The Ocean Environment

Ocean Environment

The sea is the most obvious feature of the earth's surface.

Approximately seventy percent of this surface is covered by water, in one way or another. Beneath this water are the familiar sands of the beaches, bottoms of bays, and the inshore ocean. Farther offshore this water covers an amazing submarine topography of underwater canyons, trenches, mountains, and plains.

Unlike the continents, which are physically separated from one another, the oceans are continuous and interconnected. Since the "world ocean is continuous"(M.J. Keen) it has similar characteristics throughout. In the early

1870s oceanographers collected seawater samples from all of the seas of the world at a variety of depths. When analyzed, the samples were found to have quite similar characteristics. These findings convinced many that a method of study was needed. The study of oceans was named oceanography.

Density, salinity, and temperature are very important concepts in the study of oceanography. The salinity and temperature of the water influence its density, and the differences in density are the major factor in understanding the formation of currents and the positions of water masses in the sea. In addition, temperature and salinity play major roles in influencing the distribution of plants and animals.

The sediments of the sea floor may be divided into lithogenous, hydrogenous, biogenous, and cosmogenous sediments. Lithogenous sediments are the major sediments on the ocean floor. They are derived from the chemical and mechanical weathering of rocks. Biogenous sediments are composed primarily of the protective outter covering of small marine animals and plants. If these remains comprise at least thirty percent of the sediment it is called an "ooze".

"Oozes" were named for the types of organisms that formed them. Hydrogenous sediments form as a result of the chemical reactions that occur in the seawater.

These reactions result in the formation of small particles, which are deposited on the sea floor. Currents move these particles and cause them to collide with the other particles. If many of these collisions occur they may form nodules.

Nodules are found on some portions of the deep-sea floor. The sediment type frequently determines the type of organ...

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...discarge of oil from ships, and the development of emergency response systems to oil pollution accidents have contributed to the decline of ship-based souces of oil pollution over the last two decades. The moratorium on dumping of radioactive waste at sea under the London Dumping Convention also represents another response to concerns about the risks posed by such diposal. Some regions have concluded agreement which ban dumping of any radioactive waste at sea. In the

Mediterranean and Red Sea, all discharge of oily wasted from ships is also banned. The differences between terrestial regions are well known. Less well known are the features that distingush the Atlantic from the Pacific Ocean, or the coast of South America from those of Southern Africa. Regardless of this, the various regions of the world's oceans are all affected by human activity, with pollution and harvesting of resouces of resouces being common to all seas and oceans. The various marine resources, as well as the extent of human impacts on them, are examined region by region, illustrating hos stresses on the marine environmet treatened the very resistance of some habitats and species.