My current research as part of my PhD is the ecophysiology of New Zealand mangroves (Avicennia marina subsp. australasica). The specific questions relate to the water and carbon relations of those trees. My supervisor, Sebastian Leuzinger, has worked on similar projects in Europe so his expertise for this project are invaluable.
Plants are the gatekeepers of carbon entering and water leaving terrestrial ecosystems. Trees are of particular importance because they are dominant carbon sinks and sources of water to the atmosphere in terrestrial ecosystems with as much as 70% of water leaving and almost all the carbon entering via trees. Changing climate will undoubtedly influence tree survival and hence affect the ability of forest systems to store carbon and cycle water. Despite the described importance of trees there are several key questions regarding carbon and water relations that remain unanswered. A principal barrier to addressing these questions is the logistical difficulty of studying large mature trees in complex systems. My research will use New Zealand mangroves as a model system for studying water and carbon relations in trees.
New Zealand mangroves are an ideal outdoor laboratory for investigating tree carbon and water relations for several reasons. Firstly, tidal inundation with salt water induces periodic and therefore predictable stress conditions. Secondly, their canopies are easily accessible even when trees are mature. Lastly, New Zealand mangrove forests are monospecific (i.e. no interspecific competition), which removes a classic confounding factor in ecological experiments. We are using a combination of established (e.g. sap-flow and stomatal conductance) and newly developed tools (e.g. point dendrometers and leaf patch-pressure clamps) linked to an online continuous monitoring system (click here to see the data in real-time). The combination of these state-of-the-art sensors (see pictures below) will provide an unprecedented and complete understanding of water and carbon relations in mangrove trees, with the potential to apply the findings to the ecophysiology of terrestrial forest ecosystems.