Conference presentation
Terrestrial versus aquatic carbon fluxes in an agricultural coastal floodplain
ASLO Aquatic Sciences Meeting (Honolulu, USA, 26/02/2017 - 03/03/2017)
01/03/2017
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Abstract
An integrated approach to measuring all relevant carbon flux pathways is required to provide a comprehensive evaluation of the net ecosystem carbon budget (NECB). This is especially important in ecosystems that contain an aquatic component where land-atmosphere carbon exchange is not the only carbon pathway. Here, we present findings on the complete annual carbon budget of a subtropical agricultural floodplain, and explore the contribution of aquatic carbon flux to net ecosystem exchange (NEE) with other ecosystems. Carbon fluxes measured included: land-atmosphere CO2 exchange (NEE), aquatic CO2 and CH4 evasion from drainage canals, and export of DOC, POC, and DIC via discharge. The floodplain remained a large atmospheric CO2 sink throughout the study, with an annual NEE of -1057 to -900 gC m-2 yr-1. After accounting for aquatic carbon exports and biomass exchanges, the floodplain had a relatively neutral NECB of 116 gC m-2 yr-1. The largest carbon loss pathway was biomass (1,494 gC m-2 yr-1), which ultimately determined the NECB. Total aquatic carbon fluxes of export and evasion were found to be a very minor component of the NECB, offsetting only ~4% of terrestrial NEE. This is in stark contrast to northern wetlands which report aquatic carbon contributions of 10 to >100%. Despite the small contribution found at this site, the annual aquatic carbon loss of ~40 gC m-2 yr-1 was within the same order of magnitude compared to a range of other ecosystems. Multiple flood events were responsible for 80% of the total aquatic carbon flux, demonstrating the potential for floods to negatively impact NECB’s in ecosystems with smaller annual NEE.
Details
- Title
- Terrestrial versus aquatic carbon fluxes in an agricultural coastal floodplain
- Creators
- Jackie R Webb - Southern Cross UniversityIsaac R Santos - Southern Cross UniversityDamien T Maher - Southern Cross UniversityBen Macdonald - CSIROBarbara Robson - CSIROPeter IsaacIan McHugh - Monash University
- Conference
- ASLO Aquatic Sciences Meeting (Honolulu, USA, 26/02/2017 - 03/03/2017)
- Identifiers
- 991012845997602368
- Academic Unit
- Faculty of Science and Engineering; School of Environment, Science and Engineering; Science
- Resource Type
- Conference presentation