Tuesday, November 30, 2010
Census of Marine Life
The first Census of Marine Life produced the most comprehensive inventory of known marine life ever compiled and cataloged it as a basis for future research—28 million records and counting! This first baseline picture of ocean life—past, present, and future—can be used to forecast, measure, and understand changes in the global marine environment, as well as to inform the management and conservation of marine resources. The Census investigated life in the global ocean from microbes to whales, from top to bottom, from pole to pole, bringing together the world’s preeminent marine biologists, who shared ideas, data, and results. During their 10 years of discovery, Census scientists discovered new species, habitats, and connections and unlocked many of the ocean’s long-held secrets. They found and formally described more than1, 200 new marine species, with another 5,000 or more in the pipeline awaiting formal description. They discovered areas in the ocean where animals congregate, from white shark cafés in the open ocean to an evening rush hour in the Mid-Atlantic Ridge to a shoal of fish the size of Manhattan off the coast of New Jersey, USA. They unearthed a rare biosphere in the microbial world, where scarce species lie in wait to become dominant if change goes their way, and found species believed to reside at both poles. While unlocking many secrets, investigators also documented long-term and widespread declines in marine life as well as resilience of the ocean in areas where recovery was apparent.
Along with secrets came surprises. The existence of giant mats of microbes, ranked among Earth’s largest masses of life, a Jurassic shrimp (Neoglyphea neocaledonica) thought to have been extinct 50 million years ago, and multi-cellular animals (three species of the animal phylum Loricifera) thriving without oxygen at sea bottom, where only microbes were thought to survive, were but a few of the astonishing discoveries over the decadal study.
Along with surprises came extremes. Census scientists, for example, uncovered the deepest, hottest, most northerly and most southerly hydrothermal “black smoker” vents known to science, found the world’s largest biotic ecosystem created by a single type of organism, and traveled along as a sooty shearwater chased endless summer on its 64,000-kilometer (40,000-mile) pole-to-pole journey. Scientists also reported the existence of everything from a giant squid to 38,000 different kinds of bacteria in a liter of seawater. The implications of these discoveries reveal the extent of the unknown.
Related Articles : Oceana
Monday, November 29, 2010
Gonostomatidae is a family of deep-water marine fish, commonly named bristlemouths, lightfishes or anglemouths. It is a relatively small family, containing only eight known genera and 32 species. However, bristlemouths make up for their lack of diversity with numbers: Cyclothone, with 12 species, is thought to be (along with Vinciguerria), the most abundant vertebrate genus in the world.
The fossil record of this family dates back to the Miocene epoch, and was discovered by L. S. Berg in 1958. The fish are mostly found in the Atlantic Ocean, Indian Ocean and Pacific Ocean, although the species Cyclothone microdon may be found in Arctic waters. They have elongated bodies from 2 centimetres (0.79 in) to 30 centimetres (12 in) in length. They have a number of green or red light-producing photophores aligned along the undersides of their heads or bodies. Their chief common name, bristlemouth, comes from their odd equally-sized and bristle-like teeth. Due to the depth in which they live, where very little light penetrates, the fish is typically colored black so as to hide from prey.
Sunday, November 28, 2010
The hammerhead sharks are a group of sharks in the family Sphyrnidae, so named for the unusual and distinctive structure of their heads, which are flattened and laterally extended into a "hammer" shape called a "cephalofoil". Most hammerhead species are placed in the genus Sphyrna; some authorities place the winghead shark in its own genus, Eusphyra. Many, not necessarily mutually exclusive, functions have been proposed for the cephalofoil, including sensory reception, maneuvering, and prey manipulation. Hammerheads are found worldwide in warmer waters along coastlines and continental shelves. Unlike most sharks, hammerheads usually swim in schools. Some of these schools can be found near Malpelo Island in Colombia, the Cocos Islands by Costa Rica and near Molokai Island in Hawaii.
The nine known species range from 0.9 to 6 m (3.0 to 20 ft) long. The average hammerhead shark weighs about 500 pounds, but some may grow up to 1000. All the species have a projection of their face on all sides of the head that gives it a resemblance to a flattened hammer.
It was determined recently that the hammer-like shape of the head evolved to enhance the animal's vision. The positioning of the eyes give the shark good binocular vision, as well as 360-degree vision in the vertical plane, meaning they can see above and below them at all times. The shape of the head was previously thought to help the shark find food, aiding in close-quarters maneuverability and allowing sharp turning movement without losing stability. However, it was found that the unusual structure of its vertebrae allowed it to make the turns correctly, more often than its head. The hammer would also shift and provide lift.
Hammerheads are one of the most negatively buoyant of sharks. Like all sharks, hammerheads have electroreceptory sensory pores called ampullae of Lorenzini. By distributing the receptors over a wider area, hammerheads can sweep for prey more effectively. These sharks have been able to detect an electrical signal of half a billionth of a volt. The hammer also allows the nostrils to be placed farther apart, increasing its ability to detect chemical gradients and localize the source.
Hammerheads have disproportionately small mouths and seem to do a lot of bottom-hunting. They are also known to form schools during the day, sometimes in groups of over 100. In the evening, like other sharks, they become solitary hunters.
Hammerheads are notably one of the few animals that acquire a tan from prolonged exposure to sunlight. Tanning occurs when a hammerhead is in shallow waters or close to the surface for long periods.
Saturday, November 27, 2010
Lanternfishes (or myctophids, from the Greek mykter, "nose" and ophis, "serpent") are small, deep sea fish of the large family Myctophidae. One of two families in the order Myctophiformes, the Myctophidae are represented by 246 species in 33 genera, and are found in oceans worldwide. They are aptly named after their conspicuous use of bioluminescence. Their sister family, the Neoscopelidae, are much fewer in number but superficially very similar; at least one neoscopelid shares the common name 'lanternfish': the large-scaled lantern fish, Neoscopelus macrolepidotus.
Sampling via deep trawling indicates that lanternfish account for as much as 65% of all deep sea fish biomass. Indeed, lanternfish are among the most widely distributed, populous, and diverse of all vertebrates, playing an important ecological role as prey for larger organisms. With an estimated global biomass of 550 - 660 million metric tonnes, several times the entire world fisheries catch, lanternfish also account for much of the biomass responsible for the deep scattering layer of the world's oceans. In the Southern Ocean, myctophids provide an alternative food resource to krill for predators such as squid and the king penguin. Although plentiful and prolific, currently only a few commercial lanternfish fisheries exist: limited operations off South Africa, in the sub-Antarctic, and in the Gulf of Oman.
In all but one species, Taaningichthys paurolychnus, a number of photophores (light-producing organs) are present; these are paired and concentrated in ventrolateral rows on the body and head. Some may also possess specialised photophores on the caudal peduncle, in proximity to the eyes (e.g., the "headlights" of Diaphus species), and luminous patches at the base of the fins. The photophores emit a weak blue, green, or yellow light, and are known to be arranged in species-specific patterns. In some species, the pattern varies between males and females. This is true for the luminous caudal patches, with the males' being typically above the tail and the females' being below the tail.
Friday, November 26, 2010
The tube-eye or thread-tail, Stylephorus chordatus, is a deep-sea Stylephoriformes fish, the only fish in the genus Stylephorus and family Stylephoridae.
It is found in deep subtropical and tropical waters around the world, living at depths during the day and making nightly vertical migrations to feed on plankton. It is an extremely elongated fish: although its body grows only to 28 centimetres (11 in) long, it has a pair of tail fin rays that triple its length to about 90 centimetres (35 in). Its eyes are tubular in shape, resembling a pair of binoculars.
It has a tubular mouth through which it sucks seawater by enlarging its oral cavity to about forty times its original size. It then expels the water through the gills, leaving behind the copepods on which it feeds.
The tube-eye was previously thought to be related to Lampridiformes, a group of other bizzarre fishes. However it has now been placed in a new order, named Stylephoriformes.
Thursday, November 25, 2010
The Ctenophora (pronounced /tɨˈnɒfərə/, singular ctenophore, pronounced /ˈtɛnəfɔər/ or /ˈtiːnəfɔər/), (from the Greek ctena/χτένα (comb), phero/φέρω (carry) commonly known as comb jellies, are a phylum of animals that live in marine waters worldwide. Their most distinctive feature is the "combs", groups of cilia that they use for swimming, and they are the largest animals that swim by means of cilia — adults of various species range from a few millimeters to 1.5 meters (59 in) in size. Like cnidarians, their bodies consist of a mass of jelly with one layer of cells on the outside and another lining the internal cavity. In ctenophores these layers are two cells deep while those in cnidarians are only one cell deep. Ctenophores also resemble cnidarians in having a decentralized nerve net rather than a brain. Some authors combined ctenophores and cnidarians in one phylum, Coelenterata, as both groups rely on water flow through the body cavity for both digestion and respiration. Increasing awareness of the differences persuaded more recent authors to classify them in separate phyla.
Almost all ctenophores are predators, taking prey ranging from microscopic larvae and rotifers to the adults of small crustaceans; the exceptions are juveniles of two species, which live as parasites on the salps on which adults of their species feed. In favorable circumstances ctenophores can eat ten times their own weight in a day. There are only 100–150 valid species and possibly another 25 that have not been fully described and named. The textbook examples are cydippids with egg-shaped bodies and a pair of retractable tentacles fringed with tentilla ("little tentacles") that are covered with colloblasts, sticky cells that capture prey. The phylum has a wide range of body forms, including the flattened deep-sea platyctenids, in which the adults of most species lack combs, and the coastal beroids, which lack tentacles and prey on other ctenophores by using huge mouths armed with groups of large, stiffened cilia that act as teeth. These variations enable different species to build huge populations in the same area, because they specialize in different types of prey, which they capture by as wide a range of methods as spiders use.
Despite their soft, gelatinous bodies, fossils thought to represent ctenophores, apparently with no tentacles but many more comb-rows than modern forms, have been found in lagerstätten as far back as the early Cambrian, about . The position of the ctenophores in the evolutionary family tree of animals has long been debated, and the majority view at present, based on molecular phylogenetics, is that cnidarians and bilaterians are more closely related to each other than either is to ctenophores. A recent molecular phylogenetics analysis concluded that the common ancestor of all modern ctenophores was cydippid-like, and that all the modern groups appeared relatively recently, probably after the Cretaceous-Tertiary extinction . Evidence accumulating since the 1980s indicates that the "cydippids" are not monophyletic, in other words do not include all and only the descendants of a single common ancestor, because all the other traditional ctenophore groups are descendants of various cydippids.
Wednesday, November 24, 2010
The original Maelstrom (described by Poe and others) is the Moskstraumen, a powerful tidal current in the Lofoten Islands off the Norwegian coast. The Maelstrom is formed by the conjunction of the strong currents that cross the Straits (Moskenstraumen) between the islands and the great amplitude of the tides. The Maelstrom’s name comes from the Dutch words malen, to crush and stroom, meaning current.
In Norwegian the most frequently used name is Moskstraumen or Moskenstraumen (current of [island] Mosken).
The fictional depictions of the Maelstrom by Edgar Allan Poe and Jules Verne describe it as a gigantic circular vortex that reaches the bottom of the ocean, when in fact it is a set of currents and crosscurrents with a rate of 18 km.
Two of the most notable literary references to the Lofoten Maelstrom date from the nineteenth century. The first is the Edgar Allan Poe story "A Descent into the Maelström" (1841). The second is 20,000 Leagues Under the Sea (1869), the famous novel by Jules Verne. At the end of this novel, Captain Nemo seems to commit suicide, sending his Nautilus submarine into the Maelstrom (although in Verne's sequel Nemo and Nautilus survived).
In Spanish and other languages, Maelstrom is used as a synonym for whirlpool. Hence, the word "Maelstrom" appears in diverse contexts metaphorically to make reference to different subjects or objects that suggest great chaotic or sinister forces. The word maelstrom is used to denote powerful, inescapable destructive forces.
Greek Poet Homer describes a maelstrom in his "Odyssey" as Odysseus must choose to sail near the six-headed monster Scylla, or near the whirlpool Charybdis in order to reach Ithaca.
Tuesday, November 23, 2010
Siamese Fighting Fish
The Siamese fighting fish (Betta splendens), also known as the betta (particularly in the US) and simply as the fighter, is a popular species of freshwater aquarium fish. The name of the genus is derived from ikan bettah, taken from a local dialect of Thailand (Siam). Betta is pronounced /ˈbɛtə/. The wild ancestors of this fish are native to the rice paddies of Thailand, peninsular Malaysia and Cambodia and are called pla-kad or trey krem ("Fighting Fish") in Thai.
Males and females flare or puff out their gill covers (opercula) in order to appear more impressive, either to intimidate other rivals or as an act of courtship. Other reasons for flaring their gills is that they are startled by movement or change of scene in their environment. Both sexes will display horizontal bars (unless they are too light a color for this to show) if stressed or frightened; however, such a color change, common in females of any age, is very rare in mature males. Females often flare their gills at other females, especially when setting up a pecking order. Flirting fish behave similarly, with vertical instead of horizontal stripes indicating a willingness and readiness to breed (females only). Bettas sometimes require a place to hide, even in the absence of threats. They may set up a territory centered on a plant or rocky alcove, sometimes becoming highly possessive of it and aggressive toward trespassing rivals.
On average, males are more aggressive. The aggression of this fish has been studied by ethologists and comparative psychologists. Siamese fighting fish will even respond aggressively to their own reflections in a mirror; use of a mirror avoids the risk of physical damage inherent in actual conflict, although it can lead to stress in some individuals. Like other fish, the fighter may respond to the presence of humans and become trained to respond to feeding cues (such as a hand placed over the water's surface). They are quite curious and will watch humans going about their business nearby. When plant leaves reach the surface, they are useful for males to base their bubble nests on.
Monday, November 22, 2010
Phronima is a small, deep sea hyperiid amphipod of the family Phronimidae. It is found throughout the world's oceans, except in polar regions. The body of Phronima is transparent. Females attack salps, using their mouth and claws to eat the animal and hollow out its gelatinous shell. She then enters the barrel and lays her eggs inside. She then propels the barrel through the water as the larvae develop, providing them with fresh food and water.
Related Articles : Amphipods and Sandhopper
Sunday, November 21, 2010
The footballfish are a family, Himantolophidae, of globose, deep-sea anglerfishes found in tropical and subtropical waters of the Atlantic, Indian, and Pacific Ocean. The family contains c. 19 species all in a single genus, Himantolophus (from the Greek imantos, "thong, strap", and lophos, "crest").
As in other deep-sea anglerfish families, sexual dimorphism is extreme: the largest females may exceed lengths of 60 cm (two feet) and are globose in shape, whereas males do not exceed 4 cm (1.5 inches) as adults and are comparatively fusiform. Their flesh is gelatinous, but thickens in the larger females, which also possess a covering of "bucklers" — round, bony plates each with a median spine — that are absent in males. Both are a reddish brown to black in life.
The football fish was first discovered in the early 1900s by deep sea fisherman in search of flounder.Their poor musculature and cumbersome morphology indicate that female footballfish at least are probably poor swimmers and largely sedentary, lie-in-wait predators. They are primarily mesopelagic, living in open water, with very few caught below 1,000 m (3,280 ft). Females are carnivorous and feed upon other pelagic fish (such as lanternfishes and ridgeheads) and cephalopods, as well as shrimp and euphausiids that are presumably attracted to within striking distance by the footballfish' luminous lure.
Saturday, November 20, 2010
In October 2007, US and Filipino scientists travelled to the Celebes Sea in south-east Asia, searching for new species living in its deep water. When they discovered this extraordinary worm - which they named "squidworm" - they knew they had something completely different.
Friday, November 19, 2010
Talitrus saltator, a species of sand hopper, is a common amphipod crustacean of sandy coasts around Europe. The animal's typical "hopping" movement gives the animal its common name, and is produced by a flexion of the abdomen. In order to do this, it must stand on its legs (amphipods usually rest on their sides) and suddenly extend its abdomen out from under its body. It can thus leap several inches into the air, although without any control over its direction. A great deal of scientific research has been carried out on the animal, to determine the environmental cues it uses to control its behaviour.
Talitrus saltator reaches lengths between 8.2 mm (0.32 in) and 16.5 mm (0.65 in), with males being slightly larger than females. The body is greyish-brown or greyish-green in colour, with a single pair of black eyes. It has a distinct pair of antennae, with one antenna more robust than the other.
Talitrus saltator is found around the coasts of the North Sea and north-east Atlantic Ocean from southern Norway to the Mediterranean Sea. In most of its range, its daily cycle is strongly linked to the tides, with daily migrations of up to 100 m (328 ft), but where there are no significant tides (as in parts of the Mediterranean), visual cues are used instead.
Related Articles : Pram Bug and Amphipods
Thursday, November 18, 2010
Arowanas are freshwater bony fish of the family Osteoglossidae, also known as bonytongues. In this family of fishes, the head is bony and the elongate body is covered by large, heavy scales, with a mosaic pattern of canals. The dorsal and the anal fins have soft rays and are long based, while the pectoral and ventral fins are small. The name "bonytongues" is derived from a toothed bone on the floor of the mouth, the "tongue", equipped with teeth that bite against teeth on the roof of the mouth. The fish can obtain oxygen from air by sucking it into the swim bladder, which is lined with capillaries like lung tissue. The arowana is an "obligatory air breather".
Osteoglossids are carnivorous, often being specialized surface feeders. They are excellent jumpers; it has been reported that Osteoglossum species have been seen leaping more than 6 feet (almost 2 metres) from the water surface to pick off insects and birds from overhanging branches in South America, hence the nickname "water monkeys". Arowanas have been rumored to capture prey as large as low flying bats. All species are large, and the arapaima is one of the world's largest freshwater fish, at 2.5 metres (8.2 ft) in length. Arowana species typically grow to around 3 to 4 feet in captivity.
Several species of osteoglossid exhibit extensive parental care. They build nests and protect the young after they hatch. Some species are mouthbrooders, the parents holding sometimes hundreds of eggs in their mouths. The young may make several tentative trips outside the parent's mouth to investigate the surroundings before leaving permanently.These fishes are best kept with live feed and they easily outgrow the tank within a span of 8/10 months. Always preferred in a large type aquarium.
Wednesday, November 17, 2010
Strait of Magellan
The Strait of Magellan (also called the Straits of Magellan or the Magellanic Strait) comprises a navigable sea route immediately south of mainland South America and north of Tierra del Fuego. The waterway is the most important natural passage between the Pacific and the Atlantic oceans, but it is considered a difficult route to navigate because of the unpredictable winds and currents and the narrowness of the passage.
Ferdinand Magellan (the original name, in Portuguese, Fernão de Magalhães), a Portuguese sailor in service to the Spanish King, became the first European to navigate the strait in 1520, during his global circumnavigation voyage. Because Magellan's ships entered it on November 1, All Saints' Day, it was originally named Estrecho de Todos los Santos (Strait of All Saints). Later the Spanish king changed the name to Estrecho de Magallanes in honor of Magellan. Since its discovery the Spanish Empire and the Kingdom of Chile saw it as its southern boundary. The first Spanish colonization attempt was led by Pedro Sarmiento de Gamboa who founded Nombre de Jesús and Rey Don Felipe on its northern shores. The cities suffered severe food shortages, and years afterwards in 1587 the English navigator Sir Thomas Cavendish landed at the site of Rey Don Felipe and found only ruins of the settlement. He renamed the place Port Famine. Other early explorers included Francis Drake. The strait was first carefully explored and thoroughly charted by Phillip Parker King, who commanded the British survey vessel HMS Adventure, and in company with HMS Beagle, spent five years surveying the complex coasts around the strait. The result was presented at a meeting of the Royal Geographical Society in 1831.
Tuesday, November 16, 2010
The brittle star Ophiocoma wendtii inhabits coral reefs from Bermuda to Brazil. It is known for its advanced compound eyes.
Brittle stars have long, thin arms emanating from a small, disk-shaped body and are about the size of an outstretched human hand. They belong to the phylum of echinoderms, which includes sea urchins, sea cucumbers, and sea stars.
Its arms are covered with calcite crystals. In addition to functioning as an armor and giving structural support, the crystals make up its unique visual systems. They minimize spherical aberration and can detect the direction of incoming light. The lenses work by filtering and focusing light on an underlying photoreceptor system. Nerve bundles under each lens, presumed to be light-sensitive, transmit the optical information to the rest of the nervous system.
The only known animals to employ a similar visual system were the now-extinct trilobites. Phototropic chromatophores can change O. wendtii's color and regulate how much light will reach the photoreceptors.
Monday, November 15, 2010
Halibut is a flatfish of the genus Hippoglossus from the family of the right-eye flounders (Pleuronectidae). Various other flatfish are also commonly called halibut. The name is derived from haly (holy) and butt (flat fish), for its alleged popularity on Catholic holy-days. Halibut live in both the North Pacific and the North Atlantic oceans and are highly-regarded food fish.
The halibut is the largest flat fish, averaging 11–13.5 kilograms (24–30 lb), but catch as large as 333 kilograms (734 lb) have been reported; the largest recently recorded was 211 kilograms (470 lb) and 2.5 metres (8.2 ft) long. They are gray-black on the top side with an off-white underbelly. At birth they have an eye on each side of the head, and swim like a salmon. After about 6 months one eye migrates to the other side, making them look more like other flounder. At the same time the stationary-eyed side darkens to match the top side, while the other side remains white. This color scheme disguises halibut from above (blending with the ocean floor) and from below (blending into the light from the sky) and is known as countershading.
Sunday, November 14, 2010
Saturday, November 13, 2010
The ribbon eel, Rhinomuraena quaesita, or Bernis eel, is a species of saltwater eel, the only member of the genus Rhinomuraena of the Muraenidae (Moray eel) family of order Anguilliformes. What is now known as Rhinomuraena quaesita also includes the former Rhinomuraena amboinensis. R. quaesita was used for blue ribbon eels and R. amboinensis for black ribbon eels, but these are now recognized as the same species. The ribbon eel is native to the Indian and Pacific oceans.
The ribbon eel is an elegant creature with a long, thin body and high dorsal fins. The ribbon eel can easily be recognised by its expanded anterior nostrils. Juveniles and sub-adults are jet black with a yellow dorsal fin, while females are yellow with a black anal fin with white margins on the fins. The adult males are blue with a yellow dorsal fin.
The ribbon eel grows to an overall length of approximately 100 cm (36 in), and has a life span of up to twenty years. The ribbon eel is the only moray eel that is not gonochoristic.
Like many eels, the ribbon eel is sometimes thought to be angry or aggressive, because its mouth is often open, appearing ready to strike. In reality, the eel is simply breathing.
In the wild, the ribbon eel buries itself in sand or hides in rocks or reefs, dashing out to feed on shrimp, samin, and other fish.
Friday, November 12, 2010
Mekong Giant Catfish
The Mekong giant catfish, Pangasianodon gigas, is a species of catfish (order Siluriformes) in the shark catfish family (family Pangasiidae), native to the Mekong basin in Southeast Asia.
The Mekong giant catfish is perhaps the most interesting and most threatened species in the Mekong river. For this reason conservationists have chosen it as a sort of “flagship” species to promote conservation on the Mekong (Hogan et al. 2004, MGCCG, 2005). With recorded sizes of up to 10.5 ft (3.2 m) and 660 lb (300 kg), the Mekong’s giant catfish currently holds the Guinness Book of World Record’s position for the world’s largest freshwater fish (Mydans et al. 2005, Hogan et al. 2004, Hogan et al. 2007). Although research projects are currently on going, relatively little is known about this species.
Historically the fish has a natural range that reaches from the lower Mekong in Vietnam (above the tidally influenced brackish water of the river’s delta) all the way to the northern reaches of the river in the Yunnan province of China, spanning almost the entire 4,800 km length of the river (Lopez et al. 2007, Hogan et al. 2007). Due to threats which will be discussed below, this species no longer inhabits the majority of its original habitat, now believed to only exist are small, isolated populations in the middle Mekong region (Hogan et al. 2004). Fish congregate during the beginning of the rainy season and migrate up-stream to spawn (Hogan et al. 2004). They live primarily in the main channel of the river where the water depth is over 10 m (Mattson et al. 2002) while researchers, fishermen and officials have found this species in the Tonle Sap river and lake in Cambodia (also a UNESCO Biosphere reserve). In the past fishermen have reported the fish in a number of the Mekong’s tributaries, however today essentially no sightings are reported outside of the main Mekong river channel and the Tonle Sap region.
In infancy, this species feeds on zooplankton in the river and is known to be cannibalistic (Pholprasith, 1983 as cited in Mattson et al. 2002). After approximately one year, the fish becomes herbivorous, feeding on filamentous algae probably ingesting larvae and periphyton accidentally (Pookaswan, 1989 and Jensen, 1997 as cited in Mattson et al. 2002). The fish likely obtain their food from algae growing on submerged rocky surfaces, as they do not have any sort of dentition (Pholprasith, 1983 as cited in Mattson et al. 2002).
Thursday, November 11, 2010
The barnacle blenny, Acanthemblemaria spinosa, also known as the tube blenny or spinyhead blenny, is a member of the blenny family native to the Pacific ocean. It has a mottled black, white and red coloration over the entire body, which is rather elongated. As with most blennies, the head of this animal has small hair-like appendages over the eyes, which are large and red. It ranges in size from 0.75 inches (19 mm) to 1.5 inches (38 mm) in length.
A. spinosa prefers to inhabit the empty shells of barnacles, hence their name, but will also live in rock and coral crevices. They are opportunistic feeders, preferring to quickly dart out and retrieve food bits from the water column, as opposed to engaging in active foraging and hunting behavior. They eat small crustaceans and other plankton.
In the home aquarium, they are entertaining and only require moderate care. They are reef safe.
Wednesday, November 10, 2010
Christmas Tree Worm
Spirobranchus giganteus, commonly known as Christmas tree worms, are small, tube-building polychaete worms belonging to the family Serpulidae.
The worm is aptly named; Both its common and Latin names refer to the two, chromatically-hued spiral structures that are most commonly what is seen of the worm by divers. In actuality, these multicolored spirals are merely the worm's highly-derived respiratory structures.
The worms's most distinct features are the two "crowns" that are shaped like Christmas-trees. These "crowns" are actually highly modified prostomial palps which are specialized mouth appendages of the worm. Each spiral is actually composed of feather-like tentacles called radioles, which are heavily ciliated which allows any prey that are trapped in them to be transported straight towards the worm's mouth. While they are primarily feeding structures, S. giganteus also uses its radioles for respiration. It is because of this that the structures are commonly called "gills".
Christmas-tree worms are widely distributed throughout the world's tropical oceans. They have been known to occur from the Caribbean to the Indo-Pacific.
Tuesday, November 9, 2010
Chaetognatha, meaning hair-jaws, and commonly known as arrow worms, are a phylum of predatory marine worms that are a major component of plankton worldwide. About 20% of the known species are benthic, that is belonging to the lowest zone of the ocean, or benthic zone, and can attach to algae and rocks. They are found in all marine waters, from surface tropical waters and shallow tide pools to the deep sea and polar regions. Most chaetognaths are transparent and are torpedo shaped, but some deep-sea species are orange. They range in size from 2 to 120 millimetres (0.079 to 4.7 in).
There are more than 120 modern species assigned to over 20 genera. Despite the limited diversity of species, the number of individuals is large.
Chaetognaths are transparent or translucent dart-shaped animals covered by a cuticle. The body is divided into a distinct head, trunk, and tail. There are between four and fourteen hooked, grasping spines on each side of their head, flanking a hollow vestibule containing the mouth. The spines are used in hunting, and covered with a flexible hood arising from the neck region when the animal is swimming. All chaetognaths are carnivorous, preying on other planktonic animals.
Monday, November 8, 2010
Amphiuma is a genus of aquatic salamanders, the only extant genus within the family Amphiumidae (pronounced /æmfɨˈjuːmɨdiː/). They are also known to fisherman as "conger eels" or "congo snakes", which are zoologically incorrect designations. Amphiumas have one of the largest amounts of DNA in the living world, around 25 times more than a human.
Amphiumas have an elongated body, generally grey-black in color. They do have legs, but they are very small - while amphiumas can be up to 116 cm (46 in) long, their legs measure only up to about 2 cm (0.79 in). Therefore, they can resemble eels. They also lack eyelids or a tongue.
Female amphiumas lay their eggs in wet mud, and then remain coiled around them for about five months, until they hatch. The larvae have external gills, but after about four months these external gills disappear and the lungs begin to work. One pair of gill slits, with fully functioning internal gills, is retained and never disappears, so the metamorphosis remains incomplete.
Sunday, November 7, 2010
The lingcod, Ophiodon elongatus, is a fish of the greenling family Hexagrammidae. It is the only extant member of the genus Ophiodon. A slightly larger, extinct species, Ophiodon ozymandias, is known from fossils from the Late Miocene of Southern California.
It is native to the North American west coast from Shumagin Islands in the Gulf of Alaska to Baja California, Mexico. It has been observed up to a size of 152 cm and a weight of 59 kg. It is spotted in various shades of grey. The lingcod is a popular eating fish, and is thus prized by anglers. Though not closely related to either ling or cod, the name lingcod originated because it somewhat resembles those fish.
Lingcod are voracious predators, feeding on nearly anything they can fit in their mouths including invertebrates and many species of fish, such as herring, Clupea harengus, salmon and Pacific hake, Merluccius productus. One of their favorite foods are smaller octopus, and they will also readily devour large rockfish. Lingcod that survive the larval stages have few predators themselves, and are vulnerable mainly to marine mammals such as sea lions and harbor seals.
Saturday, November 6, 2010
Crinoids, also known as sea lilies or feather-stars, are marine animals that make up the class Crinoidea of the echinoderms (phylum Echinodermata). Crinoidea comes from the Greek word krinon, "a lily", and eidos, "form". They live both in shallow water and in depths as great as 6,000 meters.
Crinoids are characterized by a mouth on the top surface that is surrounded by feeding arms. They have a U-shaped gut, and their anus is located next to the mouth. Although the basic echinoderm pattern of fivefold symmetry can be recognized, most crinoids have many more than five arms. Crinoids usually have a stem used to attach themselves to a substrate, but many live attached only as juveniles and become free-swimming as adults.
There are only a few hundred known modern forms, but crinoids were much more numerous both in species and numbers in the past. Some thick limestone beds dating to the mid- to late-Paleozoic are almost entirely made up of disarticulated crinoid fragments.
Friday, November 5, 2010
The Spanish shawl, Flabellina iodinea, is a species of aeolid nudibranch, a very colorful sea slug. This is a marine gastropod mollusk in the family Flabellinidae.
This species is native to the west coast of North America and further south. It has been reported as far north as British Columbia, Canada, and as far south as Punta Asunción, Baja California Sur, Mexico. In addition it is found in the Gulf of California and the Galapagos Islands.
It has been found off the coast of Santa Catalina Island, California. It has also been found off the coast of San Diego, California.
This nudibranch displays a stunning set of colors: the body is purple, the cerata are orange and the rhinophores are scarlet. The neon orange appendages on the back of Flabellina iodinea are the cerata which extract oxygen from the sea water they live in. The cerata are also extensions of the digestive system, and are used to store the stinging cells of the anemones and fan-like hydroids they eat. The red rhinophores are sensory structures used for detecting the presence of possible mates and prey. The purple, red, and orange colors are derived from a single carotenoid pigment, astaxanthin. The pigment appears in three modified states, leading to the three distinct colors.
Scientists guess the reason why the Spanish Shawl's gills are orange is so they can camouflage with their prey while they are eating. The orange gills on their backs are also a warning to potential predators. The color tells their predators that they are either poisonous or distasteful.
Spanish shawls are hermaphrodites, which means they have both male and female sex organs. However, self-fertilisation very rarely occurs. When threatened by other predators, they can gracefully move away by flexing their body strongly and pushing off from the substrate and into midwater.
Thursday, November 4, 2010
The Telescope Octopus (Amphitretus pelagicus) is a species of pelagic octopus found in tropical regions of the Indian and Pacific Oceans. It is transparent, almost colorless and has 8 arms. It is the only octopus to have tubular eyes, hence its common name.
Wednesday, November 3, 2010
The arapaima, pirarucu, or paiche (Arapaima gigas) is a South American tropical freshwater fish. It is a living fossil and one of the largest freshwater fishes in the world.
Arapaima can reach lengths of more than 2 m (6.6 ft), in some exceptional cases even more than 2.5 m (8.2 ft) and over 100 kg (220 lbs). The often cited maximum length of 4.5 m (14.8 ft) comes from a single second-hand-report from the first half of the nineteenth century, and is not confirmed. The maximum-cited weight for the species is 200 kg (440 lbs). As one of the most sought after food fish species in South America, it is often captured primarily by handheld nets for export, by spearfishing for local consumption, and, consequently, large arapaima of more than 2 m are seldom found in the wild today.
Tuesday, November 2, 2010
Osedax is a genus of deep-sea siboglinid polychaetes, commonly called boneworms, zombie worms or bone-eating worms. Osedax is Latin for "bone-eating", the name alluding to how the worms bore into the bones of whale carcasses to reach enclosed lipids, on which they rely for sustenance.
Scientists from the Monterey Bay Aquarium Research Institute (MBARI) using the submarine ROV Tiburon first discovered the genus in Monterey Bay, California, in February 2002. The worms were found living on the bones of a decaying gray whale in the Monterey Canyon, at a depth of 2,893 m (9,491 ft).
Lacking stomach and mouth, Osedax rely on symbiotic species of bacteria to digest whale fat and oils and release nutrients that they can absorb. Osedax have colorful feathery plumes that act as gills, and unusual root-like structures that absorb nutrients. Between 50 and 100 microscopic dwarf males live inside a single female, and never develop past the larval stage.
Following its discovery in 2002, the genus was announced in Science in 2004.
In late 2005, an experiment by Swedish marine biologists resulted in the discovery of a species of the worm in the North Sea off the west coast of Sweden. In the experiment, a minke whale carcass that had been washed ashore had been sunk to a depth of 120 m (390 ft) and monitored for several months. Biologists were surprised to find that unlike the previous discoveries, the new species, colloquially known as "bone eating snot flower" after its scientific name (Osedax mucofloris; a more accurate translation would be "slimeflower bone-eater"), lived in very shallow waters compared to the previous discoveries.
In November 2009, researchers reported finding as many as 15 species of boneworms living in Monterey Bay on the California coast.
Monday, November 1, 2010
Whale fall is the term used for a whale carcass that has fallen to the ocean floor. Whale falls were first observed in the 1980s, with the advent of deep-sea robotic exploration.
When a whale dies in shallow water, its carcass is typically devoured by scavengers over a relatively short period of time—within several months. However, in deeper water (depths of 2,000 m/6,600 ft or greater), fewer scavenger species exist, and the carcass can provide sustenance for a complex localized ecosystem Some of the organisms that have been observed at whale falls are squat lobsters, bristleworms, prawns, shrimp, lobsters, hagfish, over periods of decades.Osedax (bone-eating worms), crabs, sea cucumbers, octopuses, clams, and even deep-sea sleeper sharks. Whale falls are often inhabited by large colonies of tubeworms. Over 30 previously unknown species have been discovered at whale falls.
A whale fall was first observed by marine biologists led by University of Hawaii oceanographer Craig Smith in 1987, discovered accidentally by the submersible Alvin using scanning sonar at 1,240 m (4,068 ft) in Santa Catalina, California Basin. Whale falls have since been found by other scientists, and by military submarines. They can be found by using side-scan sonar to examine the ocean floor for large aggregations of matter.
The first sign that whale carcasses could host specialized animal communities came in 1854 when a new mussel species was extracted from a piece of floating whale blubber. Beginning in the 1960s, deep sea trawlers unintentionally recovered other new mollusk species including limpets (named Osteopelta) attached to whale bones.