Marginal sea of the northeastern indian Ocean

torso of water

Andaman Sea
Burmese name
Burmese ကပ္ပလီပင်လယ်
IPA Kappale Painlaal
Thai name
Thai

ทะเลอันดามัน

RTGS Thale Xạndāmạn
Malay name
Malay Laut Andaman
Indonesian name
Indonesian Laut Andaman
Bengali name
Bengali

আন্দামান সাগর

Hindi name
Hindi

अंडमान सागर

The Andaman Sea ( historically besides known as the Burma Sea ) [ 4 ] is a marginal sea of the northeastern amerind Ocean bounded by the coastlines of Myanmar and Thailand along the Gulf of Martaban and west side of the Malay Peninsula, and separated from the Bay of Bengal to its west by the Andaman Islands and the Nicobar Islands. Its southerly end is at Breueh Island good north of Sumatra, with the Strait of Malacca farther southeast. traditionally, the sea has been used for fishery and transportation system of goods between the coastal countries and its coral reefs and islands are popular tourist destinations. The fishery and tourist infrastructure was hard damaged by the 2004 indian Ocean earthquake and tsunami .

geography [edit ]

localization [edit ]

The Andaman Sea, which extends over 92°E to 100°E and 4°N to 20°N, occupies a very meaning status in the indian Ocean, yet remained undiscovered for long period of time. To the south of Myanmar, west of Thailand, and north of Indonesia, this ocean is separated from Bay of Bengal by the Andaman and Nicobar Islands and an consort range of sea mounts along the Indo – burmese plate boundary. The Strait of Malacca ( between Malay Peninsula and Sumatra ) forms the southern exit way of the basin, which is 3 kilometer wide and 37 megabyte deep .

extent [edit ]

The International Hydrographic Organization defines the limits of the “ Andaman or Burma Sea ” as follows : [ 4 ] : p.21

On the Southwest. A course running from “Oedjong Raja” [ “Ujung Raja” or “Point Raja” ] ( ) in Sumatra to Poeloe Bras ( Breuëh ) and on through the westerly Islands of the Nicobar Group to Sandy Point in Little Andaman Island, in such a way that all the narrow waters appertain to the Burma Sea. On the Northwest. The Eastern specify of the Bay of Bengal [ A argumentation running from Cape Negrais ( 16°03’N ) in Burma [ Myanmar ] through the larger islands of the Andaman group, in such a way that all the narrow-minded waters between the islands lie to the Eastward of the production line and are excluded from the Bay of Bengal, adenine far as a target in Little Andaman Island in latitude 10°48’N, longitude 92°24 ‘ E ] .
On the Southeast. A occupation joining Lem Voalan ( 7°47’N ) in Siam [ Thailand ], and Pedropunt ( 5°40’N ) in Sumatra .

Oedjong means “ cape “ and Lem means “ point in dutch terminology on maps of the Netherlands East Indies ( Indonesia ). [ 5 ] Lem Voalan [ Phromthep Cape ] is the southern extremity of Goh Puket ( Phuket Island ). [ 6 ]

exclusive economic zone [edit ]

exclusive economic zones in Andaman Sea : [ 7 ]

geology [edit ]

Satellite prototype of the Andaman Sea showing the green alga and silt up deposits due to the Irrawaddy River in its northerly part The northern and eastern side of the river basin is shoal, as the continental ledge off the coast of Myanmar and Thailand extends over 200 km ( marked by 300 m isobath ). About 45 percentage of the basin area is shallower ( less than 500 thousand depth ), which is the direct consequence of the presence of the broad shelf. The continental gradient which follows the easterly shelf is quite steep between 9°N and 14°N. here, the position view of the submarine topography sectioned along 95°E exposes the abrupt resurrect in astuteness of ocean by about 3,000 m within a short horizontal distance of a degree. Isobaths corresponding to 900 m and 2000 megabyte are besides shown in the design to emphasize the abruptness of the slope. promote, it may be noted that the deep ocean is besides not dislodge from sea mounts ; hence entirely around 15 percentage of the sum sphere is deeper than 2,500 m. [ 3 ] [3] The bathymetry ( in metres ) of the Andaman Sea in 2D and 3D ( sectioned along 95°E ) [3] percentage of total area of Andaman Sea corresponding to different depth ranges The northerly and easterly parts are shallower than 180 meters ( 590 feet ) ascribable to the silt up deposited by the Irrawaddy River. This major river flows into the sea from the union through Myanmar. The western and central areas are 900–3,000 meters ( 3,000–9,800 foot ) deep. Less than 5 % of the ocean is deeper than 3,000 meters ( 9,800 feet ), and in a system of bomber valleys east of the Andaman-Nicobar Ridge, the depth exceeds 4,000 meters ( 13,000 feet ). [ 2 ] The ocean floor is covered with pebbles, annoy, and sand. [ 1 ] The western boundary of the Andaman Sea is marked by volcanic islands and sea mounts, with straits or passages of variable depths that control the entrance and exit of water to the Bay of Bengal. There is a drastic change in water depth over a short circuit distance of 200 km, as one moves from the Bay of Bengal ( around 3,500 m deep ) to the vicinity of islands ( up to 1,000 m astuteness ) and further into the Andaman Sea. Water is exchanged between the Andaman Sea and the Bay of Bengal through the straits between the Andaman and Nicobar Islands. Out of these, the most authoritative straits ( in terms of width and astuteness ) are : Preparis Channel ( personal computer ), Ten Degree Channel ( TDC ), and Great Channel ( GC ). personal computer is the widest but shallowest ( 250 meter ) of the three and separates south Myanmar from north Andaman. TDC is 600 thousand cryptic and lies between Little Andaman and Car Nicobar. GC is 1,500 meter deep and separates Great Nicobar from Banda Aceh .

Ocean floor tectonics [edit ]

tectonic put of Sumatra earthquake ( 2004 ) Running in a rough north–south line on the ocean floor of the Andaman Sea is the boundary between two tectonic plates, the Burma Plate and the Sunda Plate. These plates ( or microplates ) are believed to have once been region of the larger eurasian Plate, but were formed when transform demerit activity intensified as the indian Plate began its meaty collision with the eurasian celibate. As a result, a back-arc basin center was created, which began to form the marginal basin which would become the Andaman Sea, the stream stages of which commenced approximately 3–4 million years ago ( Ma ). [ 8 ] The boundary between two major tectonic plates results in high seismic natural process in the region ( visualize list of earthquakes in Indonesia ). numerous earthquakes have been recorded, and at least six, in 1797, 1833, 1861, 2004, 2005, and 2007, had the magnitude of 8.4 or higher. On 26 December 2004, a bombastic part of the limit between the Burma plate and the Indo-Australian denture slipped, causing the 2004 indian Ocean earthquake. This megathrust earthquake had a order of magnitude of 9.3. between 1,300 and 1,600 kilometres ( 810 and 990 security service ) of the boundary undergo drive blame and shifted by about 20 metres ( 66 foot ), with the sea floor being uplift several meters. [ 9 ] This upgrade in the ocean deck generated a massive tsunami with an estimate height of 28 meters ( 92 feet ) [ 10 ] that killed approximately 280,000 people along the coast of the indian Ocean. [ 11 ] The initial quiver was followed by a serial of aftershocks along the arc of the Andaman and Nicobar Islands. The entire event sternly damaged the fish infrastructure. [ 12 ] : 40–42

volcanic natural process [edit ]

eruption of the Barren Island volcano in 1995. Andaman Islands ( on peak ) are c. 90 kilometer distant Within the sea, to the east of the main Great Andaman island group, lies Barren Island, the only presently active vent associated with the indian subcontinent. This island-volcano is 3 kilometer ( 2 mile ) in diameter and rises 354 metres ( 1,161 foot ) above ocean level. Its holocene action resumed in 1991 after a lull time period of about 200 years. [ 13 ] It is caused by the ongoing subduction of the India home plate below the Andaman island arch, which forces magma to rise in this placement of the Burma plate. The last eruption started on 13 May 2008 and even continues. [ 14 ] The volcanic island of Narcondam, which lies further north, was besides formed by this process. No records exist of its activity. [ 15 ]

Sediments to the Sea [edit ]

jointly, the modern Ayeyarwady ( Irrawaddy ) and Thanlwin ( Salween ) rivers deliver > 600 Mt/yr of sediment to the sea. [ 16 ] Most holocene stuy show : 1 ) There is little modern sediment accumulating on the ledge immediately off the Ayeyarwady River mouths. In contrast, a major mud hacek with a distal depocenter, up to 60 m in thickness, has been deposited offshore in the Gulf of Martaban, extending to ~130 megabyte water depth into the Martaban Depression. Further, 2 ) There is no evidence showing that modern sediment has accumulated or is transported into the Martaban Canyon ; 3 ) There is a mud drape/blanket wrapping around the narrow-minded western Myanmar Shelf in the easterly Bay of Bengal. The thickness of the mud situate is up to 20 m nearshore and gradually thins to the gradient at −300 m water depth, and probably escapes into the abstruse Andaman Trench ; 4 ) The estimated sum sum of Holocene sediments deposited offshore is ~1290 × 109 tons. If we assume this has chiefly accumulated since the middle Holocene highstand ( ~6000 year BP ) like other major deltas, the historical annual hateful depositional flux on the ledge would be 215 Mt/yr, which is equivalent to ~35 % of the modern Ayeyarwady-Thanlwin rivers derived sediments ; 5 ) Unlike other big river systems in Asia, such as the Yangtze and Mekong, this analyze indicates a bi-directional transportation and depositional model controlled by the local currents that are influenced by tides, and seasonally varying monsoons winds and waves. [ 16 ]

climate [edit ]

The climate of the Andaman Sea is determined by the monsoons of southeast Asia, [ 3 ] as the predominate winds reverse with the begin of either season. The region experiences north-easterlies with an average windspeed of 5 m/s ( 18 kilometers per hour ) in the months of November-February. During these months, the western separate of the knowledge domain experiences maximum wind instrument volume. It weakens by March–April and reverses to strong south-westerlies from May to September, with intend wind speeds touching 8 m/s ( 29 kilometers per hour ) in June, July and August, distributed near-uniformly over the entire river basin. Wind speeds plummet by October and switch back to north-easterlies from November .
[3] monthly averaged winds in the Andaman Sea for the year 2011, expressed in mps Air temperature is stable over the year at 26 °C in February and 27 °C in August. haste is american samoa senior high school as 3,000 mm/year and largely occurs in summer. Sea currents are south-easterly and easterly in winter and south-westerly and prevailing westerly in summer. The average surface water temperature is 26–28 °C in February and 29 °C in May. The water temperature is constant at 4.8 °C at the depths of 1,600 m and downstairs. Salinity is 31.5–32.5‰ ( parts per thousand ) in summer and 30.0–33.0‰ in winter in the southern part. In the northern part, it decreases to 20–25‰ due to the inflow of fresh urine from the Irrawaddy River. Tides are semidiurnal with an amplitude of up to 7.2 metres ( 24 foot ). [ 1 ] [3] monthly averaged Ekman pumping speed ( in thousand per day ) for June and December The effect of fart tension on the ocean open can be explained by wind stress curl. The net discrepancy of water in the ocean blend layer results in Ekman pumping. [ 3 ] The contrast between the two seasons elicits a very impregnable negative pumping speed of more than 5 molarity ( 16 foot ) per day along the north seashore of Indonesia from May to September ( shown here, June ). This may signify coastal downwelling in the summer. It is besides observed that the region develops a weak but positive pump speed of less than 3 thousand ( 9.8 foot ) per sidereal day at the mouth of GC in winter ( here, December ) .

stream and beckon fluid dynamics [edit ]

[3] monthly averaged OSCAR surface currents in January, April, June and October, expressed in cm/s by and large, currents are found to be stronger in the south than any early character of the basin. [ 3 ] An acute surface outflux through GC, of the order of 40 cm/s, occurs during summers and winters. While this flow is directed westwards in winter, it is southwards along the west coast of Indonesia in summer. On the other hand, the TDC has strong surface inflow in summer, which weakens by October. This is followed by a hardy outflux in winter, which wanes by the calendar month of April. Although the surface flow through personal computer is broadly inward during summer monsoon, the precede and succeed months feel escape ( impregnable escape in October, but weak outflow in April ). During April and October, when the effects of local winds are minimal, Andaman Sea experiences the intensification of meridional surface currents in the poleward direction along the continental gradient on the easterly side of the basin. This is characteristic of the propagation of Kelvin Waves. [ 3 ] [ 17 ] [3] temporal variations of the washbasin rain, river inflow, and sea coat altitude anomaly, expressed in volume of water It is observed that the water level rises in the basin between April and November with the maximum rate of piling up of urine during April and October ( marked by the steep slope of the curve ). [ 3 ] The rise in sea surface stature ( SSH ) is attributed to rainfall, clean urine inflow from rivers, and inflow of water system through the three major straits. The first two of these are quantifiable and are hence expressed in volumes of water for comparison. From this, the expected inflow through the straits ( = SSH anomaly – Rainfall – River Influx ) could be deduced. A possible fourthly factor, evaporative losses, is negligible in comparison. ( previous studies [ 18 ] display that the annual mean fresh water gain ( haste minus vaporization ) of the Andaman Sea is 120 curium per year. ) It is found that the SSH of the basin is chiefly determined by the transportation of water through the straits. The contributions from rain and rivers become solid only during summer. Hence, a final in stream occurs through the straits between April and November, followed by a net outbound transportation until March. [ 17 ] temporal magnetic declination of depth of 20-degree isotherm ( 95°E to 96°E averaged ) in metres evolution of relative vorticity in Andaman Sea The washbasin has a very high rate of ecstasy of water through the straits in April and October. This is a time period of equatorial Wyrtki jets, which hit the coast of Sumatra and reflect back as Rossby waves and coastal Kelvin waves. These Kelvin waves are guided along the eastern boundary of indian Ocean, and a separate of this bespeak propagates into the Andaman Sea. The northern slide of Sumatra is the inaugural to be affected. The 20 °C isotherm which deepens [ 3 ] during the lapp menstruation is indicative of the downwelling nature of Kelvin waves. The waves further propagate along the easterly boundary of the Andaman Sea, which is confirmed by the differential deepening of the 20-degree isotherm along longitudes 94°E and 97°E ( averaged over latitudes 8°N and 13°N ). These longitudes are chosen sol that one represents the western part of the basin ( 94°E ) and the other along the steep continental slope on the eastern side of the basin ( 97°E ). It is observed that both these longitudes experience deepening of the isotherms in April and October, but the effect is more marked at 97°E ( isotherms deepen by 30m in April and 10m in October ). This is a concrete signature of downwelling in the basin and is decidedly not forced [ 3 ] locally as the winds are weaker during this period. This confirms unambiguously that the sudden explosion of water into the washbasin through the straits, the intensification of easterly boundary currents and the coincident deepening of isotherms in April and October are the aim consequence of the generation of downwelling Kelvin waves in the Andaman Sea, remotely forced by equatorial Wyrtki jets. [ 3 ] The development of vorticity in the basin is suggestive of strong shear in the flow during unlike times of the class, and far indicates the bearing of low frequency geophysical waves ( such as westbound propagating Rossby waves ) and other transient eddies .

ecology [edit ]

Flora [edit ]

Mangrove trees on the slide, Neil Island, Andaman and Nicobar Islands The coastal areas of the Andaman Sea are characterized by mangrove forests and seagrass meadows. Mangroves cover between more than 600 km2 ( 232 sq myocardial infarction ) of the Thai shores of Malay Peninsula whereas seagrass meadows occupy an area of 79 km2 ( 31 sq mile ). [ 12 ] : 25–26 Mangroves are largely responsible for the high productivity of the coastal waters – their roots trap territory and sediment and provide protection from predators and nursery for pisces and small aquatic organisms. Their body protects the shore from the wind and waves, and their debris are a part of the aquatic food chain. A significant separate of the Thai mangrove forests in the Andaman Sea was removed during the across-the-board brackish water prawn farming in 1980s [ citation needed ]. Mangroves were besides importantly damaged by the 2004 tsunami. They were partially replanted after that, but their area is still gradually decreasing due to human activities. [ 12 ] : 6–7 early significant sources of nutrients in the Andaman Sea are seagrass and the mud bottoms of lagoons and coastal areas. They besides create a habitat or worldly shelter for many burrow and benthic organisms. many aquatic species migrate from and to seagrass either daily or at sealed stages of their liveliness cycle. The human activities which damage seagrass beds include pine away water discharge from coastal diligence, shrimp farms and early forms of coastal development, adenine well as trawl and the use of push nets and dragnets. The 2004 tsunami affected 3.5 % of seagrass areas along the Andaman Sea via siltation and sandpaper deposit and 1.5 % suffered sum habitat loss. [ 12 ] : 7

Fauna [edit ]

dugong starfish, Andaman Sea The sea waters along the Malay Peninsula favor molluscan growth, and there are about 280 edible pisces species belonging to 75 families. Of those, 232 species ( 69 families ) are found in mangroves and 149 species ( 51 families ) reside in seagrass ; thus 101 species are common to both habitats. [ 12 ] : 26 The sea besides hosts many vulnerable animal species, including dugong ( Dugong dugon ), respective dolphinfish species, such as Irrawaddy dolphinfish ( Orcaella brevirostris ) and four species of sea turtles : critically endangered leatherback turtle turtleneck ( Dermochelys coriacea ) and hawksbill turtle turtle ( Eletmochelys imbricata ) and threatened green capsize ( Chelonia mydas ) and olive ridley turtle ( Lepidochelys olivacea ). There are only about 150 dugongs in the Andaman Sea, scattered between Ranong and Satun Provinces. These species are medium to the degradation of seagrass meadows. [ 12 ] : 8 coral reefs are estimated to occupy 73,364 rai ( 117 km2 ) in the Andaman Sea with entirely 6.4 percentage in ideal condition. [ 19 ]

human activities [edit ]

The sea has long been used for fish and exile of goods between the coastal countries .

Fishing [edit ]

Thailand entirely harvested about 943,000 tonnes of fish in 2005 [ 20 ] and about 710,000 tonnes in 2000. Of those 710,000 tonnes, 490,000 are accounted for by trawling ( 1,017 vessels ), 184,000 by purse seine ( 415 vessels ), and about 30,000 by gillnets. Of Thailand ‘s total marine catch, 41 percentage is caught in the Gulf of Thailand and 19 percentage in the Andaman Sea. Forty percentage is caught in waters outside Thailand ‘s EEZ. [ 21 ] production numbers are importantly smaller for malaysia and are comparable, or higher, for Myanmar. [ 22 ] Competition for pisces resulted in numerous conflicts between Myanmar and Thailand. In 1998 and 1999, they resulted in fatalities on both sides and about escalated into a military conflict. In both cases, the Thai united states navy intervened when burmese vessels tried to intercept Thai fishing boats in the contested ocean areas, and Thai fighter aircraft were thought to be deployed by the National Security Council. Thai fishing boats were besides frequently confronted by the malaysian united states navy to the extent that the Thai government had to caution its own fishers against fishing without license in foreign waters. [ 23 ] The 2004 marine output in Thailand was composed of : oceanic fish 33 percentage, demersal fish 18 percentage, cephalopod 7.5 percentage, crustaceans 4.5 percentage, methamphetamine fish 30 percentage and others 7 percentage. [ 12 ] : 12 Trash pisces refers to non-edible species, comestible species of broken commercial value and juveniles, which are released to the sea. [ 12 ] : 16 Pelagic fishes were distributed between anchovies ( Stolephorus spp., 19 percentage ), Indo-Pacific mackerel ( Rastrelliger brachysoma, 18 percentage ), sardinellas ( Sardinellars spp., 14 percentage ), scad ( 11 percentage ), longtail tuna ( Thunnus tonggol, 9 percentage ), eastern little tuna ( Euthynnus affinis, 6 percentage ), trevallies ( 6 percentage ), bigeye scad ( 5 percentage ), indian mackerel ( Rastrelliger kanagurta, 4 percentage ), king mackerel ( Scomberomorus cavalla, 3 percentage ), torpedo scad ( Megalaspis cordyla , 2 percentage ), wolf herrings ( 1 percentage ), and others ( 2 percentage ). [ 12 ] : 13 Demersal fish output was dominated by purple-spotted bigeye ( Priacanthus tayenus ), threadfin sea bream ( Nemipterus hexodon ), brushtooth lizardfish ( Saurida undosquamis ), slender lizardfish ( Saurida elongata ) and Jinga prawn ( Metapenaeus affinis ). Most species are overfished since the 1970s–1990s, except for spanish mackerel ( Scomberomorus commersoni ), carangidae and bomber scad ( Meggalaspis spp. ). The overall overfishing rate was 333 percentage for oceanic and 245 percentage for demersal species in 1991. [ 12 ] : 14 Cephalopods are divided into squid, cuttlefish and mollusk, where squid and cuttlefish in Thai waters consists of 10 families, 17 genus and over 30 species. The main mollusk species captured in the Andaman Sea are scallop, rake ripple ( Anadara granosa ) and short-necked clam. Their solicitation requires buttocks dredge gears, which damage the sea floor and the gears themselves and are becoming unpopular. sol, the mollusk production has decreased from 27,374 tonnes in 1999 to 318 tonnes in 2004. While crustaceans composed only 4.5 percentage of the sum marine products in 2004 by volume, they accounted for 21 percentage of the total measure. They were dominated by banana prawn, tiger prawn, king prawn, school prawn, bay lobster ( Thenus orientalis ), mantis prawn, swimming crabs and mud crab. The total catch in 2004 was 51,607 tonnes for squid and cuttlefish and 36,071 tonnes for crustaceans. [ 12 ] : 18–19

Mineral resources [edit ]

The sea ‘s mineral resources include canister deposits off the coasts of Malaysia and Thailand. major ports are Port Blair in India ; Dawei, Mawlamyine and Yangon in Myanmar ; Ranong port in Thailand ; George Town and Penang in Malaysia ; and Belawan in Indonesia. [ 2 ]

tourism [edit ]

The Andaman Sea, particularly the western slide of the Malay Peninsula, and the Andaman and Nicobar Islands of India and Myanmar are rich in coral reefs and offshore islands with spectacular topography. Despite having been damaged by the 2004 Sumatra earthquake and tsunami, they remain democratic tourist destinations. [ 24 ] The nearby coast besides has numerous marine national parks – 16 merely in Thailand, and four of them are candidates for inclusion body into UNESCO World Heritage Sites. [ 12 ] : 7–8

See besides [edit ]

References [edit ]

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