Oceans For Dummies. Joseph Kraynak

1. To find out how the ocean formed and how marine life evolved (how the ocean as we know it came to be), head to Chapter 3. To scope out different areas of the ocean, head to Part 2, where we divide the ocean into zones and ecosystems and check out the seafloor.

      All chapters in Part 3 are required reading, but feel free to just flip through them at your leisure to look at all the pretty pictures. Words just can’t capture the beauty of the ocean and the creatures that call it home as well as photos can. Chapter 21 is also required reading. One of the primary reasons we wrote this book is to recruit you to join our mission to save the ocean — one of the world’s most precious resources. In Chapter 24, we provide a menu of easy ways you can help.

      Other than that, you’re pretty much on your own to explore at your own pace and as your curiosity leads you. Enjoy!

Part 1

      Getting Started with Your Ocean Voyage

IN THIS PART …

      Take a quick primer on ocean fundamentals — from dividing the ocean into oceans (plural) and getting up to speed on the water cycle to engaging in a quick meet-and-greet with the ocean’s inhabitants.

      Take inventory of the various ways the ocean contributes to our health and happiness, not to mention our very existence.

      Discover how the ocean and oceans formed and how life on Earth may have begun.

      Trace the evolution of marine life from the Paleozoic to the Cenozoic era and everything in between.

      Look ahead to find out what the future of the ocean might look like.

Chapter 1

      Brushing Up on Ocean Fundamentals

      IN THIS CHAPTER

       Getting a big-picture view of the ocean and related bodies of water

       Wrapping your brain around the water cycle

       Sampling the vast diversity of ocean life

       Building a mutually beneficial relationship with the ocean

      Before you dive into any large or complex topic, you’re wise to step back and look at the big picture. A general understanding provides a framework on which to hang the details. In this chapter, we provide that framework, establishing a context for understanding the many facets of the ocean and how they all fit together.

      We start by introducing you to the ocean and breaking it down into its five “oceans.” Then, we get into a few topics in the realm of physical oceanography — the water cycle, the shapes of the ocean basins, meteorology, and other properties and processes that explain what makes the ocean tick from a physical standpoint. We then introduce you to the various groups of life-forms that populate the ocean — plants, animals, and beings that fit in neither (or both) categories. Finally, we wrap things up with a discussion of the ocean’s current state and the human-ocean relationship — the benefits we gain from the ocean and our responsibilities as environmental stewards in protecting and preserving it.

      Get ready for a wild ride. In this chapter, we cover a lot of ground, not to mention all that water!

Taking a Nickel Tour of the Ocean(s)

      The ocean is big. How big? Well, it covers about 360 million square kilometers (140 million square miles), which is just a smidgen more than 70 percent of Earth’s surface. Volume-wise it contains approximately 1.3 billion cubic kilometers (321 million cubic miles) of water — that translates to about 352 quintillion gallons, which accounts for about 97 percent of Earth’s water. In terms of living space, the ocean comprises about 99 percent of the biosphere — all land, water, and atmosphere where life on Earth exists.

      Because it’s so big, people have developed all sorts of ways to slice and dice it to better understand and describe the different areas that make it up.

      Dividing the ocean into oceans … or not

Earth has only one ocean, which is why we will refer to it as the ocean (singular) throughout this book. Geographically, it’s divided into four or five oceans, depending on who’s doing the dividing. Prior to the year 2000, text books recognized four oceans: the Atlantic, Pacific, Indian, and Arctic. Sometime around the year 2000, the International Hydrographic Organization designated a fifth ocean the Southern Ocean — a band that wraps around the world from the coast of Antarctica to 60 degrees south latitude (see Figure 1-1). Here’s a brief description of each of the five oceans, in order of size, because, well, size matters.

       Pacific Ocean: The largest of the five “oceans,” the Pacific stretches from the Arctic to the Southern Ocean and from east of Asia and Australia to the Americas. It covers more area than all the land on Earth combined and is more than double the surface area of the Atlantic Ocean. It also wins the deepest point in the ocean contest with the Mariana Trench, which is nearly 11 kilometers (about 7 miles) deep.

       Atlantic Ocean: This next largest ocean lies between the Americas and the continents of Europe and Africa. It’s home to the Bermuda Triangle, the Sargasso Sea, the Gulf Stream, and the hurricanes that rattle the Caribbean Islands and the southern and eastern coasts of the U.S. The North Atlantic is by far the most thoroughly explored, best understood, and most heavily fished of the five “oceans.”

       Indian Ocean: Nestled between Africa (to the west) and Australia (to the east) and between Asia (to the north) and the Southern Ocean (below it), the Indian Ocean ranks third in surface area but first in warmth.

       Southern Ocean: The Southern Ocean is relatively small, but its average depth is greater than the average depth of any of the other four oceans — four to five kilometers (2.5 to 3 miles) deep! It’s best known for its strong, sustained easterly winds, its huge waves (due to the strong, sustained winds), and its frigid environment; during its winter, nearly the entire surface of the Southern Ocean is frozen. It’s also home to the world’s largest ocean current — the Antarctic Circumpolar Current — and it is chock full of nutrients.

       Arctic Ocean: Surrounding the North Pole and bordering the northern edges of North America, Asia, and Europe is the Arctic Ocean. Most of it is located within the Arctic Circle, from the North Pole down to about 70 degrees northern latitude. It’s the smallest and shallowest of the five “oceans,” and for most of the year, most of its surface area consists of ice 1 to 10 meters (3 to 33 feet) thick. The Arctic Ocean is best known for its wildlife (including polar bears, whales, and seals) and for its natural resources (primarily oil).

      ©John Wiley & Sons, Inc.

      FIGURE 1-1: The ocean’s