Mon. Dec 6th, 2021


November 19, 1969, CCS Hudson Nova Scotia slipped through the icy waters of Halifax Harbor and plunged into the open sea. The research ship was embarking on what Many marine scientists on board The last great, unpublished sea voyage: America’s first complete circumnavigation. The ship was bound for Rio de Janeiro, where it would take more scientists before passing through Cape Horn — the southernmost point of the Americas — and then crossing the ice-filled north path through the Pacific Ocean back to Halifax Harbor.

Along the way, Hudson Will stop frequently so that its scientists can collect samples and take measurements. One of those scientists, Ray Sheldon, rode Hudson Valparaiso, in Chile. Sheldon, a marine environmentalist at the Bedford Institute of Oceanography in Canada, was fascinated by the microscopic plankton that seemed to be everywhere in the ocean: how far and wide were these tiny creatures? To find out, Sheldon and his colleagues took up buckets of seawater HudsonUsing its laboratory and a plankton-counting instrument to sum up the size and number of animals they found.

Life at sea, They discovered, Follows a simple mathematical rule: the abundance of an organism is closely related to its body size. In other words, the smaller the creature, the more of them you will find in the ocean. One billion times smaller than krill tuner, for example, but a billion times more abundant.

What was even more surprising was how accurately this rule was seen to play. When Sheldon and his colleagues organized their plankton samples into order of magnitude, they found that the animals in each size bracket had exactly the same mass. In one bucket of seawater, one third of the mass of plankton will be between 1 and 10 micrometers, another third will be between 10 and 100 micrometers and the final third will be between 100 micrometers to 1 millimeter. Each time they rise above a size group, the number of individuals in that group is reduced by a factor of 10. The total mass was the same, when the size of the population changed.

Sheldon thought that this rule could control all life at sea, from the smallest bacteria to the largest whale. This idea turned out to be true. The Sheldon spectrum, as it was known, has also been observed in plankton, fish, and freshwater ecosystems. (Actually, a The Russian zoologist observed Sheldon had the same pattern on the ground three decades ago, but his discovery was largely unnoticed). “It’s kind of suggestive that no size is better than any other size,” said Eric Galbraith, a professor of Earth and Planetary Science at McGill University in Montreal. “Everyone has the same size cell. And basically, for a cell, no matter what body shape you’re in, you tend to do the same thing. “



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