Interdisciplinary Seminar: Lu Han

The UNC-CH Department of Marine Sciences presents the interdisciplinary seminar of graduate student, Lu Han. This event is scheduled for Monday, September 23rd, at 12:30 pm in room G201 on the ground floor of Murray/Venable Hall at the University of North Carolina at Chapel Hill. This seminar will also be broadcast live to seminar room 222 at the Institute of Marine Sciences (IMS) in Morehead City, NC and online via Zoom (Meeting ID: 396-860-047).

Seminar Title: Mechanisms for Carbon Pump in the Celtic Continental Shelf Sea

Abstract: Since the Industrial Revolution, energy-driven consumption of fossil fuels has led to a rapid increase in carbon dioxide (CO2) emissions. The ocean is an important buffer for atmospheric CO2, absorbing about a quarter of annual anthropogenic CO2 emissions. Continental shelves provide an additional sink of 27% to ∼30% of the CO2 uptake by the open oceans, even though they occupy only 7–10% of global ocean area. Sea-air CO2 flux varies on different types of shelves, due to different mechanisms for carbon cycling. The Celtic Sea is a seasonally stratified, temperate sea that forms part of the northwest European continental shelf. Previous studies of its surface waters have shown that it acts as a net sink of atmospheric CO2. This region was the target of extensive biogeochemical sampling from March 2014 to September 2015 as part of the UK Shelf Sea Biogeochemistry research programme, which provides an opportunity to study the mechanism of the nutrient conserving carbon pump in this temperate, seasonally stratified system throughout 1.5 seasonal cycles. Following the onset of stratification, near-surface biological primary production during spring and summer removed dissolved inorganic carbon and nutrients, and a fraction of the sinking particulate organic matter was subsequently remineralised beneath the thermocline, stored within a long-lived organic matter (OM) pool with a lifetime of several months or more. Accumulation of such a long-lived and potentially C-rich OM pool and the deeper nutricline support the large carbon sink at the study site, while providing a mechanism through which a nutrient-conserving continental shelf pump for CO2 could potentially operate in this and other similar regions.