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Anna Ikonen, PhD student (2023-)

Temperature adaptation in resurrected phytoplankton across the European
coastal ecosystem














Amalia Skrifvars, Masters thesis (2023)

Phytoplankton community composition during contrasting winter conditions in a shallow bay in the northern Baltic Sea 

Karin Madsén, Masters thesis (2022)

Studying phytoplankton parasites in a Baltic Sea spring bloom using imaging flow cytometry

Anna Ikonen, Masters thesis (2021)

Microbial and molecular biostimulation of resting stages of phytoplankton

Resurrection ecology tries to understand how, e.g. global warming, affects organisms. The best way is to use organisms that haven’t been exposed to the current conditions, and resting stages of diatoms are great for that. In my thesis I ask if you with addition of melatonin can wake up resting stages, or get cells to enter a resting phase. I also ask will there be any changes in growth if you add melatonin. The idea is to find better methods to be able to wake up even older resting stages than what we have accomplished so far. My results imply that the growth decreases with high concentrations of melatonin and melatonin seems to affect the production of resting stages, but not their ability to wake up.        

Maximilian Gareis, Masters thesis (2020)

Anpassning hos kiselalgen Skeletonema marinoi till stigande vattentemperaturer under 1900-talet

Adaptation of the diatom Skeletonema marinoi to increasing temperatures during the 1900s

In my thesis, we are investigating if the diatom Skeletonema marinoi has adapted to the increasing temperatures in the Baltic Sea during the last decades. We have resurrected resting stages from the years 1960, 1986 and 2012 (seven strains per time point). We expect that the strains from 1960 have a higher growth rate in the lower temperatures and that the strains from 2012 have a higher growth rate in the warmer temperatures. We also expect to observe a difference in cell size between the three time points. We grew the strains in four different temperature treatments (6, 8, 10 and 14 °C) and estimated growth rates using daily fluorescence measurements of in vivo chl a. In 6 °C, the strains from 1960 had the highest growth rate. The cell size results showed a difference between years (smaller in more modern populations) but no significant difference between temperatures.

Ronja Lanndér, Masters thesis (2020)

Succession of the winter to spring phytoplankton community in the Åland Islands - a comparison of microscopic and rRNA gene analyses

Janni Heikkinen, Masters thesis (2019)

The role of genetic diversity in the marine diatom Skeletonema marinoi during and after antibiotic stress

In my master’s thesis I investigated the importance of the microbiome associated with the diatom species Skeletonema marinoi in means of ecological performance, the change in the associated bacterial community composition when subjected to stress, whilst also considering the role of diatoms’ genetic diversity when the microbiome is stressed. These questions were answered by conducting laboratory experiments where antibiotics disrupt the bacteria associated with clonal and mixed strains of S. marinoi. This a subject of great importance, since knowledge regarding diatom-bacteria interactions in the Baltic Sea is very limited.

PhD student, Anna Ikonen
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