IV. The Physical Environment
Learning Objectives
- Refresh knowledge of the names and locations of the major oceans
- Grow familiarity the average depth of the ocean
- Gain proficiency in understanding how oceanographers can map the seafloor
- Appreciate the relationship between depth and pressure
- Be able to describe temperature profiles for different regions of the ocean
- Strengthen understanding of the relationships between density, temperature, pressure, and salinity
- Understand of how density changes with depth and latitude
- Explore how sound travels through water, and what physical factors impact sound transmission
- Establish the limitations of light penetration through water
This chapter is from Introduction to Oceanography by Paul Webb which is licensed under the CC BY 4.0 International License.
There are many reasons why people study oceanography. An understanding of ocean processes is vital to oceanographers, marine biologists, environmental scientists, and ocean engineers. Additionally, there are numerous other scientific fields where the oceans play an important role. The oceans are a major contributor to global climate patterns, and can give us clues to past climate conditions. Knowledge of oceanography is important for resource or energy extraction, such as commercial fishing or aquaculture, oil and gas exploration, and clean energy resources such as wind, wave, or tidal energy. The oceans are the major route for international trade through commercial shipping, and are still a significant factor in the transportation of people across the seas. But even the recreational user benefits from an understanding of the ocean, from winds and currents for the casual sailor, tides and habitat conditions for a fisherman, to wave patterns for surfers. And finally, for anyone who has ever stood on the shore and gazed out at the ocean with a sense of wonder at what lies beneath the surface, the study of oceanography can begin to reveal some of the ocean’s mysteries.
Picture yourself swimming in the ocean. Are you imaging frolicking in warm, crystal-clear water? Well scrap that idea, as that idyllic setting represents the conditions in only a tiny portion of the global ocean. The conditions in the vast majority of the ocean are nothing like those at the surface; most of the ocean is very cold, dark, and subjected to crushing pressures. The vast majority of ocean engineering applications take place near the surface of the ocean, which minimizes the challenges of crushing pressures, but not the issue of interactions with waves and weather.
This chapter begins with a basic overview of the world oceans, before discussing some of the ways that the features of the ocean can be classified. Next, we will examine the techniques that are used, and have been used, to map the ocean floor. The chapter continues with an examination of the physical environment of the ocean such as temperature, and light and sound transmission. The field of physical oceanography typically also includes the fluid properties of ocean water, such as waves, tides, and circulation. Those topics will be addressed in subsequent chapters, in great detail.
