Artificial gills are devices that exist in
science fictionScience fiction is a genre of fiction. It differs from fantasy in that, within the context of the story, its imaginary elements are largely possible within scientifically-established or scientifically-postulated laws of nature...
, and being developed in reality, to extract
oxygenOxygen Oxygen Oxygen (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O...
dissolved in
waterWater is an ubiquitous chemical substance that is composed of hydrogen and oxygen and is essential for all known forms of life.In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71%...
, thus allowing
humanHumans are bipedal primates belonging to the species Homo sapiens in Hominidae, the great ape family. They are the only surviving member of the genus Homo. Humans have a highly developed brain, capable of abstract reasoning, language, introspection, and problem solving...
s to survive
underwaterUnderwater is a term describing the realm below the surface of water where the water exists in a natural feature such as an ocean, sea, lake, pond, or river. Three quarters of the planet Earth is covered by water. A majority of the planet's solid surface is abyssal plain, at depths between 4000...
.
Several potential methods exist for the development of artificial gills. Dr Landé has proposed the use of
liquid breathingLiquid breathing is a postulated form of respiration in which a normally air-breathing organism breathes an oxygen-rich liquid , rather than breathing air. In theory, liquid breathing could assist in the treatment of patients with severe pulmonary or cardiac trauma, especially in pediatric cases...
with a
membrane oxygenatorA membrane oxygenator is a device used to add oxygen to, and remove carbon dioxide from the blood. It can be used in two principal modes: to imitate the function of the lungs in cardiopulmonary bypass , and to oxygenate blood in longer term life support, termed Extracorporeal membrane oxygenation,...
to solve the problem of
carbon dioxideCarbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state...
retention, the major limiting factor in liquid breathing. It is thought that a system such as this would allow for diving without risk of
decompression sicknessDecompression sickness describes a condition arising from the precipitation of dissolved gasses into bubbles inside the body on depressurisation...
.
It is generally thought that they would be unwieldy and bulky, because of the massive amount of water that would have to be processed to extract enough oxygen to supply an active diver, as an alternative to a
scuba setA scuba set is an independent breathing set that provides a scuba diver with the breathing gas necessary to breathe underwater during scuba diving. It is much used for sport diving and some sorts of work diving....
.
Artificial gills are devices that exist in
science fictionScience fiction is a genre of fiction. It differs from fantasy in that, within the context of the story, its imaginary elements are largely possible within scientifically-established or scientifically-postulated laws of nature...
, and being developed in reality, to extract
oxygenOxygen Oxygen Oxygen (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O...
dissolved in
waterWater is an ubiquitous chemical substance that is composed of hydrogen and oxygen and is essential for all known forms of life.In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71%...
, thus allowing
humanHumans are bipedal primates belonging to the species Homo sapiens in Hominidae, the great ape family. They are the only surviving member of the genus Homo. Humans have a highly developed brain, capable of abstract reasoning, language, introspection, and problem solving...
s to survive
underwaterUnderwater is a term describing the realm below the surface of water where the water exists in a natural feature such as an ocean, sea, lake, pond, or river. Three quarters of the planet Earth is covered by water. A majority of the planet's solid surface is abyssal plain, at depths between 4000...
.
Methods
Several potential methods exist for the development of artificial gills. Dr Landé has proposed the use of
liquid breathingLiquid breathing is a postulated form of respiration in which a normally air-breathing organism breathes an oxygen-rich liquid , rather than breathing air. In theory, liquid breathing could assist in the treatment of patients with severe pulmonary or cardiac trauma, especially in pediatric cases...
with a
membrane oxygenatorA membrane oxygenator is a device used to add oxygen to, and remove carbon dioxide from the blood. It can be used in two principal modes: to imitate the function of the lungs in cardiopulmonary bypass , and to oxygenate blood in longer term life support, termed Extracorporeal membrane oxygenation,...
to solve the problem of
carbon dioxideCarbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state...
retention, the major limiting factor in liquid breathing. It is thought that a system such as this would allow for diving without risk of
decompression sicknessDecompression sickness describes a condition arising from the precipitation of dissolved gasses into bubbles inside the body on depressurisation...
.
It is generally thought that they would be unwieldy and bulky, because of the massive amount of water that would have to be processed to extract enough oxygen to supply an active diver, as an alternative to a
scuba setA scuba set is an independent breathing set that provides a scuba diver with the breathing gas necessary to breathe underwater during scuba diving. It is much used for sport diving and some sorts of work diving....
. However, Like-A-Fish is an ongoing attempt to develop such a system in the real world.
As sea water contains 7 ppm oxygen, 1,000,000 kg (1,000 tonnes) of sea water holds 7 kg (1,000 short tons holds 14 lb) of O
2, the equivalent of 5,350
litreThe litre or liter is a unit of volume. There are two official symbols: the Latin letter L in lower and upper case . The lower case L is also often written as a cursive ℓ, though this symbol has no official approval by any international bureau...
s (1,400 U.S.
gallonA gallon is a measure of volume of approximately four litres. Historically it has had many different definitions, but there are three definitions in current use. These are the U.S. liquid gallon and the lesser used U.S...
s) of oxygen gas at atmospheric pressure.
An average diver with a fully closed-circuit
rebreatherA rebreather is a type of breathing set that provides a breathing gas containing oxygen and recycled exhaled gas. This recycling reduces the volume of breathing gas used, making a rebreather lighter and more compact than an open-circuit breathing set for the same duration in environments where...
needs 1 litre (roughly 1 quart) of oxygen per minute. As a result, at least 192 litres (51 gallons) of sea water per minute, or 3.2 liters (3.5 quarts) each second, would have to be passed through the system, and this system would not work in
anoxicHypoxia or oxygen depletion is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point detrimental to aquatic organisms living in the system...
water.
Natural
gillA gill is an anatomical structure found in many aquatic organisms. It is a respiration organ whose function is the extraction of oxygen from water and the excretion of carbon dioxide...
s work because nearly all animals with gills are
cold-bloodedA poikilotherm is an animal whose internal temperature varies along with that of the ambient environmental temperature. Most, but not all, ectotherms are poikilothermic...
and so need much less oxygen than a
warm-bloodedIn biology, a warm-blooded animal species is one whose members maintain thermal homeostasis; that is, they keep their body temperature at a roughly constant level, regardless of the ambient temperature. This involves the ability to cool down or produce more body heat. Warm-blooded animals mainly...
animal the same size.
Like-A-Fish
Like-A-Fish Technologies is an
IsraelIsrael officially the State of Israel , is a developed state in Western Asia located on the eastern shore of the Mediterranean Sea. It borders Lebanon in the north, Syria in the northeast, Jordan in the east, and Egypt on the southwest, and contains geographically diverse features within its...
i business, founded by Alan Bodner in 2001, that is developing a human artificial gill system; they have developed a prototype. Like-A-Fish's technology uses a
centrifugeA centrifuge is a piece of equipment, generally driven by an electric motor , that puts an object in rotation around a fixed axis, applying a force perpendicular to the axis...
causing lower pressure at the center, where dissolved air comes out of the water.
As with any artificial gill, air from a huge volume of seawater would have to be extracted to provide enough for breathing, requiring large amounts of power for pumping. So a key issue remaining is
batteryAn electrical battery is a combination of one or more electrochemical cells, used to convert stored chemical energy into electrical energy. Since the invention of the first Voltaic pile in 1800 by Alessandro Volta, the battery has become a common power source for many household and industrial...
life. Currently a one
kilogramThe kilogram is the base unit of mass in the International System of Units .[The spelling kilogram is the modern spelling used by the International Bureau of Weights and Measures , the U.S...]
battery would only last for one hour, whereas a regular
scubaScuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater for recreation, commercial or industrial reasons.Unlike early diving, which relied exclusively on air pumped from the surface, scuba...
tank can last longer (depending on depth). Regular scuba gear is also far simpler, and thus safer, as there is less to go wrong.
The biggest possibilities lie in underwater habitats, which have access to electricity, but need constant refilling of air tanks. Additional possible uses include systems for scuba divers and submarines, among others.
Like-A-Fish currently holds patents in Europe for its system.
External links