PhD Studentship: Will Saltmarshes Remain a Carbon Sink Under Global Changes? Shedding Light on the Belowground Processes and Associated C Fluxes

belowground processes and associated C fluxes (CENTA 2025-B6)

Saltmarshes are among the most carbon dense ecosystems worldwide with high primary productivity and burial rates. As wetland soils are typically saturated, a large portion of the CO2 taken up by plants through photosynthesis and stored in belowground biomass is buried for centuries. Yet, the blue carbon stored in saltmarsh soils may be offset by the potent greenhouse gases (GHG), CH4 and N2O, which are produced and consumed during soil biogeochemical processing and have the potential to increase under global climate change. Because most of the biogeochemistry that controls GHG emissions occurs belowground, it is critical to understand root production, mortality and exudation to forecast the future carbon sink potential of saltmarshes.

Despite the importance of saltmarshes for carbon sequestration, understanding of how their ecosystem functioning will be altered due to global change is not fully understood. There is the potential for both increased primary productivity and carbon burial, and increased soil decomposition and greenhouse gas emissions. In the Salt Marsh Accretion Response to Temperature eXperiment (SMARTX) at SERC, temperature and atmospheric CO2 have been manipulated in-situ for 8 years. Initial results show that elevated temperature (eT) and elevated atmospheric CO2 (eCO2) treatments alter annual biomass allocation, CH4 emissions and C sequestration. These trends are strongly driven by seasonal patterns of root production, mortality and exudation. To fully understand the belowground mechanisms that control ecosystem-level responses to climate change it is critical to quantify root dynamics and relate them to soil biogeochemical processes and GHGs. The proposed approach will use in-situ experimental treatments and controlled laboratory manipulation of individual drivers. This will enable understanding of synergistic versus antagonistic effects of salt marsh resilience to global change. Thus, the findings from this project will improve understanding of broader saltmarsh responses to climate change, and the resilience of their ecosystem services, which is valuable for global efforts to comprehend and mitigate the effects of climate change. This is critical given recent work to include blue carbon in the UK’s national greenhouse gas inventory requiring better understanding of current and future blue carbon storage capacity and may inform restoration and management strategies.

For further information on this project and details of how to apply to it please click on the above 'Apply' button

Further information on how to apply for a CENTA studentship can be found on the CENTA website: https://centa.ac.uk/

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