The densest water in the ocean is known as the Antarctic Bottom Water. It is formed along the Antarctic ice shelves where water freezes on the ocean's surface. The Antarctic Bottom Water plays a big role in the global circulation of ocean waters around the world. This dense water is carried along the ocean floor, delivering oxygen and nutrients to the deepest parts of oceans. Scientists have evidence that the Antarctic Bottom Water is becoming fresher and warmer. What are two changes that could happen as a result of this?