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90-626: The Treaty of Bissandugu was signed there on the 25 March 1887. The treaty had France obtain major rights of navigation on the Niger River , an important prelude to the French conqueests of West Africa . The treaty also delimited the Wassoulou Empire's borders with France and made the Wassoulou Empire a French protectorate. On April 9, 1891, the city was attacked and burned by French forces commanded by Colonel Louis Archinard during

180-637: A Berber language, in which "gher" means "watercourse", confusion could easily arise. Pliny connected these two rivers as one long watercourse which flowed (via lakes and underground sections) into the Nile, a notion which persisted in the Arab and European worlds – and further added the Senegal River as the "Ger" – until the 19th century. While the true course of the Niger was presumably known to locals, it

270-577: A sump to reduce nitrates and other nutrients in the water. Mangroves also appear in home aquariums , and as ornamental plants, such as in Japan . The Manzanar Mangrove Initiative is an ongoing experiment in Arkiko , Eritrea , part of the Manzanar Project founded by Gordon H. Sato , establishing new mangrove plantations on the coastal mudflats . Initial plantings failed, but observation of

360-556: A tropical rainforest biome may contain thousands of tree species, but this is not to say mangrove forests lack diversity. Though the trees are few in species, the ecosystem that these trees create provides a habitat for a great variety of other species, including as many as 174 species of marine megafauna . Mangrove plants require a number of physiological adaptations to overcome the problems of low environmental oxygen levels, high salinity , and frequent tidal flooding . Each species has its own solutions to these problems; this may be

450-603: A 2009 study by the World Resources Institute (WRI) indicates the ecosystems contribute US$ 174 to US$ 249 million per year to Belize's national economy. From 1990, in Tanzania, Adelaida K. Semesi led aresearch programme which resulted in Tanzania being one of the first countries to have an environmental management plan for mangroves. Nicknamed "mama mikoko" ("mama mangroves" in Swahili), Semesi also

540-668: A complex mosaic of adjacent vegetation types such as grasslands, saltmarshes, and woodlands, and this can mean that flexibility in foraging strategy and choice of foraging habitat may be advantageous for highly mobile forest birds. Relative to other forest types, mangroves support few bird species that are obligate habitat (mangrove) specialists and instead host many species with generalised foraging niches. Mangrove forests are home and sanctuaries for many of aquatic bird species, including: The intricate root system of mangrove forests makes them attractive to adult fish seeking food and juvenile fish seeking shelter. Mangrove forests are among

630-641: A drone in days, and at a fraction of the cost. Seventy percent of mangrove forests have been lost in Java , Indonesia . Mangroves formerly protected the island's coastal land from flooding and erosion. Wetlands International , an NGC based in the Netherlands, in collaboration with nine villages in Demak where lands and homes had been flooded, began reviving mangrove forests in Java. Wetlands International introduced

720-538: A habitat for microbial biofilms which are actively involved in different N-cycling pathways such as nitrification, denitrification and dissimilatory nitrate reduction to ammonium (DNRA). Colonizing the carapace of crabs may be advantageous for specific bacteria, because of host activities such as respiration, excretion, feeding and horizontal and vertical migrations. However, the ecological interactions between fiddler crabs and bacteria, their regulation and significance as well as their implications at scales spanning from

810-413: A higher concentration of white mangroves. Mangrove forests are an important part of the cycling and storage of carbon in tropical coastal ecosystems. Knowing this, scientists seek to reconstruct the environment and investigate changes to the coastal ecosystem over thousands of years using sediment cores. However, an additional complication is the imported marine organic matter that also gets deposited in

900-576: A low-cost alternative to wood and charcoal stoves. These may help in reducing the demand for charcoal. Mangroves have been reported to be able to help buffer against tsunami, cyclones, and other storms, and as such may be considered a flagship system for ecosystem-based adaptation to the impacts of climate change. One village in Tamil Nadu was protected from tsunami destruction—the villagers in Naluvedapathy planted 80,244 saplings to get into

990-417: A maximum potential of 0.316996250 Gt (6.9885710 × 10  lb) of CO 2 emissions . Globally, mangroves have been shown to provide measurable economic protections to coastal communities affected by tropical storms. Heterogeneity in landscape ecology is a measure of how different parts of a landscape are from one another. It can manifest in an ecosystem from the abiotic or biotic characteristics of

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1080-595: A quarter of the destruction of mangrove forests. Likewise, the 2010 update of the World Mangrove Atlas indicated that approximately one fifth of the world's mangrove ecosystems have been lost since 1980, although this rapid loss rate appears to have decreased since 2000 with global losses estimated at between 0.16% and 0.39% annually between 2000 and 2012. Despite global loss rates decreasing since 2000, Southeast Asia remains an area of concern with loss rates between 3.6% and 8.1% between 2000 and 2012. By far

1170-529: A small piece of iron and a pierced plastic bag with fertilizer containing nitrogen and phosphorus are buried with the propagule. As of 2007 , after six years of planting, 700,000 mangroves are growing; providing stock feed for sheep and habitat for oysters, crabs, other bivalves, and fish. Another method of restoring mangroves is by using quadcopters (which are able to carry and deposit seed pods). According to Irina Fedorenko, an amount of work equivalent to weeks of planting using traditional methods can be done by

1260-712: Is already occurring. The fine, anoxic sediments under mangroves act as sinks for a variety of heavy (trace) metals which colloidal particles in the sediments have concentrated from the water. Mangrove removal disturbs these underlying sediments, often creating problems of trace metal contamination of seawater and organisms of the area. Mangrove swamps protect coastal areas from erosion , storm surge (especially during tropical cyclones ), and tsunamis . They limit high-energy wave erosion mainly during events such as storm surges and tsunamis. The mangroves' massive root systems are efficient at dissipating wave energy. Likewise, they slow down tidal water enough so that its sediment

1350-407: Is an accepted version of this page (Period: 1971–2000)7,922.3 m /s (279,770 cu ft/s) The Niger River ( / ˈ n aɪ dʒ ər / NY -jər ; French : (le) fleuve Niger [(lə) flœv niʒɛʁ] ) is the main river of West Africa , extending about 4,180 kilometres (2,600 miles). Its drainage basin is 2,117,700 km (817,600 sq mi) in area. Its source

1440-497: Is deposited as the tide comes in, leaving all except fine particles when the tide ebbs. In this way, mangroves build their environments. Because of the uniqueness of mangrove ecosystems and the protection against erosion they provide, they are often the object of conservation programs, including national biodiversity action plans . Worldwide there are about 80 described species of mangroves that live along marine coasts. About 60 of these species are true mangroves which live only in

1530-889: Is in the Guinea Highlands in south-eastern Guinea near the Sierra Leone border. It runs in a crescent shape through Mali , Niger , on the border with Benin and then through Nigeria , discharging through a massive delta , known as the Niger Delta , into the Gulf of Guinea in the Atlantic Ocean . The Niger is the third-longest river in Africa, exceeded by the Nile and the Congo River . Its main tributary

1620-413: Is intersected by a complex network of tidal waterways, mudflats and small islands of salt-tolerant mangrove forests. The interconnected network of waterways makes almost every portion of the forest accessible by boat. The area is known as an important habitat for the endangered Bengal tiger , as well as numerous fauna including species of birds, spotted deer , crocodiles and snakes. The fertile soils of

1710-407: Is more readily consumed in the interior of the mangrove forest. Anthropogenic inputs may push the limits of survival in many mangrove microhabitats. For example, shrimp ponds constructed in mangrove forests are considered the greatest anthropogenic threat to mangrove ecosystems. These shrimp ponds reduce estuary circulation and water quality which leads to the promotion of diel-cycling hypoxia. When

1800-418: Is not becoming more carbon dense, then carbon has to be lost at a rate equal to the amount of carbon fixed as NPP. Hence this productivity is either retained within the mangrove forest, as a standing stock of live material such as wood, buried in sediments , or exported to neighbouring habitats as litter, particulate and dissolved organic carbon (POC and DOC) and dissolved inorganic carbon (DIC), or lost to

1890-463: Is only available for about half of the global area of mangroves. However, of those areas for which data has been collected, it appears that 35% of the mangroves have been destroyed. Since the 1980s, around 2% of mangrove area is estimated to be lost each year. Assessments of global variation in mangrove loss indicates that national regulatory quality mediates how different drivers and pressures influence loss rates. Shrimp farming causes approximately

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1980-477: Is part of the larger African massive physiographic division. The Niger River basin, located in western Africa , covers 7.5% of the continent and spreads over ten countries. Niger River basin: areas and rainfall by country within the basin rainfall in the basin (mm) Hydrometric stations on the Niger River kilometer (rkm) (m) (km ) start Average, minimum and maximum discharge of

2070-657: Is the Benue River . The Niger has different names in the different languages of the region: The earliest use of the name "Niger" for the river is by Leo Africanus in his Della descrittione dell’Africa et delle cose notabili che ivi sono , published in Italian in 1550. Nevertheless, "Nigris" was already the name of a river in West Africa, as mentioned by Pliny the Elder and Solinus, among others. Whether this river

2160-416: Is used, as this is connected to the sea and subjected to the tides, and less diseases occur, and as far less mangrove is destroyed for it. Grassroots efforts to protect mangroves from development and from citizens cutting down the mangroves for charcoal production , cooking, heating and as a building material are becoming more popular. Solar cookers are distributed by many non-government organizations as

2250-689: The Guinness Book of World Records . This created a kilometre-wide belt of trees of various varieties. When the 2004 tsunami struck, much of the land around the village was flooded, but the village suffered minimal damage. Compared to seagrass meadows and coral reefs , hypoxia is more common on a regular basis in mangrove ecosystems, through ocean deoxygenation is compounding the negative effects by anthropogenic nutrient inputs and land use modification. Like seagrass, mangrove trees transport oxygen to roots of rhizomes , reduce sulfide concentrations, and alter microbial communities. Dissolved oxygen

2340-498: The Kainji Dam , Shiroro Dam , Zungeru Dam , and Jebba Dam are used to generate hydropower. The water resources of the Niger River are under pressure because of increased water abstraction for irrigation. The construction of dams for hydropower generation is underway or envisaged in order to alleviate chronic power shortages in the countries of the Niger basin. The FAO estimates the irrigation potential of all countries in

2430-508: The Mandingo Wars . The French colonial administration re-established control in the area. Traces of the ancient fortifications of the city can still be found just outside the modern-day village. After Guinea attained independence, Ture's great-grandson Ahmed Sékou Touré was elected as the country's first president. This Guinea location article is a stub . You can help Misplaced Pages by expanding it . Niger River This

2520-591: The Scramble for Africa at the end of the 19th century. As part of the West Africa Sahel region, Niger River has a hot climate characterized by very high temperatures year-round; a long, intense dry season from October–May; and a brief, irregular rainy season linked to the West African monsoon. The Niger River is a relatively clear river, carrying only a tenth as much sediment as the Nile because

2610-588: The Wadi Ghir on the north-western edge of the Tuat , along the borders of modern Morocco and Algeria . This would likely have been as far as Ptolemy would have had consistent records. The Ni-Ger was likely speculation, although the name stuck as that of a river south of the Mediterranean's "known world". Suetonius reports Romans traveling to the "Ger", although in reporting any river's name derived from

2700-400: The red , white , and black mangroves occupy different ecological niches and have slightly different chemical compositions, so the carbon content varies between the species, as well between the different tissues of the plant (e.g., leaf matter versus roots). There is a clear succession of these three trees from the lower elevations, which are dominated by red mangroves, to farther inland with

2790-425: The 18th-century visits of Mungo Park , who travelled down the Niger River and visited the great Sahelian empires of his day, that Europeans correctly identified the course of the Niger and extended the name to its entire course. The modern nations of Nigeria and Niger take their names from the river, marking contesting national claims by colonial powers of the "upper", "lower" and "middle" Niger river basin during

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2880-592: The 1980s. The Niger takes one of the most unusual routes of any major river, a boomerang shape that baffled geographers for two centuries. Its source ( Tembakounda ) is 240 km (150 mi) inland from the Atlantic Ocean, but the river runs directly away from the sea into the Sahara Desert , then takes a sharp right turn near the ancient city of Timbuktu and heads southeast to the Gulf of Guinea . This strange geography apparently came about because

2970-519: The 5° N and 5° S latitudes. Approximately 75% of world's mangroves are found in just 15 countries. Estimates of mangrove area based on remote sensing and global data tend to be lower than estimates based on literature and surveys for comparable periods. In 2018, the Global Mangrove Watch Initiative released a global baseline based on remote sensing and global data for 2010. They estimated the total mangrove forest area of

3060-537: The Indian Sundarbans were assessed as endangered in 2020 under the IUCN Red List of Ecosystems framework. There is a consistent pattern of depleted biodiversity or loss of species and the ecological quality of the forest is declining. The unique ecosystem found in the intricate mesh of mangrove roots offers a quiet marine habitat for young organisms. In areas where roots are permanently submerged,

3150-571: The Inner Delta between Ségou and Timbuktu to seepage and evaporation. The water from the Bani River , which flows into the Delta at Mopti , does not compensate for the losses. The average loss is estimated at 31 km /year but varies considerably between years. The river is then joined by various tributaries but also loses more water to evaporation. The quantity of water entering Nigeria

3240-654: The Interior of Africa . Park proposed a theory that the Niger and Congo were the same river. Although the Niger Delta would seem like an obvious candidate, it was a maze of streams and swamps that did not look like the head of a great river. He died in 1806 on a second expedition attempting to prove the Niger-Congo connection. The theory became the leading one in Europe. Several failed expeditions followed; however

3330-412: The Niger River at Koulikoro (Upper Niger), Niamey (Middle Niger) and Lokoja (Lower Niger). Period from 2000/06/01 to 2024/05/31. Average discharge of the Niger River at Niger Delta (period from 2010 to 2018): Niger River at Lokoja average, minimum and maximum discharge (1946 to 2023): The main tributaries from the mouth: tributary tributary (km) (km ) (m /s) At

3420-467: The Niger River is two ancient rivers joined together. The upper Niger, from the source west of Timbuktu to the bend in the current river near Timbuktu , once emptied into a now dry lake to the east northeast of Timbuktu, while the lower Niger started to the south of Timbuktu and flowed south into the Gulf of Guinea. Over time upstream erosion by the lower Niger resulted in stream capture of the upper Niger by

3510-481: The Niger bend region also brought Islam to the region in approximately the 14th century CE. Much of the northern Niger basin remains Muslim today, although the southern reaches of the river tend to be Christian. Classical writings on the interior of the Sahara begin with Ptolemy , who mentions two rivers in the desert: the "Gir" (Γειρ) and farther south, the "Nigir" (Νιγειρ). The first has been since identified as

3600-922: The Niger river basin at 2.8 million hectares. Only 0.93m hectares (ha) were under irrigation in the late 1980s. The irrigation potential was estimated at 1.68m ha in Nigeria 0.56m ha in Mali, and the actual irrigated area was 0.67m ha and 0.19m ha. Mangrove forest Mangrove forests , also called mangrove swamps , mangrove thickets or mangals , are productive wetlands that occur in coastal intertidal zones . Mangrove forests grow mainly at tropical and subtropical latitudes because mangrove trees cannot withstand freezing temperatures. There are about 80 different species of mangroves, all of which grow in areas with low-oxygen soil, where slow-moving waters allow fine sediments to accumulate. Many mangrove forests can be recognised by their dense tangle of prop roots that make

3690-700: The Niger's headwaters lie in ancient rocks that provide little silt . Like the Nile, the Niger floods yearly; this begins in September, peaks in November, and finishes by May. An unusual feature of the river is the Inner Niger Delta , which forms where its gradient suddenly decreases. The result is a region of braided streams , marshes , and large lakes; the seasonal floods make the Delta extremely productive for both fishing and agriculture. The river loses nearly two-thirds of its potential flow in

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3780-479: The abundant Ocipodid crabs, mainly represented by fiddler crabs, do not permanently ventilate their burrows. These crabs may temporarily leave their burrows for surface activities, or otherwise plug their burrow entrance during tidal inundation in order to trap air. A recent study showed that these crabs can be associated with a diverse microbial community, either on their carapace or in their gut. The exoskeleton of living animals, such as shells or carapaces, offers

3870-425: The amount of carbon fixed by mangroves normally greatly exceeds the amount stored within the forest, although the scale of outwelling varies considerably between forests, due to differences in coastal geomorphology , tidal regimes, freshwater flow and productivity. In the 1990s, global estimates could account for 48% of the total global mangrove primary production of 218 ± 72 million tons C yr (see diagram on

3960-487: The areas where mangroves did survive by themselves led to the conclusion that nutrients in water flow from inland were important to the health of the mangroves. Trials with the Eritrean Ministry of Fisheries followed, and a planting system was designed to provide the nitrogen, phosphorus, and iron missing from seawater. The propagules are planted inside a reused galvanized steel can with the bottom knocked out;

4050-410: The atmosphere. The outwelling hypothesis argues that export of locally derived POC and DOC is an important ecosystem function of mangroves, which drives detrital based food webs in adjacent coastal habitats. Export of mangrove carbon has been estimated to make a significant trophic contribution to adjacent ecosystems. The theory of outwelling is supported by mass balance evaluations that show

4140-1102: The availability of energy-yielding electron acceptors and increase nitrogen turnover via direct excretion. Thus, macrofauna may alleviate nitrogen limitation by priming the remineralisation of refractory nitrogen (that is, the nitrogen that can't be biologically decomposed), reducing plant-microbe competition. Such activity ultimately promotes nitrogen recycling, plant assimilation and high nitrogen retention, as well as favours its loss by stimulating coupled nitrification and denitrification . Mangrove sediments are highly bioturbated by decapods such as crabs. Crab populations continuously rework sediment by constructing burrows, creating new niches, transporting or selectively grazing on sediment microbial communities. In addition, crabs can affect organic matter turnover by assimilating leaves and producing finely fragmented faeces, or by carrying them into their burrows. Therefore, crabs are considered important ecosystem engineers shaping biogeochemical processes in intertidal muddy banks of mangroves. In contrast to burrowing polychaetes or amphipods,

4230-541: The beginning of the river near Kissidougou in Guinea, walking at first till a raft could be used, then changing to various local crafts as the river broadened and changed. Two of them reached the ocean on March 25, 1947, with Ponty having left the expedition at Niamey , somewhat past the halfway mark. They carried a 16mm movie camera , the resulting footage giving Rouch his first two ethnographic documentaries: "Au pays des mages noirs", and "La chasse à l’hippopotame". A camera

4320-451: The brushwood, it serves to catch floating mangrove seeds and provide them with a stable base to germinate, take root and regrow. This creates a green belt of protection around the islands. As the mangroves mature, more sediment is held in the catchment area; the process is repeated until a mangrove forest has been restored. Eventually the protective structures will not be needed. By late 2018, 16 km (9.9 mi) of brushwood barriers along

4410-429: The chemistry of this peat and represent approximately 2% of above ground carbon storage in mangroves. As the nests are buried over time this carbon is stored in the sediment, and the carbon cycle continues. Mangroves are an important source of blue carbon . Globally, mangroves stored 4.19 Gt (9.2 × 10  lb) of carbon in 2012. Two percent of global mangrove carbon was lost between 2000 and 2012, equivalent to

4500-410: The coastline had been completed. A concern over reforestation is that although it supports increases in mangrove area it may actually result in a decrease in global mangrove functionality and poor restoration processes may result in longer term depletion of the mangrove resource. In terms of local and national studies of mangrove loss, the case of Belize's mangroves is illustrative in its contrast to

4590-500: The delta have been subject to intensive human use for centuries, and the ecoregion has been mostly converted to intensive agriculture, with few enclaves of forest remaining. Additionally, the Sundarbans serves a crucial function as a protective barrier for millions of inhabitants against floods that result from cyclones . Four protected areas in the Sundarbans are listed as UNESCO World Heritage Sites . Despite these protections,

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4680-746: The end of the African humid period around 5,500 years before present, the modern Sahara Desert, once a savanna , underwent desertification . As plant species sharply declined, humans migrated to the fertile Niger River bend region, with abundant resources including plants for grazing and fish. Like in the Fertile Crescent , many food crops were domesticated in the Niger River region, including yams , African rice ( Oryza glaberrima ), and pearl millet . The Sahara aridification may have triggered, or at least accelerated, these domestications. Agriculture, as well as fishing and animal husbandry, led to

4770-582: The environment. For example, coastal mangrove forests are located at the land-sea interface, so their functioning is influenced by abiotic factors such as tides, as well as biotic factors such as the extent and configuration of adjacent vegetation. For forest birds, tidal inundation means that the availability of many mangrove resources fluctuates daily, suggesting foraging flexibility is likely to be important. Mangroves also offer estuarine prey items, such as mudskippers and crabs, that are not found in terrestrial forest types. Further, mangroves are often situated in

4860-444: The equator because they cannot withstand freezing temperatures. Many mangrove forests can be recognised by their dense tangle of prop roots that make the trees appear to be standing on stilts above the water. This tangle of roots allows the trees to handle the daily rise and fall of tides, which means that most mangroves get flooded at least twice per day. The roots slow the movement of tidal waters , causing sediments to settle out of

4950-975: The global picture. A recent, satellite-based study —funded by the World Wildlife Fund and conducted by the Water Center for the Humid Tropics of Latin America and the Caribbean (CATHALAC)—indicates Belize's mangrove cover declined by a mere 2% over a 30-year period. The study was born out of the need to verify the popular conception that mangrove clearing in Belize was rampant. Instead, the assessment showed, between 1980 and 2010, under 16 km (6.2 sq mi) of mangroves had been cleared, although clearing of mangroves near Belize's main coastal settlements (e.g. Belize City and San Pedro)

5040-527: The idea of developing tropical versions of techniques traditionally used by the Dutch to catch sediment in North Sea coastal salt marshes. Originally, the villagers constructed a sea barrier by hammering two rows of vertical bamboo poles into the seabed and filling the gaps with brushwood held in place with netting. Later the bamboo was replaced by PVC pipes filled with concrete. As sediment gets deposited around

5130-998: The interface between the land, the ocean, and the atmosphere, and are centres for the flow of energy and matter between these systems. They have attracted much research interest because of the various ecological functions of the mangrove ecosystems, including runoff and flood prevention, storage and recycling of nutrients and wastes, cultivation and energy conversion. The forests are major blue carbon systems, storing considerable amounts of carbon in marine sediments , thus becoming important regulators of climate change . Marine microorganisms are key parts of these mangrove ecosystems. However, much remains to be discovered about how mangrove microbiomes contribute to high ecosystem productivity and efficient cycling of elements. There are about 80 different species of mangrove trees. All of these trees grow in areas with low-oxygen soil, where slow-moving waters allow fine sediments to accumulate. Mangrove forests grow only at tropical and subtropical latitudes near

5220-526: The intertidal zone between high and low tides. "Mangroves once covered three-quarters of the world's tropical coastlines, with Southeast Asia hosting the greatest diversity. Only 12 species live in the Americas. Mangroves range in size from small bushes to the 60-meter giants found in Ecuador. Within a given mangrove forest, different species occupy distinct niches. Those that can handle tidal soakings grow in

5310-475: The local fish populations, which are an essential food source. The environmental costs of shrimp farms in the mangrove forests grossly outweigh the economic benefits of them. Cessation of shrimp production and restoration of these areas reduce eutrophication and anthropogenic hypoxia. In some areas, mangrove reforestation and mangrove restoration is also underway. Red mangroves are the most common choice for cultivation, used particularly in marine aquariums in

5400-578: The lower Niger. The northern part of the river, known as the Niger bend , is an important area because it is the major river and source of water in that part of the Sahara. This made it the focal point of trade across the western Sahara and the centre of the Sahelian kingdoms of Mali and Gao . The surrounding Niger River Basin is one of the distinct physiographic sections of the Sudan province, which in turn

5490-511: The more productive and diverse ecosystems on the planet, despite limited nitrogen availability. Under such conditions, animal-microbe associations ( holobionts ) are often key to ecosystem functioning. An example is the role of fiddler crabs and their carapace -associated microbial biofilm as hotspots of microbial nitrogen transformations and sources of nitrogen within the mangrove ecosystem. Among coastal ecosystems, mangrove forests are of great importance as they account for three quarters of

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5580-398: The most damaging form of shrimp farming is when a closed ponds system (non- integrated multi-trophic aquaculture ) is used, as these require destruction of a large part of the mangrove, and use antibiotics and disinfectants to suppress diseases that occur in this system, and which may also leak into the surrounding environment. Far less damage occurs when integrated mangrove-shrimp aquaculture

5670-509: The mystery of the Niger would not be solved for another 25 years, in 1830, when Richard Lander and his brother became the first Europeans to follow the course of the Niger to the ocean. In 1946, three Frenchmen, Jean Sauvy, Pierre Ponty and movie maker Jean Rouch , former civil servants in the African French colonies , set out to travel the entire length of the river, as no one else seemed to have done previously. They travelled from

5760-405: The nitrogen supply was unlimited. In addition to species variation, different environmental conditions can also affect the nitrogen assimilation rates in mangrove plants. Because Cl ions can reduce protein synthesis and nitrogen assimilation , soil pore water salinity appears to be a negative factor that significantly alters the nitrogen uptake rates of mangrove plants. Adequate data

5850-415: The open sea, in sheltered bays, and on fringe islands. Trees adapted to drier, less salty soil can be found farther from the shoreline. Some mangroves flourish along riverbanks far inland, as long as the freshwater current is met by ocean tides." Mangroves can be found in 118 countries and territories in the tropical and subtropical regions of the world. The largest percentage of mangroves is found between

5940-596: The organic matter produced and retained in mangroves can slow the recycling of nutrients, particularly of nitrogen. Nitrogen limitation in such systems may be overcome by microbial nitrogen fixation when combined with high rates of bioturbation by macrofauna , such as crabs and lobsters. Bioturbation by macrofauna affect nitrogen availability and multiple nitrogen related microbial processes through sediment reworking, burrow construction and bioirrigation , feeding and excretion. Macrofauna mix old and fresh organic matter, extend oxic–anoxic sediment interfaces, increase

6030-542: The organisms they host include algae , barnacles , oysters , sponges , and bryozoa , which all require a hard surface for anchoring while they filter-feed. Shrimp and mud lobsters use the muddy bottoms as their home. Mangrove crabs eat the mangrove leaves, adding nutrients to the mangal mud for other bottom feeders. In at least some cases, the export of carbon fixed in mangroves is important in coastal food webs. Mangrove plantations host several commercially important species of fish and crustaceans. In Puerto Rico ,

6120-661: The plant litter and break it down chemically into organic compounds , minerals, carbon dioxide, and nitrogenous wastes . The intertidal existence to which these trees are adapted represents the major limitation to the number of species able to thrive in their habitat. High tide brings in salt water, and when the tide recedes, solar evaporation of the seawater in the soil leads to further increases in salinity. The return of tide can flush out these soils, bringing them back to salinity levels comparable to that of seawater. At low tide, organisms are exposed to increases in temperature and reduced moisture before being then cooled and flooded by

6210-587: The primary reason why, on some shorelines, mangrove tree species show distinct zonation. Small environmental variations within a mangal may lead to greatly differing methods for coping with the environment. Therefore, the mix of species is partly determined by the tolerances of individual species to physical conditions, such as tidal flooding and salinity, but may also be influenced by other factors, such as crabs preying on plant seedlings. Once established, mangrove roots provide an oyster habitat and slow water flow, thereby enhancing sediment deposition in areas where it

6300-416: The quality of the water degrades, the shrimp ponds are quickly abandoned leaving massive amounts of wastewater. This is a major source of water pollution that promotes ocean deoxygenation in the adjacent habitats. Due to these frequent hypoxic conditions, the water does not provide habitats to fish. When exposed to extreme hypoxia, ecosystem function can completely collapse. Extreme deoxygenation will affect

6390-472: The right). By incorporating information on carbon burial, CO 2 efflux and carbon outwelled as leaf litter , POC and DOC, the remaining 52% was thought outwelled as DIC, though there was insufficient data to confirm this. More recent assessments of DIC export at two sites in Australia ; supported the estimates of Bouillon et al. in 2008, although in 2014 Alongi suggested that only 40% of NPP

6480-504: The rise of settlements like Djenné-Djenno in the Inner Delta, now a World Heritage Site . The region of the Niger bend, in the Sahel , was a key origin and destination for trans-Saharan trade , fueling the wealth of great empires such as the Ghana , Mali, and Songhai Empires . Major trading ports along the river, including Timbuktu and Gao, became centers of learning and culture. Trade to

6570-410: The river Niger. As Timbuktu was the southern end of the principal Trans-Saharan trade route to the western Mediterranean , it was the source of most European knowledge of the region. Medieval European maps applied the name Niger to the middle reaches of the river, in modern Mali, but Quorra ( Kworra ) to the lower reaches in modern Nigeria , as these were not recognized at the time as being

6660-692: The river – the myth connecting the Niger to the Nile persisted. Many European expeditions to plot the river were unsuccessful. In 1788 the African Association was formed in England to promote the exploration of Africa in the hopes of locating the Niger, and in June 1796 the Scottish explorer Mungo Park was the first European to lay eyes on the middle portion of the river since antiquity (and perhaps ever). He wrote an account in 1799, Travels in

6750-529: The same river. When European colonial powers began to send ships along the west coast of Africa in the 16th and 17th centuries, the Senegal River was often postulated to be the seaward end of the Niger. The Niger Delta, pouring into the Atlantic through mangrove swamps and thousands of distributaries along more than 160 kilometres (100 mi), was thought to be coastal wetlands. It was only with

6840-495: The sediment through the tidal flushing of mangrove forests. Mangrove forests can decay into peat deposits because of fungal and bacterial processes as well as by the action of termites . It becomes peat in good geochemical , sedimentary, and tectonic conditions. The nature of these deposits depends on the environment and the types of mangroves involved. Termites process fallen leaf litter , root systems and wood from mangroves into peat to build their nests. Termites stabilise

6930-406: The single individual to the ecosystem are not well understood. Mangrove forests are amongst the world's most productive marine ecosystems, with net primary productivity (NPP) in the order of 208 Tg C yr . Mangrove forests achieve a steady state once the forest reaches maximum biomass at around 20–30 years through a constant process of mortality and renewal  so, assuming the living biomass

7020-443: The tide. Thus, for a plant to survive in this environment, it must tolerate broad ranges of salinity, temperature, and moisture, as well as several other key environmental factors—thus only a select few species make up the mangrove tree community. A mangrove swamp typically features only a small number of tree species. It is not uncommon for a mangrove forest in the Caribbean to feature only three or four tree species. For comparison,

7110-595: The trees appear to be standing on stilts above the water. This tangle of roots allows the trees to handle the daily rise and fall of tides, as most mangroves get flooded at least twice per day. The roots slow the movement of tidal waters, causing sediments to settle out of the water and build up the muddy bottom. Mangrove forests stabilise the coastline, reducing erosion from storm surges , currents, waves, and tides. The intricate root system of mangroves also makes these forests attractive to fish and other organisms seeking food and shelter from predators. Mangrove forests live at

7200-449: The tropical coastline and provide different ecosystem services. Mangrove ecosystems generally act as a net sink of carbon, although they release organic matter to the sea in the form of dissolved refractory macromolecules, leaves, branches and other debris. In pristine environments, mangroves are among the most productive ecosystems on the planet, despite growing in tropical waters that are often nutrient depleted. The refractory nature of

7290-472: The water and build up the muddy bottom. Mangrove forests stabilise the coastline, reducing erosion from storm surges, currents, waves, and tides. The intricate root system of mangroves makes these forests attractive to fishes and other organisms seeking food and shelter from predators. The main contribution of mangroves to the larger ecosystem comes from litter fall from the trees, which is then decomposed by primary consumers . Bacteria and protozoans colonise

7380-516: The world as of 2010 at 137,600 km (53,100 sq mi), spanning 118 countries and territories. Following the conventions for identifying geographic regions from the Ramsar Convention on Wetlands, researchers reported that Asia has the largest share (38.7%) of the world's mangroves, followed by Latin America and the Caribbean (20.3%), Africa (20.0%), Oceania (11.9%), and Northern America (8.4%). The largest mangrove forest in

7470-755: The world is in the Sundarbans . The Sundarban forest lies in the vast delta on the Bay of Bengal formed by the super confluence of the Brahmaputra and Meghna rivers with distributaries of the Ganges . The seasonally flooded Sundarbans freshwater swamp forests lie inland from the mangrove forests on the coastal fringe. The forest covers 10,000 km (3,900 sq mi) of which about 6,000 km (2,300 sq mi) are in Bangladesh. The Sundarbans

7560-483: Was a Council Member for the International Society for Mangrove Ecosystems . In May 2019, ORNL DAAC News announced that NASA 's Carbon Monitoring System (CMS), using new satellite-based maps of global mangrove forests across 116 countries, had created a new dataset to characterize the "distribution, biomass, and canopy height of mangrove-forested wetlands". Mangrove forests move carbon dioxide "from

7650-463: Was a mystery to the outside world until the late 18th century. The connection to the Nile River was made not simply because this was then known as the great river of " Aethiopia " (by which all lands south of the desert were called by Classical writers), but because the Nile like the Niger flooded every summer. Through the descriptions of Leo Africanus and even Ibn Battuta – despite his visit to

7740-469: Was estimated at 25 km /year before the 1980s and at 13.5 km /year during the 1980s. The most important tributary is the Benue River which merges with the Niger at Lokoja in Nigeria. The total volume of tributaries in Nigeria is six times higher than the inflow into Nigeria, with a flow near the mouth of the river standing at 177.0 km /year before the 1980s and 147.3 km /year during

7830-610: Was exported as DIC. Mangrove forests and coastal marshes are typically considered N-limited ecosystems because of their high primary production. Therefore, mangrove plants are highly efficient at utilising soil nitrogen, making them an important sink for excess nitrogen from upstream. However, different mangrove species may still utilise nitrogen at different efficiencies, even though they share similar nitrogen pathways (see diagram on right). Reported nitrogen assimilation rates in mangrove plants ranged from 2 to 8 μmol g h under ambient nitrogen conditions, and 19 to 251 μmol g h when

7920-400: Was relatively high. The rate of loss of Belize's mangroves—at 0.07% per year between 1980 and 2010—was much lower than Belize's overall rate of forest clearing (0.6% per year in the same period). These findings can also be interpreted to indicate Belize's mangrove regulations (under the nation's) have largely been effective. Nevertheless, the need to protect Belize's mangroves is imperative, as

8010-511: Was the same as the actual Niger, or rather the river also known as Ger (currently known as Oued Guir, in Morocco), is a matter of discussion. This Nigris was said to divide "Africa proper" from the land of the (Western) Ethiopians to the south, and its name (as well as that of the river Ger) might well come from the Berber phrase gr-n-grwn meaning "river of rivers", as the current Tuareg name for

8100-743: Was used to illustrate Rouch's subsequent book "Le Niger En Pirogue" (Fernand Nathan, 1954), as well as Sauvy's "Descente du Niger" (L'Harmattan, 2001). A typewriter was brought as well, on which Ponty produced newspaper articles he mailed out whenever possible. The water in the Niger River basin is partially regulated through dams. In Mali the Sélingué Dam on the Sankarani River is mainly used for hydropower but also permits irrigation. Two diversion dams, one at Sotuba just downstream of Bamako , and one at Markala , just downstream of Ségou , are used to irrigate about 54,000 hectares. In Nigeria

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