Protect Our Oceans: Why We Must Stop Disturbing the Seafloor

The ocean is like a giant sponge that absorbs a lot of carbon dioxide—around 30% of the world’s yearly emissions. However, study shows that human activities, especially bottom trawling for fish and dredging to clear harbors, are making this sponge less effective. These activities disturb the seafloor, leading to changes that limit the ocean’s ability to absorb carbon.

When fishermen drag heavy nets across the sea floor, it doesn’t just catch fish; it also releases a significant amount of carbon dioxide—between 2 to 8 million metric tons each year. This is similar to the emissions produced by about a million U.S. homes. While this number may seem small compared to global fossil fuel emissions, it’s still a significant impact.

Sebastiaan van de Velde, a marine geochemist from the University of Otago, emphasizes that reducing emissions is essential, but we also need to understand how our fishing methods affect the environment. He argues that fishing practices, particularly bottom trawling, are often overlooked in discussions about carbon emissions.

Changing how we fish could reduce greenhouse gas emissions significantly—possibly more than all existing carbon capture facilities combined. The potential benefits of modifying fishing methods are incredibly promising. For instance, limiting trawling to certain areas could lead to substantial carbon savings. Says van de Velde, “It’s possible to have a productive fishing industry without heavy climate impacts.”

Research indicates that bottom fishing contributes to the release of greenhouse gases like carbon dioxide, especially by bringing organic materials from the seafloor back to the surface. Previous studies have focused on this organic carbon. However, van de Velde’s study explores inorganic carbon generated by chemical processes on the seafloor. These processes help counteract ocean acidification, which is crucial for the ocean’s ability to absorb additional carbon.

When trawling occurs, it disrupts these natural chemical cycles. It introduces excess oxygen into the water, which changes the seafloor chemistry and ultimately increases acidity. This makes it harder for the ocean to absorb CO2 because acidified waters can’t hold more gas.

To understand this impact, van de Velde and his team used data on seafloor carbon, oxygen levels, and acidity, creating a mathematical model. They found that muddy coastal areas, often targeted by dredging and trawling, are vital for maintaining the natural balance of alkalinity, which helps the ocean absorb CO2.

Despite some uncertainties in their calculations, they hope this study encourages industries and regulators to adapt their practices. Modernizing trawling gear can lessen environmental harm and improve operation efficiency. In some regions, we could limit trawling to just 40% of current fishing grounds. This shift might only reduce fish yields by 10%, allowing more areas to be protected.

This research signals a significant step in understanding how our fishing practices impact the climate and marine ecosystems. With a little effort and innovation, we can balance fishing needs while protecting our oceans.

For more insights on ocean carbon absorption, you can check a detailed report from the National Oceanic and Atmospheric Administration.

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