Väitös (biologia): MSc Nina Cossin-Sevrin

MSc Nina Cossin-Sevrin esittää väitöskirjansa ”How can cellular-level energy production explain how wild birds cope with environmental stress?” julkisesti tarkastettavaksi Turun yliopistossa perjantaina 14.06.2024 klo 12.00 (Turun yliopisto, päärakennus, Tauno Nurmela -sali, Turku).

Yleisön on mahdollista osallistua väitökseen myös etäyhteyden kautta: https://utu.zoom.us/j/67046108305 (kopioi linkki selaimeen).

Vastaväittäjänä toimii professori Jan-Åke Nilsson (Lundin yliopisto, Ruotsi) ja kustoksena professori Katja Anttila (Turun yliopisto). Tilaisuus on englanninkielinen. Väitöksen alana on biologia.

Väitöskirja yliopiston julkaisuarkistossa: https://www.utupub.fi/handle/10024/177363


Tiivistelmä väitöstutkimuksesta:

Nothing happens in Nature without energy. Within cells, mitochondria produce that energy by oxidizing nutrients: but how efficiently they do that varies between individuals, and this variation can have far ranging effects, modulating growth, reproduction and survival.

During my PhD, I investigated how metabolic efficiency could be used as an indicator of quality in wild birds. I focused on particularly stressful episodes in their life: growth, and reproduction. In order to obtain more generalisable results, I studied two extremely different bird species: a tiny, fast-paced forest passerine, the Palearctic Great tit, and a large, slow-paced seabird: the Subantarctic King penguin.

One of the key results of my work is to show that early life stress, defined either hormonally as an increase in stress hormone, or more generally as adversity in life conditions, can indeed impact mitochondrial metabolism. Experimentally elevated stress hormones, a high mortality risk, or a mismatched birth date (being born under unfavourable conditions) all have the capacity to modulate energy production in the mitochondria. When focusing on the parents, I also found that maintaining energy production through the stress of breeding requires specific strategies, and that males and females can find different ways of achieving that.

This work also allowed me to explore both the use and the limits of in-vitro high-resolution respirometry methods for studying wildlife. Methodologically, I focused on the metabolically active red blood cells, which provide a low-invasive way of studying wild birds. However, this work was also an opportunity to reflect on the difficulty of defining even central concepts as mitochondrial efficiency and, in the end, metabolism itself, within the framework of ecology – especially when faced with such remarkable physiological feats as surviving a freezing Finnish winter for a 20-gram passerine, or endlessly swimming through the great southern ocean for a King penguin.