We Have a Surprising Underwater Ally in Combatting Climate Change: Zooplankton

When we think about fighting climate change, images of towering trees, sprawling forests, and sprawling solar farms likely come to mind. However, beneath the sea’s surface lives an often overlooked but incredibly important ally in our battle against global warming: zooplankton. These tiny, drifting marine creatures play an outsized role in carbon sequestration – the process of capturing and storing atmospheric carbon dioxide – thereby helping slow down climate change.

In this article, we’ll dive deep into the fascinating world of zooplankton, explore their role in our planet’s climate system, and reveal why protecting them is vital for a sustainable future.

What Are Zooplankton?

Zooplankton are microscopic or small animals that drift in oceans, seas, and freshwater systems. Unlike phytoplankton – which are photosynthetic and plant-like – zooplankton are consumers. They feed on phytoplankton, bacteria, and other small organisms, and are a crucial link in the aquatic food web.

Common types of zooplankton include:

• Copepods
• Krill
• Jellyfish larvae
• Larval stages of various fish and crustaceans

The Climate Connection: How Zooplankton Combat Climate Change

1. Carbon Sequestration via the Biological Pump

One of the most critical ways zooplankton help combat climate change is through their contribution to the biological carbon pump. As zooplankton feed on phytoplankton, which absorb CO2 during photosynthesis, they incorporate carbon into their bodies. When zooplankton produce fecal pellets or eventually die, this carbon-rich material sinks to the deep ocean, effectively removing carbon dioxide from the atmosphere for decades or even centuries.

2. Vertical Migration – A Natural Carbon Conveyor

Many zooplankton species engage in diel vertical migration, rising to the ocean surface at night to feed and descending back to the depths during the day to avoid predators. This daily movement transports carbon from surface waters to the deep ocean, making them key players in moving carbon downwards.

3. Supporting Ocean Ecosystems and Health

Healthy populations of zooplankton sustain rich marine ecosystems by feeding fish, whales, and other animals. A balanced marine food web helps maintain ocean productivity, which supports phytoplankton populations that continually absorb CO2 from the atmosphere.

Benefits of Zooplankton to Climate and Human Society

Understanding the ecological and societal benefits of zooplankton helps highlight why their conservation matters:

• Enhanced carbon storage: Increased zooplankton populations bolster carbon export to the deep sea, trapping CO2 for long periods.
• Support for fisheries: Many commercial fish species depend on zooplankton directly or indirectly, driving food security and coastal economic health.
• Indicators of ocean health: Changes in zooplankton abundance and diversity provide early warnings for ocean warming and acidification.
• Scientific insight: Studying zooplankton improves climate models by integrating complex marine carbon cycles.

Case Study: The Role of Copepods in the Southern Ocean

The Southern Ocean is home to massive populations of small crustaceans called copepods. Research has shown these copepods actively contribute to carbon sequestration in one of the planet’s most important blue carbon sinks. By feeding on vast amounts of phytoplankton and sinking their fecal pellets deep into the ocean, copepods help lock away gigatons of CO2 each year.

However, rising sea temperatures and ocean acidification threaten these populations. Protecting the ecological balance here is critical; if copepod populations decline, so does the Southern Ocean’s ability to combat rising carbon levels.

How You Can Help Protect Zooplankton and Support Their Role in Climate Mitigation

While zooplankton might be out of direct human reach, there are practical steps we can take to protect their environment and by extension, our planet:

• Reduce plastic pollution: Microplastics endanger zooplankton health, so cutting plastic use prevents contamination.
• Support sustainable fisheries: Overfishing disrupts the marine food web that zooplankton sustain.
• Advocate for ocean protection policies: Marine sanctuaries help preserve critical habitats.
• Promote climate action: Reducing greenhouse gas emissions slows ocean warming that threatens zooplankton survival.
• Stay informed and spread awareness: Educating others about oceanic allies like zooplankton fosters community-driven conservation.

Conclusion: Embracing Zooplankton as Unsung Climate Warriors

While small, zooplankton pack a powerful punch in the global effort to combat climate change. They serve as essential stewards of the ocean’s carbon cycle, underpinning food webs and helping sequester vast amounts of carbon naturally. Recognizing and protecting these invisible ocean inhabitants is vital, not only for marine biodiversity but for the future health of our planet.

As we push forward in climate strategies, let’s remember the incredible role of zooplankton – a tiny yet mighty underwater ally working silently beneath the waves to keep our climate in balance.