6: The Seafloor
- Page ID
- 31570
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)When you stand in the shallow water on the foreshore of a beach, you stand on the outermost edge of an expanse of Earth that covers 71 percent of our planet’s surface. Simply put, you are standing on the floor of the ocean, the seafloor.
If you were to keep walking—outfitted, of course, in a deep-sea atmospheric dive suit (ADS) with plenty of rations for you and some fishy friends—you would come across some of the most extraordinary regions of our planet: grand canyons, majestic mountain ranges, and massive dunes that rival those of Arrakis, the desert planet in Frank Herbert’s best-selling 1965 sci-fi novel Dune. The seafloor boasts its own Yellowstone-like geysers and mud pots and bizarre pools of methane that look like underwater lakes. It’s a world largely unseen and unknown.
But technology is changing our ability to “see” the seafloor. Thanks to new tools for mapping the seafloor (Chapter 5) and telepresence technology that streams pictures and video to any internet-connected device (Chapter 4), you can explore these incredible habitats in the comfort of your home. In the 21st century, the seafloor has become visible to us in ways we could only dream of a few decades ago. Submersibles have provided access to the very deepest parts of the ocean (Chapter 3). Satellites and their ability to very precisely map the sea bottom from bumps and wiggles in the sea surface have brought the major seafloor features into view (Chapter 4). Remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs) have expanded our ability to see (via cameras) and map (via sonar devices) the seafloor (Chapter 4). Multibeam and side-scan sonar allow us to visualize the three-dimensional topography of the ocean bottom in unprecedented detail (Chapter 5). So while it’s popular to say that we know more about the surface of the Moon or Mars than we know about the bottom of the ocean, that perception ignores the great advances that have been made in recent decades (e.g., Hillier et al. 2008; Harris and Macmillan-Lawler 2018; Jamieson 2023).
In this chapter, we survey the major features of the seafloor. In particular, we emphasize the significance of these features to geological, chemical, physical, and biological processes in the world ocean. If you’ve ever traveled anywhere on land, you know that a little advance knowledge of the places you intend to visit can make the experience more enjoyable. So, too, can knowledge of the seafloor open your eyes to a geological wonderland beneath the waves. So grab the controls of your virtual ADS and let’s dive in, ocean explorer.