NEAR ALTAMIRA, BRAZIL - JUNE 15: The Amazon rainforest is seen near construction of the Belo Monte dam complex in the Amazon basin on June 15, 2012 near Altamira, Brazil. Belo Monte will be the world?s third-largest hydroelectric project and will displace up to 20,000 people while diverting the Xingu River and flooding as much as 230 square miles of rainforest. The controversial project is one of around 60 hydroelectric projects Brazil has planned in the Amazon to generate electricity for its rapidly expanding economy. While environmentalists and indigenous groups oppose the dam, many Brazilians support the project. The Brazilian Amazon, home to 60 percent of the world?s largest forest and 20 percent of the Earth?s oxygen, remains threatened by the rapid development of the country. The area is currently populated by over 20 million people and is challenged by deforestation, agriculture, mining, a governmental dam building spree, illegal land speculation including the occupation of forest reserves and indigenous land and other issues. Over 100 heads of state and tens of thousands of participants and protesters will descend on Rio de Janeiro, Brazil, later this month for the Rio+20 United Nations Conference on Sustainable Development or ?Earth Summit?. Host Brazil is caught up in its own dilemma between accelerated growth and environmental preservation. (Photo by Mario Tama/Getty Images) (/)
Por que é incorreta a afirmação de que a Amazônia é o ''pulmão'' do mundo?
Enviado por Caroline Wanie
As árvores da Floresta Amazônica, apesar de produzirem uma grande quantidade de oxigênio na fotossíntese, também respiram e acabam consumindo todo (ou quase todo) este gás durante o processo de respiração aeróbica. No final o resultado da relação produção de O2 (na fotossíntese) / consumo de O2 (na respiração aeróbica) tende ao empate, não há “sobra” de oxigênio.
O verdadeiro “pulmão” do mundo é o conjunto das algas marinhas nos oceanos, que joga na atmosfera cerca de 55% de todo o oxigênio produzido no planeta.
Isso não quer dizer que podemos derrubar toda a floresta! Ela tem papel importante na regulação do clima, principalmente influenciando o regime de chuvas da própria região amazônica, bem como o de outras regiões.
