Home Archived April 13, 2016

U.S. Geological Survey

Maps, Imagery, and Publications Hazards Newsroom Education Jobs Partnerships Library About USGS Social Media

USGS Newsroom

USGS Newsroom  

Amazon Carbon Dynamics: Understanding the Photosynthesis-Climate Link
Released: 3/11/2014 1:00:00 PM

Contact Information:
U.S. Department of the Interior, U.S. Geological Survey
Office of Communications and Publishing
12201 Sunrise Valley Dr, MS 119
Reston, VA 20192
Leslie Gordon 1-click interview
Phone: 650-329-4006

FLAGSTAFF, Ariz. — Researchers at the U.S. Geological Survey, the University of Michigan, the University of Arizona, and the University of Technology, Sydney (Australia) are collaborating with scientists in Brazil on a three-year research project that investigates a basic yet unanswered question in Earth-system and global carbon-cycle science: What controls the response of photosynthesis in Amazon tropical forests to seasonal variations in climate?

Results of the study will help improve the reliability of global climate forecasts by guiding improvements in the treatment of tropical forest photosynthesis and related water-cycle processes in Earth-system models.

This question of photosynthesis' response to climate variations, despite its seeming simplicity, is the subject of an ongoing scientific puzzle that has so far been remarkably difficult to answer with confidence.  For example, seasonal patterns of photosynthesis simulated by several state-of-the-art, numerical models of the Earth system, and seasonal patterns of vegetation "greenness" as inferred from observations by Earth-observing satellites, disagree with patterns seen in measurements of ecosystem-atmosphere carbon dioxide exchange at monitoring sites in the central Amazon.

"Improving our understanding of how a changing climate affects the fundamental processes that control absorption of atmospheric carbon dioxide by tropical forests, can help us improve Earth system models, and help improve the reliability of global climate forecasts," said USGS geographer and project leader, Dennis Dye.

The project is designed to resolve disagreements between the computer models, and actual forest measurements by developing new knowledge and deeper understanding of seasonal climate, photosynthesis, and water relationships in Amazon tropical forests, through the use of advanced remote-sensing techniques and field observations. The project focuses on existing tropical forest study sites near Manaus and Santarem, Brazil.  Scientists will measure physiological properties of leaves and trees, and water flow, and use innovative remote-sensing instruments to monitor the light-reflecting properties of the forest and the effects of clouds and smoke on solar radiation. Scientists will also model the three-dimensional variation in photosynthesis in various forest structures and light levels.

"The ability to monitor the ecohydrologic function of the rainforest at a range of scales – from leaf, to tree, to stand levels – will offer an unprecedented observational support for testing hypotheses and developing new types of forest representation in land-surface models," said University of Michigan Hydrologist Valeriy Ivanov.

The project is supported in part by the U.S. Department of Energy, Office of Biological and Environmental Research, Climate and Environmental Sciences Division, GOAmazon campaign.

USGS provides science for a changing world. Visit USGS.gov, and follow us on Twitter @USGS and our other social media channels.
Subscribe to our news releases via e-mail, RSS or Twitter.

Links and contacts within this release are valid at the time of publication.



Accessibility FOIA Privacy Policies and Notices

USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://www.usgs.gov/newsroom/article.asp?ID=3822
Page Contact Information: Ask USGS
Page Last Modified: 3/11/2014 10:08:31 AM