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Urchin Barren
An urchin barren is commonly defined as an urchin-dominated area with little or no kelp. Urchin grazing pressure on kelp is a direct and observable cause of a "barren" area. However, determining which factors contribute to shifting a kelp bed to an urchin barren is a complex problem and remains a matter of debate among scientists. Loss of "top" predators, particularly the historic hunting of sea otters (''Enhydra lutris''), has often been cited as a cause of these barrens. When urchins are left "unchecked," their populations increase, and this has further effects on primary production in the ecosystem. This type of shift is called a trophic cascade. Such theories have emphasized the "top-down" pressures by predators, including other urchin predators, exerting pressure at different life stages (including at the planktonic larval stage). Others theories have emphasized "bottom-up" factors, including abiotic environmental variables affecting urchin recruitment and the abundance and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purple Sea Urchins (7622488604)
Purple is a color similar in appearance to Violet (color), violet light. In the RYB color model historically used in the arts, purple is a secondary color created by combining red and blue pigments. In the CMYK color model used in modern printing, purple is made by combining magenta pigment with either cyan pigment, black pigment, or both. In the RGB color model used in computer and television screens, purple is created by Additive color, mixing red and blue light in order to create colors that appear similar to violet light. According to color theory, purple is considered a cool color. Purple has long been associated with royalty, originally because Tyrian Purple, Tyrian purple dye—made from the secretions of sea snails—was extremely expensive in antiquity. Purple was the color worn by Roman magistrates; it became the imperial color worn by the rulers of the Byzantine Empire and the Holy Roman Empire, and later by Roman Catholic bishops. Similarly in Japan, the color is tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Urchin
Sea urchins or urchins () are echinoderms in the class (biology), class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal zone to deep seas of . They typically have a globular body covered by a spine (zoology), spiny protective test (biology), tests (hard shells), typically from across. Sea urchins move slowly, crawling with their tube feet, and sometimes pushing themselves with their spines. They feed primarily on algae but also eat slow-moving or sessility (motility), sessile animals such as crinoids and sponges. Their predators include sharks, sea otters, starfish, wolf eels, and triggerfish. Like all echinoderms, adult sea urchins have pentagonal symmetry with their Echinoderm#Larval development, pluteus larvae featuring Bilateral symmetry, bilateral (mirror) symmetry; The latter indicates that they belong to the Bilateria, along with chordates, arthropods, annelids and molluscs. Sea urchins are found in every ocea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kelp
Kelps are large brown algae or seaweeds that make up the order (biology), order Laminariales. There are about 30 different genus, genera. Despite its appearance and use of photosynthesis in chloroplasts, kelp is technically not a plant but a stramenopile (a group containing many protists). Kelp grow from stalks close together in kelp forest, very dense areas like forests under shallow temperate and Arctic oceans. They were previously thought to have appeared in the Miocene, 5 to 23 million years ago based on fossils from California. New fossils of kelp holdfasts from early Oligocene rocks in Washington State show that kelps were present in the northeastern Pacific Ocean by at least 32 million years ago. The organisms require nutrient-rich water with temperatures between . They are known for their high growth rate—the genera ''Macrocystis'' and ''Nereocystis'' can grow as fast as half a metre a day (that is, about 20 inches a day), ultimately reaching .Thomas, D. 2002. ''Seaweed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Otters
The sea otter (''Enhydra lutris'') is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Adult sea otters typically weigh between , making them the heaviest members of the weasel family, but among the smallest marine mammals. Unlike most marine mammals, the sea otter's primary form of insulation is an exceptionally thick coat of fur, the densest in the animal kingdom. Although it can walk on land, the sea otter is capable of living exclusively in the ocean. The sea otter inhabits nearshore environments, where it dives to the sea floor to forage. It preys mostly on marine invertebrates such as sea urchins, various mollusks and crustaceans, and some species of fish. Its foraging and eating habits are noteworthy in several respects. Its use of rocks to dislodge prey and to open shells makes it one of the few mammal species to use tools. In most of its range, it is a keystone species, controlling sea urchin populations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Production
In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. It principally occurs through the process of photosynthesis, which uses light as its source of energy, but it also occurs through chemosynthesis, which uses the oxidation or reduction of inorganic chemical compounds as its source of energy. Almost all life on Earth relies directly or indirectly on primary production. The organisms responsible for primary production are known as '' primary producers'' or autotrophs, and form the base of the food chain. In terrestrial ecoregions, these are mainly plants, while in aquatic ecoregions algae predominate in this role. Ecologists distinguish primary production as either ''net'' or ''gross'', the former accounting for losses to processes such as cellular respiration, the latter not. Overview Primary production is the production of chemical energy, in organic compounds by living organisms. The main source of such energy i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophic Cascade
Trophic cascades are powerful indirect interactions that can control entire ecosystems, occurring when a trophic level in a food web is suppressed. For example, a top-down cascade will occur if predators are effective enough in predation to reduce the abundance, or alter the behavior of their prey, thereby releasing the next lower trophic level from predation (or herbivory if the intermediate trophic level is a herbivore). The trophic cascade is an ecological concept which has stimulated new research in many areas of ecology. For example, it can be important for understanding the knock-on effects of removing top predators from food webs, as humans have done in many places through hunting and fishing. A top-down cascade is a trophic cascade where the top consumer/predator controls the primary consumer population. In turn, the primary producer population thrives. The removal of the top predator can alter the food web dynamics. In this case, the primary consumers would overpopula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abiotic Component
In biology and ecology, abiotic components or abiotic factors are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. Abiotic factors and the phenomena associated with them underpin biology as a whole. They affect a plethora of species, in all forms of environmental conditions, such as marine or terrestrial animals. Humans can make or change abiotic factors in a species' environment. For instance, fertilizers can affect a snail's habitat, or the greenhouse gases which humans utilize can change marine pH levels. Abiotic components include physical conditions and non-living resources that affect living organisms in terms of growth, maintenance, and reproduction. Resources are distinguished as substances or objects in the environment required by one organism and consumed or otherwise made unavailable for use by other organisms. Component degradation of a substance occurs by chemical or physical processes, e. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subtidal
The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth. From the point of view of marine biology it forms a relatively stable and well-illuminated environment for marine life, from plankton up to large fish and corals, while physical oceanography sees it as where the oceanic system interacts with the coast. Definition (marine biology), context, extra terminology In marine biology, the neritic zone, also called coastal waters, the coastal ocean or the sublittoral zone, refers to the zone of the ocean where sunlight reaches the ocean floor, that is, where the water is never so deep as to take it out of the photic zone. It extends from the low tide mark to the edge of the continental shelf, with a relatively shallow depth extending to about 200 meters (660 feet). Above the neritic zone lie the intertidal (or eulittoral) and supralittoral zones; below it the continental slop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kelp Bed
Kelp forests are underwater areas with a high density of kelp, which covers a large part of the world's coastlines. Smaller areas of anchored kelp are called kelp beds. They are recognized as one of the most productive and dynamic ecosystems on Earth. Although algal kelp forest combined with coral reefs only cover 0.1% of Earth's total surface, they account for 0.9% of global primary productivity. Kelp forests occur worldwide throughout temperate and polar coastal oceans. In 2007, kelp forests were also discovered in tropical waters near Ecuador. Physically formed by brown macroalgae, kelp forests provide a unique habitat for marine organisms and are a source for understanding many ecological processes. Over the last century, they have been the focus of extensive research, particularly in trophic ecology, and continue to provoke important ideas that are relevant beyond this unique ecosystem. For example, kelp forests can influence coastal oceanographic patterns and provide ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrocystis
''Macrocystis'' is a monospecific genus of kelp (large brown algae) with all species now synonymous with ''Macrocystis pyrifera''. It is commonly known as giant kelp or bladder kelp. This genus contains the largest of all the Phaeophyceae or brown algae. ''Macrocystis'' has pneumatocysts at the base of its blades. Sporophytes are perennial and the individual may live for up to three years; stipes/fronds within a whole individual undergo senescence, where each frond may persist for approximately 100 days. The genus is found widely in subtropical, temperate, and sub-Antarctic oceans of the Southern Hemisphere and in the northeast Pacific. ''Macrocystis'' is often a major component of temperate kelp forests. Despite its appearance, it is not a plant; it is a heterokont. Giant kelp is common along the coast of the northeastern Pacific Ocean, from Baja California north to southeast Alaska, and is also found in the southern oceans near South America, South Africa, Australia, and N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alternative Stable State
In ecology, the theory of alternative stable states (sometimes termed alternate stable states or alternative stable equilibria) predicts that ecosystems can exist under multiple "states" (sets of unique biotic and abiotic conditions). These alternative states are non-transitory and therefore considered stable over ecologically-relevant timescales. Ecosystems may transition from one stable state to another, in what is known as a state shift (sometimes termed a phase shift or regime shift), when perturbed. Due to ecological feedbacks, ecosystems display resistance to state shifts and therefore tend to remain in one state unless perturbations are large enough. Multiple states may persist under equal environmental conditions, a phenomenon known as hysteresis. Alternative stable state theory suggests that discrete states are separated by ecological thresholds, in contrast to ecosystems which change smoothly and continuously along an environmental gradient. Theory Alternative stabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Angeles Times
The ''Los Angeles Times'' is an American Newspaper#Daily, daily newspaper that began publishing in Los Angeles, California, in 1881. Based in the Greater Los Angeles city of El Segundo, California, El Segundo since 2018, it is the List of newspapers in the United States, sixth-largest newspaper in the U.S. and the largest in the Western United States with a print circulation of 118,760. It has 500,000 online subscribers, the fifth-largest among U.S. newspapers. Owned by Patrick Soon-Shiong and published by California Times, the paper has won over 40 Pulitzer Prizes since its founding. In the 19th century, the paper developed a reputation for civic boosterism and opposition to Trade union, labor unions, the latter of which led to the Los Angeles Times bombing, bombing of its headquarters in 1910. The paper's profile grew substantially in the 1960s under publisher Otis Chandler, who adopted a more national focus. As with other regional newspapers in California and the United Sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
