Marajó Archipelago: Brazil's Ecological and Cultural Treasure

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Marajó Archipelago: Brazil's Ecological and Cultural Treasure

The Marajó Archipelago, the largest fluvial-maritime archipelago on Earth, is a breathtaking expanse in northern Brazil. This unique and ecologically diverse region stretches from the mouth of the Amazon River to the Atlantic Ocean, encapsulating many natural wonders and rich cultural history.

Marajó Island and Beyond: Exploring the World's Largest Fluvial-Maritime Archipelago

The Marajó Archipelago, the largest fluvial-maritime archipelago on Earth, is a breathtaking expanse located in the states of Amapá and Pará in Brazil. Comprising approximately 2,500 islands, this unique and ecologically diverse region stretches from the mouth of the Amazon River to the Atlantic Ocean, encapsulating a myriad of natural wonders and rich cultural history. Renowned for its ecological significance and archaeological treasures, the Marajó Archipelago offers a fascinating glimpse into the intricate interplay between nature and human civilization over millennia.

Geographical and Ecological Overview

Marajó Island: The Heart of the Archipelago

The main island of the Marajó Archipelago, also named Marajó, holds the distinction of being the largest coastal island in Brazil and the world's largest fluvial island. Covering about 40,000 square kilometers (15,500 square miles), Marajó Island is bordered by the Amazon River to the west and northwest, the Atlantic Ocean to the northeast, and the Pará River to the east. Geographically, the island is divided into two distinct halves: the eastern region, characterized by extensive savannas, and the western region, dominated by dense forests.

The Marajó Várzea Ecoregion

The Marajó várzea ecoregion encompasses the sedimentary islands and floodplains of the archipelago. This region is subjected to twice-daily flooding due to ocean tides pushing river waters onto the land. These flooded forests provide vital habitats for a plethora of fauna, including fruit-eating fish, aquatic mammals, and diverse bird species. However, this delicate ecosystem faces threats from cattle and water buffalo ranching and large-scale commercial logging.

Climate and Hydrology

Marajó Island experiences a tropical savanna climate, with a significant rainy season from January to July, during which approximately 70% of the island floods. Annual rainfall ranges from 2,000 to 2,500 millimeters (80 to 100 inches). The island's unique hydrology includes numerous tidal rivers in the western forested region and an enormous inland basin in the eastern part that collects rainwater, causing seasonal inundation.

Historical and Cultural Significance

The Marajoara Culture

From around 400 BC to 1600 AD, the Marajó Archipelago was home to the advanced Pre-Columbian Marajoara culture. At its peak, this civilization may have numbered more than 100,000 people. The Marajoara are known for their sophisticated ceramics, intricate social structures, and impressive earthworks, leaving behind a rich archaeological legacy that continues to intrigue researchers.

Environmental Protection

The Marajó Archipelago Environmental Protection Area was established to safeguard the unique fluvial marine islands where the Amazon and Tocantins rivers meet and flow into the Atlantic Ocean. Spanning nearly 60,000 square kilometers (23,000 square miles), this protected area aims to mitigate ecological damage while allowing limited human activity, ensuring the conservation of its diverse ecosystems.

Modern-Day Marajó

Water Buffalo and Ranching

In the early 20th century, Indian water buffalo were introduced to Marajó Island. According to local lore, these buffalo were originally destined for British Guiana but ended up on Marajó due to a shipwreck. Today, the island is renowned for its large water buffalo population, which is raised commercially for meat and utilized for transportation, significantly shaping the island's contemporary economy and lifestyle.

Flora and Fauna

The vegetation of Marajó Island is shorter and less diverse than surrounding areas, with palms being particularly dominant. Despite this, the island boasts rich biodiversity, especially in its avifauna, with about 540 bird species recorded. The flooded forests and mangroves support a wide variety of wildlife, making the archipelago a vital ecological hotspot.


The Marajó Archipelago stands as a testament to Brazil's natural grandeur and cultural depth. Its vast landscapes, from the savannas and forests of Marajó Island to the intricate network of tidal rivers and floodplains, offer a unique blend of ecological and historical richness. Protecting this region is crucial for preserving its unique biodiversity and the cultural heritage of the Marajoara civilization, ensuring that this remarkable archipelago continues to be a source of wonder and inspiration.

Satellite image of mouths of Amazon River in Brazil, with Marajó Island in the center, and the cities (in red) of Macapá (left) and Belém (right).

Satellite image of the mouth of the Amazon River in Brazil with Marajó Archipelago in the center, the city of Macapá on the left and the town of Belém on the right (in red).