Review: Stung! On Jellyfish Blooms and the Future of the Ocean
by Lisa-ann Gershwin (University of Chicago Press, 2013)
Jellyfish made their first appearance in a very different world than any we can imagine. Their history is told by a fossil record that dates back to the Ediacaran period, about 570 million years ago. The Cambrian explosion had to wait 27 million years to explode, so there were no arthropods (trilobites, crustaceans, spiders, and insects), no vertebrates, no fish. Jellyfish and sponges are the only animals surviving from this long past world that we might recognize. (I will explain why later in this essay.)
Although jellyfish have been around for an unimaginably long time, few of us think about them beyond being annoyed when they invade a favorite beach during a too-short vacation. But, if we continue mining the worlds oceans, raising global temperatures, and adding endlessly ingenious witch’s brews of toxic chemicals to already overstressed seas, jellyfish will assuredly occupy a much bigger portion of our consciousness. Our current course is set to take us on a journey to a world in which we will live on clusters of islands (which were connected to each other before the rising seas flooded the low-lying areas) surrounded by Proterozoan seas that no longer sustain us with protein and oxygen and which are no longer capable of mediating our climate. Whoever observed that history repeats itself had no idea of the deeper truth of his maxim.
Phylogenically, jellyfish are cnidarians which means they are closely related to coral and anemones. They are radially symmetrical and have only two cell layers. (We are bilaterally symmetrical and have a third layer of cells.) They have signaling networks, but no brain, a single opening which serves as a mouth and an anus, a digestive area (but no gut). Although most species are planktonic, several swim impressively fast. Jellyfish make a living by consuming small fish, various phytoplankton, and just about anything they can manage to capture with their long tentacles which are armed with venomous harpoon-like stinging cells called cnidocytes.
Ecologically - and more importantly for us - jellyfish are weeds. They are low-energy, fast-growing, and reproductively prolific animals. Their reproductive success depends on numbers rather than on parental investment in tending offspring. They thrive in disturbed habitats – habits in which there are few predators and few competitors. As weeds, they thrive in polluted, over-heated, poorly oxygenated oceans which are hostile to the animals we depend upon for protein and which are incompatible with the ocean currents we depend upon for a stable climate. Lisa-ann Gershwin’s Stung! On Jellyfish Blooms and the Future of the Ocean is a story about biology, ecology, economic loss and consequences. It is a horrifying and compelling tale of the massive resurgence by jellyfish in response to a thoughtlessly and wantonly spoiled ocean. In Stung!, Gershwin weaves an ecological horror story to awake political-man, corporate-man, and citizen-man from our collective torpor in the hope that we will rally to save ourselves from ruin before it is too late.
Newspapers have, over the past decade, printed countless articles about jellyfish behaving badly. Most of us read them, scratch our head, and move on. But consider just three of the costly and dangerous ways in which jellyfish have misbehaved recently:
· On July 27, 2006 thousands of jellyfish were sucked into the condensers of the USS Ronald Reagan, a 100,000 ton, 1,092 foot, $4.5 billion aircraft carrier, an event which all but completely disabled the ship.
· On December 10, 1999 40 million people across the southern half of the Philippines were convinced that a coup had toppled their government when they lost electrical power due to fifty truck-loads of jellyfish sucked into the seawater cooling system of the coal-fired Sual power station.
· On October 21, 2008 so many jellyfish were sucked into the cooling system of the Diablo Canyon nuclear power plant (Australia) that they disabled the reactor for three days.
Clearly, something is going on that we should be paying attention to.