Headlands and bays
Both headland and bay are two coastal features that are related and found on the same coastline. A bay is a body of water—usually seawater and sometimes fresh water— surrounded by land, whereas a headland is surrounded by water on three sides. Headlands are characterized by rocky shores, intense erosion and steep sea cliffs. Bays have less wave activity and have sandy beaches. Headlands and bays form on discordant coastlines, where the land consists of bands of rock of alternating resistance that run perpendicular to the coast. Bays form where less resistant rocks, such as sands and clays, are eroded, leaving bands of stronger, or more resistant rocks, which form a headland or peninsula. Refraction of waves occurs on headlands concentrating wave energy on them, so many other landforms, such as caves, natural arches, stacks, form on headlands. Wave energy is directed at right angles to the wave crest, lines drawn at right angles to the wave crest represent the direction of energy expenditure. Orthogonals converge on headlands and diverge in bays, which concentrates wave energy on the headlands and dissipates wave energy in the bays.
In the formation of sea cliffs, wave erosion undercuts the slopes at the shoreline, which retreat landward. This accelerates mass movement; the debris from these landslides collects at the base of the cliff and is removed by the waves during storms, when wave energy is greatest. This debris provides sediment, transported through longshore current for the nearby bay. Joints in the headlands are eroded back to form caves; these gaps collapse and leave tall stacks at the ends of the headlands. These too are eroded by the waves. Wave refraction disperses wave energy through the bay, along with the sheltering effect of the headlands, this protects bays from storms; this effect means that the waves reaching the shore in a bay are weaker than the waves reaching the headland, the bay is thus a safer place for water activities like surfing or swimming. Through the deposition of sediment within the bay and the erosion of the headlands, coastlines straighten out, but the same process starts all over again.
A beach is a dynamic geologic feature that can fluctuate between advancement and retreat of sediment. The natural agents of fluctuation include waves, tides and winds. Man-made elements such as the interruption of sediment supply, such as a dam, withdrawal of fluid can affect beach stabilization. Static equilibrium refers to a beach, stable and experiences neither littoral drift nor sediment deposition nor erosion. Waves diffract around the headland and near the beach when the beach is in a state of static equilibrium. Dynamic equilibrium occurs when the beach sediments are deposited and eroded at equal rates. Beaches that have dynamic equilibrium are near a river that supplies sediment and would otherwise erode away without the river supply. Unstable beaches are a result of human interaction, such as a breakwater or dammed river. Unstable beaches are reshaped by continual erosion or deposition and will continue to erode or deposit until a state of equilibrium is reached in the bay. GeoResources - diagrams of headland and bay formation
The orange-bellied parrot is a small broad-tailed parrot endemic to southern Australia, one of only three species of parrot that migrate. It was described by John Latham in 1790. A small parrot around 20 cm long, it exhibits sexual dimorphism; the adult male is distinguished by its bright grass-green upperparts, yellow underparts and orange belly patch. The adult female and juvenile are duller green in colour. All birds have blue outer wing feathers; the orange-bellied parrot breeds in Tasmania and winters near the coast, foraging on saltmarsh species, beach or dune plants and a variety of exotic weed species on southern mainland Australia. The diet consists of berries of small coastal grasses and shrubs. With a wild population of 6 birds as of early February 2019, it is regarded as a critically endangered species; the orange-bellied parrot is rated as critically endangered on the International Union for Conservation of Nature's Red List of Endangered species. Orange-bellied parrots are being bred in a captive breeding program with parrots in Taroona, Healesville Sanctuary, Adelaide Zoo, Moonlit Sanctuary Wildlife Conservation Park and Priam Parrot Breeding Centre.
The captive population consists of around 300 birds, with a target of 350 birds by 2016–17. Because of the decline in the wild population in recent years, an additional 21 birds from the wild population were captured in 2010–2011 to improve the genetic diversity of the species' captive breeding program. Taken as a whole, the captive population, an example of ex situ conservation, is termed an "insurance population" against extinction; the orange-bellied parrot was first described by ornithologist John Latham as Psittacus chrysogaster in 1790, from a specimen, collected from Adventure Bay in Tasmania in March 1773 on the second voyage of James Cook or in January 1777 on his third voyage, subsequently been in Joseph Banks' collection. The specific name was derived from the Ancient Greek words chrysos'golden' and gaster'belly'. John Gould described it in 1841 as Euphema aurantia, from an adult male specimen collected in southeast Tasmania that became the lectotype; the species name was the Latin adjective for "orange".
T. J. Ewing named. Italian ornithologist Tommaso Salvadori erected the new genus Neophema in 1891, placing the orange-bellied parrot within it and giving it its current scientific name. One of six species of grass parrot in the genus Neophema, one of four classified in the subgenus Neonanodes. No subspecies are recognised."Orange-bellied parrot" has been designated the official name by the International Ornithologists' Union. Gould called it the orange-bellied grass parakeet, it has been known as the'orange-breasted parrot'—a name given to the orange-bellied parrot in 1926 by the Royal Australasian Ornithologists Union or RAOU when the word'belly' was considered inelegant. Other names include yellow-bellied parrot, orange-bellied grass-parakeet, trumped-up corella; the orange-bellied parrot is a small parrot around 20 cm long. The feathers of the cheeks and underparts are yellow-green with lime green tips and fringes, hence appear more bright green when the bird has just moulted and more yellowish as the plumage wears.
Feathers on the crown are bright green with darker green tips. It has a prominent, two-toned blue frontal band, with a lighter blue border both above and below the horizontal dark blue band. On the belly is an oval patch of orange around 2 cm in diameter; the undertail coverts are yellow to pale yellow. The uppertail is green-blue with yellow sides; the under wing-coverts and flight feathers are dark blue, with paler blue median wing-coverts. The upper mandible of the bill is blackish grey with a greyish, orange-brown or salmon-coloured base and cutting edge, while the lower mandible a brownish orange a grey-black tip; the cere is blackish grey with a pale brown tinge around the nostrils, the orbital eye-ring is light grey and the iris is dark brown. The legs and feet are dark grey with a red tinge between scales; the adult female has duller shades of green plumage overall, with a paler blue frontal band. Its orange belly patch is less distinct. Moulting takes place in early spring; the juvenile is a duller green to yellow-olive colour overall, with a much less prominent blue frontal band above the eyes.
It has a dull yellowish or orange bill, which darkens to brown by the time the bird is three months old. The orange-bellied parrot most utters a single-note buzzing sound, repeated every one to three seconds as a contact call; this is made orange-bellied parrots while flying, but by birds seeing others in flight. The alarm call is a repeated tzeet that has a buzzing quality. Individuals may make this call; the gurgle-buzz call is made by birds acting as sentries at feeding areas, is a mixture of an alarm call interspersed with chattering and hissing. When feeding, orange-bellied parrots may make soft low-pitched chitting sounds; the blue-winged and elegant parrots can be mistaken for the orange-bellied parrot, however their tinkling alarm calls and lighter olive-green upperparts distinguish them. Their blue frontal bands have only light blue border on one side. One of three migratory parrot species, the orange-bellied parrots breeds in South West Tasmania, it nests in eucalypts bordering on button gras
Australia the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania and numerous smaller islands. It is the world's sixth-largest country by total area; the neighbouring countries are Papua New Guinea and East Timor to the north. The population of 25 million is urbanised and concentrated on the eastern seaboard. Australia's capital is Canberra, its largest city is Sydney; the country's other major metropolitan areas are Melbourne, Brisbane and Adelaide. Australia was inhabited by indigenous Australians for about 60,000 years before the first British settlement in the late 18th century, it is documented. After the European exploration of the continent by Dutch explorers in 1606, who named it New Holland, Australia's eastern half was claimed by Great Britain in 1770 and settled through penal transportation to the colony of New South Wales from 26 January 1788, a date which became Australia's national day; the population grew in subsequent decades, by the 1850s most of the continent had been explored and an additional five self-governing crown colonies established.
On 1 January 1901, the six colonies federated. Australia has since maintained a stable liberal democratic political system that functions as a federal parliamentary constitutional monarchy, comprising six states and ten territories. Being the oldest and driest inhabited continent, with the least fertile soils, Australia has a landmass of 7,617,930 square kilometres. A megadiverse country, its size gives it a wide variety of landscapes, with deserts in the centre, tropical rainforests in the north-east and mountain ranges in the south-east. A gold rush began in Australia in the early 1850s, its population density, 2.8 inhabitants per square kilometre, remains among the lowest in the world. Australia generates its income from various sources including mining-related exports, telecommunications and manufacturing. Indigenous Australian rock art is the oldest and richest in the world, dating as far back as 60,000 years and spread across hundreds of thousands of sites. Australia is a developed country, with the world's 14th-largest economy.
It has a high-income economy, with the world's tenth-highest per capita income. It is a regional power, has the world's 13th-highest military expenditure. Australia has the world's ninth-largest immigrant population, with immigrants accounting for 26% of the population. Having the third-highest human development index and the eighth-highest ranked democracy globally, the country ranks in quality of life, education, economic freedom, civil liberties and political rights, with all its major cities faring well in global comparative livability surveys. Australia is a member of the United Nations, G20, Commonwealth of Nations, ANZUS, Organisation for Economic Co-operation and Development, World Trade Organization, Asia-Pacific Economic Cooperation, Pacific Islands Forum and the ASEAN Plus Six mechanism; the name Australia is derived from the Latin Terra Australis, a name used for a hypothetical continent in the Southern Hemisphere since ancient times. When Europeans first began visiting and mapping Australia in the 17th century, the name Terra Australis was applied to the new territories.
Until the early 19th century, Australia was best known as "New Holland", a name first applied by the Dutch explorer Abel Tasman in 1644 and subsequently anglicised. Terra Australis still saw occasional usage, such as in scientific texts; the name Australia was popularised by the explorer Matthew Flinders, who said it was "more agreeable to the ear, an assimilation to the names of the other great portions of the earth". The first time that Australia appears to have been used was in April 1817, when Governor Lachlan Macquarie acknowledged the receipt of Flinders' charts of Australia from Lord Bathurst. In December 1817, Macquarie recommended to the Colonial Office. In 1824, the Admiralty agreed that the continent should be known by that name; the first official published use of the new name came with the publication in 1830 of The Australia Directory by the Hydrographic Office. Colloquial names for Australia include "Oz" and "the Land Down Under". Other epithets include "the Great Southern Land", "the Lucky Country", "the Sunburnt Country", "the Wide Brown Land".
The latter two both derive from Dorothea Mackellar's 1908 poem "My Country". Human habitation of the Australian continent is estimated to have begun around 65,000 to 70,000 years ago, with the migration of people by land bridges and short sea-crossings from what is now Southeast Asia; these first inhabitants were the ancestors of modern Indigenous Australians. Aboriginal Australian culture is one of the oldest continual civilisations on earth. At the time of first European contact, most Indigenous Australians were hunter-gatherers with complex economies and societies. Recent archaeological finds suggest. Indigenous Australians have an oral culture with spiritual values based on reverence for the land and a belief in the Dreamtime; the Torres Strait Islanders, ethnically Melanesian, obtained their livelihood from seasonal horticulture and the resources of their reefs and seas. The northern coasts and waters of Australia were visited s
An inlet is an indentation of a shoreline long and narrow, such as a small bay or arm, that leads to an enclosed body of salt water, such as a sound, lagoon, or marsh. In sea coasts, the term "inlet" refers to the actual connection between a bay and the ocean and is called an "entrance" or a recession in the shore of a sea, lake, or river. A certain kind of inlet created by glaciation is a fjord but not always in mountainous coastlines and in montane lakes. Complexes of large inlets or fjords may be called e.g. Puget Sound, Howe Sound, Karmsund; some fjord-type inlets are called canals, e.g. Portland Canal, Lynn Canal, Hood Canal, some are channels, e.g. Dean Channel and Douglas Channel. Tidal amplitude, wave intensity, wave direction are all factors that influence sediment flux in inlets. On low slope sandy coastlines, inlets separate barrier islands and can form as the result of storm events. Alongshore sediment transport can cause inlets to close if the action of tidal currents flowing through an inlet do not flush accumulated sediment out of the inlet.
Alaska Panhandle British Columbia Coast Calanque Inside Passage Ria Bruun, Per. J. Mehta. Stability of Tidal Inlets: Theory and Engineering. Amsterdam: Elsevier Scientific Pub. Co. p. 510. ISBN 978-0-444-41728-2. Be pub co Coastal Inlets Research Program Hood Canal on Google Maps
Daveys Bay is a small shallow bay of Port Phillip, located in Victoria, Australia. It is one of several small bays adjoining the town of Mount Eliza and is the closest region of the Shire of Mornington Peninsula to Melbourne. Daveys Bay is named after James Davey. Davey used the jetty to load his ketch with produce destined for the Melbourne markets. Davey's Bay Yacht Club, founded in 1909, is located at the jetty; the north-eastern shoreline of Daveys Bay features an exposure of the Manyung Fault, part of the main Selwyn Fault system. Davey's Bay Yacht Club
A wetland is a distinct ecosystem, inundated by water, either permanently or seasonally, where oxygen-free processes prevail. The primary factor that distinguishes wetlands from other land forms or water bodies is the characteristic vegetation of aquatic plants, adapted to the unique hydric soil. Wetlands play a number of functions, including water purification, water storage, processing of carbon and other nutrients, stabilization of shorelines, support of plants and animals. Wetlands are considered the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal life. Whether any individual wetland performs these functions, the degree to which it performs them, depends on characteristics of that wetland and the lands and waters near it. Methods for assessing these functions, wetland ecological health, general wetland condition have been developed in many regions and have contributed to wetland conservation by raising public awareness of the functions and the ecosystem services some wetlands provide.
Wetlands occur on every continent. The main wetland types are swamp, marsh and fen. Many peatlands are wetlands; the water in wetlands is either brackish, or saltwater. Wetlands can be non-tidal; the largest wetlands include the Amazon River basin, the West Siberian Plain, the Pantanal in South America, the Sundarbans in the Ganges-Brahmaputra delta. The UN Millennium Ecosystem Assessment determined that environmental degradation is more prominent within wetland systems than any other ecosystem on Earth. Constructed wetlands are used to treat municipal and industrial wastewater as well as stormwater runoff, they may play a role in water-sensitive urban design. A patch of land that develops pools of water after a rain storm would not be considered a "wetland" though the land is wet. Wetlands have unique characteristics: they are distinguished from other water bodies or landforms based on their water level and on the types of plants that live within them. Wetlands are characterized as having a water table that stands at or near the land surface for a long enough period each year to support aquatic plants.
A more concise definition is a community composed of hydric soil and hydrophytes. Wetlands have been described as ecotones, providing a transition between dry land and water bodies. Mitsch and Gosselink write that wetlands exist "...at the interface between terrestrial ecosystems and aquatic systems, making them inherently different from each other, yet dependent on both."In environmental decision-making, there are subsets of definitions that are agreed upon to make regulatory and policy decisions. A wetland is "an ecosystem that arises when inundation by water produces soils dominated by anaerobic and aerobic processes, which, in turn, forces the biota rooted plants, to adapt to flooding." There are four main kinds of wetlands – marsh, swamp and fen. Some experts recognize wet meadows and aquatic ecosystems as additional wetland types; the largest wetlands in the world include the swamp forests of the Amazon and the peatlands of Siberia. Under the Ramsar international wetland conservation treaty, wetlands are defined as follows: Article 1.1: "...wetlands are areas of marsh, peatland or water, whether natural or artificial, permanent or temporary, with water, static or flowing, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres."
Article 2.1: " may incorporate riparian and coastal zones adjacent to the wetlands, islands or bodies of marine water deeper than six metres at low tide lying within the wetlands." Although the general definition given above applies around the world, each county and region tends to have its own definition for legal purposes. In the United States, wetlands are defined as "those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, that under normal circumstances do support, a prevalence of vegetation adapted for life in saturated soil conditions. Wetlands include swamps, marshes and similar areas"; this definition has been used in the enforcement of the Clean Water Act. Some US states, such as Massachusetts and New York, have separate definitions that may differ from the federal government's. In the United States Code, the term wetland is defined "as land that has a predominance of hydric soils, is inundated or saturated by surface or groundwater at a frequency and duration sufficient to support a prevalence of hydrophytic vegetation adapted for life in saturated soil conditions and under normal circumstances supports a prevalence of such vegetation."
Related to this legal definitions, the term "normal circumstances" are conditions expected to occur during the wet portion of the growing season under normal climatic conditions, in the absence of significant disturbance. It is not uncommon for a wetland to be dry for long portions of the growing season. Wetlands can be dry during the dry season and abnormally dry periods during the wet season, but under normal environmental conditions the soils in a wetland will be saturated to the surface or inundated such that the soils become anaerobic, those conditions will persist through the wet portion of the growing season; the most important factor producing wetlands is flooding. The duration of flooding or prolonged soil saturation by groundwater determines whether the resulting wetland has aquatic, marsh or swamp vegetation