Streams move carbon from land into oceans and the atmosphere. Carbon in streams can come from leaf litter decomposing in the water. How quickly that leaf litter decomposes depends upon the temperature of the water — the higher the temperature of the water, the faster the rate of decomposition. With climate change, stream temperatures are expected to rise. The rise in stream temperature is projected to increase rates of leaf litter decomposition, thereby affecting the carbon cycle. A team of scientists, including Andrews Forest scientist Sherri Johnson, synthesized 1025 records of litter breakdown in streams and rivers to quantify its temperature sensitivity.
The study indicates average breakdown rates may increase 5 percent to 21 percent with a 1 degree to 4-degree Celsius rise in water temperature — half as much as the 10 percent to 45 percent increase predicted by metabolic theory. Mean annual water temperature for some streams and rivers is currently rising at an annual rate of about 0.01 degrees to 0.1 degrees Celsius due to changes in climate and land use. Read more in a University of Utah press release on the article.
The study “Global synthesis of the temperature sensitivity of leaf litter breakdown in streams and rivers” was published February 2016 in Global Change Biology. View the full article.