The age of the Amazon's breath

摘要

The inorganic carbon carried in rivers of the Amazon basin seems to originate largely from the decomposition of young plant material ― a finding that improves our understanding of the role of rivers in the carbon cycle. Increases in atmospheric carbon dioxide from the burning of fossil fuels have unknown effects on the global climate and economy. Scientists aim to understand more about these effects by studying the mechanisms that control the exchange of carbon between land, the atmosphere and the oceans. Processes that remove CO_2 from the atmosphere, where it could cause global warming, and move it into long-term storage on land or in the oceans, are of particular interest in this context. Because they connect land and sea, rivers are a vital link in these processes (Fig. 1, overleaf). On page 538 of this issue, Mayorga et al. provide insights into how this river linkage works for the world's largest river system ― the Amazon.