The ocean covers 71 percent of the planet, contains 97 percent of the planet’s water, is home to 50 to 80 percent of all life on Earth (94 percent of life on Earth is aquatic), and supplies at least 50 percent of the world’s oxygen, (scientists estimate it’s anywhere from 50 to 80 percent, according to NOAA). It serves up about 200 billion pounds of seafood each year and supplies an important source of protein for billions of people around the world. It plays a big role in transportation, both travel and shipping, and a huge role in regulating climate and weather and making Earth habitable. It is drilled for crude oil, mined for minerals, tapped for development of new medications, and desalinated to provide drinking water. It is home to some of the most beautiful and amazing creatures on the planet and is an unfathomable source of wonder. We literally can’t live without it.
The ocean is truly a gift that keeps on giving. Every planet wants one, other planets and moons across the universe probably have them, but Earth is the only planet we know of that has such a healthy, vibrant ocean teeming with life.
In this chapter, we look at the many ways the ocean makes Earth habitable and such a wonderful place to live, not to mention all the valuable resources it provides to us. Think of this chapter as a celebration of Ocean Appreciation Day.
worldoceansday.org for details.)
Supplying Over Half of the World’s Oxygen
You’ve probably heard the Amazon described as “the lungs of our planet.” However, while this incredible ecosystem is very important, rainforests supply only about 28 percent of the oxygen on our planet. That’s nothing to sneeze at, unless, of course, you’re allergic to rainforests. So where does the other roughly 70 percent come from? Well, over half of all oxygen produced on Earth comes from the sea (by some estimates it is as high as 80 percent!). While most of it is consumed by marine organisms, a small fraction of it escapes and over geologic time has given rise to an atmosphere that is about 20 percent oxygen, which has made life as we know it possible. Thank you, ocean. And this is mostly thanks to microscopic plantlike organisms floating in the sea, the tiny but mighty phytoplankton. (See Chapters 7 and 8 for more about phytoplankton and other ocean plants.)
Powered by the sun, these microscopic wonders turn carbon dioxide and water into sugar and oxygen through the process of photosynthesis, as do plants that grow on land (and in your flower pots), but it performs this magic on a much larger scale. According to some estimates, phytoplankton account for only one percent of all the biomass on our planet. Now, that may be a tiny slice of the pie, but they are able to conduct nearly as much photosynthesis as all the land plants that account for a much larger fraction of that pie. Without phytoplankton creating oxygen in the ocean, life on Earth, in its current form, could not exist.
Playing a Key Role in Regulating Climate and Weather
The ocean is like a massive version of the heating, ventilation, and air-conditioning (HVAC) units used to heat and cool most homes, but instead of circulating hot and cold air, it captures heat from the sun and distributes it through the circulation of water. Imagine Earth’s frozen poles as air conditioners, the equator as its heater, and the ocean as the blower and ductwork, distributing the heat and cold all around the world.
Ocean currents transport warm water from the equator to the poles and cold water from the poles to the tropics. These currents act like a gigantic conveyor belt, moving warm and cool water to areas of contrasting temperature, thereby keeping the entire planet at a fairly comfortable 58.3 degrees Fahrenheit (on average). Sure, that’s sweater weather for people and might make a polar bear break out in a sweat, but as an average temperature it’s perfect.
Without ocean currents, regional temperatures would be more extreme — super hot at the equator and far more frigid than it already is at the poles — and much less of Earth’s land would be habitable. See Chapter 16 for more about how the ocean circulates water and Chapter 17 for how it influences climate and weather.
DIFFERENTIATING CLIMATE FROM WEATHER
Nobody has trouble with the concept of weather because it impacts us every day. We check weather forecasts daily to plan our outdoor activities, to find out how to dress ourselves and our kids, to decide whether or not to carry an umbrella, and more. On the other hand, many people struggle with the concept of climate. For example, some people wonder how climate change (or global warming, as it is sometimes called) can be real when they experience a rogue snowstorm in the spring.
Well, the difference between weather and climate is that weather is affected by short-term changes in the atmosphere, which can still cause a cold spell when there shouldn’t be one, whereas climate describes the AVERAGE weather in an area over a LONG PERIOD of time. For example, weather in a desert may be rainy or sunny on a particular day, but the climate is dry. Likewise, most of South Florida has a tropical climate (hot and humid), but the weather on some days may be cool and dry relative to Florida’s seasonal climate.
So let’s be very clear: Climate change (global warming) is real. According to an ongoing temperature analysis conducted by scientists at NASA’s Goddard Institute for Space Studies (GISS), the average global temperature on Earth has increased by more than 1 degree Celsius (1.8 degrees Fahrenheit) since 1880. That may not seem like much, but it is. Head over to Chapter 17 for more about climate change (global warming) and how it’s bad news for the ocean and for us.
The ocean also plays a key role in the water cycle — the continuous process by which water is carried around the world through evaporation, condensation, precipitation (rain and snow), and transpiration (the movement of water through plants). Even though the ocean is salt water, water that evaporates from the ocean’s surface is fresh water, and much of it falls to the ground as rain or snow, bringing us essential water for drinking and for growing food.
The water that evaporates combined with heat from the ocean’s surface is responsible for the powerful storms that unleash their energy over land, often damaging coastlines and destroying property, but this is all part of the ocean’s role in regulating the weather and contributing to the water cycle. By the way, the ocean’s surface temperature can also impact the severity of storms, making them weaker or stronger.
Producing Protein for Billions of People
Humans and our ancestors have been eating seafood for a looooooooooong time. Yep, in a cave called Figueira Brava, located outside Lisbon (Portugal), remains of harvested mussels date back to a Neanderthal dinner some 80,000 to 160,000 years ago. Evidence also shows that Homo