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Emil Jespersen: Effects of climate warming on phragmites in coastal wetlands

Seminar: Akvatisk biologi

04.06.2019 | Anne Kirstine Mehlsen

Dato tor 13 jun
Tid 09:45 10:30
Sted Institut for Bioscience, Ole Worms Alle 1, bygning 1135-234

Foredragsholder: Emil Jespersen, Akvatisk biologi, AU



Global climate changes is expected to affect plant performance and distribution on a global scale and the effects are not uniform at different latitudes as high latitude will undergo a higher temperature increase compared to their low latitude counterparts. Increased temperature affects many different biologically processes such as photosynthesis, respiration but also litter breakdown and mineralization of nutrients. Changes in these processes has the ability to alter ecosystem productivity and thereby the carbon source-sink relationships. Under the current climatic conditions, wetlands are mitigating the effects of climate changes because function as carbon sinks due to their anoxic and highly reduced soils combined with very high primary productivity, however we lack knowledge about how the sink-source relationship are affected by higher temperature.

Here we present preliminary data from a field study where temperature was increased above ambient with open top chambers in natural wetlands dominated by Phragmites australis. The study was conducted at three sites along a 700 km north south gradient at the northeastern Chinese coast.

Changes in source sink relations is evaluated based on photosynthetic gas exchange parameters from both light and CO2 response curves (A-I and A-Ci respectively) and plant morphologically and biochemically traits such as plant height, basal stem diameter, Carbon:Nitrogen ratio and elemental composition. In addition, decomposition and breakdown will be evaluated with the Tea Bag Index. Our results will give insight in which plant traits are affected by higher temperature and how these traits affects the sink-source strength in coastal wetlands. Based on our north south gradient we will be also able to elucidate the strength of the differentially impact at different latitudes. Our results are likely to have implications for how we can mitigate negative effects from increased atmospheric CO2 with natural wetlands in a warmer future.


Institut for Bioscience, Offentligheden / Pressen, Medarbejdere