Guanabara Verde

For a Greener Guanabara Bay

Baía de Guanabara is a body of water covering around 400 km2 It is bordered by seven municipalities: Rio de Janeiro, Duque de Caxias, Magé, Guapimirim, Itaboraí, São Gonçalo and Niterói. More than 8 million people live near the bay. Its water basin extends to approximately 4,000 km2 and 35 major rivers flow into it. These rivers carry silt, sand, clay, leaves and branches into the bay, and also all kinds of manmade waste, harming its mangroves, beaches and cliffs.

At the time of the Rio de Janeiro Olympic Games, much was said about Baía de Guanabara and its state. Some claim that the bay is dead. It isn’t! This immense body of water contains a channel regularly dredged by the Brazilian Navy, which allows currents from far away to flow in. Every 12 days, these currents replace 50% of the bay’s water.

Mangroves, recognized as nurseries of the sea, are still to be found in this great ecosystem. At one point, they were found all around the bay. The history of mangrove degradation dates back to the arrival of the Portuguese royal family in Rio de Janeiro. When construction of the city began, many trees were cleared. Entire hills were leveled. Later, many of the rivers were artificially straightened (although nature is well aware of the need for sinuous rivers).

Later, in the 1960s and 1970s, the remaining mangrove trees faced a new threat: the use of wood to fire the ovens of potteries, to make tiles and bricks used by the growing communities around the bay. Between the cities of Niterói and Rio de Janeiro, and more or less in the middle of Baía de Guanabara, the resilience of the mangrove ecosystem allows small patches to resist bravely. But mangroves have not been able to recolonize most of the bay.


However, the war is not lost. In one corner of Baía de Guanabara, spanning four municipalities (Magé, Guapimirim, Itaboraí and São Gonçalo), there is an oasis called the Guapi-Mirim Environmental Protection Area. In 1984, it was the first mangrove area in Brazil to be declared a protected conservation area. Later, in 2006, another conservation area was established next to it, to further protect this beautiful and misunderstood ecosystem: the Guanabara Ecological Area.

Following the creation of these conservation areas, the removal of wood ceased. Much of the vegetation cover has managed to regenerate itself, thanks to its resilience. However, there are areas where the ecosystem was so intensely damaged that trees have been unable to return, losing space to opportunistic vegetation.


Aware of all this history and seeking to make Baía de Guanabara greener, OceanPact sponsors the Guanabara Verde Project. It is carried out by Guardiões do Mar, a non-governmental organization, in partnership with the Instituto Mar Urbano. The project works in two main areas: restoration and environmental education. In the first area, 12.2 hectares are being restored, as 30,000 trees of three native mangrove species are planted. However, OceanPact understands that planting trees is not enough. It is necessary to disseminate information and good practices, so that the seedlings gain strength to continue on their own, becoming new trees that will become a forest and nursery of the sea, boosting the sustainability of hundreds of families in the area. Hence the importance of the project’s environmental education work, which informs students, teachers, community leaders and public officials about this ecosystem’s key role in maintaining the health of Baía de Guanabara. Through the restoration work, OceanPact understands that it is helping reduce the impacts on mangroves and increase their vegetation cover. Through the environmental education activities, it seeks to demonstrate that everyone can do a little bit and together make Baía de Gunabara greener every day.

Text written by Pedro Belga, manager of Guardiões do Mar, a non-governmental organization