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54-598: Msangazi River is a river of Tanzania. It is part of the Pangani River basin. 6°05′20″S 37°36′29″E  /  6.089°S 37.608°E  / -6.089; 37.608 This article related to a river in Tanzania is a stub . You can help Misplaced Pages by expanding it . Pangani River For much of its length the river flows along the regional borders of Kilimanjaro Region and Manyara Region , before flowing into Tanga Region , which contains

108-573: 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

162-529: 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

216-408: 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

270-563: 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

324-436: 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

378-477: 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

432-460: Is Mount Kovu Kovu, 360 feet (110 m) in height, while on the south bank is a ridge 400 feet (120 m) high. Pombwe , one of the principal settlements on the river, is situated about 1 mile (1.6 km) west of Kovu Kovu. Above Pombwe, the West African oil palm grows, while below Pombwe, the trees are chiefly areca and coconut palms. The village of Lemkuna and the hamlet of Ngage are on

486-455: 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

540-478: Is a good deal of trade here, dhows loading and unloading on the river. Produce is brought down the river, principally on rafts made of the Moale palm, which are then broken up and become articles of commerce. In 1878, the most common crop cultivated on the river's banks was reported to be sugar. 5°26′S 38°58′E  /  5.433°S 38.967°E  / -5.433; 38.967 Estuary An estuary

594-541: 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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648-513: 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

702-411: 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

756-566: 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

810-673: Is one of Tanzania's nine drainage basins. Extending from the northern highlands to Tanzania's north-eastern coastline, the PB is approximately 56,300 square kilometres (21,700 sq mi) in size, of which 4,880 square kilometres (1,880 sq mi) is within Kenya. Five sub-basins comprise the basin: the Pangani River (43,650 square kilometres (16,850 sq mi)), the Umba River (8,070 square kilometres (3,120 sq mi)),

864-646: 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

918-748: 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

972-903: The International Union for Conservation of Nature (IUCN), the SNV Netherlands Development Organisation , the GIZ German Development Organisation and the local non-governmental organization PAMOJA . The project also receives funds from the government of Tanzania, IUCN, the European Commission , and the Global Environment Facility through the United Nations Development Programme . There

1026-610: 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

1080-640: 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

1134-575: The Moshi municipality in the Kilimanjaro Region. Its other two offices are in Arusha and Tanga . The PBWB consists of ten professionals from public institutions and private sector LGAs, UWSAs, and other committees. The river system is under pressure because of conflicting water uses and major overallocations of its water. Many farmers rely on the river for irrigation. Damming projects along

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1188-825: The Msangazi River (5,030 square kilometres (1,940 sq mi)), the Zigi River , and the Mkulumuzi River plus other coastal rivers (2,080 square kilometres (800 sq mi)). All of these empty into the Indian Ocean. The Pangani Basin Water Board (PBWB) was established in July 1991 under the Water Utilization (Control and Regulation) Act No. 42 of 1974. Its headquarters is in

1242-785: The Pare Mountains , the Usambara Mountains and the Wasegiia wilderness join the Pangani in its course. These include the Kibaya, Komkuza, Kwachigulu, Kwamwadyau and Mnyusi. Average monthly flow of Pangani measured at the hydrological station in Korogwe Estate, about 110 km above the mouth in m³ / s (1959–77). The Pangani flows stimulate time-dependent, like most rivers in the region. The Pangani Basin (PB)

1296-734: 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

1350-478: 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

1404-595: The 68 MW Pangani Power Station and the Pangani Falls Dam . There are several inhabited islands within the river. The river is full of crocodiles; hippopotami are scarcer in its lower parts. A main source of Pangani originates on Kilimanjaro, where it is the River Lumi . Lake Jipe may be considered a backwater of the Lumi. Below Lake Jipe and above the falls, the river is referred to as "Ruvu". Formerly

1458-400: 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,

1512-513: 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"

1566-452: 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

1620-409: 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

1674-401: 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

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1728-423: The entrance is a flat sandy beach that extends from the head of the bay. There are several settlements at the entrance, two on the northern and two on the southern bank. Historically, the town of Pangani , on the river's left bank, had a reputation for fevers. At its estuary , by Pangani town, the river is about 600 feet (180 m) in breadth, and 12–15 feet (3.7–4.6 m) deep. Several tributaries coming from

1782-601: 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

1836-424: 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

1890-776: 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

1944-609: 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

1998-400: 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

2052-420: 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

2106-767: The main course towards the sea was alternatively called "Ruvu" and "Pangani". Nowadays that has been settled as "Pangani" from the Nyumba ya Mungu reservoir to the Ocean. While the Swahili call it " Pangani " (meaning distribute or arrange), it is called " Luffu " by the Wasambara (indigenous to the Nderema area, on the three ridges nearer the coast) and the Zigua (who live on the river's islands). Almost all authorities agree that

2160-525: 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

2214-422: 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

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2268-575: 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

2322-440: 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

2376-539: The river "Rhaptus" of Ptolemy 's topographical maps is the Pangani of modern maps. The Pangani is 500 kilometres (310 mi) in length. One source of the river rises in Kilimanjaro, about 120 miles (190 km) from the sea. Known as the Lumi in this area, its course runs through Lake Jipe. The other is at Mount Meru in the west and is known as the Kikuletwa . Like all African rivers, its depth varies with

2430-510: The river have reduced the river's flow from several hundred cubic metres per second to less than 40 cubic metres per second (1,400 cu ft/s). This has affected coastal communities, which have seen large reductions in fish populations and saltwater intrusion In 2002, the Pangani River Basin Management Project was established to manage the basin's water resources. It receives technical assistance from

2484-399: The river is narrow. This section is not navigable for any considerable distance on account of the falls, which are about 30 miles (48 km) from the mouth. Approximately 4 miles (6.4 km) from the mouth, dense mangrove swamp covers the flatland between the hills on either side. In this area, near Teufelsfelsen, are higher land, a fertile area, and the arid Masai Steppe . On this bank

2538-418: The river's west bank, while Mvungwe and Meserani are on its eastern bank. The mouth is located 52 kilometres (32 mi) south of Tanga . The river is tidal for a distance of 22 miles (35 km) from the entrance. The southern side of the entrance is marked by a perpendicular bluff named Bweni, about 200 feet (61 m) high; there is a village of the same name, Bweni, situated here. The northern side of

2592-733: The season. The river is highest around May and lowest around October. Another source is the Saunyi River in Kilindi District . It is navigable for small craft between the lake and the Höhnel Cataracts , a series of rapids. Below the Höhnel Cataracts, it has numerous tributaries, and many islands with villages on them. The stream is strongest above Koleni , within 5 miles of the Pangani Falls, where

2646-427: 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

2700-411: 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

2754-456: 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

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2808-453: 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

2862-624: 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

2916-835: 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

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