Is it correct?

Hi. Is the following passage correct? Thank you in advance.

Under water noise pollution is a serious threat for marine life. Marine mammals like daulphins and whales have their own way of talking just like humans do. They use hearing like humans use sight. They use sounds to find their families, food, and their way in the darkest ocean. Today, the ocean is noisier than ever before, because of man-make ocean noise. During military exercises when warships turn on their sonar. The extremely sonar sound spreads for tens to hundred miles in all directions and are used to detect sub-marines.This greatly affect the whales, and leads to their death. Another human activity that affects the ocean life are gas and oil companies. The noise caused by the seismic explorations for gas and oil is also loud, pervasive, and continuous. This injures whales, leading some of them to fatally beach on the shores, while others to die unnoticed in the open sea and sink. Noise pollution not only harm the humans’lives, but also the sea life. Therefore, a healthy ocean is a healthy planet, and a healthy future for all of us.