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Amazon Delta

Coordinates: 0°08′04″N 50°25′33″W / 0.13444°N 50.42583°W / 0.13444; -50.42583
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Amazon Delta
Delta do Amazonas (Portuguese)
Satellite image of the Amazon Delta captured by NASA in 2005
Satellite image of the Amazon Delta captured by NASA in 2005
Amazon Delta is located in Brazil
Amazon Delta
Location in Brazil
Coordinates: 0°08′04″N 50°25′33″W / 0.13444°N 50.42583°W / 0.13444; -50.42583
LocationNorth Region, Brazil
StatesAmapá, Pará

The Amazon Delta (Portuguese: delta do Amazonas) is a vast river delta formed by the Amazon River and the Tocantins River (through the Pará River distributary channel) in northern South America.[1][2][3] It is located in the Brazilian states of Amapá and Pará[4] and encompasses the Marajó Archipelago, with Marajó Island as its largest island. The region is 160,000 km2 and has 49 towns, with most of these being small towns with less than 20,000 inhabitants.[5] The main cities located in the vicinity are Belém and Macapá, each with its respective metropolitan area.[6]

It is the largest river delta in the world. It releases one fifth of the total amount of freshwater that is discharged into the earths oceans, into the Atlantic Ocean, with some estimating that equates to 200,000 litres a second. The area has wetlands, streams, lagoons and rich ecosystems and biodiversity. It is a vital area for wildlife, with extensive mangroves in wetland forests, that cover an area of 38,304 km2 of the delta, with 75% of Brazil's mangroves located in the Amazon Delta.[7][8][9][10]

Climate

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The Amazon Delta has a tropical climate with high humidity and high temperatures. It has a wet season with frequent flooding and a dry season where the delta dries out. The wet season is considered to be January to June, with precipitation peaking in February, March and April. The dry season is July to December, with September, October and November seeing the least rainfall.[11] Extreme flooding occurred in 2009, 2012, 2021, and 2022.[12] These seasons shape the environment of the Amazon Delta and the life in it, such as the water buffalo for which Marajó Island is well known, three-toed sloth, capybara, giant anteater, giant otter, jaguar and pink river dolphins.[13]

Population

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Historically, most settlements in the region were by the rivers, for transportation reasons. As these have expanded and small towns have developed along the banks of the watercourse, the floodplain and wetlands have been altered and large areas of vegetation have been cleared, with environmental consequences such as flooding, land movement and erosion.[12]

Over 1.5 million people live locally to the Amazon Delta. The population in the region is growing, with basic infrastructure and public services often lacking, such as sanitation, drinking water, housing and medical care. Housing in the region is often constructed on stilts. Due to these factors, combined with the flooding that occurs in the region, there are health risks to the people living in the region, particularly from waterborne diseases such as cholera and typhoid fever and from vector-borne diseases, such as malaria, yellow fever and dengue.[14]

Economic activity stems from industries such as agroforestry, fishing, mining, agriculture, and ranching, with these industries providing employment to people living in the region.[14] Approximately 50,000 people living in the region rely on natural resource exploitation for employment.[15]

Marajó archipelago

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The Marajó archipelago is based in the Amazon Delta region and includes 2,500 islands, with Marajó island being the largest. An area known as the Marajó Várzea ecoregion includes the archipelago's islands and floodplains. Tidal activity from the Atlantic ocean results in twice daily flooding, as these tides cause the river water to disperse onto land. This creates a unique ecosystem, with fruit eating fish feeding on açaí palm, which is plentiful in the area. There are over 540 known bird species, including the scarlet ibis, black-collared hawk, parrots and macaws. The Amazon river dolphin can be found in the area, as well as water buffalo. It is designated as a protected area to help to safeguard it and to prevent ecological damage, known as the Marajó Archipelago Environmental Protection Area.[16][17]

Untypical delta

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Due to the vast amounts of sediment and freshwater released by the Amazon, the delta is not a traditional one, for example in shape.[13] The sedimentary environment near the Amazon's mouth has limited subaerial expression, untypical of a river delta.[18] As a result, some people do not describe it as being a delta.[19]

Environmental concerns

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In 2025, approval was given to Petrobras to drill in a location 500km from the mouth of the Amazon River.[20] This decision raised concerns from environmentalists, with Brazil’s Climate Observatory NGO describing this as being "disastrous from an environmental, climate, and sociobiodiversity perspective”.[21] Oil drilling, which had commenced in October 2025, was put on hold by Brazils oil regulator in January 2026 whilst it sought further information after a leak of synthetic fluid occurred, when the company drilled the first of several wells planned in the region. The company confirmed it had contained the leak and that the fluid released was biodegradable and posed no environmental risk.[22]

References

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  1. ^ Geografia do Brasil: Região norte. Rio de Janeiro: Instituto Brasileiro de Geografia e Estatística (IBGE). 1977.
  2. ^ de Araujo Barbosa, C. C.; Atkinson, P.; Dearing, J. (December 2014). "The spatial extent of change in tropical forest ecosystem services in the Amazon delta". AGU Fall Meeting Abstracts. 2014. United States: ADS Abstract Service (Harvard University): PA21A–11. Bibcode:2014AGUFMPA21A..11D.
  3. ^ "NASA Images: STS046-80-009 > Mouths of the Amazon River, Brazil, South America". images.nasa.gov. United States: NASA. Archived from the original on 2020-03-28.
  4. ^ "Fapespa participa de workshop sobre indicadores de vulnerabilidade do Delta do Amazonas". FAPESPA. 2015. Archived from the original on 2020-02-26. Retrieved 2020-03-27.
  5. ^ Carmo, Monique Bruna Silva do; Costa, Sandra Maria Fonseca da; Brondizio, Eduardo S. (May 2023). "Singularities and Similarities of Amazonia's Small Towns: A Comparative Analysis of Urban Categorizations and Typologies of the Amazon Estuary-Delta Region = Singularidades e semelhanças das pequenas cidades amazônicas: uma análise comparativa das categorizações e tipologias urbanas da região do estuário-delta amazônico". Journal of Latin American Geography. 22 (1): 116–142. doi:10.1353/lag.2023.a899556.
  6. ^ Benchimol, Samuel. Manual de introdução 'a Amazônia. Manaus: Edição Reprográfica.
  7. ^ "The Amazon Delta – Vast Labyrinth of Waterways Between Macapá and Belém". Highbury Nomad. 2018-10-24. Retrieved 2026-01-30.
  8. ^ Bernardino, Angelo F.; Mazzuco, Ana Carolina A.; Souza, Fernanda M.; Santos, Thuareag M. T.; Sanders, Christian J.; Massone, Carlos G.; Costa, Rodolfo F.; Silva, Antônio Elves B.; Ferreira, Tiago O.; Nóbrega, Gabriel N.; Silva, Thiago S. F.; Kauffman, J. Boone (2022-08-22). "The novel mangrove environment and composition of the Amazon Delta". Current Biology. 32 (16): 3636–3640.e2. Bibcode:2022CBio...32E3636B. doi:10.1016/j.cub.2022.06.071. hdl:1893/34759. ISSN 0960-9822. PMID 35863350.
  9. ^ "The Amazon: A Forest of Rivers". Amazon Frontlines. 2024-04-22. Retrieved 2026-01-30.
  10. ^ Anthony, Edward J.; Brondizio, Eduardo S.; dos Santos, Valdenira F.; Gardel, Antoine; Besset, Manon (2021-05-14). "Sustainable Management, Conservation, and Restoration of the Amazon River Delta and Amazon-Influenced Guianas Coast: A Review". Water. 13 (10): 1371. Bibcode:2021Water..13.1371A. doi:10.3390/w13101371. ISSN 2073-4441.
  11. ^ Rocha, Yuri Antonio da Silva; Lima, Aline Maria Meiguins de; Silva, Cláudio Moisés Santos e; Franco, Vânia dos Santos; Raiol, Lucas Lima; Oliveira, Ilziane Simões de; Dias, Maria Luiza Nascimento; Beltrão Júnior, Paulo Roberto Estumano (2025-04-15). "Hydro-meteorological dynamics of rainfall erosivity risk in the Amazon River Delta-Estuary". Journal of Water and Climate Change. 16 (5): 1673–1694. doi:10.2166/wcc.2025.544. ISSN 2040-2244. Archived from the original on 2025-07-18.
  12. ^ a b Meiguins de Lima, Aline M; Queiroz do Nascimento, Vitor Gabriel; Siqueira Martins, Saulo; Souza de Oliveira, Arthur Cesar; Antonio da Silva Rocha, Yuri (2025). "Mass Movements in Wetlands: An Analysis of a Typical Amazon Delta-Estuary Environment". GeoHazards. 6 (3). doi:10.3390/geohazard. ISSN 2624-795X. Archived from the original on 2025-08-03.
  13. ^ a b "Amazon Delta". WorldAtlas. 2023-10-21. Retrieved 2024-10-17.
  14. ^ a b Mansur, Andressa V.; Brondízio, Eduardo S.; Roy, Samapriya; Hetrick, Scott; Vogt, Nathan D.; Newton, Alice (2016-07-01). "An assessment of urban vulnerability in the Amazon Delta and Estuary: a multi-criterion index of flood exposure, socio-economic conditions and infrastructure". Sustainability Science. 11 (4): 625–643. doi:10.1007/s11625-016-0355-7. ISSN 1862-4057.
  15. ^ de Araujo Barbosa, Caio C.; Atkinson, Peter M.; Dearing, John A. (2016-04-15). "Extravagance in the commons: Resource exploitation and the frontiers of ecosystem service depletion in the Amazon estuary". Science of The Total Environment. 550: 6–16. doi:10.1016/j.scitotenv.2016.01.072. ISSN 0048-9697.
  16. ^ "Marajó Archipelago: Brazil's Ecological & Cultural Treasure". lacgeo.com. 2024-06-21. Retrieved 2026-02-23.
  17. ^ "Tides of Life: The Marajó Várzea Ecosystem". lacgeo.com. 2024-10-13. Retrieved 2026-02-23.
  18. ^ NITTROUER, C. A.; KUEHL, S. A.; DEMASTER, D. J.; KOWSMANN, R. O. (1986). "The deltaic nature of Amazon shelf sedimentation". Geological Society of America Bulletin. 97 (4): 444. Bibcode:1986GSAB...97..444N. doi:10.1130/0016-7606(1986)97<444:TDNOAS>2.0.CO;2. ISSN 0016-7606. Archived from the original on 2018-06-02.
  19. ^ "Delta". education.nationalgeographic.org. Retrieved 2026-01-30.
  20. ^ "Brazil grants state oil firm exploration license in Amazon region". BBC News. 2025-10-20. Retrieved 2026-01-31.
  21. ^ France-Press, Agence (2025-10-20). "Brazil greenlights oil drilling in Amazon as environmentalists raise alarm". The Guardian. ISSN 0261-3077. Retrieved 2026-01-31.
  22. ^ Teixeira, Fabio; Nogueira, Marta (2026-01-08). "Brazil's oil regulator puts Petrobras drilling at Foz do Amazonas on hold". Reuters. Retrieved 2026-02-23.