117-509: Cuttlefish , or cuttles , are marine molluscs of the suborder Sepiina . They belong to the class Cephalopoda which also includes squid , octopuses , and nautiluses . Cuttlefish have a unique internal shell , the cuttlebone , which is used for control of buoyancy . Cuttlefish have large, W-shaped pupils , eight arms , and two tentacles furnished with denticulated suckers, with which they secure their prey. They generally range in size from 15 to 25 cm (6 to 10 in), with
234-437: A closed circulatory system. Like other marine mollusks, cuttlefish have ink stores that are used for chemical deterrence, phagomimicry , sensory distraction, and evasion when attacked. Its composition results in a dark colored ink, rich in ammonium salts and amino acids that may have a role in phagomimicry defenses. The ink can be ejected to create a " smoke screen " to hide the cuttlefish's escape, or it can be released as
351-622: A deimatic display to warn off potential predators. Under some circumstances, cuttlefish can be trained to change color in response to stimuli, thereby indicating their color changing is not completely innate. Cuttlefish can also affect the light's polarization, which can be used to signal to other marine animals, many of which can also sense polarization, as well as being able to influence the color of light as it reflects off their skin. Although cuttlefish (and most other cephalopods) lack color vision, high-resolution polarisation vision may provide an alternative mode of receiving contrast information that
468-410: A halocline . If a zone undergoes a strong, vertical chemistry gradient with depth, it contains a chemocline . Temperature and salinity control ocean water density. Colder and saltier water is denser, and this density plays a crucial role in regulating the global water circulation within the ocean. The halocline often coincides with the thermocline, and the combination produces a pronounced pycnocline ,
585-493: A mid-ocean ridge , which creates a long mountain range beneath the ocean. Together they form the global mid-oceanic ridge system that features the longest mountain range in the world. The longest continuous mountain range is 65,000 km (40,000 mi). This underwater mountain range is several times longer than the longest continental mountain range – the Andes . Oceanographers state that less than 20% of
702-797: A pseudomorph of similar size to the cuttlefish, acting as a decoy while the cuttlefish swims away. Human use of this substance is wide-ranged. A common use is in cooking with squid ink to darken and flavor rice and pasta. It adds a black tint and a sweet flavor to the food. In addition to food, cuttlefish ink can be used with plastics and staining of materials. The diverse composition of cuttlefish ink, and its deep complexity of colors, allows for dilution and modification of its color. Cuttlefish ink can be used to make noniridescent reds, blues, and greens, subsequently used for biomimetic colors and materials. A common gene between cuttlefish and almost all other cephalopods allows them to produce venom, excreting it through their beak to help kill their prey. Additionally,
819-405: A specific energy on par with some advanced foams made from more compliant materials such as metals and polymers . The high energy absorption is a result of several factors. The failure of the cuttlebone occurs in three distinct stages: local crack formation, crack expansion, and densification. Crack formation typically occurs in the middle of the vertical walls in the chambered structure of
936-412: A boundary between less dense surface water and dense deep water. Cuttlebone Cuttlebone , also known as cuttlefish bone , is a hard, brittle internal structure (an internal shell ) found in all members of the family Sepiidae , commonly known as cuttlefish , within the cephalopods . In other cephalopod families it is called a gladius . Cuttlebone is composed primarily of aragonite . It
1053-432: A cuttlefish can be independent of the other side of the body; males can display courtship signals to females on one side while simultaneously showing female-like displays with the other side to stop rival males interfering with their courtship. The deimatic display (a rapid change to black and white with dark 'eyespots' and contour, and spreading of the body and fins) is used to startle small fish that are unlikely to prey on
1170-606: A cuttlefish is an unusual shade of green-blue, because it uses the copper-containing protein haemocyanin to carry oxygen instead of the red, iron-containing protein haemoglobin found in vertebrates' blood. The blood is pumped by three separate hearts: two branchial hearts pump blood to the cuttlefish's pair of gills (one heart for each), and the third pumps blood around the rest of the body. Cuttlefish blood must flow more rapidly than that of most other animals because haemocyanin carries substantially less oxygen than haemoglobin. Unlike most other mollusks, cephalopods like cuttlefish have
1287-423: A depth of 200 to 600 metres (660 to 1,970 ft) . Because of this limitation, most species of cuttlefish live on the seafloor in shallow water, usually on a continental shelf . When the cuttlefish dies, only the cuttlebone remains and will often wash up on a beach. In the past, cuttlebones were ground up to make polishing powder, which was used by goldsmiths . The powder was also added to toothpaste , and
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#17327810242101404-795: A female cuttlefish. Changing their body color, and even pretending to be holding an egg sack , disguised males are able to swim past the larger guard male and mate with the female. Cephalopods are able to communicate visually using a diverse range of signals. To produce these signals, cephalopods can vary four types of communication element: chromatic (skin coloration), skin texture (e.g. rough or smooth), posture, and locomotion. Changes in body appearance such as these are sometimes called polyphenism . The common cuttlefish can display 34 chromatic, six textural, eight postural and six locomotor elements, whereas flamboyant cuttlefish use between 42 and 75 chromatic, 14 postural, and seven textural and locomotor elements. The Caribbean reef squid ( Sepioteuthis sepioidea )
1521-595: A gentle breeze on a pond causes ripples to form. A stronger gust blowing over the ocean causes larger waves as the moving air pushes against the raised ridges of water. The waves reach their maximum height when the rate at which they are travelling nearly matches the speed of the wind. In open water, when the wind blows continuously as happens in the Southern Hemisphere in the Roaring Forties , long, organized masses of water called swell roll across
1638-610: A greater number of polarized light displays than males and also alter their behavior when responding to polarized patterns. The use of polarized reflective patterns has led some to suggest that cephalopods may communicate intraspecifically in a mode that is "hidden" or "private" because many of their predators are insensitive to polarized light. Leucophores, usually located deeper in the skin than iridophores, are also structural reflectors using crystalline purines , often guanine, to reflect light. Unlike iridophores, however, leucophores have more organized crystals that reduce diffraction. Given
1755-437: A large competitor arrives to threaten the male cuttlefish. In these instances, the male first attempts to intimidate the other male. If the competitor does not flee, the male eventually attacks it to force it away. The cuttlefish that can paralyze the other first, by forcing it near its mouth, wins the fight and the female. Since typically four or five (and sometimes as many as 10) males are available for every female, this behavior
1872-535: A pattern called the intense zebra pattern, considered to be an honest signal . If a male is intending to attack, it adopts a "dark face" change, otherwise, it remains pale. In at least one species, female cuttlefish react to their own reflection in a mirror and to other females by displaying a body pattern called "splotch". However, they do not use this display in response to males, inanimate objects, or prey. This indicates they are able to discriminate same-sex conspecifics , even when human observers are unable to discern
1989-455: A result, the photic zone is the most biodiverse and the source of the food supply which sustains most of the ocean ecosystem . Ocean photosynthesis also produces half of the oxygen in the Earth's atmosphere. Light can only penetrate a few hundred more meters; the rest of the deeper ocean is cold and dark (these zones are called mesopelagic and aphotic zones). The continental shelf is where
2106-496: A shallow area and this, coupled with a low pressure system, can raise the surface of the ocean dramatically above a typical high tide. The average depth of the oceans is about 4 km. More precisely the average depth is 3,688 meters (12,100 ft). Nearly half of the world's marine waters are over 3,000 meters (9,800 ft) deep. "Deep ocean," which is anything below 200 meters (660 ft), covers about 66% of Earth's surface. This figure does not include seas not connected to
2223-527: A shell with a phragmocone divided into chambers separated by septa. The pores provide it with buoyancy , which the cuttlefish regulates by changing the gas-to-liquid ratio in the chambered cuttlebone via the ventral siphuncle . Each species ' cuttlebone has a distinct shape, size, and pattern of ridges or texture. The cuttlebone is unique to cuttlefish, and is one of the features that distinguish them from their squid relatives. Cuttlefish, like other cephalopods, have sophisticated eyes. The organogenesis and
2340-673: A source of white light, they produce a white shine, in red they produce red, and in blue they produce blue. Leucophores assist in camouflage by providing light areas during background matching (e.g. by resembling light-colored objects in the environment) and disruptive coloration (by making the body appear to be composed of high-contrasting patches). The reflectance spectra of cuttlefish patterns and several natural substrates ( stipple , mottle , disruptive ) can be measured using an optic spectrometer . Cuttlefish sometimes use their color patterns to signal future intent to other cuttlefish. For example, during agonistic encounters, male cuttlefish adopt
2457-403: A wave-cut platform develops at the foot of the cliff and this has a protective effect, reducing further wave-erosion. Material worn from the margins of the land eventually ends up in the sea. Here it is subject to attrition as currents flowing parallel to the coast scour out channels and transport sand and pebbles away from their place of origin. Sediment carried to the sea by rivers settles on
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#17327810242102574-406: A zone undergoes dramatic changes in temperature with depth, it contains a thermocline , a distinct boundary between warmer surface water and colder deep water. In tropical regions, the thermocline is typically deeper compared to higher latitudes. Unlike polar waters , where solar energy input is limited, temperature stratification is less pronounced, and a distinct thermocline is often absent. This
2691-439: Is a bay , a small bay with a narrow inlet is a cove and a large bay may be referred to as a gulf . Coastlines are influenced by several factors including the strength of the waves arriving on the shore, the gradient of the land margin, the composition and hardness of the coastal rock, the inclination of the off-shore slope and the changes of the level of the land due to local uplift or submergence. Normally, waves roll towards
2808-410: Is a chambered structure that the animal can fill with gas or liquid for buoyancy control. On the ventral (bottom) side of the cuttlebone is the highly modified siphuncle ; this is the organ with which the cuttlebone is filled with gas or liquid. The microscopic structure of cuttlebone consists of narrow layers connected by numerous upright pillars. Depending on the species, cuttlebones implode at
2925-431: Is about 1–2 years. Studies are said to indicate cuttlefish to be among the most intelligent invertebrates . Cuttlefish also have one of the largest brain-to-body size ratios of all invertebrates. The Greco-Roman world valued the cuttlefish as a source of the unique brown pigment the creature releases from its siphon when it is alarmed. The word for the cuttlefish in both Greek and Latin , sepia , now refers to
3042-743: Is about −2 °C (28 °F). In all parts of the ocean, deep ocean temperatures range between −2 °C (28 °F) and 5 °C (41 °F). Constant circulation of water in the ocean creates ocean currents . Those currents are caused by forces operating on the water, such as temperature and salinity differences, atmospheric circulation (wind), and the Coriolis effect . Tides create tidal currents, while wind and waves cause surface currents. The Gulf Stream , Kuroshio Current , Agulhas Current and Antarctic Circumpolar Current are all major ocean currents. Such currents transport massive amounts of water, gases, pollutants and heat to different parts of
3159-444: Is an important reference point for oceanography and geography, particularly as mean sea level . The ocean surface has globally little, but measurable topography , depending on the ocean's volumes. The ocean surface is a crucial interface for oceanic and atmospheric processes. Allowing interchange of particles, enriching the air and water, as well as grounds by some particles becoming sediments . This interchange has fertilized life in
3276-411: Is customarily divided into five principal oceans – listed below in descending order of area and volume: The ocean fills Earth's oceanic basins . Earth's oceanic basins cover different geologic provinces of Earth's oceanic crust as well as continental crust . As such it covers mainly Earth's structural basins , but also continental shelfs . In mid-ocean, magma is constantly being thrust through
3393-399: Is due to the fact that surface waters in polar latitudes are nearly as cold as deeper waters. Below the thermocline, water everywhere in the ocean is very cold, ranging from −1 °C to 3 °C. Because this deep and cold layer contains the bulk of ocean water, the average temperature of the world ocean is 3.9 °C. If a zone undergoes dramatic changes in salinity with depth, it contains
3510-434: Is inevitable. Cuttlefish are indeterminate growers , so smaller cuttlefish always have a chance of finding a mate the next year when they are bigger. Additionally, cuttlefish unable to win in a direct confrontation with a guard male have been observed employing several other tactics to acquire a mate. The most successful of these methods is camouflage; smaller cuttlefish use their camouflage abilities to disguise themselves as
3627-456: Is irregular, unevenly dominating the Earth's surface . This leads to the distinction of the Earth's surface into a water and land hemisphere , as well as the division of the ocean into different oceans. Seawater covers about 361,000,000 km (139,000,000 sq mi) and the ocean's furthest pole of inaccessibility , known as " Point Nemo ", in a region known as spacecraft cemetery of
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3744-449: Is just as defined. The cuttlefish's wide pupil may accentuate chromatic aberration, allowing it to perceive color by focusing specific wavelengths onto the retina. The three broad categories of color patterns are uniform, mottle, and disruptive. Cuttlefish can display as many as 12 to 14 patterns, 13 of which have been categorized as seven "acute" (relatively brief) and six "chronic" (long-lasting) patterns. although other researchers suggest
3861-454: Is produced and magma is forced up creating underwater mountains, some of which may form chains of volcanic islands near to deep trenches. Near some of the boundaries between the land and sea, the slightly denser oceanic plates slide beneath the continental plates and more subduction trenches are formed. As they grate together, the continental plates are deformed and buckle causing mountain building and seismic activity. Every ocean basin has
3978-407: Is pushed across the surface of the ocean by the wind, but this represents a transfer of energy and not horizontal movement of water. As waves approach land and move into shallow water , they change their behavior. If approaching at an angle, waves may bend ( refraction ) or wrap around rocks and headlands ( diffraction ). When the wave reaches a point where its deepest oscillations of the water contact
4095-423: Is reflected back out of the water. Red light is most easily absorbed and thus does not reach great depths, usually to less than 50 meters (164 ft). Blue light, in comparison, can penetrate up to 200 meters (656 ft). Second, water molecules and very tiny particles in ocean water preferentially scatter blue light more than light of other colors. Blue light scattering by water and tiny particles happens even in
4212-428: Is served as deep-fried strips or in a variant of feijoada , with white beans. Black pasta is often made using cuttlefish ink. Marine (ocean) The ocean is the body of salt water that covers approximately 70.8% of Earth . In English , the term ocean also refers to any of the large bodies of water into which the world ocean is conventionally divided. The following names describe five different areas of
4329-480: Is sometimes referred to as the World Ocean, global ocean or the great ocean . The concept of a continuous body of water with relatively unrestricted exchange between its components is critical in oceanography . The word ocean comes from the figure in classical antiquity , Oceanus ( / oʊ ˈ s iː ə n ə s / ; ‹See Tfd› Greek : Ὠκεανός Ōkeanós , pronounced [ɔːkeanós] ),
4446-552: Is the open ocean's water column from the surface to the ocean floor. The water column is further divided into zones based on depth and the amount of light present. The photic zone starts at the surface and is defined to be "the depth at which light intensity is only 1% of the surface value" (approximately 200 m in the open ocean). This is the zone where photosynthesis can occur. In this process plants and microscopic algae (free floating phytoplankton ) use light, water, carbon dioxide, and nutrients to produce organic matter. As
4563-436: Is thought to communicate to potential prey – "stop and watch me" – which some have interpreted as a type of "hypnosis". Cuttlefish are able to rapidly change the color of their skin to match their surroundings and create chromatically complex patterns, despite their inability to perceive color, through some mechanism which is not completely understood. They have been seen to have the ability to assess their surroundings and match
4680-416: Is thought to have up to 35 distinct signalling states. Cuttlefish are sometimes referred to as the " chameleons of the sea" because of their ability to rapidly alter their skin color – this can occur within one second. Cuttlefish change color and pattern (including the polarization of the reflected light waves), and the shape of the skin to communicate to other cuttlefish, to camouflage themselves, and as
4797-691: The North Sea or the Red Sea . There is no sharp distinction between seas and oceans, though generally seas are smaller, and are often partly (as marginal seas ) or wholly (as inland seas ) bordered by land. The contemporary concept of the World Ocean was coined in the early 20th century by the Russian oceanographer Yuly Shokalsky to refer to the continuous ocean that covers and encircles most of Earth. The global, interconnected body of salt water
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4914-847: The Qing Dynasty manual of Chinese gastronomy , the Suiyuan shidan , the roe of the cuttlefish, is considered a difficult-to-prepare, but sought-after delicacy. Cuttlefish thick soup is a signature dish in Taiwan . Cuttlefish are quite popular in Europe. For example, in northeast Italy, they are used in risotto al nero di seppia (risotto with cuttlefish ink), also found in Croatia and Montenegro as crni rižot (black risotto), and in various recipes (either grilled or stewed) often served together with polenta . Catalan cuisine , especially that of
5031-481: The South Pacific Ocean , at 48°52.6′S 123°23.6′W / 48.8767°S 123.3933°W / -48.8767; -123.3933 ( Point Nemo ) . This point is roughly 2,688 km (1,670 mi) from the nearest land. There are different customs to subdivide the ocean and are adjourned by smaller bodies of water such as, seas , gulfs , bays , bights , and straits . The ocean
5148-592: The Thames Barrier is designed to protect London from a storm surge, while the failure of the dykes and levees around New Orleans during Hurricane Katrina created a humanitarian crisis in the United States. Most of the ocean is blue in color, but in some places the ocean is blue-green, green, or even yellow to brown. Blue ocean color is a result of several factors. First, water preferentially absorbs red light, which means that blue light remains and
5265-406: The coastline and structure of the world ocean. A global ocean has existed in one form or another on Earth for eons. Since its formation the ocean has taken many conditions and shapes with many past ocean divisions and potentially at times covering the whole globe. During colder climatic periods, more ice caps and glaciers form, and enough of the global water supply accumulates as ice to lessen
5382-462: The diffraction of light within the stacked plates. Orientation of the chemochromes determines the nature of the color observed. By using biochromes as colored filters, iridophores create an optical effect known as Tyndall or Rayleigh scattering , producing bright blue or blue-green colors. Iridophores vary in size, but are generally smaller than 1 mm. Squid at least are able to change their iridescence. This takes several seconds or minutes, and
5499-591: The ocean floor , they begin to slow down. This pulls the crests closer together and increases the waves' height , which is called wave shoaling . When the ratio of the wave's height to the water depth increases above a certain limit, it " breaks ", toppling over in a mass of foaming water. This rushes in a sheet up the beach before retreating into the ocean under the influence of gravity. Earthquakes , volcanic eruptions or other major geological disturbances can set off waves that can lead to tsunamis in coastal areas which can be very dangerous. The ocean's surface
5616-442: The Earth's biosphere . Oceanic evaporation , as a phase of the water cycle, is the source of most rainfall (about 90%), causing a global cloud cover of 67% and a consistent oceanic cloud cover of 72%. Ocean temperatures affect climate and wind patterns that affect life on land. One of the most dramatic forms of weather occurs over the oceans: tropical cyclones (also called "typhoons" and "hurricanes" depending upon where
5733-487: The European common squid ( Alloteuthis subulata ) has yellow and red, and the common octopus has yellow, orange, red, brown, and black. In cuttlefish, activation of a chromatophore can expand its surface area by 500%. Up to 200 chromatophores per mm of skin may occur. In Loligo plei , an expanded chromatophore may be up to 1.5 mm in diameter, but when retracted, it can measure as little as 0.1 mm. Retracting
5850-456: The Moon are 20x stronger than the Moon's tidal forces on the Earth.) The primary effect of lunar tidal forces is to bulge Earth matter towards the near and far sides of the Earth, relative to the moon. The "perpendicular" sides, from which the Moon appears in line with the local horizon, experience "tidal troughs". Since it takes nearly 25 hours for the Earth to rotate under the Moon (accounting for
5967-403: The Moon's 28 day orbit around Earth), tides thus cycle over a course of 12.5 hours. However, the rocky continents pose obstacles for the tidal bulges, so the timing of tidal maxima may not actually align with the Moon in most localities on Earth, as the oceans are forced to "dodge" the continents. Timing and magnitude of tides vary widely across the Earth as a result of the continents. Thus, knowing
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#17327810242106084-471: The Moon's gravity, oceanic tides are also substantially modulated by the Sun's tidal forces, by the rotation of the Earth, and by the shape of the rocky continents blocking oceanic water flow. (Tidal forces vary more with distance than the "base" force of gravity: the Moon's tidal forces on Earth are more than double the Sun's, despite the latter's much stronger gravitational force on Earth. Earth's tidal forces upon
6201-400: The Moon's position does not allow a local to predict tide timings, instead requiring precomputed tide tables which account for the continents and the Sun, among others. During each tidal cycle, at any given place the tidal waters rise to maximum height, high tide, before ebbing away again to the minimum level, low tide. As the water recedes, it gradually reveals the foreshore , also known as
6318-648: The Okeanos is represented with a dragon-tail on some early Greek vases. Scientists believe that a sizable quantity of water would have been in the material that formed Earth. Water molecules would have escaped Earth's gravity more easily when it was less massive during its formation. This is called atmospheric escape . During planetary formation , Earth possibly had magma oceans . Subsequently, outgassing , volcanic activity and meteorite impacts , produced an early atmosphere of carbon dioxide , nitrogen and water vapor , according to current theories. The gases and
6435-741: The World Ocean, such as the Caspian Sea . The deepest region of the ocean is at the Mariana Trench , located in the Pacific Ocean near the Northern Mariana Islands . The maximum depth has been estimated to be 10,971 meters (35,994 ft). The British naval vessel Challenger II surveyed the trench in 1951 and named the deepest part of the trench the " Challenger Deep ". In 1960, the Trieste successfully reached
6552-421: The amounts in other parts of the water cycle. The reverse is true during warm periods. During the last ice age, glaciers covered almost one-third of Earth's land mass with the result being that the oceans were about 122 m (400 ft) lower than today. During the last global "warm spell," about 125,000 years ago, the seas were about 5.5 m (18 ft) higher than they are now. About three million years ago
6669-479: The atmosphere are thought to have accumulated over millions of years. After Earth's surface had significantly cooled, the water vapor over time would have condensed, forming Earth's first oceans. The early oceans might have been significantly hotter than today and appeared green due to high iron content. Geological evidence helps constrain the time frame for liquid water existing on Earth. A sample of pillow basalt (a type of rock formed during an underwater eruption)
6786-416: The atmosphere, is cited as a potential threat. Some studies suggest that ocean acidification does not impair normal embryonic development, survival rates or body size. Unlike other cephalopods, cuttlefish possess a unique internal structure called the cuttlebone , a highly modified internal shell, which is porous and is made of aragonite . Except for spirula , they are the only coleoid cephalopods with
6903-408: The best den during mating season. During this challenge, no direct contact is usually made. The animals threaten each other until one of them backs down and swims away. Eventually, the larger male cuttlefish mate with the females by grabbing them with their tentacles, turning the female so that the two animals are face-to-face, then using a specialized tentacle to insert sperm sacs into an opening near
7020-407: The bottom of the trench, manned by a crew of two men. Oceanographers classify the ocean into vertical and horizontal zones based on physical and biological conditions. The pelagic zone consists of the water column of the open ocean, and can be divided into further regions categorized by light abundance and by depth. The ocean zones can be grouped by light penetration into (from top to bottom):
7137-636: The bottom sublayer consists of nanorods rotated with respect to each other to form a " plywood " structure. Overall, this chambered microstructure results in the cuttlebone having a porosity over 90% by volume. The cuttlebone has been studied extensively due to its ability to be simultaneously lightweight, stiff , and tolerant to damage. This combination of mechanical properties has led to research into cuttlebone-inspired biomimetic ceramic foams . In addition, due to its mechanical properties, cuttlebone has been used as scaffolding in superconductors and tissue engineering applications. The light weight of
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#17327810242107254-473: The chromatophore. These are under neural control and when they expand, they reveal the hue of the pigment contained in the sac. Cuttlefish have three types of chromatophore: yellow/orange (the uppermost layer), red, and brown/black (the deepest layer). The cuttlefish can control the contraction and relaxation of the muscles around individual chromatophores, thereby opening or closing the elastic sacs and allowing different levels of pigment to be exposed. Furthermore,
7371-459: The chromatophores contain luminescent protein nanostructures in which tethered pigment granules modify light through absorbance, reflection, and fluorescence between 650 and 720 nm. For cephalopods in general, the hues of the pigment granules are relatively constant within a species, but can vary slightly between species. For example, the common cuttlefish and the opalescent inshore squid ( Doryteuthis opalescens ) have yellow, red, and brown,
7488-414: The chromatophores reveals the iridophores and leucophores beneath them, thereby allowing cuttlefish to use another modality of visual signalling brought about by structural coloration . Iridophores are structures that produce iridescent colors with a metallic sheen. They reflect light using plates of crystalline chemochromes made from guanine . When illuminated, they reflect iridescent colors because of
7605-469: The coastal regions, uses cuttlefish and squid ink in a variety of tapas and dishes such as arròs negre . Breaded and deep-fried cuttlefish is a popular dish in Andalusia . In Portugal , cuttlefish is present in many popular dishes. Chocos com tinta (cuttlefish in black ink), for example, is grilled cuttlefish in a sauce of its own ink. Cuttlefish is also popular in the region of Setúbal , where it
7722-769: The coasts of East and South Asia, Western Europe, and the Mediterranean, as well as all coasts of Africa and Australia, but are totally absent from the Americas. By the time the family evolved, ostensibly in the Old World, the North Atlantic possibly had become too cold and deep for these warm-water species to cross. The common cuttlefish ( Sepia officinalis ), is found in the Mediterranean, North and Baltic seas, although populations may occur as far south as South Africa. They are found in sublittoral depths, between
7839-401: The color, contrast and texture of the substrate even in nearly total darkness. The color variations in the mimicked substrate and animal skin are similar. Depending on the species, the skin of cuttlefish responds to substrate changes in distinctive ways. By changing naturalistic backgrounds, the camouflage responses of different species can be measured. Sepia officinalis changes color to match
7956-423: The cuttlebone derives from its high porosity (over 90% by volume). The stiffness of the cuttlebone arises from the chambered structure composition of approximately 95% aragonite (a stiff material) and 5% organic material . Since the stiffness of a composite will be dominated by the material with the largest volume fraction, the cuttlebone is also stiff. The specific stiffness of the cuttlebone in one species
8073-442: The cuttlebone into separate chambers. These chambers are supported by the vertical pillars which have a corrugated (or "wavy") structure. The thickness of these pillars varies from species to species, but are typically a few microns thick. The horizontal septa are typically thicker than the vertical pillars and consist of a double-layered structure. The upper layer of the septa and walls consist of vertically aligned crystals, whereas
8190-419: The cuttlebone, a process known as densification occurs whereby the walls gradually compact while fracture continues. Significant energy is dissipated in the continued cracking of the walls while densification is occurring. It has also been observed that under compressive stresses, the horizontally layered chambers of the cuttlebone will fail sequentially. While one chamber is undergoing fracture and densification,
8307-407: The cuttlebone. The location of crack formation is controlled by the waviness in the corrugated structure of the walls. The waviness of the walls in the cuttlebone provides an optimized balance between stiffness and brittleness of the overall structure. This wavy structure inhibits crack propagation, increasing the energy input necessary for failure. After sufficient damage has occurred to the walls of
8424-469: The cuttlefish becomes texturally as well as chromatically similar to objects in its environment such as kelp or rocks. While the preferred diet of cuttlefish is crabs and fish, they feed on small shrimp shortly after hatching. Cuttlefish are caught for food in the Mediterranean, East Asia, the English Channel, and elsewhere. In East Asia, dried, shredded cuttlefish is a popular snack food. In
8541-409: The cuttlefish, but use the flamboyant display towards larger, more dangerous fish, and give no display at all to chemosensory predators such as crabs and dogfish. One dynamic pattern shown by cuttlefish is dark mottled waves apparently repeatedly moving down the body of the animals. This has been called the passing cloud pattern. In the common cuttlefish, this is primarily observed during hunting, and
8658-401: The egg. In consequence, they may prefer to hunt the prey they saw before hatching. Cuttlefish have eight arms and two additional elongated tentacles that are used to grasp prey. The elongated tentacles and mantle cavity serve as defense mechanisms; when approached by a predator, the cuttlefish can suck water into its mantle cavity and spread its arms in order to appear larger than normal. Though
8775-509: The elder of the Titans in classical Greek mythology . Oceanus was believed by the ancient Greeks and Romans to be the divine personification of an enormous river encircling the world. The concept of Ōkeanós has an Indo-European connection. Greek Ōkeanós has been compared to the Vedic epithet ā-śáyāna-, predicated of the dragon Vṛtra-, who captured the cows/rivers. Related to this notion,
8892-900: The end of the Cretaceous period, represented by Ceratisepia from the Late Maastrichtian Maastricht Formation of the Netherlands. Although the Jurassic Trachyteuthis was historically considered possibly related to cuttlefish, later studies considered it to be more closely related to octopuses and vampire squids. The family Sepiidae, which contains all cuttlefish, inhabits tropical and temperate ocean waters. They are mostly shallow-water animals, although they are known to go to depths of about 600 m (2,000 ft). They have an unusual biogeographic pattern; they are present along
9009-420: The female's mouth. As males can also use their funnels to flush others' sperm out of the female's pouch, the male then guards the female until she lays the eggs a few hours later. After laying her cluster of eggs, the female cuttlefish secretes ink on them making them look very similar to grapes. The egg case is produced through a complex capsule of the female accessory genital glands and the ink bag. On occasion,
9126-591: The final structure of the cephalopod eye fundamentally differ from those of vertebrates , such as humans. Superficial similarities between cephalopod and vertebrate eyes are thought to be examples of convergent evolution . The cuttlefish pupil is a smoothly curving W-shape. Although cuttlefish cannot see color, they can perceive the polarization of light , which enhances their perception of contrast . They have two spots of concentrated sensor cells on their retinas (known as foveae ), one to look more forward, and one to look more backward. The eye changes focus by shifting
9243-447: The first two months. Before death, cuttlefish go through senescence when the cephalopod essentially deteriorates, or rots in place. Their eyesight begins to fail, which affects their ability to see, move, and hunt efficiently. Once this process begins, cuttlefish tend to not live long due to predation by other organisms. Cuttlefish start to actively mate at around five months of age. Male cuttlefish challenge one another for dominance and
9360-412: The formation of unusually high rogue waves . Most waves are less than 3 m (10 ft) high and it is not unusual for strong storms to double or triple that height. Rogue waves, however, have been documented at heights above 25 meters (82 ft). The top of a wave is known as the crest, the lowest point between waves is the trough and the distance between the crests is the wavelength. The wave
9477-421: The interface between water and air is called swell – a term used in sailing , surfing and navigation . These motions profoundly affect ships on the surface of the ocean and the well-being of people on those ships who might suffer from sea sickness . Wind blowing over the surface of a body of water forms waves that are perpendicular to the direction of the wind. The friction between air and water caused by
9594-482: The intertidal zone. The difference in height between the high tide and low tide is known as the tidal range or tidal amplitude. When the sun and moon are aligned (full moon or new moon), the combined effect results in the higher "spring tides", while the sun and moon misaligning (half moons) result in lesser tidal ranges. In the open ocean tidal ranges are less than 1 meter, but in coastal areas these tidal ranges increase to more than 10 meters in some areas. Some of
9711-400: The largest species , the giant cuttlefish ( Sepia apama ), reaching 50 cm (20 in) in mantle length and over 10.5 kg (23 lb) in mass. Cuttlefish eat small molluscs, crabs, shrimp, fish, octopuses, worms, and other cuttlefish. Their predators include dolphins, larger fish (including sharks), seals, seabirds, and other cuttlefish. The typical life expectancy of a cuttlefish
9828-739: The largest tidal ranges in the world occur in the Bay of Fundy and Ungava Bay in Canada, reaching up to 16 meters. Other locations with record high tidal ranges include the Bristol Channel between England and Wales, Cook Inlet in Alaska, and the Río Gallegos in Argentina. Tides are not to be confused with storm surges , which can occur when high winds pile water up against the coast in
9945-622: The low tide line and the edge of the continental shelf, to about 180 m (600 ft). The cuttlefish is listed under the Red List category of "least concern" by the IUCN Red List of Threatened Species. This means that while some over-exploitation of the marine animal has occurred in some regions due to large-scale commercial fishing, their wide geographic range prevents them from being too threatened. Ocean acidification, however, caused largely by higher levels of carbon dioxide emitted into
10062-471: The majority of Earth's surface. It includes the Pacific , Atlantic , Indian , Southern/Antarctic , and Arctic oceans. As a general term, "the ocean" and "the sea" are often interchangeable. Strictly speaking, a "sea" is a body of water (generally a division of the world ocean) partly or fully enclosed by land. The word "sea" can also be used for many specific, much smaller bodies of seawater, such as
10179-475: The mantle cavity is used for jet propulsion, the main parts of the body that are used for basic mobility are the fins, which can maneuver the cuttlefish in all directions. The suckers of cuttlefish extend most of the length of their arms and along the distal portion of their tentacles. Like other cephalopods, cuttlefish have "taste-by-touch" sensitivity in their suckers, allowing them to discriminate among objects and water currents that they contact. The blood of
10296-520: The mechanism is not understood. However, iridescence can also be altered by expanding and retracting the chromatophores above the iridophores. Because chromatophores are under direct neural control from the brain, this effect can be immediate. Cephalopod iridophores polarize light. Cephalopods have a rhabdomeric visual system which means they are visually sensitive to polarized light. Cuttlefish use their polarization vision when hunting for silvery fish (their scales polarize light). Female cuttlefish exhibit
10413-612: The muscles of the flamboyant cuttlefish ( Metasepia pfefferi ) contain a highly toxic, unidentified compound as lethal as the venom of fellow cephalopod, the blue-ringed octopus . However, this toxin is found only in the muscle and is not injected in any form, classifying it as poisonous, not venomous. Sleep is a state of immobility characterized by being rapidly reversible, homeostatically controlled, and increasing an organism's arousal threshold. To date one cephalopod species, Octopus vulgaris , has been shown to satisfy these criteria. Another species, Sepia officinalis , satisfies two of
10530-408: The ocean faces many environmental threats, such as marine pollution , overfishing , and the effects of climate change . Those effects include ocean warming , ocean acidification and sea level rise . The continental shelf and coastal waters are most affected by human activity. The terms "the ocean" or "the sea" used without specification refer to the interconnected body of salt water covering
10647-423: The ocean meets dry land. It is more shallow, with a depth of a few hundred meters or less. Human activity often has negative impacts on marine life within the continental shelf. Ocean temperatures depend on the amount of solar radiation reaching the ocean surface. In the tropics, surface temperatures can rise to over 30 °C (86 °F). Near the poles where sea ice forms, the temperature in equilibrium
10764-508: The ocean, on land and air. All these processes and components together make up ocean surface ecosystems . Tides are the regular rise and fall in water level experienced by oceans, primarily driven by the Moon 's gravitational tidal forces upon the Earth. Tidal forces affect all matter on Earth, but only fluids like the ocean demonstrate the effects on human timescales. (For example, tidal forces acting on rock may produce tidal locking between two planetary bodies.) Though primarily driven by
10881-469: The ocean. If the wind dies down, the wave formation is reduced, but already-formed waves continue to travel in their original direction until they meet land. The size of the waves depends on the fetch , the distance that the wind has blown over the water and the strength and duration of that wind. When waves meet others coming from different directions, interference between the two can produce broken, irregular seas. Constructive interference can lead to
10998-493: The ocean: Pacific , Atlantic , Indian , Antarctic/Southern , and Arctic . The ocean contains 97% of Earth's water and is the primary component of Earth's hydrosphere and is thereby essential to life on Earth. The ocean influences climate and weather patterns, the carbon cycle , and the water cycle by acting as a huge heat reservoir . Ocean scientists split the ocean into vertical and horizontal zones based on physical and biological conditions. The pelagic zone
11115-419: The oceans absorb CO 2 from the atmosphere , a higher concentration leads to ocean acidification (a drop in pH value ). The ocean provides many benefits to humans such as ecosystem services , access to seafood and other marine resources , and a means of transport . The ocean is known to be the habitat of over 230,000 species , but may hold considerably more – perhaps over two million species. Yet,
11232-425: The oceans could have been up to 50 m (165 ft) higher. The entire ocean, containing 97% of Earth's water, spans 70.8% of Earth 's surface, making it Earth's global ocean or world ocean . This makes Earth, along with its vibrant hydrosphere a "water world" or " ocean world ", particularly in Earth's early history when the ocean is thought to have possibly covered Earth completely. The ocean's shape
11349-434: The oceans have been mapped. The zone where land meets sea is known as the coast , and the part between the lowest spring tides and the upper limit reached by splashing waves is the shore . A beach is the accumulation of sand or shingle on the shore. A headland is a point of land jutting out into the sea and a larger promontory is known as a cape . The indentation of a coastline, especially between two headlands,
11466-537: The oceans may have always been on the Earth since the beginning of the planet's formation. In this model, atmospheric greenhouse gases kept the oceans from freezing when the newly forming Sun had only 70% of its current luminosity . The origin of Earth's oceans is unknown. Oceans are thought to have formed in the Hadean eon and may have been the cause for the emergence of life . Plate tectonics , post-glacial rebound , and sea level rise continually change
11583-446: The patterns occur on a continuum. The color-changing ability of cuttlefish is due to multiple types of cells. These are arranged (from the skin's surface going deeper) as pigmented chromatophores above a layer of reflective iridophores and below them, leucophores . The chromatophores are sacs containing hundreds of thousands of pigment granules and a large membrane that is folded when retracted. Hundreds of muscles radiate from
11700-451: The photic zone, the mesopelagic zone and the aphotic deep ocean zone: The pelagic part of the aphotic zone can be further divided into vertical regions according to depth and temperature: Distinct boundaries between ocean surface waters and deep waters can be drawn based on the properties of the water. These boundaries are called thermoclines (temperature), haloclines (salinity), chemoclines (chemistry), and pycnoclines (density). If
11817-482: The position of the entire lens with respect to the retina, instead of reshaping the lens as in mammals. Unlike the vertebrate eye, no blind spot exists, because the optic nerve is positioned behind the retina. They are capable of using stereopsis , enabling them to discern depth/distance because their brain calculates the input from both eyes. The cuttlefish's eyes are thought to be fully developed before birth, and they start observing their surroundings while still in
11934-418: The power of a storm wave impacting on the foot of a cliff has a shattering effect as air in cracks and crevices is compressed and then expands rapidly with release of pressure. At the same time, sand and pebbles have an erosive effect as they are thrown against the rocks. This tends to undercut the cliff, and normal weathering processes such as the action of frost follows, causing further destruction. Gradually,
12051-501: The production of calcitic lime . Because cuttlebone is able to withstand high temperatures and is easily carved, it serves as mold-making material for small metal castings for the creation of jewelry and small sculptural objects. It can also be used in the process of pewter casting, as a mould. The microstructure of the cuttlebone consists of two components, horizontal septa and vertical pillars. Both components are composed predominantly of aragonite . The horizontal septa divide
12168-733: The reddish-brown color sepia in English. "Cuttle" in "cuttlefish", sometimes called "cuttles", is derived from the Old English name for the species, cudele . The word may be cognate with the Old Norse koddi (cushion) and the Middle Low German Kudel (rag). Over 120 species of cuttlefish are currently recognized, grouped into six families divided between two suborders. One superfamily and three families are extinct. The earliest fossils of cuttlefish are from
12285-413: The sand and appear one way, with another animal a few feet away in a slightly different microhabitat , settled in algae for example, will be camouflaged quite differently. Cuttlefish are also able to change the texture of their skin. The skin contains bands of circular muscle which as they contract, push fluid up. These can be seen as little spikes, bumps, or flat blades. This can help with camouflage when
12402-455: The seabed between adjoining plates to form mid-oceanic ridges and here convection currents within the mantle tend to drive the two plates apart. Parallel to these ridges and nearer the coasts, one oceanic plate may slide beneath another oceanic plate in a process known as subduction . Deep trenches are formed here and the process is accompanied by friction as the plates grind together. The movement proceeds in jerks which cause earthquakes, heat
12519-407: The seabed causing deltas to form in estuaries. All these materials move back and forth under the influence of waves, tides and currents. Dredging removes material and deepens channels but may have unexpected effects elsewhere on the coastline. Governments make efforts to prevent flooding of the land by the building of breakwaters , seawalls , dykes and levees and other sea defences. For instance,
12636-478: The sex of a cuttlefish in the absence of sexual dimorphism . Female cuttlefish signal their receptivity to mating using a display called precopulatory grey. Male cuttlefish sometimes use deception toward guarding males to mate with females. Small males hide their sexually dimorphic fourth arms, change their skin pattern to the mottled appearance of females, and change the shape of their arms to mimic those of nonreceptive, egg-laying females. Displays on one side of
12753-401: The shore at the rate of six to eight per minute and these are known as constructive waves as they tend to move material up the beach and have little erosive effect. Storm waves arrive on shore in rapid succession and are known as destructive waves as the swash moves beach material seawards. Under their influence, the sand and shingle on the beach is ground together and abraded. Around high tide,
12870-409: The substrate by disruptive patterning (contrast to break up the outline), whereas S. pharaonis matches the substrate by blending in. Although camouflage is achieved in different ways, and in an absence of color vision, both species change their skin colors to match the substrate. Cuttlefish adapt their own camouflage pattern in ways that are specific for a particular habitat. An animal could settle in
12987-456: The system forms). As the world's ocean is the principal component of Earth's hydrosphere , it is integral to life on Earth, forms part of the carbon cycle and water cycle , and – as a huge heat reservoir – influences climate and weather patterns. The motions of the ocean surface, known as undulations or wind waves , are the partial and alternate rising and falling of the ocean surface. The series of mechanical waves that propagate along
13104-501: The three criteria but has not yet been tested on the third (arousal threshold). Recent research shows that the sleep-like state in a common species of cuttlefish, Sepia officinalis , shows predictable periods of rapid eye movement, arm twitching and rapid chromatophore changes. The lifespan of a cuttlefish is typically around one to two years, depending on the species. They hatch from eggs fully developed, around 6 mm ( 1 ⁄ 4 in) long, reaching 25 mm (1 in) around
13221-434: The very clearest ocean water, and is similar to blue light scattering in the sky . Ocean water represents the largest body of water within the global water cycle (oceans contain 97% of Earth's water ). Evaporation from the ocean moves water into the atmosphere to later rain back down onto land and the ocean. Oceans have a significant effect on the biosphere . The ocean as a whole is thought to cover approximately 90% of
13338-476: The world, and from the surface into the deep ocean. All this has impacts on the global climate system . Ocean water contains dissolved gases, including oxygen , carbon dioxide and nitrogen . An exchange of these gases occurs at the ocean's surface. The solubility of these gases depends on the temperature and salinity of the water. The carbon dioxide concentration in the atmosphere is rising due to CO 2 emissions , mainly from fossil fuel combustion. As
13455-508: Was measured to be as high as 8.4 [(MN)m/kg]. The most intriguing property of cuttlebone is its ability to tolerate damage given that aragonite is a brittle material. The high tolerance to damage can be linked to the cuttlebone's unique microstructure . Due to the marine lifestyle of the cuttlefish, the cuttlebone must be capable of both withstanding large compressive forces from the water while avoiding sudden brittle failure . The cuttlebone of some species under compression has demonstrated
13572-775: Was recovered from the Isua Greenstone Belt and provides evidence that water existed on Earth 3.8 billion years ago. In the Nuvvuagittuq Greenstone Belt , Quebec , Canada, rocks dated at 3.8 billion years old by one study and 4.28 billion years old by another show evidence of the presence of water at these ages. If oceans existed earlier than this, any geological evidence either has yet to be discovered, or has since been destroyed by geological processes like crustal recycling . However, in August 2020, researchers reported that sufficient water to fill
13689-463: Was used as an antacid for medicinal purposes or as an absorbent . They were also used as an artistic carving medium during the 19th and 20th centuries. Today, cuttlebones are commonly used as calcium -rich dietary supplements for caged birds , chinchillas , hermit crabs , reptiles , shrimp , and snails . These are not intended for human consumption. As a carbonate-rich biogenic raw material, cuttlebone has potential to be used in
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