Central Questions

Previous integrated studies of rivers and adjacent margins (ex. AmasSeds, STRATAFORM) have provided a solid foundation (particularly geological framework) from which a carbon cycle program can be launched. There are many unanswered questions about organic carbon inputs, cycling and fates in RiOMar environments. New initiatives, as well as ongoing and recently initiated programs such as MARGINS, can provide additional research opportunities and infrastructure to address many of these questions in a truly interdisciplinary manner. Representative general questions, concerning the role of RiOMar environments in global change, are listed below. A specific goal of the RiOMar workshop will be to refine and amend these questions and to generate a list of specific questions for each research theme by community consensus.

Are RiOMar environments net global sources or sinks for organic carbon, on annual, decadal, and millennial time scales? What roles do the marginal seas associated with RiOMars play in terms of CO2 and organic carbon exchanges (source / sink)?

How does the role of RiOMar environments (as global carbon sources or sinks) change over time as a result of long-term climatic forcing (i.e., glacial-interglacial changes) as well as due to short-term human activities (e.g., land-use changes, dam construction)?

Are RiOMars environments highly efficient "filters" and/or transformers of organic matter? The flux of terrestrial organic matter from the continents to the oceans can alone account for the radiocarbon-based residence times of organic carbon in the oceans (almost exclusively as dissolved organic carbon, DOC). Yet we find only trace amounts of analytically identifiable terrestrial material in any part of the ocean, including its margins.

How will climate variations (eg. El Niño / La Niña) affect carbon cycling in RiOMar environments? How do significant changes in rainfall rates within the drainage basin, and the frequency of catastrophic floods and discharge events affect the magnitude of organic carbon sequestration and transformation.

How do changes in marine biological community structure influence the fate of organic carbon in RiOMar environments?

Is the response of RiOMar regions to global change similar to or different from open ocean environments? If so how does this influence the oceanic and global carbon cycles?

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