EGU2020-12621
https://doi.org/10.5194/egusphere-egu2020-12621
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Parsing the DOM sources using calibrated biomarkers in the San Francisco Bay Estuary

Chia-Ying Chuang1, Francois Guillemette2, Jennifer Harfmann3, Karl Kaiser4, Robert Spencer5, Brian Bergamaschi6, and Peter Hernes3
Chia-Ying Chuang et al.
  • 1Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan (anderinchuang@gate.sinica.edu.tw)
  • 2Département des Sciences de l'environnement, Université du Québec à Trois-Rivières, QC, Canada
  • 3Department of Land, Air, and Water Resources, University of California Davis, CA, USA
  • 4Department of Marine Sciences, Texas A&M University at Galveston, TX, USA
  • 5Earth, Ocean & Atmospheric Science Department, Florida State University, FL, USA
  • 6United States Geological Survey, Sacramento, CA, USA

The San Francisco Bay Estuary (SFBE) together with the Sacramento–San Joaquin River Delta is the second largest estuary in the United States and represents a highly dynamic ecosystem. From 2014 to 2016, we conducted three transects across a salinity gradient to investigate the roles of sources, hydrologic and seasonal changes on the DOM composition. Sampling started with a riverine endmember, through a vast area of marshes, wetlands, to the Golden Gate, the largest estuary in western North America. The winter transect at its maximum discharge allowed the study of DOM dynamics largely in the absence of photodegradation processes and low levels of algal production; the summer transect captured significant photodegradation and algal production; the spring transect revealed the signal of stored DOM from the snowmelt cold water flows. Multiple studies indicated that algal primary production alone cannot support the SFBE foodweb, and the wetlands could also serve to reduce DOM loadings coming off of the delta.  Hence, other sources of organic matter must be considered, including autochthonous and allochthonous DOM. Terrestrial DOM export in SFBE were revealed by dissolved lignin dynamics. Optical proxies (UV-vis and fluorescence) were also used to study the photochemical and biological transformations of DOM.

How to cite: Chuang, C.-Y., Guillemette, F., Harfmann, J., Kaiser, K., Spencer, R., Bergamaschi, B., and Hernes, P.: Parsing the DOM sources using calibrated biomarkers in the San Francisco Bay Estuary, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12621, https://doi.org/10.5194/egusphere-egu2020-12621, 2020