1.1: Introduction

About half of the world’s human population lives within a few tens of kilometers of the oceans. A large proportion of the remainder live within a few tens of kilometers of a river or estuary that is connected to the oceans. These facts hint at, but do not fully reveal, the importance of the oceans to human civilizations.

In this text, we will explore the fundamental physical, chemical, geological, and biological features and processes of the oceans, why the oceans are difficult to study, and review the difficulties of studying the oceans and the methods ocean scientists have used. We will discuss the range of resources that the oceans provide us, and the impacts from human use of the oceans and the exploitation of their resources. We will also examine the direct and indirect effects of climate change, not just on human civilization and natural ecosystems but also on the fundamental chemistry of the global ocean. Some of these changes pose a long-term threat of extinction for many ocean species. After reading this text, you will have a new appreciation for the intimate and intricate linkages between our lives and the oceans. More importantly, you will be better prepared to analyze, understand, and assess the growing influx of scientific and popular reports on ocean-related findings, theories, and the impact of human activities.

In recent decades, human interest in the oceans has grown in response to our rapidly deepening knowledge and understanding of the creatures that inhabit the underwater world. Scuba diving has become a popular pastime, avocation, or sport, and all forms of ocean recreation have grown explosively. New and higher-quality videos are becoming available, allowing us to experience the ocean from the comfort of our homes. Many cities now have ocean aquariums that allow the public to see ocean life up close. A large portion of the planet’s population experiences the ocean at beaches, when boating or enjoying other water sports, or by sailing the oceans on cruise ships. On a more somber note, humans are also fascinated and terrified by the death and destruction caused by tsunamis, hurricanes, severe storms, ships running aground or sinking, and sharks. These interactions with the ocean lead to such questions as:

• Why do some say that we know less about the oceans than we do about the moon or the planet Mars?
• Why are the world’s active volcanoes located where they are?
• Why does the east coast of the United States have many barrier islands and tidal wetlands (marshes and mangrove swamps), whereas the west coast does not?
• What is a tsunami, and what should I do if I am ever on a beach when one is approaching?
• What is a rip current (rip tide), and how can I survive one?
• What is unique about water, and how do these unique properties affect daily life and our environment?
• What do we need to know about the oceans to understand and predict climate changes?
• Why are fisheries concentrated mostly in coastal zones, and why do some areas of the coastal ocean produce more fish than others?
• Almost all hurricanes in the Atlantic Ocean, especially large hurricanes causing severe damage, make landfall in the Caribbean, Gulf of America or on the coast of the Southeast United States. Only a very few weak hurricanes make landfall in the Northeast United States and hurricanes virtually never make landfall on the Atlantic Africa or Southern European coasts. Why is this?
• Is ocean pollution from oil spills and industrial discharges as bad as many reports often portray it?
• What are the main causes of the widely reported destruction of coral reefs and damage to other ocean ecosystems?
• What is ocean acidification, and why is it important?
• What is ocean deoxygenation? What are its causes and consequences?
• There have been at least 5 mass extinctions in Earth’s 4.6-billion-year history. Why do many scientists now believe that the planet may already have entered a new mass extinction of species? What long-term changes in ocean physical characteristics and chemistry are expected to contribute to this mass extinction?

Answers to some of the questions listed above may be found in a single section or chapter of this text. However, the oceans are a complex environment in which geology, physics, chemistry, and biology are all linked in intricate ways. As a result, finding answers to many of these questions requires fitting together information from several different chapters. You will be reminded numerous times of the interdisciplinary nature of ocean sciences as you study this text.

One particular theme that exemplifies the interdisciplinary nature of ocean sciences is revisited many times throughout this book. This theme concerns what may be the most important scientific questions facing contemporary human society: Is human activity permanently altering the environment in a manner that will ultimately damage or diminish civilization itself? Specifically, will the release of gases from the combustion of fossil fuels alter the oceans and atmosphere and cause major changes in the global climate and ecosystems?