Rivers & the Global Carbon Cycle

Organic carbon (OC) records can provide for a crucial and direct linkage between Holocene environmental variability, fluvial sediment export, and the coastal sedimentological record. The stable and radiogenic isotopic records contained within organic-carbon compounds provide a powerful tool to understanding the sources and transfer times of sediment eventually deposited in the coastal system. Furthermore, the coastal zone has a large OC storage potential and is a region of flux between terrestrial and marine organic carbon reservoirs. It therefore plays a crucial role in the global recycling of organic carbon, a key driving factor in atmospheric CO₂ levels and, thus, long-term climate.

Current Studies

Carbon export and burial in the Amazon River mudbanks

Overview: The Amazon River is one of the largest and most important rivers in the world. It not only carries water through the Amazon rain forests, it also carries mud - lots of mud, forming massive mud banks that run north to Guyana that serve as a storage for carbon that had been removed from the atmosphere by the Amazon rainforest, dropped to the forest floor and washed into the river, ultimately transported into the Amazon delta. This project uses new science and technology to gain a mechanistic & quantitative understanding of the fate of terrestrial OC in the coastal ocean offshore of the Amazon River, potentially changing the way we look at river carbon cycling in the ocean. Members of the Coastal Geology Lab will join a research cruise, currently planned for May 2023, and led by collaborators Rosenheim & Galy.

Collaborators: Brad Rosenheim (University of South Florida), Valier Galy (WHOI), and an ever-changing cast of characters

Funding: National Science Foundation Chemical Oceanography program (to Rosenheim & Galy)

Human impacts on organic-carbon-export dynamics in the Ganges-Brahmaputra river system

Overview: We are using compound-specific stable-isotope (δ¹³C, δD) and Δ¹⁴C measurements of bulk organic matter and biomarkers to characterize the impacts of human land-use changes on the dynamics of sediment and terrestrial OC transfer from the Ganges-Brahmaputra rivers to the coastal Bay of Bengal over the last ~100 years. Earlier work on the Ganges-Brahmaputra system using these same tools, but applying them over the period since the Last Glacial Maximum were published in Earth and Planetary Science Letters in 2017 (paleoclimatic and provenance reconstructions) and in Nature in 2020 (OC residence time and soil turnover rates).

Collaborators: Valier Galy (WHOI)

Publications

Please feel free to contact us for pdf copies of any of the following publications.

Hein, C.J., Usman, M., Eglinton, T.I., Haghipour, N., Galy, V.V., 2020. Millennial-scale hydroclimate control of tropical soil carbon storage, Nature, v. 581, p. 63-66, doi: 10.1038/s41586-020-2233-9.

French, K.L., Hein, C.J., Haghipour, N., Wacker, L., Kudrass, H., Eglinton, T.I., Galy, V.V., 2018, Millennial soil retention of terrestrial organic matter deposited in the Bengal Fan, Nature Scientific Reports, v. 8, 11997, doi: 10.1038/s41598-018-30091-8.

Hein, C.J., Galy, V., Galy, A., France-Lanord, C., Kudrass, H., Schwenk, T., 2017, Post-glacial climate forcing of surface processes in the Ganges-Brahamaputra river basin and implications for carbon sequestration, Earth and Planetary Science Letters, v. 478, p. 89-101, doi: 10.1016/j.epsl.2017.08.013.

Galy, V., Hein, C., France-Lanord, C., Eglinton, T., 2014, The evolution of carbon signatures carried by the Ganges-Brahmaputra River system: a source-to-sink perspective, In: Bianchi, T., Allison, M., and Cai, W.-J. (eds), Biogeochemical Dynamics at Major River-Coastal Interfaces: Linkages with Global Change, Cambridge, England: Cambridge University Press, p. 353-372.

Abstracts & Presentations

Please feel free to contact us for pdf copies of any of the following abstracts or their associated presentations or posters.

French, K.L., Hein, C.J., Haghipour, N., Wacker, L., Kudrass, H., Eglinton, T.I., Galy, V.V., 2018, Millennial soil retention of labile terrestrial organic matter deposited in the Bengal Fan, Goldschmidt 2018, Boston, MA, August 2018.

Galy, V. Hein, C.J., Eglinton, T., 2018, Hydroclimate forcing of the terrestrial organic carbon cycle during the last deglaciation, Goldschmidt 2018, Boston, MA, August 2018.

Hein, C.J., Galy, V.V., Eglinton, T.I., 2017, Post-glacial climate forcings and feedbacks of the carbon cycle in the Ganges-Brahmaputra Basin, Goldschmidt 2017, Paris, France, August 2017.

Galy, V.V., French, K.L., Hein, C.J., Haghipour, N., Wacker, L., Kudrass, H., Eglinton, T.I., 2017, Compound-specific radiocarbon dating reveals the age distribution of plant-wax biomarkers exported to the Bengal Fan, AGU Fall Meeting, New Orleans, LA, December 2017.

Hein, C.J., Galy, V., France-Lanord, C., Galy, A., Kudrass, H., and Peucker-Ehrenbrink, B., 2016, Post-glacial climate forcing of surface processes in the Ganges-Brahmaputra basin and implications for the global carbon cycle, AGU Fall Meeting, San Francisco, CA, December 2016.

Galy, V., Hein, C.J. (presenter), Kudrass, H., Eglinton, T., Peucker-Ehrenbrink, B., 2014, INVITED, Climate forcing of the terrestrial organic carbon cycle during the last deglaciation: the Himalaya-Bengal fan example, GSA Abs. with Programs, vol. 46, no 6, abstract 248259.

Hein, C.J., Galy, V., Peucker-Ehrenbrink, B., Eglinton, T.I., 2012, Climatic forcing of organic-carbon-export dynamics from the Ganges-Brahmaputra River System, Eos Transactions, AGU, Fall Meeting Suppl., Abstract B13A-0469.

Galy, V., Hein, C.J., Peucker-Ehrenbrink, B., Eglinton, T.I., 2012, Dynamics of fluvial release of terrestrial organic carbon: climatic, geomorphologic or human forcing?, 5^th International Workshop on Soil and Sedimentary Organic Matter: 7-11 October 2012, Zurich, Switzerland.

Hein, C.J., Galy, V., Peucker-Ehrenbrink, B., Eglinton, T.I., 2012, Preliminary evidence for a monsoonal forcing of the dynamics of terrestrial organic carbon export to the Bay of Bengal, Gordon Research Conference in Organic Geochemistry: 30 July – 3 August 2012, Plymouth, NH, USA.