The world ocean | Middle school Earth and space science | Khan Academy

The speaker researches wildlife on islands like Midway Atoll, where over a million albatross breed annually. These seabirds, which spend 95% of their lives soaring the North Pacific eating squid, are increasingly ingesting plastic. Most plastic, transported by ocean currents from the mainland, forms giant loops called gyres. These gyres drive the ocean conveyor belt, circulating water and heat globally, influencing climate, salinity, and nutrient distribution. However, gyres also pull in pollution and marine debris, trapping it in stable centers, forming areas like the Great Pacific Garbage Patch—a "soup" of suspended plastic. This debris, whether ingested or entangling wildlife, poses a significant problem. Oceans, covering over 70% of Earth, host 25% of marine life in coral reefs and produce 50-80% of Earth's oxygen via plankton. Life adapts to extreme conditions as depth increases, with scavengers and unique tube worms thriving even in the deep, dark Mariana's Trench. Oceans are vital for food, oil, shipping, and travel. Indicator species like albatross, found with plastic in their stomachs, signal human impact. The interconnectedness of oceans through conveyor belts means local actions have global consequences, emphasizing the need for protection.