The Life Aquatic

It’s often said we know more about space than our own oceans. Whilst this fact may be debatable, one thing is for certain: we have explored very little of the oceans’ depths and the wondrous mysteries they hold. Just like space exploration itself, only a handful of people have ever ventured to the deepest depths of the ocean – a cold world devoid of light yet teeming with some of the strangest, alien-like life forms on earth!

Let’s for a moment pretend you’re an aquanaut, a bold explorer of the oceans in much the same way an astronaut explores the dark reaches of space. You’ve been assigned a mission to explore the marine world in its entirety, beginning from the shorelines whipped by winds and lashed by waves, through the sun-kissed shallows and upper reaches of the open ocean and finally, deep down into the dark, unknown abyss. To prepare you for this incredible voyage, you’re going to need to do a little bit of research. You’ll need to know what environmental conditions you might face, what creatures you’ll encounter (maybe even discover!), and where exactly you might find them should you wish to seek them.

The day your mission begins is drawing close and final preparations are wrapping up. You’ve just experienced a tiring day of physical assessments and you decide to head back to your cabin form some much-needed rest. Upon returning, you notice a book has been left on your bedside table, The Marine World: A Natural History of Ocean Life. The cover shows a ghost-like jellyfish illuminating itself in a glow of neon blue and pink – no doubt, a sign of the strange new world you’re yet to see. Propping yourself up in bed, you open the cover and browse its contents.

Nicely encapsulated in three main sections, you find everything you need to know about the marine world. In the first part, you learn of the ocean’s physical and chemical properties, such as the tides, varying salinity, and changing pressures at great depths. Flicking through the second section, you’re introduced to the ‘living’ ocean and to concepts like food webs, habitat zonation and the various adaptations life has evolved to deal with a variety of challenging conditions. Finally, you reach the last part where the majority of known marine phyla (large groups of life classified by scientists) are catalogued. In this last section, you discover the sheer array of life forms ranging from the microscopic protozoa to the open ocean-cruising whales.

Each page you read contains amazing fact after amazing fact, complemented by beautifully detailed line drawings, illustrations and colour photographs. The language is simple, clear and free of any unnecessary jargon and, despite your fatigued body and mind, it is by no means a chore to read. You’re drawn in more and more, and with each page you find yourself repeatedly going ‘Ah-ha!’ as you begin to understand the complexity of the marine world - the flows of major oceanic currents, nutrient upwellings supporting entire ecosystems, and even how the Antarctic yeti crab (Kiwa tyleri) ‘grows’ its own food at freezing-cold depths! The tapestry of marine life unravels before your eyes and you can clearly see how each life form is intrinsically linked to another, just as each differently coloured brush stroke is woven into a single masterpiece.

Yeti crab (Kiwa sp.). Attached to the hairs (setae) of the crab are filamentous bacteria which are believed to be ’farmed’ by the crab as food. Image:   David Shale, Nature Picture Library.

Yeti crab (Kiwa sp.). Attached to the hairs (setae) of the crab are filamentous bacteria which are believed to be ’farmed’ by the crab as food. Image: David Shale, Nature Picture Library.

Amidst the revelations of each organism’s life history, unique adaptations in form and function, and quirky behaviour, you notice a repeating element. It startles you at first and as you progress through each class of organism it becomes increasingly sobering. It’s a small paragraph at the end of nearly each section titled ‘Uses, Threats, Status and Management’. It dawns upon you that our actions throughout history, particularly in just the last couple of centuries, are threatening life in the oceans. Yet, hinted at in the title is the fact that with greater knowledge and compassion, we can make positive change through ‘managing’ our actions. This buoys you with hope. It is a poignant reminder as to why you signed up for this adventure – to unravel the ocean’s secrets and share its beauty with the world, lest it be lost forever.

Your eyes are heavy now and your body is aching. You slowly close the cover, rest the book down, and your eyes close. You hear the gentle roll of waves, the caw of seagulls and begin to dream of the adventure of a lifetime.

This book belongs on your bookshelf if... you have even the slightest bit of curiosity about life on Earth and what secrets our oceans hold.

Banner image by Evatt Chirgwin.

Leonardo Guida

Following a childhood love for sharks, Leo recently completed his PhD at Monash University investigating the effects of fishing on shark and ray populations. He is Director of Community Operations for Wild Melbourne.

You can find him on Twitter at @ElasmoBro.