Research

This is the raw research I've found. I will be summarizing it and using it in my report.

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Artemia (Brine shrimp) are a food source for crustaceans and fish. Cultured brine shrimp feed on yeast, wheat flour, soybean powder or egg yolk. Sea, aquarium or kosher salt and pH of 8-9 is required for the eggs to hatch. Their young hatch out of cysts, which are metabolically-inactive, at the optimal temperature of 25 to 27 degrees Celsius (room temperature). Artemia eggs take about 24 to 48 hours to hatch. Crustaceans, like Artemia, do not have ears. They have tiny hairs, called mecanoreceptors, on their shell that respond to physical stimuli such as water movement, vibration or touch by sending a message to the nervous system. A type of mechanoreceptors that respond particularly to vibration or changes in water pressure are called "hearing hairs". Some crustaceans use noise for orientation.

Sound waves propagating underwater are alternating compressions and rarefactions (decrease in density and pressure of sound wave) of the water. They travel through the air and get refracted when they pass through a medium with gradually varying properties (e.g. water). Sound waves are transmitted through water as a pressure waves. High intensity sound is transmitted by high intensity pressure waves. These pressure waves cause vibrations in the water and hence, affect the hatching process of brine shrimp eggs.

Frequency is the number of cycles/waves a sound makes per second. It is a periodic vibration and a property (subset) of sound that determines pitch. It is measured in Hertz (Hz). Low-frequency noise refer to sounds below 200Hz. Broadband source levels are the sum of the acoustic energy over all of the frequencies generated by the source. Lower frequencies result in higher intensity sound waves that cause greater vibrations of the water.

The world's oceans are mostly polluted with low-frequency sounds due to boats, ships, underwater industrial activities, or seismic military and scientific explorations. I intend to test broadband source levels of:

• Ships- 186 Hz (noise generated by a large tanker ship)
• Ships- 171 Hz (noise generated by a tug and barge aka tugboat)
• Seismic survey- 259 Hz (noise generated by airgun array)
• Military sonar- 223 Hz (noise generated by U. S. Navy tactical mid-frequency sonar, center frequencies 6.8 to 8.2 kHz)

Prawns [shrimps] are very sensitive to sound, just like many fish, and hence, ocean noise have potential impacts on them in the marine ecosystem. (Lovell et al. 2005). Such low-frequency sounds have shown to have detrimental, lethal effects on marine life, damaging their hearing and interfering with their feeding habits and other life cycles such as reproduction.

Hard materials, such as plastic, are dissimilar to the air that sound waves move through and hence, the walls reflect most of the sound waves and little is absorbed. This would cause a reverberation, prolonging the music and diffusing it to all parts of the tank. Therefore, plastic is an ideal material for the tank.