The story Flannery tells is extracted from a book by Lisa-ann Gershwin: Stung! On Jellyfish Blooms and the Future of the Ocean. Gershwin has spent a good portion of her life studying jellyfish.
Jellyfish are perhaps the oldest species of marine animal. They are thought to predate the Cambrian era when nature went wild experimenting with new types of creatures. Given half a billion years of evolution, they exist in many different forms and they have learned how to survive in much more hostile environments than exist today. The theme of Gershwin’s book is that as we upset the delicate balance in the marine ecosystem by overfishing, polluting, and changing the chemistry of the oceans, we are creating an environment where jellyfish can thrive at the expense of other species.
By eliminating or diminishing jellyfish predators, lowering the oxygen level, and raising the acidity level in our oceans, we are creating conditions that are difficult for many species, but leave jellyfish relatively unaffected. Flannery includes this quote from the book:
Shellfish seem to have a dim future. Acidity rises as more carbon dioxide is absorbed into the water.
Jellyfish are also designed to survive in the oxygen-poor environment we are creating in our oceans.
Jellyfish unleashed make a formidable foe. The box jellyfish, native to the waters around Australia, is referred to as the "most venomous creature on earth."
"Most jellyfish are little more than gelatinous bags containing digestive organs and gonads, drifting at the whim of the current. But box jellyfish are different. They are active hunters of medium-sized fish and crustaceans, and can move at up to twenty-one feet per minute. They are also the only jellyfish with eyes that are quite sophisticated, containing retinas, corneas, and lenses. And they have brains, which are capable of learning, memory, and guiding complex behaviors."
And then there is the nasty little jellyfish known as Irukandi, an Aboriginal word.
"It’s now known that the brush of a single tentacle is enough to induce "Irukandji syndrome." It sets in twenty to thirty minutes after a sting so minor it leaves no mark, and is often not even felt. Pain is initially focused in the lower back. Soon the entire lumbar region is gripped by debilitating cramps and pounding pain—as if someone is taking a baseball bat to your kidneys. Then comes the nausea and vomiting, which continues every minute or so for around twelve hours. Shooting spasms grip the arms and legs, blood pressure escalates, breathing becomes difficult, and the skin begins to creep, as if worms are burrowing through it. Victims are often gripped with a sense of "impending doom" and in their despair beg their doctors to put them out of their misery."
Jellyfish really are on the move—including Irukandi.
What makes jellyfish a worldwide problem is their efficiency in reproduction. Consider the specimen known as Mnemiopsis.
Jellyfish eggs hatch as polyps that attach themselves to hard surfaces. These polyps then proceed to produce a stream of jellyfish.
Jellyfish do not make good neighbors. They are voracious eaters with apparently unlimited appetite.
For those who are not yet worried about the effects of uncontrolled jellyfish population growth, consider what occurred when Mnemiopsis infiltrated the Black Sea.
"By 2002 the total weight of Mnemiopsis in the Black Sea had grown so prodigiously that it was estimated to be ten times greater than the weight of all fish caught throughout the entire world in a year. The Black Sea had become effectively jellified."
If jellyfish can destroy that ecosystem, they can destroy others. The term "jellification" is not as bizarre as it sounds.
Gershwin believes we have passed some point of no return with respect to our oceans. They will evolve to an unknown, but definitely undesirable state. Flannery provides her final thoughts.
Her advice to humanity:
All of this may seem a bit overwrought. However, in the grand sweep of the earth’s history it has often become a rather hostile place for life. There have been several instances that have risen to the category of "mass extinctions." The most severe episode occurred about 250 million years ago and earned itself the title "The Great Dying."
Who knows? Perhaps what we are facing is the second edition of "the revenge of the jellyfish."
It is good to encounter articles like this occasionally. They give one something to worry about when they grow weary of worrying about the economy.