This time Aleksandr will present his PhD work in the Green-blue project. We will meet at the meeting room 2418 in the Kristine Bonnevies hus building. It is also possible to follow his talk on Zoom. This link will be sent via email to CBA members.
A short description about Aleksandr's research :
The North Sea, Norwegian coastal waters and the Baltic Sea are all interconnected and influenced by the organic matter loads coming from land. The quantity and quality of the organic matter getting into the water systems is heavily dependent on current climate. Northern latitudes are disproportionately affected by the climate change. Russian and Scandinavian taigas are getting more vegetation growth as a result of warmer temperatures and heavier rainfall. More vegetation generally means that more organic matter enter the water systems. Once in a water body organic matter gets dissolved into water column and remains there as dissolved organic matter (DOM). DOM can potentially affect marine ecosystems, by diminishing light, becoming effectively a “competitor” to phytoplankton for light availability. This means that high concentrations of DOM can reduce photosynthetic activity in a water body, resulting in lower biomass of phytoplankton. Phytoplankton community structure also undergoes changes, as different species of phytoplantkton react differently to changes in DOM concentrations. Some are disadvantaged by the decreased light availability, while others become more competitive. Phytoplankton adjust to such changes in the environment by shifting their bloom timing. Over the past century spring phytoplankton bloom was delayed by 22 days, this was attributed to coastal darkening
I have tested optical qualities of the water column in Glomma vicinity, as well as testing the sampled water samples for light absorption. This allowed to test the absorbance ratios of four light absorbing elements (i.e. water, DOM, detritus and pigments), as well as to test whether elevated DOM concentrations affect photosynthetic capabilities of phytoplankton in the area.