By Julia Zeh
Edited by Bryce Harlan
Our oceans cover over 70% of the Earth’s surface. Everyone has heard this at some point in their lives, whether they learned it in school or read it somewhere. But sometimes, I think we forget how vast and expansive 70% of the Earth’s surface really is. Even more amazing is the fact that we’ve explored less than 5% of it. That leaves a humongous portion of the Earth unexplored and unknown. We know more about the Moon, which is about 238,900 miles away from us, than we do about the oceans that, for some of us, are right next door.
These facts become more incredible as we begin to think about what is living in the oceans, both known and unknown, big and small. After all, life began in the oceans and the biggest animal on Earth lives in the ocean: the blue whale. The ocean contains a multitude of diverse species, ranging from microscopic to almost 20 times the height of a human.
The giant squid is one of these uniquely large marine creatures--one of the many incredible megafaunal species supported by the marine ecosystem. Giant squids are legends and fishermen’s tales come true. The image of the kraken, a colossal sea creature with enormously long tentacles living in the dark depths of the oceans, is realized by the giant squid. They have the largest eyes in the animal kingdom (about 25 cm in diameter) and are themselves terrifyingly huge, growing up to 13 meters (43 feet) long. However, despite their size, giant squids are rarely seen, and much of what we know about them comes from dead squids washing ashore. The giant squid had not been caught on video in its natural habitat until 2012, despite hundreds of attempts. The team which managed to obtain the footage worked in the Pacific Ocean near Japan and eventually succeeded by capturing footage of a three meter squid (that would have been about 8 meters if it weren’t missing its two longest tentacles) using quiet equipment and red lighting invisible to the eyes of most deep sea creatures.
The team that filmed the giant squid for the first time did so using a method that focused on attracting the target organism, rather than scaring it away. To do this, they created a lure with a pattern of flashing blue light that imitated that of a jellyfish. The jellyfish produces this light when being attacked by a predator so as to attract the giant squid. Giant squid are not a predator of jellyfish, but rather of the larger fish that prey on the jellyfish, so the jellyfish is saved if the giant squid arrives and eats the larger fish. This is an example of bioluminescence, a glow created by a chemical reaction within an organism, which is used for defense against predators or to attract prey or mates. Most recognize the anglerfish, with its glowing bauble hanging in front of its face, as the classic example of bioluminescence. But there are many other examples of bioluminescent organisms as well.
The oceans are full of bioluminescent creatures that glow and put on light displays in the dark depths, mimicking the night sky and the multitude of galaxies and stars that illuminate it. The oceans represent an unknown akin to outer space, but they do not command the same level of curious excitement. Both are dark mysteries full of intrigue and in need of further study. This is particularly true because there are mounting concerns that our rate of species discovery may be slower than high extinction rates, and species may be lost before we are even able to study them. The oceans contain a large portion of such undiscovered species representing a great need for protection from pollution, overfishing, habitat destruction, acidification, rising water levels and temperatures.
The oceans are a frontier full of mysteries. Whether it’s something as huge as the giant squid or a small newly discovered species of ctenophore (comb jelly), there is much to be discovered and further explored. Physically and biologically, the oceans are captivating and alien--holding never-ending wonders. So we must make an effort to explore beneath the water’s surface with the same vigor with which we look beyond the Earth’s atmospheric boundaries. Further, we must work towards protecting it, both for well-known species and those which we have yet to discover.