Disentangling the impact of Hydrology and Climate on Interannual Intermittent Stream Metabolism

Rivers and stream networks are the means by which terrestrial carbon is transported to marine systems. Additionally, the biogeochemical processes during this transport create reactive fluxes of carbon in the form of greenhouse gasses, namely carbon dioxide and methane. This process, quantified as ecosystem metabolism, has become an important means to quantify reactive carbon fluxes at broad spatial and temporal scales. When quantifying carbon cycling and greenhouse gas emissions from stream networks average hydrologic conditions are often used to annualize estimates. However, with increased variability and intensity of climatic regimes it is unclear the degree to which these assumptions mask the impact of hydrologic extremes. Flooding, droughts, and increased global intermittency of stream networks requires a paradigm shift for reporting annual rates of carbon cycling from riparian systems. This work, based on multi-year ecosystem metabolism modeling from streams in coastal Australia seeks to partition carbon processing by hydrologic and climatic regimes. This provides a rigorous means to assess the appropriate use of average annual conditions used in upscaling reactive carbon fluxes. Furthermore, the degree to which seasonality and the El Nino Southern Oscillation (ENSO) impact interannual drivers of carbon cycling is explicitly resolved. The results have important implications for upscaling and annualizing protocols used in regional, continental, and global bookkeeping of carbon and greenhouse gas budgets.

Presentation Preference: Oral

Primary Presenter: Ryan Felton, Southern Cross University (r.felton.11@student.scu.edu.au)

Authors:

Ryan Felton, Southern Cross University  (r.felton.11@student.scu.edu.au)

Joanne Oakes, Southern Cross University  (joanne.oakes@scu.edu.au)

Judith Rosentreter, Southern Cross University  (judith.rosentreter@scu.edu.au)

Bradley Eyre, Southern Cross University  (bradley.eyre@scu.edu.au)

Naomi Wells, Lincoln University  (naomi.wells@lincoln.ac.nz)