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08 APR 2024 (MON) 11:00-13:00

Updated: Apr 15


Departmental Research Seminars Series

From Swamp to Sea: the fate of tropical peatland carbon in the coastal ocean

Date: 08 APR 2024 (Monday)

Time: 11:00-13:00 (HKT)

Mode: Hybrid Mode

Venue: CLL, Department of Geography, 10F, The Jockey Club Tower, Centennial Campus, HKU

Zoom: Zoom link will be provided upon successful registration



Southeast Asia’s tropical peat swamps are a globally significant carbon pool, and their widespread deforestation and drainage are a large source of CO2 to the atmosphere. A less recognised fact is that they also account for about 10% of the global flux of dissolved organic carbon (DOC) from land to sea, which flows out from peatland-draining “blackwater” rivers. In this talk, I will discuss the progress we are making to understand the biogeochemical fate of this DOC in Southeast Asia’s coastal sea. Based on ocean colour remote sensing, we have found evidence that peatland drainage has increased the flux of DOC to the ocean. From long-term observations of carbon concentrations and stable isotope ratios, we have also found that the majority of this DOC is remineralized to CO2 in coastal waters. This production of CO2 at sea has a strong acidifying effect on coastal seawater that will interact with long-term ocean acidification, and thus peatland DOC has emerged as a key biogeochemical driver of coastal carbon cycling in Southeast Asia. I will also show how we are quantifying the rates of photochemical and microbial remineralization of peatland DOC with laboratory experiments that are specially designed to allow both processes to interact realistically, and how we are working towards representing these rates in a regional ocean model.

Professor Patrick Martin

Associate Professor, Nanyang Technological University

Patrick obtained a B.Sc. (Hons.) in Biology from the University of York, and a Ph.D. in oceanography from the University of Southampton / National Oceanography Centre, UK. He then worked as a postdoc at Woods Hole Oceanographic Institution, and at Nanyang Technological University, before joining the faculty at NTU in 2016. His research currently focuses on coastal carbon cycling, and includes dissolved organic matter optical properties, satellite remote sensing and coral-core palaeo-reconstructions of coastal dissolved organic matter concentrations, photochemical and microbial degradation processes, and variability in coastal inorganic carbon chemistry. In 2017, he started a monthly biogeochemical time series in Singapore that is still continuing, now as part of Singapore’s Marine Environment Sensing Network (


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