Resources from Ocean Sediments

Ocean beds are rich in potential mineral and organic resources. Much of these resources, however, are not easily accessible, so their recovery involves technological challenges and high cost.

Energy

The main energy resources associated with marine sediments are petroleum and gas hydrates. The ancient remains of microscopic organisms, buried within marine sediments before they could decompose, are the source of today s petroleum (oil and natural gas) deposits. Petroleum products account for 95% of the economic value of the ocean beds. This mainly includes the oil produced from offshore regions. Today major offshore reserves exist in the Persian Gulf, in the Gulf of Mexico, off Southern California and in the North Sea.

Gas hydrates  are unusually compact chemical structures made of water and natural gas. They form only when high pressures squeeze chilled water and gas molecules into an icelike solid. Although hydrates can contain a variety of gases including carbon dioxide, hydrogen sulfide, and larger hydrocarbons such as ethane and propane; methane hydrates are by far the most common hydrates in nature.

Gas hydrates occur beneath Arctic permafrost areas on land and under the ocean floor, where they were discovered in 1976. In deep-ocean sediments, where pressures are high and temperatures are low, water and natural gas combine in such a way that the gas is trapped inside a lattice like cage of water molecules.

Sand and Gravel

The offshore sand and gravel industry is second in economic value only to the petroleum industry.  These include the rock fragments that are washed out to sea and shells of marine organisms, is mined by offshore barges  using a suction dredge. This material is primarily used as aggregate in concrete, as a fill material in grading projects, and on recreational beaches.

Evaporative Salts

When seawater evaporates, the salts increase in concentration until they can no longer remain dissolved, so they precipitate out of solution and form salt deposits. The most economically useful salts are gypsum and halite i.e, common salt.

Manganese Nodules and Crusts

Manganese nodules are rounded, hard, golf- to tennis-ball-sized lumps of metals that contain significant concentrations of manganese, iron, and smaller concentrations of copper, nickel, and cobalt, all of which have a variety of economic uses.