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Including animals in carbon cycle models boosts ecosystem health

We all know how trees and other greenery help keep our planet healthy. They pull carbon dioxide, a major greenhouse gas, out of the air and store it. But what about animals? Does a grazing cow or a hungry hippo actually affect how much carbon cycles our planet?

Scientists have recently created a new model that proves animals are key players in the global carbon cycle – and it’s about time we paid attention.

The carbon cycle

The carbon cycle describes how carbon moves around the Earth. It includes the following:

Plants capture carbon

Plants absorb carbon dioxide from the atmosphere and use it during photosynthesis to create the energy they need to survive. This process stores carbon within the plants’ tissues.

Animals consume carbon

Animals eat plants, taking in the carbon stored within plant material. Some of this carbon becomes part of the animal’s body. The remaining carbon is released back into the environment.

Carbon is released

Animals release carbon through several processes:

  • Exhalation: Animals breathe out carbon dioxide as a byproduct of respiration.
  • Waste: Animal waste products contain carbon, which decomposers break down.
  • Decomposition: When animals die, their bodies decompose thanks to microbes. This process releases carbon into the soil or the atmosphere.

The cycle repeats

Carbon released back into the atmosphere or soil becomes available for other organisms. Plants can then take it up again, beginning the carbon cycle anew.

Why include animals in carbon models?

For many years, scientists primarily focused on plants and microbes when developing models to predict how carbon cycles through ecosystems. This approach assumed that these two groups were the main players in carbon storage and release.

However, recent research has revealed a significant flaw in this approach. Animals, it turns out, play a surprisingly critical role in the carbon cycle.

By excluding them from models, scientists were overlooking a major factor influencing how much carbon is stored and released within ecosystems.

“Future modeling of carbon dynamics, important for understanding climate change and designing nature-based carbon sequestration projects, should take animals into consideration as well,” the researchers explained.

How animals help in carbon cycle

Animals impact the carbon cycle in tons of ways, both directly and indirectly:

Nutrient cycling

Animal waste acts as a natural fertilizer. It contains essential nutrients that enrich the soil, promoting plant growth. Healthier and more abundant plants can absorb increased amounts of carbon dioxide from the atmosphere.

Stimulating plant growth

Herbivores consume plant matter, but their grazing also stimulates plant regrowth. This forces plants to work harder to rebuild their tissues, leading to increased photosynthesis and greater carbon dioxide uptake.

Ecosystem disturbance

Animals physically interact with their environment by trampling vegetation, digging, and wallowing. These actions disturb the soil, which can accelerate plant growth cycles and increase the rate at which dead organic matter decomposes. While decomposition releases some carbon, the overall effect boosts carbon storage due to the increase in plant growth.

Animal inclusion in carbon cycle models

The team led by Matteo Rizzuto from Yale University conducted a crucial experiment, comparing a standard carbon cycle model with a modified one that factored in both herbivores and predators. The results were eye-opening.

On average, when the models included animals, ecosystems demonstrated a twofold increase in carbon sequestration.

This means that ecosystems with animals were twice as effective at removing and storing carbon from the atmosphere compared to those models that didn’t account for animals.

Interestingly, the highest carbon storage occurred in models with only herbivores present. When predators were introduced, the amount of stored carbon decreased.

However, it’s important to note that this level was still significantly higher than in models with no animals at all.

This underscores the intricate relationships within ecosystems and how different animal groups influence carbon cycling.

Significance of animals in carbon cycle models

By understanding the animal kingdom’s role in the carbon cycle, scientists can refine existing climate models. These enhanced models give us a more precise prediction of how much carbon the Earth’s ecosystems can naturally store.

This knowledge is crucial for developing effective strategies to combat climate change. It tells us where to focus conservation efforts to maximize the planet’s natural ability to fight rising carbon dioxide levels.

The research confirms that maintaining healthy animal populations helps store carbon in ecosystems. This knowledge paves the way for innovative conservation strategies that act as natural carbon sinks.

Protecting animal habitats and supporting balanced ecosystems isn’t just about biodiversity. It can also serve as a powerful tool in mitigating climate change, working alongside strategies like reforestation.

This research shows that from worms to wildebeests, every creature has its role. Taking care of wildlife is vital for the health of our planet.

The study is published in the Journal of Geophysical Research: Biogeosciences.


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