Ocean Of Birds

Life on the ocean wave

Life on the ocean wave as some would know and name such an experience as a remarkable one is a fascinating and surprising experience to experience. Some of the ship captains and others in such a line would regard this fact and likewise love to experience it the more. We know that many millions of seabirds live there, yet on rare days of glassy calm the sea looks featureless, flat and lifeless to a casual observer. wild wet and frightening days it may still seem superficially barren.

life on the ocean wave

But appearances are deceptive, and the winds which whip the surface into such varied responses also power the currents which are the key to unlock a cornucopian abundance of food supporting unimaginable numbers of birds. At first sight it seems eccentric behaviour for a bird to commit its life to these empty wastes but there is, of course, method in the madness. Provided they can learn to live with some demanding requirements, there is a good living to be made at sea. 

Life On The Ocean; Earth’s Rotation

The sea’s bounty is unleashed by the driving forces of climate, wind and the Earth’s rotation. Although it can be quirky and variable in association with land masses, at sea the wind’s force is remarkably persistent and stable over vast areas. On either side of the Equatorial Trough -more popularly known as the doldrums – are the reliable trade winds, blowing an average moderate breeze (force 4) north-easterly in the Northern and south-easterly in the Southern Hemisphere. In the East Atlantic, the northern Part of the Indian Ocean, the western part of the North Pacific and Northern Australia they are replaced by monsoons which are Characterised by seasonal reversals of wind and weather systems. Powered by the constant factor of the Earth’s spin, the wind Create currents which are in turn, affected by the character of ocean floor and the land masses with their associated shallow water shelves.

life on the ocean wave

Currents are created mainly by the direct action of wind on the sea, hen frictional drag pulls the surface water in its direction and they are therefore generally stronger at the surface. in both the South Atlantic and the Pacific the trade winds drag an immense band of water eastwards over some 500 of latitude revolving round the polar continent and balanced by a much narrower belt of west-going counter-current at the equator. The global effect is of continuous circulations in the great oceans, in the Northern and anti-clockwise in the Southern Hemisphere. 

Life On The Ocean; Currents

Currents are complex and monstrous in their capacity. In the North Atlantic, the Gulf Stream carries an astonishing six and a half million cubic yards of warm water per second. As it moves to the surface on its northward journey it cools and sinks, returning southwards at depth. And the effect of the currents, from the point of view of all life in and above the sea, is crucial.

life on the ocean wave: currents

For where currents meet, or where they are faced with immovable objects like islands or land masses, there are areas of turbulence. And it is in these confused waters that food is most plentiful, as a direct result of the mineral nutrients carried by the movement of waters. Where cold deep water rises to the surface to replace water driven from a coast by persistent winds it brings nitrates and phosphates harvested from distant sea beds; these nutrient salts are characteristic of the upwelling’s which generate life-forms in unimaginable numbers. 

The food available to sustain sea-going birds relates in quantity indirectly to the concentrations of nutrients in upwelling waters. For these nutrients, along with the power of the sun’s light and warmth and the saltiness of the sea are the raw materials which are taken up by microscopic plants like diatoms in the free-floating Phytoplankton. In turn the surface ‘meadows’ of plankton plants are ‘grazed’ by copepods and a myriad of other plankton animals of the Zooplankton. And these tiny morsels are in turn hunted by larger invertebrates and by fish. And in their turn those crustaceans and molluscs and fish are hunted by larger fish and by birds’ Seals, whales and man. In the course of time those ‘higher’ animals return to the sea, a generous proportion of their food as excrement and at last they bequeath their bodies to decay and sink to the bottom to be scavenged and to provide basic nutrients all over again in a merry-go-round of life-forces.

 

 

 

 

 

 

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