Oceanology: The Secrets of the Sea Revealed

Book Preface

We manifest an intrinsic fascination with those things on the brink of our knowledge. There’s a romance, a yearning, seemingly a need to wonder about things beyond our reach. Deep space, other planets, aliens …but, as is often cited, we may actually know more about these phenomena than about the inhabitants of our own oceans because 80 percent of them are unmapped, unobserved, and unexplored for the so very simple reason that this environment is beyond your reach and mine. We are terrestrial, airbreathing mammals, and while some humans swim well, free dive, or use increasingly sophisticated scuba kit or robots to explore the oceanic unknown, the rest of us “land lubbers” just watch the waves.

Beneath those waves is another world—one that, thanks to science and technology, we are learning a lot more about, a lot more quickly. And, as this fabulous book shows, it is almost incomprehensibly beautiful and fantastic. From the smallest to the largest, the shallows to the deep, the fierce to the fearful, these organisms share our planet but live in a different dimension.

How exciting!

So here is an opportunity to meet the neighbors, the “wet ones,” the extraordinary diversity of miraculous life that has evolved in the oceans. And yet, remote as it can seem, the cultural aspects of our relationship with the sea reveal how we have always had a close connection to this charismatic, dangerous, and rewarding realm. But the tides have turned. Now we are the greater danger, and no drop of our seas is secure. Coral reefs are bleached. Plastic litters the greatest depths and fills the bellies of turtles and whales and chokes albatross chicks. The acidification of the water, pollution, and overfishing threaten the entire ocean ecosystem. There has never been a more important time to immerse ourselves in the wonder of the briny world and thus learn to love and protect it. Dive in, swim among stranger things, and then stand up for our oceans.

CHRIS PACKHAM
NATURALIST, BROADCASTER,
AUTHOR, AND PHOTOGRAPHER

what are oceans?
Earth is a watery world, with 68 percent of the surface covered
by saltwater oceans. Each of the five major ocean basins (the
Arctic, Atlantic, Indian, Pacific, and Southern) is a deep
depression in Earth’s surface. Connected to the oceans, and
typically partly enclosed by land, are numerous smaller seas
such as the Mediterranean and Bering Seas. The oceans are
partially separated by landmasses but are all interconnected

ocean
marine world
history
The familiar layout of Earth’s continents and oceans is very
different from the way it was in the prehistoric past. Today’s
oceans and their seas arose gradually as early landmasses split
up and moved apart. Scientific evidence suggests that the original
ocean formed from water vapor that escaped from the molten
surface of the planet. Around 3.8 billion years ago, conditions
cooled and this vapor started to condense and fall as rain.

ocean climates
The world’s oceans and their climates are inextricably linked through
a complex web of interactions. The oceans absorb and store heat from
the Sun, especially at the equator. From here, wind-driven surface ocean
currents circulate water around each of the main ocean basins. In turn,
the Sun’s heat and Earth’s rotation set the pattern of prevailing winds.
Rainfall is highest in tropical areas, because the oceans are warmest
here, so evaporation is high. The oceans slowly release heat, which
is why the oceanic climate found around continental coastlines is less
extreme than the climate far inland.

ocean depths
Marine organisms inhabit a vast, three-dimensional space and can
be found from the water surface down to the deepest depths. An
organism near the surface will experience very different conditions
from one in the deep ocean. Scientists divide the oceans into zones
of decreasing sunlight and temperature, but pressure increases
continuously from the surface to the deep. Surface layers are well-lit
and have a good supply of nutrients and food. In deep zones, the
sunlight fades and temperatures decrease, which limits life there.