Project title: Assessment of Tropical blue carbon reserves
Supervisors: Professor Peter Ralph (C3 UTS), Professor Hilary Kennedy (University of Bangor, UK), Dr Peter Macreadie ( UTS)
PhD conferred: 2016
Industrialisation and rapid population growth have caused an increase in greenhouse gas emissions. Increasing atmospheric carbon dioxide levels are having severe impacts worldwide including changing weather patterns, ecosystem destruction and the loss of livelihoods. While the critical role of terrestrial ecosystems as a source and sink of organic carbon is well known, the importance of carbon sequestration in vegetated coastal ecosystems, called “Blue Carbon” is increasingly being acknowledged.
Seagrass beds are one of the most important blue carbon sinks in the ocean. Although they cover only ~ 0.1% of the coastal ocean, 15% of total carbon that accumulates in the ocean is in seagrass sediments. However human activities such as coastal development, dredging and industrial runoff have caused a rapid loss in seagrass meadows worldwide. About one-third of the global seagrass area has been destroyed and seagrass loss is accelerating: from 0.9% per year in the 1970s to more than 7% per year since 2000. Thus natural blue carbon sinks are in decline, and consequently, their capacity to remove global anthropogenic carbon emissions. While the potential for seagrass beds as blue carbon sinks has been widely reported, the evidence to support the influence of seagrass loss on a changing capacity to store organic carbon in sediment, the source of organic carbon and sediment properties is still needed. Equally the influence of seagrass density and cover on those stores of organic carbon content, carbon sources and the sediment properties needs to be investigated.
This study of sources of organic carbon input to the sediment will provide the evidence to support the important role of seagrass as a significant blue carbon sink. Moreover, this research will examine how the growth and development of seagrass meadows modifies the sediment conditions by enhancing sediment accretion, trapping the particulate suspended particles from the water column and reducing the resuspension rate within the complexity of above and below ground systems.
This project aims to
(i) examine the influences of seagrass loss on sediment carbon storage capacity, sediment properties and origin of organic carbon,
(ii) examine the influences of seagrass species with different canopy structure, cover and biomass on sediment carbon storage capacity and sediment properties and to
(iii) examine how the sources of sediment organic carbon in tropical seagrass beds are affected by canopy structure, cover and biomass.
Contact details: Peter.Ralph@uts.edu.au