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Foredune
A foredune is a dune ridge that runs parallel to the shore of an ocean, lake, bay, or estuary. Foredunes consist of sand deposited by wind on a vegetated part of the shore. Foredunes can be classified generally as ''incipient'' or ''established''. Formation Foredunes may begin as ''shadow dunes'' that form in the wind shadows of clumps of vegetation. Several shadow dunes may eventually join to form an incipient foredune. When an incipient foredune reaches a height of about , it has a significant wind shadow of its own. Wind-blown sand will tend to fall on this incipient dune rather than traveling further inland. When a foredune becomes high, it may trap all of the wind-blown sand from the beach. In active dune systems, the foredunes appear closest to the sea or other body of water. However, some dune systems, such as those on eroding coasts, do not have foredunes. In those systems, other kinds of dunes may be closest to the water. A foredune ecosystem begins with the first du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dune
A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat regions covered with wind-swept sand or dunes with little or no vegetation are called ''ergs'' or ''sand seas''. Dunes occur in different shapes and sizes, but most kinds of dunes are longer on the stoss (upflow) side, where the sand is pushed up the dune, and have a shorter ''slip face'' in the lee side. The valley or trough between dunes is called a ''dune slack''. Dunes are most common in desert environments, where the lack of moisture hinders the growth of vegetation that would otherwise interfere with the development of dunes. However, sand deposits are not restricted to deserts, and dunes are also found along sea shores, along streams in semiarid climates, in areas of glacial outwash, and in other areas where poorly cemented sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dune
A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat regions covered with wind-swept sand or dunes with little or no vegetation are called ''ergs'' or ''sand seas''. Dunes occur in different shapes and sizes, but most kinds of dunes are longer on the stoss (upflow) side, where the sand is pushed up the dune, and have a shorter ''slip face'' in the lee side. The valley or trough between dunes is called a ''dune slack''. Dunes are most common in desert environments, where the lack of moisture hinders the growth of vegetation that would otherwise interfere with the development of dunes. However, sand deposits are not restricted to deserts, and dunes are also found along sea shores, along streams in semiarid climates, in areas of glacial outwash, and in other areas where poorly cemented sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammophila Arenaria
''Ammophila arenaria'' is a species of grass in the family Poaceae. It is known by the common names marram grass and European beachgrass. It is one of two species of the genus ''Ammophila (Poaceae), Ammophila''. It is native to the coastlines of Europe and North Africa where it grows in the sands of beach dunes. It is a perennial grass forming stiff, hardy clumps of erect stems up to in height. It grows from a network of thick rhizomes which give it a sturdy anchor in its sand substrate and allow it to spread upward as sand accumulates. These rhizomes can grow laterally by in six months. One clump can produce 100 new shoots annually. The rhizomes tolerate submersion in sea water and can break off and float in the currents to establish the grass at new sites. The leaves are up to long and sharply pointed. The cylindrical inflorescence is up to long. It is adapted to habitat made up of shifting, accreting sand layers, as well as that composed of Sand dune stabilization, stabilis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass. The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz. Calcium carbonate is the second most common type of sand, for example, aragonite, which has mostly been created, over the past 500million years, by various forms of life, like coral and shellfish. For example, it is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years like the Caribbean. Somewhat more rarely, sand may be composed of calciu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invasive Species
An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native species that become harmful to their native environment after human alterations to its food webfor example the purple sea urchin (''Strongylocentrotus purpuratus'') which has decimated kelp forests along the northern California coast due to overharvesting of its natural predator, the California sea otter (''Enhydra lutris''). Since the 20th century, invasive species have become a serious economic, social, and environmental threat. Invasion of long-established ecosystems by organisms is a natural phenomenon, but human-facilitated introductions have greatly increased the rate, scale, and geographic range of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erysimum Menziesii
''Erysimum menziesii'' is a species of ''Erysimum'' known by the common name Menzies' wallflower. This rare plant is endemic to California. It is found only in the declining beach sand dune habitat in three areas on the California coastline, in Humboldt, Mendocino, and Monterey Counties. It is listed as an endangered species on the California state and federal levels. There are three to four subspecies depending on the authority, and each is rare. Description ''Erysimum menziesii'' is a mustardlike biennial or perennial herb which is short in size, reaching maximum heights of usually not more than 15 centimeters. The leaves are long and straight along the stem, and often thicker, hairier, and lobed in shape at the base. The top of the stem is occupied by a thick bunch of flowers with bright yellow, rounded petals. The flowers fall away to leave behind the fruits, which are very long siliques sticking straight out. The plant can vary in appearance, particularly across subspecie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Layia Carnosa
''Layia carnosa'' is a species of flowering plant in the family Asteraceae known by the common name beach tidytips, or beach layia. It is endemic to California, where it lives in beach habitat. It is known from several areas of mostly fragmented coastal habitat, and it was listed as an endangered species in California. On March 31, 2022, the category was changed from endangered species to threatened species by the US Department of the Interior Fish and Wildlife Service. Description This is a petite annual herb producing a short, glandular stem along the ground or somewhat upright to a maximum length of about 18 centimeters. The fleshy green leaves are oval in shape, with the larger ones roughly lobed and up to 4 or 5 centimeters in length. The inflorescence is borne on a short peduncle. The flower head has a base of overlapping green phyllaries which form a cup to hold several small white ray florets. The center is filled with yellow disc florets with purple anthers. The fruits ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromus Diandrus
''Bromus diandrus'' is a species of grass known by the common names great brome and "ripgut brome". Description This is a brome grass which is native to the Mediterranean but has been introduced to much of the rest of the world. It does best in areas with a Mediterranean climate, such as California and parts of southern Australia, but it is quite tolerant of many climates. Ripgut brome is a winter annual that grows throughout winter and spring and matures in the summer. The adult plant is one to three feet in height with hairy, rough leaves about a centimeter wide. The membranous ligule is prominent, white with spiky hairs. The wide panicle nods like that of an oat plant, and it bears a large, splayed spikelet with a very long awn which can exceed five centimeters in length. The seeds easily break out of the spikelet. They are very sharp and very rough due to tiny barb-like hairs that face backward, allowing the seed to catch and lodge-like a fish hook. This characteristic make ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanacetum Vulgare
Tansy (''Tanacetum vulgare'') is a perennial, herbaceous flowering plant in the genus ''Tanacetum'' in the aster family, native to temperate Europe and Asia. It has been introduced to other parts of the world, including North America, and in some areas has become invasive. It is also known as common tansy, bitter buttons, cow bitter, or golden buttons. The Latin word ''vulgare'' means "common". Description Tansy is a flowering herbaceous plant with finely divided compound leaves and yellow, button-like flowers. It has a stout, somewhat reddish, erect stem, usually smooth, tall, and branching near the top. The leaves are alternate, long and are pinnately lobed, divided almost to the center into about seven pairs of segments, or lobes, which are again divided into smaller lobes having saw-toothed edges, giving the leaf a somewhat fern-like appearance. The roundish, flat-topped, button-like, yellow flower heads are produced in terminal clusters from mid-to-late summer. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saltation (geology)
In geology, saltation () is a specific type of particle transport by fluids such as wind or water. It occurs when loose materials are removed from a bed and carried by the fluid, before being transported back to the surface. Examples include pebble transport by rivers, sand drift over desert surfaces, soil blowing over fields, and snow drift over smooth surfaces such as those in the Arctic or Canadian Prairies. Process At low fluid velocities, loose material rolls downstream, staying in contact with the surface. This is called ''creep'' or ''reptation''. Here the forces exerted by the fluid on the particle are only enough to roll the particle around the point of contact with the surface. Once the wind speed reaches a certain critical value, termed the ''impact'' or ''fluid threshold'', the drag and lift forces exerted by the fluid are sufficient to lift some particles from the surface. These particles are accelerated by the fluid, and pulled downward by gravity, causing them to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suspension (chemistry)
In chemistry, a suspension is a heterogeneous mixture of a fluid that contains solid particles sufficiently large for sedimentation. The particles may be visible to the naked eye, usually must be larger than one micrometer, and will eventually settle, although the mixture is only classified as a suspension when and while the particles have not settled out. Properties A suspension is a heterogeneous mixture in which the solute particles do not dissolve, but get suspended throughout the bulk of the solvent, left floating around freely in the medium. The internal phase (solid) is dispersed throughout the external phase (fluid) through mechanical agitation, with the use of certain excipients or suspending agents. An example of a suspension would be sand in water. The suspended particles are visible under a microscope and will settle over time if left undisturbed. This distinguishes a suspension from a colloid, in which the colloid particles are smaller and do not settle. Colloids a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humboldt Bay
Humboldt Bay is a natural bay and a multi-basin, bar-built coastal lagoon located on the rugged North Coast of California, entirely within Humboldt County, United States. It is the largest protected body of water on the West Coast between San Francisco Bay and Puget Sound, the second-largest enclosed bay in California, and the largest port between San Francisco and Coos Bay, Oregon. The largest city adjoining the bay is Eureka, the regional center and county seat of Humboldt County, followed by the city of Arcata. These primary cities, together with adjoining unincorporated communities and several small towns, comprise a Humboldt Bay Area with a total population of nearly 80,000 people. This comprises nearly 60% of the population of Humboldt County. The bay is home to more than 100 plant species, 300 invertebrate species, 100 fish species, and 200 bird species. In addition, the bay and its complex system of marshes and grasses support hundreds of thousands of migrating and l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
