November 10, 2013

Hidden treasure of the sea

ONE OF THE GREATEST WONDERS of the sea is the sheer amount of life it sustains, most of which goes unobserved as we plow our way through or over it.

William Beebe, the famous naturalist, writer, and explorer, once undertook the laborious task of counting the number of tiny creatures he caught in a net. Here’s his account, from The Arcturus Adventure (G. P. Putnam’s Sons):

“One dark moonless evening I put out a silk surface net, the mouth of which was round and about a yard in diameter. At the farther end of the net a quart preserve jar was tied to receive and hold any small creatures which might be caught as the net was drawn slowly along the surface of the water. This was done at the speed of two knots and kept up for the duration of one hour.

“When drawn in, the net sagged heavily and we poured out an overflowing mass of rich pink jelly into a flat white tray. This I weighed carefully and then took, as exactly as possible, a one-hundred-and-fiftieth portion.

“I began to go over this but soon became discouraged, and again divided it and set to work on one-sixth of the fraction on which I had first started.”

After many hours of eye-straining and counting under the microscope, Beebe conservatively estimated that his 1/150th part of the hour’s plankton haul came to 271,080 individuals.

“If we multiply this by 150,” he said, “we get 40,662,000 individuals . . . a very conservative estimate.”

Most of the these individuals were primitive crustaceans, which make plankton a rich, nourishing food, even raw.

It’s also worthwhile mentioning that all these creatures that we call plankton were caught at the surface on a dark night. Beebe repeated the experiment in full daylight and caught only about 1,000 individuals instead of 40,000,000.

“Plankton will have nothing of the sun or even of moonlight,” he observed, “and remains well below the reach of the stronger rays.”

In fact, the very word plankton derives from the Greek word for a wanderer — a reference to its habit of migrating upward in the ocean at night, and down during the day.

Today’s Thought
Shipwrecked men in an open boat, if their lot is cast on waters rich in plankton, never need to starve to death if they can manage to drag an old shirt, net, fashion, through the water at night.
— William Beebe, The Arcturus Adventure

 “They’re such a devoted couple next door.  Every time he goes out he kisses her. Why don’t you ever do that?”
“Why should I?  I hardly know the woman.”

(Drop by every Monday, Wednesday, Friday for a new Mainly about Boats column.)


Kenneth Sherwood said...

I appreciate your blog immensely. But your post on the richness of the sea comes across while I happen to be reading Callum Robert's _Unnatural History of The Sea_. Do you know it? The basic idea, documented in detail, is that we have never known the true richness ofthe sea. That since Puritan times here (and earlier in other parts of the world) we've only known an impoverished marine eco system.

John Vigor said...

Hi Kenneth,

No I don't know Callum Roberts' book. Sounds very interesting, so thanks for drawing my attention to it.


John V.