Project description; PhD nr. 6, MANTEL
Objectives: it is still unknown how extreme weather events such as storms will affect a lake?s function as a carbon source or sink. Current estimates suggest that lakes globally emit between 8-48 Tg CH yr^(-1) (equivilant to 6-16% of total natural methane emissions) which is greater than oceanic methane emission. There are indications that storms can severely alter greenhouse gas dynamics and alter phytoplankton and microbial dynamics. The LakeLab mesocosms are fully equipped with automatic profilers allowing for a high temporal and spatial monitoring of all important limnological variables including phytoplankton dynamics. A preliminary experiment, mimicking a storm event in July 2014, led to the formation of a massive cyanobacterial bloom (Dolichosperum flos-aquae) which resulted in alteration of microbial dynamics and hence C-cycling, and in particular changes in calcite precipitation rendering thbe lake from a C-sink to a C-source. The overall objective of this project is to study the microbial response to simulated mixing events in different seasons to better evaluate the effect of mixing in both the productive (summer) and less productive (winter) seasons (contributing to WT 3.2).
Specific objectives include:
To carry out a set of experiments informed by current/procjected intensity and duration of storm events at MANTEL sites.
To collect and collate profiler data (temperature, pH, conductivity, oxygen, PAR, pigments, turbidity etc.).
Observe changes in the microbial community structure (Next Generation Sequencing and microscopic counts) and activities (gross primary production, net ecosystem respiration, bacterial production, sedimentation and whole lake metabolism).
Using these data, evaluate whether future storm events have the potential to significantly alter ecosystem dynamics and function rendering lakes from C-sources to C-sinks.
MSCA-TOPP-UT-Toppfinansiering av MSCA utgående kandidater