In Chapter 1 we have added a discussion of the scientific method, including an explanation of the difference between a hypothesis and a theory. We have also undated information on the Integrated Ocean Drilling Program. In Chapter 4 we have updated the discussion of gas hydrates. A new table on the properties of water has been added to Chapter 5, and we have extended the discussion of specific heat and heat capacity to make the difference between the two clear to readers. We have reorganized Chapter 6 to put the discussion of pH after the discussion of dissolved gases in seawater. We have also rewritten large sections of the discussion on gases in seawater. In Chapter 7 we have updated the material on greenhouse gases and the ozone holes over the Arctic and Antarctic. We have also included a discussion of the effects of Hurricanes Katrina and Rita on the Gulf Coast. In Chapter 10 we have written about the devastating tsunami in the Indian Ocean. In addition, we have a new guest essay entitled "Field Notes: Modeling the December 26,2004 Sumatra Tsunami" written by Dr. Eddie Bernard. In Chapter 11 we have updated the tide and current tables and added a number of new study questions at the end of the chapter to help students understand the tides. Chapter 13 has an updated discussion of the Gulf of Mexico dead zone as well as the tanker Prestige oil spill. Chapter 14 has been revised and updated and includes a new discussion of biomechanics. In addition, more examples are presented for the roles microorganisms play in the marine environment. New images of microorganisms have been included. Chapter 15 has been revised and updated. More detailed discussions of satellite images, food web dynamics, and the biological pump have been added. A more detailed section has also been included to describe a decade's worth of large-scale iron fertilization experiments. New satellite images have been included. Chapter 16's description of phytoplankton and bacterioplankton has been updated. The section on toxic phytoplankton has been expanded. Some of the latest techniques for analyzing the very smallest plankton, including DNA analyses and flow cytometry, are described. New images of phytoplankton have been included.