U.S. Forest Service Pacific Northwest Research Station Science Findings
Pacific Northwest forests play a significant role in the global carbon cycle. Because they sequester atmospheric carbon, they are considered long-term carbon sinks when one is calculating the carbon budget for the region. Yet a forested landscape is more than trees; numerous headwater streams are tucked within the landscape. As these headwater streams transport water downstream, carbon hitches a ride.
This carbon is derived from a number of sources. When leaf litter rots in the stream, carbon is released. Fish and other organisms living in the stream respire carbon dioxide (CO2), and even microbial communities buried beneath the streambanks respire carbon as a byproduct of their metabolism. The amount of carbon exported by these sources, however, is largely unknown. Compared to larger rivers, few data are available on headwater streams and their role in cycling carbon.