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60-531: Stromness Bay is a bay 3 miles (4.8 km) wide, entered between Cape Saunders and Busen Point on the north coast of South Georgia . Stromness Bay, like Leith Harbour takes its name from a location in Scotland, Stromness , on the Orkney Mainland . This is partially because both places called Stromness were whaling centres. The headland forming the southeast side of the entrance to Stromness Bay

120-441: A bay often reduces the strength of winds and blocks waves . Bays may have as wide a variety of shoreline characteristics as other shorelines. In some cases, bays have beaches , which "are usually characterized by a steep upper foreshore with a broad, flat fronting terrace". Bays were significant in the history of human settlement because they provided easy access to marine resources like fisheries . Later they were important in

180-453: A bay unless its area is as large as (or larger than) that of the semi-circle whose diameter is a line drawn across the mouth of that indentation — otherwise it would be referred to as a bight . There are various ways in which bays can form. The largest bays have developed through plate tectonics . As the super-continent Pangaea broke up along curved and indented fault lines, the continents moved apart and left large bays; these include

240-573: 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

300-529: 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

360-408: 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

420-563: 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

480-436: 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

540-477: 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

600-455: 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

660-541: Is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea . Estuaries form a transition zone between river environments and maritime environments and are an example of an ecotone . Estuaries are subject both to marine influences such as tides , waves , and the influx of saline water , and to fluvial influences such as flows of freshwater and sediment. The mixing of seawater and freshwater provides high levels of nutrients both in

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720-513: 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

780-411: 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

840-566: 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

900-582: Is named Busen Point . Bucentaur Rock lies close northeast of Busen Point. It was probably first seen in 1775 by Captain James Cook , and named in about 1912, presumably by Norwegian whalers who frequented its harbours. Its historical significance is that it represents the destination of Ernest Shackleton 's epic rescue journey in 1916. During the Second World War the whaling stations were closed except Grytviken and Leith Harbour . Most of

960-502: Is probably for Leganger Hansen, manager of the whaling station at Leith Harbor at that time. Harbour Point 54°09'S, 36°41'W A point separating Leith and Stromness Harbors, in Stromness Bay, South Georgia. This descriptive name was in use as early as 1920 and was probably applied by whalers operating from Stromness Bay. Harrison Point 54°10'S, 36°36'W A point marked by a string of off-lying rocks, lying 1.5 mi W of Busen Point on

1020-646: 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

1080-536: The Gulf of Guinea , the Gulf of Mexico , and the Bay of Bengal , which is the world's largest bay. Bays also form through coastal erosion by rivers and glaciers . A bay formed by a glacier is a fjord . Rias are created by rivers and are characterised by more gradual slopes. Deposits of softer rocks erode more rapidly, forming bays, while harder rocks erode less quickly, leaving headlands . Estuary An estuary

1140-748: 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

1200-610: 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

1260-640: 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

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1320-734: 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

1380-478: 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

1440-712: The Antarctic. Following the survey by SGS, 1951-52, the feature was renamed Bucentaur Rock after the floating factory Bucentaur, which was anchored at Husvik in the early years of the whaling station after 1907, and from which the Husvik transport Busen and the catchers Busen I, II, III, etc., derive their names. Brain Island 54°10'S, 36°42'W Island at the N side of Husvik Harbor, in Stromness Bay, South Georgia. Charted and named by DI personnel in 1928. Camana Rock 54°10'S, 36°37'W A rock midway between Kelp Point and Harrison Point in

1500-539: The British and Norwegian whaling factories and catchers were destroyed by German raiders, while the rest were called up to serve under Allied command. The resident British Magistrates (W. Barlas and A.I. Fleuret) attended to the island's defence throughout the War. The Royal Navy armed the merchant vessel Queen of Bermuda to patrol South Georgian and Antarctic waters, and deployed two four-inch guns at key locations protecting

1560-588: The S part of Stromness Bay, South Georgia. Mapped by DI personnel under Lt. Cdr. J.M. Chaplin in 1927 and 1929. Named in 1957 by the UK-APC for the sailing vessel Camana, owned by Tønsberg Hvalfangeri, Husvik, located at the head of Husvik Harbor in Stromness Bay. Discovery Rock 54°09'S, 36°35'W Submerged rock in Stromness Bay, lying 0.7 mi NNE of Ems Rock. The rock was positioned by Discovery Investigations personnel under Lt. Cdr. J.M. Chaplin, RN, who made surveys of Stromness Bay in 1927 and 1929. They probably applied

1620-671: The S side of Stromness Bay. Charted in 1927 by DI personnel and named Matthews Point for L. Harrison Matthews, British zoologist and member of the staff of the Discovery Investigations, 1924-35, who worked at South Georgia in 1924-27. In 1954, the UK-APC recommended that this name be altered to Harrison Point to avoid duplication with Matthews Point (also named for L. Harrison Matthews), a better known feature in Undine Harbor, South Georgia. This change allows Harrison Matthews' name to be retained for this feature, while

1680-525: The UK-APC for the sailing vessel Ems, owned by the Tønsberg Hvalfangeri, Husvik, located at the head of Husvik Harbor in Stromness Bay. Bucentaur Rock 54°09'S, 36°33'W The outermost of three rocks lying close NE of Busen Point, at the SE side of the entrance to Stromness Bay. The name Low Rock was given for this feature by DI personnel during their survey in 1927, but this name is used elsewhere in

1740-400: 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,

1800-403: The W side and close to the head of Leith Harbor. The name was probably given by whalers because of its nearness to Messrs. Salvesen and Company's whaling station near the head of Leith Harbor. Hansen Point 54°08'S, 36°41'W A point lying between Factory and Harbour Points on the W side of Leith Harbor. The name appears on a chart showing the results of surveys by DI personnel in 1927 and 1929, and

1860-513: 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"

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1920-505: The approaches to Cumberland Bay and Stromness Bay, i.e. to Grytviken and Leith Harbour respectively. These batteries (still present) were manned by volunteers from among the Norwegian whalers who were trained for the purpose. The three whaling stations, Husvik , Stromness and Leith Harbour were linked by a rough track along the beach. During the whaling era, whalers from Stromness and Husvik would use it to get to Leith Harbour to use

1980-606: The basis of local usage. Alert Cove 54°11'S, 36°42'W A small cove lying S of Kanin Point in Husvik Harbor, Stromness Bay. Charted by DI personnel in 1928 and is named after Alert, the motorboat used by the DI survey party. Alert Channel 54°10'S, 36°42'W A small channel between Whaler Channel and Bar Rocks, and leading to the head of Husvik Harbor in Stromness Bay, South Georgia. Charted by DI personnel in 1928 and named after Alert,

2040-452: 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

2100-542: The confusing duplication of names is avoided. Busen Point 54°09'S, 36°33'W Point forming the SE side of the entrance to Stromness Bay. The point was known at a much earlier date, but the name was first used on the charts based upon the 1927-29 survey by DI personnel. Named for the Busen, a Norwegian whaling transport vessel which was often stationed at the head of Husvik Harbor in Stromness Bay. Bar Rocks 54°10'S, 36°42'W Group of low rocks which lie near

2160-527: The development of sea trade as the safe anchorage they provide encouraged their selection as ports . The United Nations Convention on the Law of the Sea defines a bay as a well-marked indentation in the coastline, whose penetration is in such proportion to the width of its mouth as to contain land-locked waters and constitute more than a mere curvature of the coast. An indentation, however, shall not be regarded as

2220-409: 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

2280-401: 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

2340-506: The entrance to Stromness Harbor. It was known as Mutton Island as early as 1912, but since 1920 the name Grass Island has been consistently used. Bill Rock 54°09'S, 36°39'W Rock which lies 0.3 mi E of the S end of Grass Island in Stromness Bay, South Georgia. Charted and named in 1928 by DI personnel. Ems Rock 54°10'S, 36°35'W Rock midway between Harrison Point and Busen Point in the S part of Stromness Bay. Charted by DI personnel under Lt. Cdr. J.M. Chaplin in 1927 and 1929. Named in 1957 by

2400-601: 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

2460-424: 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

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2520-776: 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

2580-609: 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

2640-400: 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

2700-500: The head of Husvik Harbor. Charted by DI personnel in 1928 and so named by them, presumably because their presence obstructs or impedes vessels approaching the head of the harbor. Black Rocks 54°08'S, 36°38'W Small group of rocks 0.5 mi SE of Framnaes Point in the N part of Stromness Bay, South Georgia. The name Blenheim Rocks has appeared for these rocks, but since about 1930 the name Black Rocks has been used more consistently. Grass Island 54°09'S, 36°40'W Conspicuous island lying across

2760-420: 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

2820-453: The island's one cinema. Husvik Harbor 54°10'S, 36°40'W The southernmost of three harbors at the head of Stromness Bay, along the N coast of South Georgia. The name dates back to about 1912, and was probably given by Norwegian whalers who frequented the harbor and established a whaling station at its head. Kanin Point 54°11'S, 36°42'E A rocky point lying 2 mi WSW of Kelp Point on the S side of Husvik Harbor. The descriptive name Rocky Point

2880-525: 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

2940-422: 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

3000-575: 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

3060-503: The motorboat used by the DI survey party. \Clear Point 54°08'S, 36°40'W Point forming the NE side of the entrance to Leith Harbor. The name appears to be first used on a 1929 British Admiralty chart. Framnaes Point 54°08'S, 36°39'W Point 1 mi SW of Cape Saunders, on the N side of Stromness Bay, South Georgia. The name was given prior to 1920, probably by Norwegian whalers operating in the area. Factory Point 54°08'S, 36°41'W Small point on

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3120-486: The name, which is now well established in local use. Bay A bay can be the estuary of a river, such as the Chesapeake Bay , an estuary of the Susquehanna River . Bays may also be nested within each other; for example, James Bay is an arm of Hudson Bay in northeastern Canada . Some large bays, such as the Bay of Bengal and Hudson Bay, have varied marine geology . The land surrounding

3180-440: 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

3240-427: 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

3300-411: 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

3360-456: 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

3420-453: 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

3480-624: The water column and in sediment , making estuaries among the most productive natural habitats in the world. Most existing estuaries formed during 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

3540-835: 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

3600-406: Was given for this feature, probably by DI personnel who surveyed Husvik Harbor in 1928. This name is used elsewhere in the Antarctic. The SGS, 1951-52, reported that this feature is known at the Husvik whaling station as Kanin Point (the word Kanin meaning rabbit). The name presumably arose from one of several attempts made since 1872 to introduce rabbits into the island. Kanin Point is approved on

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