Tale of extreme sealife should inspire wonder and protection
- By Wan Lixin
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E-mail Shanghai Daily, April 11, 2014
The abyss
“The deepest reaches of the sea really are akin to another planet, subject to conditions unimaginable on Earth’s surface. Crushing pressure, deep cold, and eternal darkness rule the world’s basement,” the book observes. On page 55 is a picture comparing a simple polystyrene foam cup and another cup that has been taken into the deep sea strapped to the hull of a submarine.
The drastically and permanently shrunken cup attests to the crushing effects of high pressure.
And there is no light. In this abyssal deep of darkness, there can be no sea life that can live off plants that can trap solar energy through photosynthesis.
Instead, giant worms have evolved to dine on bacteria living in and around hydrothermal vents. These bacteria have mastered the art of chemosynthesis: the conversion of the chemical energy of hydrogen sulfide into raw cellular energy.
Stunted by cold and deprivation, most deep sea organisms grow slowly, but these hydrothermal vents catalyze spectacular growth at Earth’s most inclement sites. Although more than 500 new species have been identified to live off the hydrothermal vents, chemosynthesis alone does not account for deep sea bio-diversity.
Some animals are fed by the riotous productivity of the sunlit layers thousands of feet above, in the form of surface-water detritus, flakes of tissue, pieces of algae, and fecal matter. As the descent can take two weeks, much of the material is consumed before it reaches the bottom.
There is also the occasional bonanza for the denizens of the deep, like a dead whale that strikes the muddy sea bottom with a gurgling thump, providing a community of scavengers a feast that can last for years.
“Scientists estimate that more than a half-million whale falls exist in the planet’s oceans at any given time, deposited every few miles along the biggest migration routes,” the Palumbis claim.
The decrease in the number of whale falls — as a result of hunting or deteriorating environment — means fewer whale falls today than in the past, and deep sea famine.
In their delightful, vivid description about the struggle for existence in the sea, the Palumbis do manage to communicate a vital message: even the extreme conditions in the deep sea are not immune from disruptive and destructive human greed.
