Deep Ocean Discoveries and Marine Life Insights

Understanding the Deep Ocean: Vessels and Instruments

Oceanographic Vessels

Conshelf

Conshelf: A diver who lives and operates both inside and outside a submarine refuge for an extended period.

Alvin

Alvin: A manned deep-ocean research submersible owned by the United States Navy and operated by the Woods Hole Oceanographic Institution (WHOI) in Woods Hole, Massachusetts.

Aluminaut

Aluminaut: The world's first aluminum submarine. This experimental vessel, an 80-ton, 15.5-meter (51 ft) manned deep-ocean research submersible, was built by Reynolds Metals Company to promote the utility of aluminum.

Essential Oceanographic Instruments

Water Bottle

Water Bottle: A container used to hold water, liquids, or other beverages for consumption.

Reversing Thermometer

Reversing Thermometer: An oceanographic device for measuring underwater temperature and pressure.

Dip Net

Dip Net: A net or wire mesh bag attached to a handle, used especially to scoop fish from water.

Current Meters

Current Meters: An acoustic current meter is a set of transducers fixed in a frame. Acoustic current meters are used to measure the velocity and direction of currents and waves.

Ocean Sediments: Formation and Types

Ocean sediments are categorized by their origin:

• Terrigenous Sediments

  Terrigenous Sediments: Derived from the erosion of rocks on land; that is, they originate from terrestrial (as opposed to marine) environments. Sources include volcanoes, weathering of rocks, wind-blown dust, grinding by glaciers, and sediment carried by icebergs.

• Biogenous Sediments

  Biogenous Sediments: Formed from the remnants of organisms that resisted dissolution. In deeper waters, shells of plankton and other microscopic organisms form these kinds of sediments.

• Cosmogenous Sediment

  Cosmogenous Sediment: Sediment derived from outside the Earth, typically minor stardust or broken-down asteroid particles. Accumulations of cosmogenous sediment can usually be identified in areas with minor terrigenous sediment and by testing isotopes.

Historical Milestones in Ocean Exploration

Discovery of the Titanic

Who discovered the Titanic in 1985? Dr. Robert Ballard couldn't sleep. It was the early morning of September 1, 1985, and the 43-year-old oceanographer was lying in his bunk aboard the research vessel Knorr.

Morse Code in Communication

Morse Code: May be represented as a binary code, which is how telegraph operators transmit messages.

Understanding Sea Ice Types

Sea ice is classified based on its age and characteristics:

• New Ice

  New Ice: A general term for recently formed ice, including frazil ice, grease ice, slush, and shuga. These types of ice are composed of ice crystals that are only weakly frozen together (if at all) and have a definite form only while afloat.

• Nilas

  Nilas: A thin, elastic crust of ice, easily bending on waves and swell. Under pressure, it grows in a pattern of interlocking “fingers” (finger rafting). Nilas has a matte surface, is up to 10 cm in thickness, and may be subdivided into dark nilas and light nilas.

• Young Ice

  Young Ice: Ice in the transition stage between nilas and first-year ice, 10-30 cm in thickness. It may be subdivided into grey ice and grey-white ice.

• First-Year Ice

  First-Year Ice: Sea ice of not more than one winter’s growth, developing from young ice; 30 cm or greater. It may be subdivided into thin first-year ice (sometimes referred to as white ice), medium first-year ice, and thick first-year ice.

• Old Ice

  Old Ice: Sea ice which has survived at least one summer’s melt. Topographic features are generally smoother than first-year ice. It may be subdivided into second-year ice and multiyear ice.

Marine Mammals: Classification and Characteristics

Classification of Marine Mammals

Marine mammals are classified into four different groups:

• Cetaceans: Whales, dolphins, and porpoises. Over 70 different species of cetaceans spend their whole lives in water.
• Pinnipeds: Seals, sea lions, and walruses.
• Sirenians: Manatees and dugongs.
• Marine Fissipeds: Polar bears and sea otters.

Cetacean Anatomy and Communication

Baleen

Baleen: A filter-feeding system inside the mouths of baleen whales. The baleen system works by a whale opening its mouth underwater and taking in water.

Flukes

Flukes: A cartilaginous fluke at the end of a cetacean's tail, used for propulsion. The fluke is set horizontally on the body, unlike fish, which have vertical tails.

Blowhole

Blowhole: The hole at the top of a cetacean's head through which the animal breathes air. It is homologous with the nostril of other mammals and evolved via gradual movement of the nostrils to the top of the head.

Ventral Pleats

Ventral Pleats: Creases that run vertically down the underside of a whale's jaw all the way to its stomach. When feeding, the ventral pleats expand like an accordion to accommodate a huge amount of food-rich water.

The Melon

The Melon: A mass of adipose tissue found in the forehead of all toothed whales.

Whale Communication: Clicks and Echolocation

Whales are very social creatures that travel in groups called “pods.” They use a variety of noises to communicate and socialize with each other. The three main types of sounds made by whales are clicks, whistles, and pulsed calls.

• Clicks: Believed to be for navigation and identifying physical surroundings.
• Echolocation: The use of sound waves and echoes to determine where objects are in space.

Threats to Cetaceans: The Impact of Sonar

Military Sonar and Marine Wildlife

Explain the peril that cetaceans face due to military sonar: Is it true that military sonar exercises actually kill marine wildlife? Unfortunately for many whales, dolphins, and other marine life, the use of underwater sonar (short for sound navigation and ranging) can lead to injury and even death.