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THE SCIENCE OF MARINE BIOLOGY

Marine Biology: the scientific study of the organisms of the sea

Life on earth probably originated in the sea

Marine life helps determine the very nature of our planet

Marine biology is closely related to oceanography, but the two are not synonymous

Oceanography: the scientific study of the oceans

Aristotle ◦ considered by many to be

the first marine biologist

◦ lived in the 4th century B.C. Greece

◦ recognized many basics of marine biology, including that fish breathe using gills

James Cook◦ one of the first explorers to make scientific

observations along the way and to include a full-time naturalist among his crew

◦ created first dependable charts

◦ brought back plant and animal specimens

James Cook (cont.)◦ one observation he made was when the crew ate

citrus fruits they did not develop scurvy

◦ today we know that scurvy is caused by a lack of vitamin C in the diet

◦ he proved that through careful observation, scientific discoveries can be made by non scientists

Charles Darwin◦ most likely the most famous shipboard naturalist

◦ sailed around the world on the HMS Beagle for 5 years

◦ best known for his theory of evolution

The “Wilkes Expedition”◦ 1838-1842 (United States Exploring Expedition)

◦ Led by Lt. Charles Wilkes of the U.S. Navy

◦ discovered at least 2,000 previously unknown species

◦ Laid the foundation for government funding of scientific research

Edward Forbes◦ discovered many previously unknown organisms

and recognized that sea floor life at different depths

The Challenger Expedition◦ 1872-1876

◦ Led scientifically by Charles Wyville Thompson

often considered the “founder of oceanography”

◦ took 19 years and 50 volumes to publish all the results

◦ brought back more information about the ocean than had been previously recorded in all human history

◦ set new standards for studying the ocean

Henri Milne Edwards and Victor Andowin◦ French zoologists and naturalists

◦ first to study shore life and bring equipment to the shore

The first U.S. marine laboratory was founded in 1930 in Woods Hole, MA◦ It is now called the Woods Hole Oceanographic

Institution

SONAR: SOundNAvigation Ranging◦ developed in response to

the growing importance of submarine warfare

◦ based on the principles of echolocation used by marine organisms

◦ refers to the use of sound to discover the location and distribution of underwater objects or features.

It can also be used to generate underwater images and measure the speed of objects

Sound travels more efficiently through water than it does through air, radar does not work well in water

Passive sonar detects sound waves given off by objects◦ involves listening to underwater sounds from

marine mammals, such as whales, or from submarines or other underwater vessels

Passive sonar can primarily determines the direction of objects

Submersibles and submarines utilize passive sonar as it does not reveal their location in the water

With active SONAR, sound is emitted into the ocean in short bursts or “pings” and then the reflections are detected

The distance to an object is calculated from the echo transmission and return interval and the speed of sound in water (~ 1 mile per second or 1.6 km/s)

Self Contained Underwater Breathing Apparatus

British inventor William James made the first scuba unit in 1825.

However, Frenchman Jacques-Yves Cousteau and Emile Gagnan did not develop the aqualung used today until 1942.

A scuba diver wears metal tanks that hold compressed air.

They supply air to the diver at the same pressure as the surrounding water pressure. ◦ A diver uses air more quickly at deeper depths

The diver exhales used air into the water

The limit of a scuba device is commonly considered to be 50m (160 ft)

1. Open Circuit

2. Closed Circuit

3. Semi-closed Circuit

“Open-circuit” scuba: The scuba equipment most often used by amateur divers (all nonhelmeted divers).

This consists of a compressed air tank that is carried by the diver.

Its mouthpiece is a regulator supplying air at normal atmospheric pressure into a face mask. The diver exhales into the mask and the characteristic stream of bubbles is produced.

“Closed-circuit” scuba: This apparatus involves either pure oxygen or an oxygen-helium mixture. Neither of these techniques is safe without extensive training or preparation.

“Semiclosed” scuba: These circuits recycle the exhaled oxygen used while diving.

How To Scuba

Submersible: small, underwater research vessels

Two common types are AUVs and ROVs◦ The most famous of which

are the Alvin and the Jason

ROV (Remotely Operated Vehicle): A robotic device controlled from a distance that is used to explore inhospitable environments such as the deep sea.

AUV (Autonomous Underwater Vehicle): A robotic device programmed to its job independently of direct human control that is also used to explore inhospitable environments such as the deep sea.

Remote sensing technology: technology used to study the earth and its oceans from afar

track ocean currents, animal migration patterns, natural disasters

Research tool designed to be worn by wild animals.

It combines video and audio recording with collection of environmental data such as depth, temperature, and acceleration.

The Crittercam was created in 1986 by marine biologist and filmmaker Greg Marshall

A shark approached Greg during a diving trip off Belize, then disappeared into the murk with three quick strokes of its tail. Greg noticed a remora clinging to the shark.

As Greg watched the shark disappear, it occurred to him that if he could put a camera in the place of the remora, he could see the shark's behavior unfold without disturbing the shark.

Bull Sharks on Crittercam

These compact systems allow scientists to study animal behavior without interference by a human observer

There are a constant improvements on this technology, including a new tracking camera called the Shark Cam

Shark Cam - Return of Jaws - Shark Week 2013

Scientific Method: The set of procedures by which scientists learn about the world◦ Scientific knowledge is

fundamentally derived from the observation of nature

◦ a way to check and verify any one person’s observations

Theory: refers to a hypothesis that has passed so many tests that it is generally accepted as true◦ it is still subject to rejection if enough evidence

accumulates against it

◦ the scientific method still has its limitations

Inductive reasoning draws conclusions through the logical process of induction

Repeat specific observations can lead to important generalizations◦ For example, “the sun always rises in the east”

Deductive reasoninguses general premises to make specific predictions

For example, iforganisms are made of cells (premise 1), and humans are organisms (premise 2), then humans are composed of cells (deductive prediction)