Doctoral StudentDepartment of Biological & Environmental
About Maria Wittemann
My PhD studies focus on tropical tree species in a changing climate. Tropical regions have been experiencing a relatively stable climate both historically (as opposed to changes in temperate zones during the ice ages) and short-term (lacking seasonality). With climate change putting an end to this, there has been growing concern about the ability of tropical trees to acclimate to rising temperatures and more extreme periods of drought and high precipitation. Yet there is discord as to the relative importance of changes in different processes causing temperature and drought sensitivity. These include the biochemistry of photosynthesis (higher temperatures shorten reaction times, but also destabilize proteins and membranes), respiration (which is restricting net photosynthesis) and water balance. The latter is naturally influenced by drought, but also by temperature, since higher temperatures cause rising transpiration. This can result in cavitation and weaken the trees substantially. In my project I attempt to resolve these relative importance and thereby offer new insight for tropical tree conservation.
Complete or overcompensatory thermal acclimation of leaf dark respiration in African tropical