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Microplastics In Monterey Bay

by Conservation Contributor Bob Garbarino

In considering a relevant conservation topic close to our home waters, I decided to look into what is going on at Monterey Bay Aquarium Research Institute, more commonly known as MBARI. I found an article from June 2019 about a study that found microplastics throughout Monterey Bay. Most all of us have heard about the “Great Garbage Patch” in the Pacific Ocean between California and Hawaii. You probably have seen television programs and photos of all sorts of plastic items floating in the ocean. I have heard some mention of microplastics, but was not aware of their widespread presence in Monterey Bay. According to the article, a microplastic is plastic debris less than 5 millimeters across.

The study found microplastics present in Monterey Bay from just below sea level all the way down to 1000 meters. The team carrying out the research used MBARI’s underwater robots to collect seawater samples. They found that the highest concentration of particles was at a depth of 200-600 meters. They also checked for the presence of the particles in two filter feed marine animals—pelagic red crabs and giant larvaceans. All of them tested were found to have microplastics in their system. The red crabs and giant larvaceans are consumed by other animals. For instance, the red crab is eaten by  bluefin tuna, humpback whales, migratory birds like albatross. The most common types of plastics found were PET, polyamide and polycarbonate—all found in consumer products like plastic drink bottles and to-go containers. One of the researchers suggested that some of the plastic moved into the bay by way of ocean currents.
Interesting—but perhaps not surprising—is that of the five top rivers that produce the most plastic trash, four are in Asia and one in Africa.
I’ve just touched on the tip of the iceberg of a huge complex problem that covers the globe. What can we as individuals do? Find and use alternatives to single-use disposable plastics is the number one recommendation.

Trash and marine debris on a beach near Tulum, Mexico.