Do Aquatic Plants Need Oxygen? Everything You Need to Know
Australia’s wildlife, from fish to insects, relies heavily on aquatic plants for food and shelter. Plants also play a big part in balancing water quality and soil around dams, preventing erosion and protecting the entire ecosystem.
Understanding plants’ oxygen needs is incredibly important. It ensures that aquatic vegetation gets what it needs to benefit your dam’s quality and functionality. This guide will cover what you need to know about the plants found in dams, the challenges they face, and how you can harness innovative nanobubble technology to create a robust ecosystem.
What Plants Are in Dams?
Depending on the location and the environment, multiple species of plants are found in, surrounding, and floating on top of dam water. While some contribute to the ecosystem, others are invasive. Here’s a closer look at the plants typically found in Australian dams:
- Lilaeopsis Brisbanica: It looks like grass and thrives in tropical temperatures, which is common in Australia.
- Marsilea Drummondii (Nardoo): Floats on the water’s surface and blocks sunlight to limit algae growth.
- Juncus Usitatus (Pin Rush): Grows along dam margins to stabilise soil and prevent erosion with deep roots.
- Lythrum Salicaria (Purple Loosestrife): Often planted around the edge of dams to provide pollination but can quickly become invasive if not controlled.
- Azolla Filiculoides (Red Azolla): Enriches water quality and converts nitrogen to help plants grow, but it can become invasive and starve other plants of oxygen.
- Salvinia Molesta: An invasive species that creates a thick layer on the water’s surface, depleting other plants of oxygen and sunlight.
- Cyperus Exaltatus (Giant Sledge): Often planted on the shallow circumference of dams to help prevent erosion.
This is just a small selection of plants found in Australia’s dams. Some are harnessed for their natural benefits, such as erosion prevention and algae control; however, they need consistent maintenance to ensure they don’t grow out of control.
Do Plants Need Oxygen in Dams?
Put simply, yes, they do. It’s common knowledge that plants need oxygen to survive, even those that live underwater in dams. Oxygen isn’t limited to the air we breathe; it exists dissolved in water, providing essential gases to animals and plants.
Oxygen is especially important for plants in dams’ root zones. It powers cellular respiration, which turns nutrients into energy and allows optimal plant growth and health.
The Effects of Poor Oxygen Levels on Plants
Without enough dissolved oxygen (DO), most plants can’t perform efficient aerobic respiration and, therefore, make it harder to absorb nutrients. If these needs aren’t met, plants are vulnerable to disease and cannot grow properly, if at all.
The ability to fight disease is especially important if the environment is low in oxygen, as this coincides with harmful algae bacteria and unpredictable temperatures.
Low oxygen levels in dams can also lead to root stress, hindering the ability to absorb water and nutrients. Moreover, plants release a small amount of carbon dioxide during respiration.
As glucose breaks down, it produces adenosine triphosphate (ATP)—the chemical energy plants use for growth and carbon dioxide as a byproduct. This respiration is essential because ATP fuels nearly every process that allows plants to repair living cells and stay alive.
The Cause of Low Oxygen Levels in Dams
Both biological and environmental factors cause low oxygen levels (also known as hypoxia) in dams.
Slow Water Movement
Dams are designed to slow or stop water movement to prevent floods, generate power, etc. However, DO levels reduce when there isn’t enough water movement due to minimal mixing with oxygen from the atmosphere. Slow-moving or stagnant water also heats up faster, causing a set of other issues.
Increase in Temperature
Warm temperatures make it difficult for water to hold oxygen, causing a stratified effect where warm water stays at the top and cold at the bottom – too cold for plants and animals to survive.
Erosion
Soil erosion from dam banks. This problem is exasperated by heavy rainfall or deforestation as the compacted soil loosens without root systems to help hold it in place.
When rocks, soil, sand, and other particles flow into the dam water, its clarity is reduced. Cloudy water makes it harder for sunlight to penetrate, limiting the photosynthesis of plant cells, which is unable to contribute to DO.
Sediment Build up
Organic materials like decaying plant matter and algae settle on the bottom of the dam, making sediment. When they inevitably begin to break down, they consume a lot of DO, leaving the rest of the plants and animals deficient.
Dams with deep sections are particularly prone to sediment buildup, as this is where oxygen circulation isn’t as strong. A detrimental cycle begins when low oxygen slows the breakdown of organic matter, causing sediment to accumulate and further deplete DO.
Using Nanobubbles to Improve Dam Oxygen Levels
Mechanical mixers and diffusers effectively release oxygen into deprived bodies of water, but they have limits regarding dams.
When water depth, flow, and temperature vary, oxygen levels need frequent management. Therefore, it can be very costly and ineffective when equipment can’t reach lower layers where more oxygen is crucial.
What Are Nanobubbles?
As their name suggests, nanobubbles measure about 70-120 nanometers yet can have a gas exchange efficiency of over 85%—better than traditional aeration systems. The process begins when the bubbles are pumped into the water, where they stay suspended for months, circulating around instead of rising to the top.
Their movement is a result of their extremely small size and negative surface charge, which repel them from one another. This spread increases the likelihood of efficient gas exchange with the surroundings. As the nanobubble slowly collapses over time, the oxygen released is slow and steady, maintaining balanced oxygen levels.
How Nanobubbles Benefit Plants in Dams
The sustained oxygenation that nanobubbles provide is essential for plants’ roots and metabolic processes. Even in low-flow areas like dams, nanobubbles can venture down to the deepest layers and release oxygen near deep-rooted plants that would otherwise die.
For these aquatic plants, the stable oxygen supply is a lifeline, providing them with the ideal environment to grow effective root systems and produce oxygen themselves. Even when environmental factors, like temperature fluctuations and sediment buildup, reduce DO, nanobubbles release energy to combat the depletion.