the gossamer bodies deep in the ocean -- 10/27/21
Today's selection -- from The Brilliant Abyss by Helen Scales. The magnificent, ethereal, jelly-based creatures of the deep:
"Midwater (as opposed to waters near the ocean surface or the deep seabed) can be the hungriest and loneliest place in the deep. It's not easy finding food and mates in the enormous, three-dimensional space of the water column between the surface and the abyss. Down on the seabed, animals at least have a surface to explore and a chance to find accumulated piles of fallen food. In open water there is much more searching to be done or waiting patiently for prey and mates to come by.
"Common in midwater are animals with delicate, gelatinous bodies. Some look like flying saucers, some like tangled feather boas, and some like round-bodied spiders with too many spindly legs; there are glistening spheres with rainbows flickering across them and elaborate glass chandeliers complete with glittering lights.
"The stillness of the deep encourages these gossamer bodies to evolve. Here they thrive beyond the reach of waves and tides, where only gentle currents flow by. Being made of jelly is a winning strategy for all these members of the plankton, the wandering organisms that never touch a solid surface and spend their whole lives afloat, supported by their watery world. Tissues made of jelly, or gelatin, a thin mix of water and the protein collagen, constitute a simple way of making a body: it's efficient to operate because it floats and comes with a low metabolic cost. Jelly-based creatures take an energy saving approach to life, cutting their need to feed and raising their chances of survival in the hungry expanses of the deep.
|Pacific sea nettle|
"This flimsy life does, however, have its drawbacks. In midwater, some animals are so dainty that a nearby swish of a fish's tail is enough to make them fall apart. And their frailty makes them difficult for scientists to study. Finding and catching these delicate animals is rather like chasing ghosts. When caught in nets, jelly animals get shredded and collapse. And with deep-adapted cells, they don't do well when brought to the surface where the pressure is hugely reduced; they can simply melt away.
"Despite the difficulty of catching them intact, many major groups of gelatinous animals were first discovered in deep midwater more than a hundred years ago. One scientist's name appears next to the monikers of the numerous fragile, deep-sea animals that he described and named. He made a great many contributions to science but is perhaps best remembered today for his artwork, which brought these ethereal creatures firmly into the public eye.
"Ernst Haeckel was born in Germany in 1834. He trained as a physician in Berlin, but his passions lay in exploring the natural world and also in art. During his medical training, he took classes on Helgoland, a small island off the German coast. Years later, looking back on that trip, Haeckel wrote that 'nothing exerted such a powerful force of attraction on me amongst the myriad animal forms, of which I had not seen living specimens until then, as the medusae.' These medusae, otherwise known as jellyfish, continued to captivate him, scientifically and artistically, and in time they helped to draw his attention into the deep."