Have you ever think about what lies in the ocean? How can oceanography help us? Or how it can influence our lives? Oceanography, a combination of physical and biological sciences, may seem like an obscure or tedious subject, but it is fascinating and vitally important to know. It examines the plant and animal life in the oceans' depths as well as the conditions that exist there that are so extreme. For example, oceanographers study currents to predict weather patterns for us on land. Currents at the ocean floor seem to have an effect on weather patterns on land too.Oceanographers are also studying how the oceans affect weather and climate. The more they understand about the oceans, the better we will be able to predict changes in climate that could impact us here on land. A record of sea level and temperatures of North American coastlines goes back thousands of years. At that point in time, the oceans were much more extensive, as you can see in this picture. In the last few decades, oceanographers have been able to unlock some clues about how the world's oceans have changed over time by examining fossils.This book coversOceanographyMarine GeographyTidesCurrentsOcean Current and ClimateWater Properties in the OceanMarine Life And The EnvironmentEffects of Exploitation and Pollution on Ocean EcosystemsOceanography and HumanityAnd much more.Many sea creatures left traces of their existence in rock layers and layers of sediment that became part of Earth's crust. These rocks formed over millions of years, so there is a record from thousands of years ago to today.Because of the geological clues found in fossils, oceanographers now know that the ocean's temperature has changed and continuously changed as time goes by. The oceans take up a lot of heat from the sun. Water also holds more heat than air because it is much denser. Surprisingly, a slight change in temperature can cause considerable changes in water density because it is so sensitive to temperature changes.Oceanography is essential for our health. Oceanic pollutants, for example, can be hazardous to many marine organisms and humans. These pollutants can include mercury and pesticides that wash off of ships into the ocean and stay there for long periods of time before bacteria break them down into more minor compounds. These tiny compounds eventually make their way to the ocean floor, where they are taken up by phytoplankton in the ocean's water column.Another pollutant found in the oceans is plastic