversion of nitrite to nitrate
This stage of the process utilises another beneficial bacteria called nitrobacter which then converts nitrite into nitrate. The nitrate is then available in the ecosystem to be taken up by the plants and helps them to grow.
4. Nitrate uptake by plants
This stage allows the plants in the pond to use the newly created nitrate as an essential nutrient for growth. It's also interesting to know that nitrogen is an essential part of chlorophyll which plants use for photosynthesis. Isn’t this fun!!
5. Old growth dies back
The last step in the cycle is the old growth or dead plants settle in the pond and contribute to step one of the cycle again, the production of Ammonia. By annually cutting back your aquatic plants, or the plants that have died, you can then physically remove that excess nitrogen that is locked up in your plants from the pond altogether. Of course some will stay behind in the bottom of the pond as the cycle starts again.
Regular addition of beneficial bacteria to your pond can help support this process.
