Presenter: Melanie Mayes, Senior Staff Scientist, Oak Ridge National Laboratory

Event Dates
Online: 8:00-9:00am AKDT, 12:00-1:00pm EDT

Seminar 5 in the Series: From Science to Solutions: The State of the Carbon Cycle, the 2nd State of the Carbon Cycle Report (SOCCR2).


Rising carbon dioxide (CO2) has decreased seawater pH at long-term observing stations around the world, driving ocean acidification that has already affected some marine species and altered fundamental ecosystem processes. Further effects are likely. While atmospheric CO2 rises at approximately the same rate all over the globe, its non-climate effects on land vary depending on climate and dominant species. In terrestrial ecosystems, rising atmospheric CO2 concentrations are expected to increase plant photosynthesis, growth, and water-use efficiency, though these effects are reduced when nutrients, drought or other factors limit plant growth. Rising CO2 would likely change carbon storage and influence terrestrial hydrology and biogeochemical cycling, but concomitant effects on vegetation composition and nutrient feedbacks are challenging to predict, making decadal forecasts uncertain. Consequences of rising atmospheric CO2 are expected to include difficult-to-predict changes in the ecosystem services that terrestrial and ocean systems provide to humans. Continued persistence of uptake of carbon by the land and ocean is uncertain. Climate and environmental change create complex feedbacks to the carbon cycle and it is not clear how feedbacks modulate future effects of rising CO2 on carbon sinks. These are several mechanisms that could reduce future sink capacity.

About the Speaker:

Dr. Melanie Mayes is a Senior Staff Scientist and Team Leader with the Environmental Sciences Division and the Climate Change Science Institute at Oak Ridge National Laboratory in Tennessee. She holds Joint Faculty Appointments with the Departments of Biosystems Engineering & Soil Science, and Earth & Planetary Sciences at the University of Tennessee. She is interested in diverse research at the intersection of water, soil minerals, solute chemistry, and biological cycling, and she designs experiments to build better models to represent natural processes. Her current research involves improving the representation of terrestrial carbon cycling processes in Earth system and process models, developing techniques to incorporate metagenomic information into nutrient cycling models, and investigating technologies to reduce mercury loading and methylmercury generation in surface and ground water systems.

Webinar Access:

We will use Adobe Connect. To join the session, go to, enter as "Guest", and please enter your first and last name. Users should use either IE or Edge on Windows or Safari if using a Mac. Audio will be available thru the computer only; no phone. Questions will be addressed in the chat window. This Webcast will be recorded, archived and made accessible in the near future.

Event Type
Webinars and Virtual Events