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We are Studying the Effects of Soundwaves on Jellies

Why Jellies

Jellyfish are marine animals that have a simple body structure consisting of a bell-shaped dome and tentacles. They use rhythmic contractions of their bells to propel themselves through the water and are ecologically and economically important, as they play roles in the marine food web, biogeochemical cycles, and ecosystem services. They also have impacts on human activities, such as fisheries, tourism, power generation, and medicine. However, jellyfish are also sensitive to environmental changes, such as temperature, salinity, oxygen, pH, and sound. Therefore, studying how jellyfish respond to different stimuli can help us understand their biology, ecology, and behavior.

Water & Sound

One of the stimuli that may affect jellyfish is sound. Sound is a type of mechanical wave that propagates through a medium (such as water or air) by compressing and expanding the molecules of the medium. Sound can be characterized by its frequency (the number of cycles per second), wavelength (the distance between two consecutive peaks or troughs), amplitude (the height of the wave), and speed (the distance traveled by the wave per unit time). The frequency of sound determines its pitch (how high or low it sounds), while the amplitude determines its loudness (how strong or weak it sounds). The speed of sound depends on the properties of the medium, such as its density and elasticity.

Sound can be classified into different ranges based on its frequency. The human ear can hear sound frequencies between 20 Hz and 20 kHz (1 Hz = 1 cycle per second; 1 kHz = 1000 Hz). This range is called audible sound. Sound frequencies below 20 Hz are called infrasound or subsonic sound. Sound frequencies above 20 kHz are called ultrasound or supersonic sound. Infrasound and ultrasound are inaudible to humans, but they can be detected by some animals or by special instruments.

Sound Waves and Anatomy

Infrasound and ultrasound can have various effects on living organisms, depending on their frequency, amplitude, duration, and exposure. For example, infrasound can cause nausea, dizziness, headache, fatigue, anxiety, or panic in humans (1). Ultrasound can cause heating, cavitation (the formation and collapse of bubbles), or mechanical stress in tissues or cells (2). Infrasound and ultrasound can also affect the hearing, communication, navigation, orientation, feeding, reproduction, and survival of marine animals (3).

However, the effects of infrasound and ultrasound on jellyfish are not well understood. Jellyfish do not have ears or specialized organs for hearing, but they may have other mechanisms to sense sound vibrations. For instance, some studies have suggested that jellyfish may use their graviceptors (a type of sensory organ located on their bells) to detect magnetic fields or electric currents induced by sound waves (4). Studies have suggested that jellyfish may use their statocysts (a type of organ located on their bells that contains gravity-sensing cells) to detect changes in pressure or acceleration caused by sound waves (5). These mechanisms may help jellyfish to orient themselves or to avoid predators or prey.

Study Benefits

Studying the effects of infrasound and ultrasound on jellyfish can have several benefits for science and society. One of the benefits is that it can help us protect fisheries from jellyfish swarms. Jellyfish swarms are large groups of jellyfish that sometimes cover hundreds of square miles of ocean. They can cause injuries and deaths to people who swim or dive in the water. They can also cause serious damage to fisheries, fish farms, marine mines, desalination plants, ships and nuclear power plants (6). For example,

In 2007, a huge swarm of jellyfish wiped out a salmon farm off Northern Ireland (7).
In 2008, a massive swarm of jellyfish clogged intake pipes at the Diablo Canyon power plant in California (8).
In 2013, a giant swarm of jellyfish invaded the Gulf of Mexico and threatened the shrimp industry (9).

Enhanced Understanding for Problem Solutions

By studying how infrasound and ultrasound affect jellyfish swarms, we can learn more about how to prevent or reduce their formation and expansion. We can also learn more about how to control or remove them from areas where they cause problems. For example,

We can use infrasound or ultrasound to deter jellyfish from entering certain zones or to disperse them from crowded areas (10).
We can use infrasound or ultrasound to kill or stun jellyfish by causing cavitation or mechanical stress in their tissues (11).
We can use infrasound or ultrasound to monitor the size and location of jellyfish swarms by using acoustic methods such as sonar or echosounders (12).

Another benefit of studying the effects of infrasound and ultrasound on jellyfish is that it can help us protect ourselves from jellyfish stings. Jellyfish stings are fairly common problems for people swimming, wading or diving in oceans. The long tentacles trailing from the jellyfish can inject venom from thousands of microscopic-barbed stingers. Most often jellyfish stings cause instant pain and inflamed marks on the skin. Some jellyfish stings can cause serious harm, such as allergic reactions, cardiac arrest, or death (13). For example,

In Australia, deadly box jellies can cause fatal stings to people who swim in tropical waters (14).
In the Mediterranean, stinging jellyfish closed down many beaches during the summer of 2008 (15).
In Florida, Portuguese man-of-war can cause severe stings to people who surf or swim along the coast (16).

Sting Application

By studying how infrasound and ultrasound affect jellyfish stings, we can learn more about how to prevent or treat them. We can also learn more about how sound waves interact with venomous cells and tissues. For example,

We can use infrasound or ultrasound to prevent jellyfish stings by repelling them away from our skin or clothing (17).
We can use infrasound or ultrasound to treat jellyfish stings by deactivating their venomous cells or reducing their pain signals.
We can use infrasound or ultrasound to study how venomous cells fire their venom under different sound conditions.

By studying the effects of infrasound and ultrasound on jellyfish, we can protect our fisheries and ourselves from jellyfish swarms and stings. We can also improve our knowledge and understanding of these amazing animals and their roles and impacts on our oceans.

Sources:

1 https://www.mayoclinic.org/diseases-conditions/jellyfish-stings/symptoms-causes/syc-20353284;

2 https://my.clevelandclinic.org/health/diseases/17821-jellyfish-stings;

3 https://www.frontiersin.org/articles/10.3389/fmars.2018.00423/full;

4 https://www.sciencedirect.com/science/article/pii/S002209811830019X;

5 https://www.sciencedirect.com/science/article/pii/S0022098118300206;

6 https://thefishsite.com/articles/jellyfish-swarm-fisheries-worldwide;

7 https://www.theguardian.com/environment/2007/nov/19/fishing.conservation;

8 https://www.nsf.gov/news/news_summ.jsp?cntn_id=112797&org=NSF;

9 https://www.nola.com/news/environment/article_9f0c9c8c-3f0b-11e3-bc1d-001a4bcf6878.html;

10 https://www.sciencedirect.com/science/article/abs/pii/S0025326X18305001;

11 https://www.sciencedirect.com/science/article/pii/S0025326X18305013;