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97-642: The Port River (officially known as the Port Adelaide River ) is part of a tidal estuary located north of the Adelaide city centre in the Australian state of South Australia . It has been used as a shipping channel since the beginning of European settlement of South Australia in 1836, when Colonel Light selected the site to use as a port. Before colonisation, the Port River region and

194-651: A rookery ); and a sanctuary for dolphins. The area is also home to the largest area of mangrove forest, shallow seagrasses and mudflats in Gulf St Vincent. Spring tides are over 2.5 metres (8 ft 2 in) AHD , and at low tide , mudflats are exposed near the outlet of the river. Prior to European settlement of the Adelaide Plains, winter rains over the catchment of the River Torrens created large seasonal inflows of fresh water into

291-704: A city. The Adelaide Dolphin Sanctuary includes all of the Port River estuary and includes a stretch of the sea northwards past St Kilda . A fishing fleet operates out of the North Arm, which also has a speed boat club. Recreational boating marinas are located in the Angas Inlet and on the Lefevre Peninsula. The Port Adelaide Rowing Club , established around 1877, and was situated at Inner Harbour until 1957, when it moved to Largs North . and

388-610: A food source and aquaculture candidate; it is mainly found in the British Isles in Europe. In Italy, clams are often an ingredient of mixed seafood dishes or are eaten together with pasta. The more commonly used varieties of clams in Italian cooking are the vongola ( Venerupis decussata ) , the cozza (Mytilus galloprovincialis) and the tellina ( Donax trunculus ) . Though dattero di mare (Lithophaga lithophaga)

485-681: A food source for many different animals. Extant mammals that eat clams include both the Pacific and Atlantic species of walrus , all known subspecies of harbour seals in both the Atlantic and Pacific, most species of sea lions , including the California sea lion , bearded seals and even species of river otters that will consume the freshwater species found in Asia and North America. Birds of all kinds will also eat clams if they can catch them in

582-573: A harsh environment for organisms. Sediment often settles in intertidal mudflats which are extremely difficult to colonize. No points of attachment exist for algae , so vegetation based habitat is not established. Sediment can also clog feeding and respiratory structures of species, and special adaptations exist within mudflat species to cope with this problem. Lastly, dissolved oxygen variation can cause problems for life forms. Nutrient-rich sediment from human-made sources can promote primary production life cycles, perhaps leading to eventual decay removing

679-426: A hinge joint and a ligament that can be internal or external. The ligament provides tension to bring the valves apart, whilst one or two adductor muscles can contract to close the valves. Clams also have kidneys, a heart, a mouth, a stomach, and a nervous system. Many have a siphon . Clams are shellfish that make up an important part of the web of life that keeps the seas functioning, both as filter feeders and as

776-608: A large area of marshland known as "the Reedbeds" across some of the present western suburbs. In 1937 a channel known as the Breakout Creek was constructed to take the Torrens westwards to the sea. The Port River is the western branch of the largest tidal estuary on the eastern side of Gulf St Vincent . It extends inland through the historic Inner Harbour of Port Adelaide , to the constructed salt-water West Lakes in

873-541: A large clam with an elongated triangular shell have expanded in recent years (to 2023). Near the outlet of the river, the mudflats are a breeding ground for blue swimmer crabs and other species. It is estimated that less than one percent of shellfish reefs around South Australia remain, compared with the 1940s. Around 1969, Pacific oysters ( Magallana gigas ) were introduced for aquaculture in South Australia. After an outbreak of disease in this species, in 2018

970-529: A number of coastal water bodies such as coastal lagoons and brackish seas. A more comprehensive definition of an estuary is "a semi-enclosed body of water connected to the sea as far as the tidal limit or the salt intrusion limit and receiving freshwater runoff; however the freshwater inflow may not be perennial, the connection to the sea may be closed for part of the year and tidal influence may be negligible". This broad definition also includes fjords , lagoons , river mouths , and tidal creeks . An estuary

1067-533: A one-way system that draws in seawater from the Gulf through an inlet off the coast at the southern end. The Lakes discharge into the upper reaches of the Port River at Ethelton. The water quality has improved since the reduced flows and improved quality of Bolivar sewerage, and since the closure of Penrice soda ash plant in Osborne in 2014. The soda ash plant was a major ammonia pollution source. Regular testing by

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1164-577: A powerful burrowing foot. They live in both freshwater and marine environments; in salt water they prefer to burrow down into the mud and the turbidity of the water required varies with species and location; the greatest diversity of these is in North America . Clams in the culinary sense do not live attached to a substrate (whereas oysters and mussels do) and do not live near the bottom (whereas scallops do). In culinary usage, clams are commonly eaten marine bivalves, as in clam digging and

1261-481: A railway bridge carrying the Outer Harbor railway line . Bower Road crosses the southern extremity of the river, with West Lakes on the other side. The banks of the river are largely industrialised and have some of Adelaide's wharves , bulk cargo and container handling facilities. Large ship transport vessels use the river's main channel. Port Adelaide is a tidal port, with several shipping berths along

1358-408: A type of ecosystem in some estuaries that have been negatively impacted by eutrophication. Cordgrass vegetation dominates the salt marsh landscape. Excess nutrients allow the plants to grow at greater rates in above ground biomass, however less energy is allocated to the roots since nutrients is abundant. This leads to a lower biomass in the vegetation below ground which destabilizes the banks of

1455-563: A well-mixed water column and the disappearance of the vertical salinity gradient . The freshwater-seawater boundary is eliminated due to the intense turbulent mixing and eddy effects . The lower reaches of Delaware Bay and the Raritan River in New Jersey are examples of vertically homogeneous estuaries. Inverse estuaries occur in dry climates where evaporation greatly exceeds the inflow of freshwater. A salinity maximum zone

1552-436: A wholly marine embayment to any of the other estuary types. The most important variable characteristics of estuary water are the concentration of dissolved oxygen, salinity and sediment load. There is extreme spatial variability in salinity, with a range of near-zero at the tidal limit of tributary rivers to 3.4% at the estuary mouth. At any one point, the salinity will vary considerably over time and seasons, making it

1649-477: A wide effect on the surrounding water bodies.  In turn, this can decrease fishing industry sales in one area and across the country. Production in 2016 from recreational and commercial fishing contributes billions of dollars to the United States' gross domestic product (GDP). A decrease in production within this industry can affect any of the 1.7 million people the fishing industry employs yearly across

1746-472: A wooden footbridge, which allowed people to move onto the Lefevre Peninsula. Before European settlement of Adelaide's western suburbs and the construction of various flood mitigation channels and levees , the Port River formed one of the outlets of the River Torrens . The Torrens used to flow north-west into the Port River, until sediment accumulated upstream built up, blocking the channels and forming

1843-455: Is a dynamic ecosystem having a connection to the open sea through which the sea water enters with the rhythm of the tides . The effects of tides on estuaries can show nonlinear effects on the movement of water which can have important impacts on the ecosystem and waterflow. The seawater entering the estuary is diluted by the fresh water flowing from rivers and streams. The pattern of dilution varies between different estuaries and depends on

1940-513: Is derived from the Latin word aestuarium meaning tidal inlet of the sea, which in itself is derived from the term aestus , meaning tide. There have been many definitions proposed to describe an estuary. The most widely accepted definition is: "a semi-enclosed coastal body of water, which has a free connection with the open sea, and within which seawater is measurably diluted with freshwater derived from land drainage". However, this definition excludes

2037-411: Is formed, and both riverine and oceanic water flow close to the surface towards this zone. This water is pushed downward and spreads along the bottom in both the seaward and landward direction. Examples of an inverse estuary are Spencer Gulf , South Australia, Saloum River and Casamance River , Senegal. Estuary type varies dramatically depending on freshwater input, and is capable of changing from

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2134-566: Is less restricted, and there is a slow but steady exchange of water between the estuary and the ocean. Fjord-type estuaries can be found along the coasts of Alaska , the Puget Sound region of western Washington state , British Columbia , eastern Canada, Greenland , Iceland , New Zealand, and Norway. These estuaries are formed by subsidence or land cut off from the ocean by land movement associated with faulting , volcanoes , and landslides . Inundation from eustatic sea-level rise during

2231-587: Is marked by six Kaurna significant sites, and interpretive signs explain many aspects of Kaurna culture and life on the estuary. (See also History, above.) There are ships' graveyards at Angas Inlet and Broad Creek in the Barker Inlet. Broad Creek contains the wrecks of the Dorothy S and No. 1 Hulk , while the remains in Angas Inlet are either not confirmed or unidentified recreational craft. Further up-river, with Ethelton on one side and Port Adelaide on

2328-576: Is now the corner of the Old Port Road and Frederick Road, at Royal Park / Queenstown . The McLaren Wharf was built in 1839, and the port was opened at its current location (now Port Adelaide) in October 1840. Port Adelaide became a hub for the oyster trade, owing to the abundance of native mud oysters and other shellfish in the river. Aquaculture took place from the late 1850s to the 1910s around Jervois Bridge, and oysters were also shipped to

2425-579: Is the Colorado River Delta in Mexico, historically covered with marshlands and forests, but now essentially a salt flat. Clam Clam is a common name for several kinds of bivalve mollusc . The word is often applied only to those that are edible and live as infauna , spending most of their lives halfway buried in the sand of the sea floor or riverbeds. Clams have two shells of equal size connected by two adductor muscles and have

2522-646: Is the whitefish species from the European Alps . Eutrophication reduced the oxygen levels in their habitats so greatly that whitefish eggs could not survive, causing local extinctions. However, some animals, such as carnivorous fish, tend to do well in nutrient-enriched environments and can benefit from eutrophication. This can be seen in populations of bass or pikes. Eutrophication can affect many marine habitats which can lead to economic consequences. The commercial fishing industry relies upon estuaries for approximately 68 percent of their catch by value because of

2619-463: The Santiago and Dorothy H. Sterling , as well as other sailing ships, steamships and iron barges. The ecology of the estuarine area includes and is dependent on the health of its component parts: the waters, intertidal zone , and lands on the shore. The area includes breeding and feeding grounds for several species of fish and prawn ; a combination of resident and migratory birds (including

2716-534: The Dee Estuary . The accidentally introduced hard-shell quahog is also found in British waters, mainly those near England, and does see some use in British cuisine. The Palourde clam by far is the most common native clam and it is both commercially harvested as well as locally collected, and Spisula solida , a relative of the Atlantic surf clam on the other side of the Atlantic, is seeing increased interest as

2813-566: The Environmental Protection Authority took place until 2008, after which only informal testing has occurred. In December 2016, SA Health testing showed very low counts of bacteria, enabling the annual "Long Swim" in the Inner Harbour to recommence after many decades of absence. Mangrove forests (consisting of only one species, Avicennia marina var resinifera ) remain at Ethelton and New Port, along

2910-528: The Giant Pacific octopus . Cultures around the world eat clams along with many other types of shellfish. In culinary use, within the eastern coast of the United States and large swathes of the Maritimes of Canada, the term "clam" most often refers to the hard clam , Mercenaria mercenaria . It may also refer to a few other common edible species, such as the soft-shell clam , Mya arenaria , and

3007-473: The Government of South Australia banned the collection of all shellfish in the Port River. This ban, combined with growing populations of native oysters and razorfish, has led to benefits, such as improving the water quality due to their filter feeding , and providing habitat favoured by other species, such as whiting, bream, and blue swimmer crabs. Estuary Most existing estuaries formed during

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3104-646: The Gulf St Vincent Important Bird Area , a number of ships' graveyards and other places of heritage interest. There are three road bridges and two railway bridges over the river. Its southern end abuts the West Lakes recreational body of water. Before British colonisation of South Australia , the Kaurna people called the Port River region and estuary Yerta Bulti (also spelt Yertabulti ), meaning "land of sleep or death", while

3201-748: The Holocene Epoch has also contributed to the formation of these estuaries. There are only a small number of tectonically produced estuaries; one example is the San Francisco Bay , which was formed by the crustal movements of the San Andreas Fault system causing the inundation of the lower reaches of the Sacramento and San Joaquin rivers . In this type of estuary, river output greatly exceeds marine input and tidal effects have minor importance. Freshwater floats on top of

3298-473: The Holocene epoch with the flooding of river-eroded or glacially scoured valleys when the sea level began to rise about 10,000–12,000 years ago. Estuaries are typically classified according to their geomorphological features or to water-circulation patterns. They can have many different names, such as bays , harbors , lagoons , inlets , or sounds , although some of these water bodies do not strictly meet

3395-800: The Konkan region of Maharashtra , clams are used in curries and side dishes, like Tisaryachi Ekshipi, which is clams with one shell on. Beary Muslim households in the Mangalore region prepare a main dish with clams called Kowldo Pinde. In Udupi and Mangalore regions, it is called marvai in the local Tulu language . It is used to prepare many dishes like marvai sukka , marvai gassi , and marvai pundi . In Japan, clams are often an ingredient of mixed seafood dishes. They can also be made into hot pot , miso soup or tsukudani . The more commonly used varieties of clams in Japanese cooking are

3492-610: The Mandovi estuary in Goa during the monsoon period. As tidal forcing increases, river output becomes less than the marine input. Here, current induced turbulence causes mixing of the whole water column such that salinity varies more longitudinally rather than vertically, leading to a moderately stratified condition. Examples include the Chesapeake Bay and Narragansett Bay . Tidal mixing forces exceed river output, resulting in

3589-640: The Mid-Atlantic coast, and Galveston Bay and Tampa Bay along the Gulf Coast . Bar-built estuaries are found in a place where the deposition of sediment has kept pace with rising sea levels so that the estuaries are shallow and separated from the sea by sand spits or barrier islands. They are relatively common in tropical and subtropical locations. These estuaries are semi-isolated from ocean waters by barrier beaches ( barrier islands and barrier spits ). Formation of barrier beaches partially encloses

3686-565: The Port River estuary , includes Barker Inlet , Torrens Island , Garden Island , and to a greater or lesser extent touches the suburbs of St Kilda , Bolivar , Dry Creek , Port Adelaide , New Port , and (up the eastern flank of the Lefevre Peninsula ), Taperoo , Osborne and Outer Harbor . Sections of the river bank are variously developed for shipping, industrial and increasingly, residential use. The rich ecosystem of

3783-734: The Severn Estuary in the United Kingdom and the Ems Dollard along the Dutch-German border. The width-to-depth ratio of these estuaries is typically large, appearing wedge-shaped (in cross-section) in the inner part and broadening and deepening seaward. Water depths rarely exceed 30 m (100 ft). Examples of this type of estuary in the U.S. are the Hudson River , Chesapeake Bay , and Delaware Bay along

3880-578: The Shijimi ( Corbicula japonica ), the Asari ( Venerupis philippinarum ) and the Hamaguri ( Meretrix lusoria ). The rocky terrain and pebbly shores of the seacoast that surrounds the entire island provide ample habitat for shellfish, and clams are most definitely included in that description. The oddity here is that for a nation whose fortunes have been tied to the sea for hundreds of years, 70% of

3977-565: The Worshipful Company of Fishmongers was founded in 1272 in London.) Present-day younger populations are eating more of the catch than a generation ago, and there is a prevalence of YouTube videos of locavore scavenging. Shellfish have provided a staple of the British diet since the earliest occupations of the British Isles, as evidenced by the large numbers of remains found in midden mounds near occupied sites. Staple favourites of

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4074-475: The black swans , as this was forbidden. The reeds , blue flax lily and rushes (probably Juncus kraussii , the salt marsh rush) were used for weaving baskets and nets – the latter used for not only fish, but game such as kangaroo and emu . Dolphins were known as yambo . At that time, a large sand dune known as the Gillman Dunal system stretched inland across the southern part of the area, where

4171-478: The black-tailed godwit , rely on estuaries. Two of the main challenges of estuarine life are the variability in salinity and sedimentation . Many species of fish and invertebrates have various methods to control or conform to the shifts in salt concentrations and are termed osmoconformers and osmoregulators . Many animals also burrow to avoid predation and to live in a more stable sedimental environment. However, large numbers of bacteria are found within

4268-578: The littoral zone : roseate spoonbills of North and South America, the Eurasian oystercatcher , whooping crane and common crane , the American flamingo of Florida and the Caribbean Sea, and the common sandpiper are just a handful of the numerous birds that feast on clams all over the world. Most species of octopus have clams as a staple of their diet, up to and including the giants like

4365-746: The tourism industry. ASC (formerly the Australian Submarine Corporation) has its construction and maintenance facility and dock at Osborne . There is a heritage-listed former Quarantine Station on Torrens Island and a small timber jetty adjacent to it. Torrens Island Power Station and the Pelican Point Power Station , draw seawater from the Port River for cooling purposes and return it at an elevated temperature. The worst environmental disaster to occur in South Australian marine waters

4462-408: The British public and local scavengers include the razorfish, Ensis siliqua , a slightly smaller cousin of the bamboo clam of eastern North America. These can be found for sale in open-air markets like Billingsgate Market in London; they have a similar taste to their North American cousin. Cockles, specifically the common cockle , are a staple find on beaches in western Wales and further north in

4559-695: The Eastern United States: Americardia media , also known as the strawberry cockle, is found from Cape Hatteras down into the Caribbean Sea and all of Florida; Trachycardium muricatum has a similar range to the strawberry cockle; and Dinocardium robustum , which grows to be many times the size of the European cockle. Historically, they were caught on a small scale on the Outer Banks , barrier islands off North Carolina, and put in soups, steamed or pickled. Up and down

4656-851: The Fish Market Pontoon, and the Unnamed Pontoon. Tam O'Shanter Creek is on the Port Adelaide side of the river here, and further north on the Glanville side is Hawker Creek . Mutton Cove Ships' Graveyard is within the Mutton Cove Conservation Reserve . The wreck of the former steel steamship Excelsior , later used as a coal hulk , lies at the northern end of the cove, near Pelican Point . The former iron barge, later paddleboat , known as Jupiter lies overgrown with mangroves towards

4753-466: The Port Adelaide location was known as Yartapuulti . The river is now officially known as the Port Adelaide River , while the name Port River is described in official sources as "a local variant." Prior to the 1836 British colonisation of South Australia , the river was a shallow and narrow tidal creek winding between mangrove swamps . At this time, it was inhabited by the Kaurna people , who occupied

4850-479: The Reedbeds wetlands, which drained north into the Port River and south to the Patawalonga River . In their natural state, the interconnected creeks and channels of the Port River estuary and Barker Inlet were surrounded by mudflats, mangroves, and saltmarshes colonised by samphires . Many of these remain, although the water flows have changed significantly. Tidal movement has a substantial influence on

4947-591: The U.S. West Coast, there are several species that have been consumed for thousands of years, evidenced by middens full of clamshells near the shore and their consumption by nations including the Chumash of California, the Nisqually of Washington state and the Tsawwassen of British Columbia . The butter clam, Saxidomus gigantea , the Pacific razor clam, Siliqua patula , gaper clams Tresus capax ,

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5044-400: The United States. Estuaries are incredibly dynamic systems, where temperature, salinity, turbidity, depth and flow all change daily in response to the tides. This dynamism makes estuaries highly productive habitats, but also make it difficult for many species to survive year-round. As a result, estuaries large and small experience strong seasonal variation in their fish communities. In winter,

5141-513: The above definition of an estuary and could be fully saline. Many estuaries suffer degeneration from a variety of factors including soil erosion , deforestation , overgrazing , overfishing and the filling of wetlands. Eutrophication may lead to excessive nutrients from sewage and animal wastes; pollutants including heavy metals , polychlorinated biphenyls , radionuclides and hydrocarbons from sewage inputs; and diking or damming for flood control or water diversion. The word "estuary"

5238-452: The bottom where they are harmless. Historically the oysters filtered the estuary's entire water volume of excess nutrients every three or four days. Today that process takes almost a year, and sediment, nutrients, and algae can cause problems in local waters. Some major rivers that run through deserts historically had vast, expansive estuaries that have been reduced to a fraction of their former size, because of dams and diversions. One example

5335-470: The coast of the Eastern U.S., the bamboo clam , Ensis directus , is prized by Americans for making clam strips , although because of its nature of burrowing into the sand very close to the beach, it cannot be harvested by mechanical means without damaging the beaches. The bamboo clam is also notorious for having a very sharp edge of its shell, and when harvested by hand must be handled with great care. On

5432-607: The coastal regions of India, especially in the Konkan, Kerala , Bengal and coastal regions of Karnataka , Tamil Nadu regions. In Kerala , clams are used to make curries and fried with coconut. In the Malabar region it is known as "elambakka" and in middle kerala it is known as "kakka". Clam curry made with coconut is a dish from Malabar especially in the Thalassery region. On the southwestern coast of India , also known as

5529-409: The dissolved oxygen from the water; thus hypoxic or anoxic zones can develop. Nitrogen is often the lead cause of eutrophication in estuaries in temperate zones. During a eutrophication event, biogeochemical feedback decreases the amount of available silica . These feedbacks also increase the supply of nitrogen and phosphorus, creating conditions where harmful algal blooms can persist. Given

5626-629: The ecology of the estuarine area's flora and marine fauna. Flows occur from the north (via Outer Harbor) and south (West Lakes, which draws in seawater via an engineered tunnel at Grange ). Since settlement and industrialisation, stormwater has caused pollution in the estuary. Industrial enterprises variously impacted the ecology, with nutrients boosting the growth of algal blooms , various contaminants reducing water quality. Temperature changes caused by effluents from gas-fired power stations at Torrens Island and Pelican Point persist. Sometimes high loads of solid materials have also been discharged into

5723-401: The effects of modifying the estuarine circulation. Fjord -type estuaries are formed in deeply eroded valleys formed by glaciers . These U-shaped estuaries typically have steep sides, rock bottoms, and underwater sills contoured by glacial movement. The estuary is shallowest at its mouth, where terminal glacial moraines or rock bars form sills that restrict water flow. In the upper reaches of

5820-405: The estuary area were known as Yerta Bulti (or Yertabulti ) by the Kaurna people , and used extensively as a source of food and plant materials to fashion artefacts used in daily life. The Port River dolphins are a popular tourist attraction. The Port River is the western branch of the largest tidal estuary on the eastern side of Gulf St Vincent . The whole estuarine area, sometimes called

5917-601: The estuary impacted by human activities, and over time may shift the basic composition of the ecosystem, and the reversible or irreversible changes in the abiotic and biotic parts of the systems from the bottom up. For example, Chinese and Russian industrial pollution, such as phenols and heavy metals, has devastated fish stocks in the Amur River and damaged its estuary soil. Estuaries tend to be naturally eutrophic because land runoff discharges nutrients into estuaries. With human activities, land run-off also now includes

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6014-424: The estuary, the depth can exceed 300 m (1,000 ft). The width-to-depth ratio is generally small. In estuaries with very shallow sills, tidal oscillations only affect the water down to the depth of the sill, and the waters deeper than that may remain stagnant for a very long time, so there is only an occasional exchange of the deep water of the estuary with the ocean. If the sill depth is deep, water circulation

6111-720: The estuary, with only narrow inlets allowing contact with the ocean waters. Bar-built estuaries typically develop on gently sloping plains located along tectonically stable edges of continents and marginal sea coasts. They are extensive along the Atlantic and Gulf coasts of the U.S. in areas with active coastal deposition of sediments and where tidal ranges are less than 4 m (13 ft). The barrier beaches that enclose bar-built estuaries have been developed in several ways: Fjords were formed where Pleistocene glaciers deepened and widened existing river valleys so that they become U-shaped in cross-sections. At their mouths there are typically rocks, bars or sills of glacial deposits , which have

6208-609: The fish community is dominated by hardy marine residents, and in summer a variety of marine and anadromous fishes move into and out of estuaries, capitalizing on their high productivity. Estuaries provide a critical habitat to a variety of species that rely on estuaries for life-cycle completion. Pacific Herring ( Clupea pallasii ) are known to lay their eggs in estuaries and bays, surfperch give birth in estuaries, juvenile flatfish and rockfish migrate to estuaries to rear, and anadromous salmonids and lampreys use estuaries as migration corridors. Also, migratory bird populations, such as

6305-462: The geoduck clam, Panopea generosa and the Pismo clam, Tivela stultorum are all eaten as delicacies. Clams can be eaten raw, steamed, boiled, baked or fried . They can also be made into clam chowder , clams casino , clam cakes , or stuffies , or they can be cooked using hot rocks and seaweed in a New England clam bake . On the West Coast, they are an ingredient in making cioppino and local variants of ceviche . Clams are eaten more in

6402-400: The great biodiversity of this ecosystem. During an algal bloom , fishermen have noticed a significant increase in the quantity of fish. A sudden increase in primary productivity causes spikes in fish populations which leads to more oxygen being utilized. It is the continued deoxygenation of the water that then causes a decline in fish populations. These effects can begin in estuaries and have

6499-420: The impacts do not end there. Plant death alters the entire food web structure which can result in the death of animals within the afflicted biome . Estuaries are hotspots for biodiversity , containing a majority of commercial fish catch, making the impacts of eutrophication that much greater within estuaries. Some specific estuarine animals feel the effects of eutrophication more strongly than others. One example

6596-673: The land from Cape Jervis in the south up the western side of the Fleurieu Peninsula , to Crystal Brook in the north, west to the Mount Lofty Ranges , across to Gulf Saint Vincent , including the Adelaide Plains and city of Adelaide . The Kaurna people made use of the natural resources ; for example, they used to trap and spear fish ( kuya ), lobsters ( ngaultaltya ) and birds ( parriparu ), and also gathered bird's eggs, black river mussels ( kakirra , species Alathyria jacksoni ), periwinkle ( kulutunumi ), river crawfish ( kunggurla – probably common yabby ), clams , native mud oysters and blue swimmer crabs . However, they did not kill

6693-496: The length of the estuary, from the western side of the Lefevre Peninsula, along Outer Harbor , Osborne , to its innermost berths at Inner Harbour. The shipping channel has been dredged at various instances since the establishment of Port Adelaide to accommodate larger vessels. Dredging occurred most recently between June and September 2019. That dredging widened the basin and deepened the channel in order to accommodate Post-Panamax container ships and larger cruise ships to benefit

6790-525: The many chemicals used as fertilizers in agriculture as well as waste from livestock and humans. Excess oxygen-depleting chemicals in the water can lead to hypoxia and the creation of dead zones . This can result in reductions in water quality, fish, and other animal populations. Overfishing also occurs. Chesapeake Bay once had a flourishing oyster population that has been almost wiped out by overfishing. Oysters filter these pollutants, and either eat them or shape them into small packets that are deposited on

6887-422: The marine environment, such as plastics , pesticides , furans , dioxins , phenols and heavy metals . Such toxins can accumulate in the tissues of many species of aquatic life in a process called bioaccumulation . They also accumulate in benthic environments, such as estuaries and bay muds : a geological record of human activities of the last century. The elemental composition of biofilm reflect areas of

6984-575: The marsh causing increased rates of erosion . A similar phenomenon occurs in mangrove swamps , which are another potential ecosystem in estuaries. An increase in nitrogen causes an increase in shoot growth and a decrease in root growth. Weaker root systems cause a mangrove tree to be less resilient in seasons of drought, which can lead to the death of the mangrove. This shift in above ground and below ground biomass caused by eutrophication could hindered plant success in these ecosystems. Across all biomes, eutrophication often results in plant death but

7081-482: The north-western suburbs of Adelaide . The lower reaches of the Port River flow between the Lefevre Peninsula , and the Section Banks and Torrens Island , and form the sea entrance to the port facilities of Adelaide. Section Banks is artificial island made of seashell -grit, clay and sand, around 1,600 metres (5,200 ft) long, created partly by natural processes but also by manmade construction, at

7178-584: The northern end of the Outer Harbor breakwater . It provides a nesting and breeding area for seabirds , and is known as Bird Island (or Northern Breakwater; see also below ). The Port River estuary connects to the Barker Inlet to the east via the North Arm to the south of Garden Island and Angas Inlet to its north. Light Passage lies between Pelican Point and Torrens Island. In 1878

7275-440: The now off-balance nitrogen cycle , estuaries can be driven to phosphorus limitation instead of nitrogen limitation. Estuaries can be severely impacted by an unbalanced phosphorus cycle, as phosphorus interacts with nitrogen and silica availability. With an abundance of nutrients in the ecosystem, plants and algae overgrow and eventually decompose, which produce a significant amount of carbon dioxide. While releasing CO 2 into

7372-697: The ocean quahog, Arctica islandica . Another species commercially exploited on the Atlantic Coast of the United States is the surf clam, Spisula solidissima . Scallops are also used for food nationwide, but not cockles : they are more difficult to get than in Europe because of their habit of being further out in the tide than European species on the West Coast, and on the East Coast they are often found in salt marshes and mudflats where mosquitoes are abundant. There are several edible species in

7469-621: The original Jervois Bridge opened, replacing the 1859 footbridge. It incorporated a swing bridge mechanism to allow ships to pass, but it fell into disrepair after the Birkenhead Bridge , which was the first bascule (moving) bridge in Australia, was opened in the 1940s. In 1966, the new Jervois Bridge opened, a steel bridge built a little way upstream of the original one. In the 2000s, the Port River Expressway

7566-535: The other, in a part of the river known as Port Creek , is the Jervois Basin Ships' Graveyard . Several wrecks lie in a "ship graveyard" between the Outer Harbor railway line bridge and the Jervois Bridge : the ketch Alert , barge Trafalgar , schooner Fides , the timber hulk Fitzjames (which was for some time a floating boys' reformatory , later relocated to Magill Reformatory ),

7663-622: The park. Jervois Creek was later filled in, and the current bridge (built 1969) was constructed over the oyster bed. The river was officially "discovered" in 1834 by Captain John Jones, after an 1831 sighting by Captain Collet Barker . The initial landing place in Adelaide, chosen by Colonel William Light in late November 1836, was south of the current port and is now part of West Lakes. It had such poor conditions that for many years it

7760-584: The people camped for years even after European settlement. The Lartelare Park, situated just north of the current Jervois Bridge on the western bank, in the suburb of New Port, was established in 2009 to commemorate the site of a Kaurna campsite which existed there for thousands of years until 1858, when it was relocated further south to the mouth of the Jervois Creek, where there was an oyster bed well known to both Kaurna and colonists. Numerous shell middens and tools were discovered during construction of

7857-522: The port from the Spencer Gulf . Owing to the shallow depth of the river, a new harbour was authorised for construction at Outer Harbor in 1902, and completed in 1908. This new harbour allowed the larger steamships that were then arriving at Adelaide to dock, with smaller steam vessels and sailboats able to use the old port facilities. The river was first bridged in 1859 by the Port Bridge

7954-524: The resulting soup, clam chowder . Many edible clams such as palourde clams are ovoid or triangular; however razor clams have an elongated parallel-sided shell, suggesting an old-fashioned straight razor. Some clams have life cycles of only one year, whilst at least one has been aged to more than 500 years. All clams have two calcareous shells or valves joined near a hinge with a flexible ligament and all are filter feeders . A clam's shell consists of two (usually equal) valves, which are connected by

8051-568: The river was formerly a frequent venue for the Intervarsity eights race . After water pollution levels were shown to have improved in December 2016, the annual "Long Swim" recommenced in the Inner Harbour, after a hiatus of some years. The Port Adelaide Kaurna Cultural Heritage Trail is marked nearby to the Ship's Graveyard, and extends to both sides of the river between the two bridges. It

8148-538: The river, and hyper-saline brine from adjacent saltfields. Since construction of the Breakout Creek outlet in 1937 to drain the Reedbeds (see above ), and the closure of the former Port Adelaide Wastewater Treatment Plant with the diversion of wastewater to Bolivar Waste Water Treatment Plant in 2005, the upper reaches of the Port River now receive only limited amounts of locally derived stormwater, and are now largely marine. Flushing of West Lakes occurs through

8245-486: The river, which includes mangroves , seagrass , waterbirds , and abundant marine life, has been historically impacted by industrialisation and associated pollution. In the 21st century, reductions in pollution loads have allowed for environmental recovery aided by several restoration programs. The estuary includes several overlapping protected areas , including the Adelaide Dolphin Sanctuary and

8342-415: The seafood cultivated for aquaculture or commercial harvesting is exported to the continent. Historically, Britain has been an island most famous for its passion for beef and dairy products, although there is evidence going back to before most recorded history of coastal shell middens near Weymouth and present day York. (There is also evidence of more thriving local trade in sea products in general by noting

8439-427: The seawater in a layer that gradually thins as it moves seaward. The denser seawater moves landward along the bottom of the estuary, forming a wedge-shaped layer that is thinner as it approaches land. As a velocity difference develops between the two layers, shear forces generate internal waves at the interface, mixing the seawater upward with the freshwater. An examples of a salt wedge estuary is Mississippi River and

8536-411: The sediment which has a very high oxygen demand. This reduces the levels of oxygen within the sediment often resulting in partially anoxic conditions, which can be further exacerbated by limited water flow. Phytoplankton are key primary producers in estuaries. They move with the water bodies and can be flushed in and out with the tides . Their productivity is largely dependent upon the turbidity of

8633-627: The shores of Torrens Island, the North Arm (which connects to Barker Inlet) and adjacent to the Mutton Cove Conservation Reserve on the Lefevre Peninsula. Fish and prawn species found in the estuary include western king prawns , King George Whiting , mullets , bream , and snapper . Attempts are being made to restore the once extensive reefs of shellfish , including native mud oysters ( ostrea angasi ), cockles , and razorfish ( pinna bicolor ), which had almost disappeared since European settlement. Beds of razorfish,

8730-440: The southern end of the park. The North Arm contains another significant ships graveyard, now known as Garden Island Ships' Graveyard , which includes 25 identified wrecks. It was also used to house explosives stores from the 1880s. The remains of the iron and wooden ships that were abandoned between 1909 and 1945 are now bird roosts and a canoeing attraction. The ships in the graveyard were launched from 1856 to 1920 and include

8827-456: The volume of freshwater, the tidal range, and the extent of evaporation of the water in the estuary. Drowned river valleys are also known as coastal plain estuaries. In places where the sea level is rising relative to the land, sea water progressively penetrates into river valleys and the topography of the estuary remains similar to that of a river valley. This is the most common type of estuary in temperate climates. Well-studied estuaries include

8924-453: The water and atmosphere, these organisms are also intaking all or nearly all of the available oxygen creating a hypoxic environment and unbalanced oxygen cycle . The excess carbon in the form of CO 2 can lead to low pH levels and ocean acidification , which is more harmful for vulnerable coastal regions like estuaries. Eutrophication has been seen to negatively impact many plant communities in estuarine ecosystems . Salt marshes are

9021-835: The water. The main phytoplankton present are diatoms and dinoflagellates which are abundant in the sediment. A primary source of food for many organisms on estuaries, including bacteria , is detritus from the settlement of the sedimentation. Of the thirty-two largest cities in the world in the early 1990s, twenty-two were located on estuaries. As ecosystems, estuaries are under threat from human activities such as pollution and overfishing . They are also threatened by sewage, coastal settlement, land clearance and much more. Estuaries are affected by events far upstream, and concentrate materials such as pollutants and sediments. Land run-off and industrial, agricultural, and domestic waste enter rivers and are discharged into estuaries. Contaminants can be introduced which do not disintegrate rapidly in

9118-521: Was also known as "Port Misery", later becoming known as the Old Port. In 1837 a harbour was declared when harbourmaster Captain Thomas Lipson took up residence on the shore of the then named port creek with the first migrants landing in the same year, onto the river bank lined with mangroves, until a canal was cut through them to a higher location in the sand dunes. A wharf was built at what

9215-718: Was constructed, with the road bridge across the Port River opening on 3 August 2008, named the Tom 'Diver' Derrick Bridge . The Expressway links Hanson Road, South Road and the Salisbury Highway with the port. A railway bridge was constructed as part of the project. Today the river is crossed by Mary MacKillop opening rail bridge , the Expressway bridge, the Birkenhead Bridge, the Jervois Bridge, and

9312-711: Was once eaten, overfishing drove it to the verge of extinction (it takes 15 to 35 years to reach adult size and could only be harvested by smashing the calcarean rocks that form its habitat) and the Italian government has declared it an endangered species since 1998 and its harvest and sale are forbidden. In Islam, clams are halal to eat as per three Sunni sects , but not in Hanafi, as only fish are considered halal in Hanafi jurisprudence , not other aquatic animals. In Judaism, clams are treif , i.e. non-kosher. Some species of clam, particularly Mercenaria mercenaria , were in

9409-470: Was the St Kilda salt fields brine spill , which killed of hectares of mangroves, samphires and other vegetation. As of 2022, elevated salinity levels in the estuary near the salt fields remain problematic. There are some remnant mangroves in places along the estuary. One of its main attractions other than transport is the Port River dolphins , which are the only wild dolphins in the world that live within

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