Bio Diversity and the Sixth Mass Extinction
We’re in the midst of the Earth’s sixth mass extinction crisis. Harvard biologist E. O. Wilson estimates that 30,000 species per year (or three species per hour) are being driven to extinction. Compare this to the natural background rate of one extinction per million species per year, and you can see why scientists refer to it as a crisis unparalleled in human history.
The current mass extinction differs from all others in being driven by a single species rather than a planetary or galactic physical process. When the human race — Homo sapiens sapiens — migrated out of Africa to the Middle East 90,000 years ago, to Europe and Australia 40,000 years ago, to North America 12,500 years ago, and to the Caribbean 8,000 years ago, waves of extinction soon followed. The colonization-followed-by-extinction pattern can be seen as recently as 2,000 years ago, when humans colonized Madagascar and quickly drove elephant birds, hippos, and large lemurs extinct. .
The Extinction Crisis (From The Center for Biological Diversity)
Sometimes just a picture can show more than words:
The authors of Human Domination of Earth’s Ecosystems, including the current director of the National Oceanic and Atmospheric Administration, concluded:
“[A]ll of these seemingly disparate phenomena trace to a single cause: the growing scale of the human enterprise. The rates, scales, kinds, and combinations of changes occurring now are fundamentally different from those at any other time in history. . . . We live on a human-dominated planet and the momentum of human population growth, together with the imperative for further economic development in most
of the world, ensures that our dominance will increase.”
For the deniers of the value of a nature unfucked by human hubris and self centeredness, here is a lesson in our industrial civilization’s monocultural attack on bio-diversity, and a glimpse into a possible future we are leaving our children and grandchildren — if any survive — a future for which they will understandably curse us:
They’re Taking Over! by Tim Flanery
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.
The Irukandjis are diminutive relatives of the box jellies. First described in 1967, most of the dozen known species are peanut- to thumb-sized. The name comes from a North Queensland Aboriginal language, the speakers of which have known for millennia how deadly these minuscule beings can be. Europeans first learned of them in 1964 when Dr. Jack Barnes, who was trying to track down the origin of symptoms suffered by swimmers in Queensland, allowed himself to be stung by one. With nobody attending but a lifeguard and his fourteen-year-old son, he was lucky to survive.
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.
It’s difficult to know how many victims the Irukandji have claimed. The extreme high blood pressure that often kills is hardly diagnostic. Many deaths have doubtless been put down to stroke, heart attack, or drowning. There is some evidence that the problem is growing: Irukandji have recently been detected in coastal waters from Cape Town to Florida.
The box jellies and Irukandjis are merely the most exotic of a group of organisms that have existed for as long as complex life itself. In Stung! On Jellyfish Blooms and the Future of the Ocean, biologist Lisa-ann Gershwin argues that after half a billion years of quiescence, they’re on the move:
If I offered evidence that jellyfish are displacing penguins in Antarctica—not someday, but now, today—what would you think? If I suggested that jellyfish could crash the world’s fisheries, outcompete the tuna and swordfish, and starve the whales to extinction, would you believe me?
Stung! On Jellyfish Blooms and the Future of the Ocean by Lisa-ann Gershwin, with a foreword by Sylvia Earle University of Chicago Press, 424 pp
Our oceans are becoming increasingly inhospitable to life—growing toxicity and rising temperatures coupled with overfishing have led many marine species to the brink of collapse. And yet there is one creature that is thriving in this seasick environment: the beautiful, dangerous, and now incredibly numerous jellyfish. As foremost jellyfish expert Lisa-ann Gershwin describes in Stung!, the jellyfish population bloom is highly indicative of the tragic state of the world’s ocean waters, while also revealing the incredible tenacity of these remarkable creatures
Recent documentaries about swarms of giant jellyfish invading Japanese fishing grounds and summertime headlines about armadas of stinging jellyfish in the Mediterranean and Chesapeake are only the beginning—jellyfish are truly taking over the oceans. Despite their often dazzling appearance, jellyfish are simple creatures with simple needs: namely, fewer predators and competitors, warmer waters to encourage rapid growth, and more places for their larvae to settle and grow. In general, oceans that are less favorable to fish are more favorable to jellyfish, and these are the very conditions that we are creating through mechanized trawling, habitat degradation, coastal construction, pollution, and climate change.
Despite their role as harbingers of marine destruction, jellyfish are truly enthralling creatures in their own right, and in Stung!, Gershwin tells stories of jellyfish both attractive and deadly while illuminating many interesting and unusual facts about their behaviors and environmental adaptations. She takes readers back to the Proterozoic era, when jellyfish were the top predator in the marine ecosystem—at a time when there were no fish, no mammals, and no turtles; and she explores the role jellies have as middlemen of destruction, moving swiftly into vulnerable ecosystems. The story of the jellyfish, as Gershwin makes clear, is also the story of the world’s oceans, and Stung! provides a unique and urgent look at their inseparable histories—and future.