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Directed motility of benthic diatoms
Diatoms are a group of highly diverse microalgae dominating aquatic systems and contributing to a quarter of the global primary production. They have a unique morphology including a biomineralized silicate-based cell wall. This rigid cell wall leads to cell size reduction during mitosis followed by size restoration through sexual reproduction. I used the model pennate diatom Seminavis robusta to determine how benthic diatoms forage for nutrients and locate their mating partners across their life cycle. A combination of video monitoring, trajectory analysis, and statistical modelling was utilized to determine how nutrient-starved or sexually-induced cells responded to the signal gradients formed by hotspot sources. I observed that cells are attracted to specific stimuli depending on their physiological conditions and needs. Nutrient foraging is consistent across the life cycle, wherein starved cells are attracted to silicate and phosphate, but not for nitrogen, and ammonium. On the other hand, once sexual, cells will also exhibit a finding mechanism for the mating pheromone, diproline. S. robusta exhibited a simultaneous tactic and kinetic mechanism towards the stimuli gradients. Despite being unicellular, diatoms can clearly prioritize between nutrient foraging and mating. It is highly possible that there is a cross-talk between dSi- and mate-sensing where motility is being regulated by the cells. The active searching behaviour can potentially contribute in shaping the aquatic environment on a microscale by influencing patchiness of biofilm communities, and on a global scale by affecting sediment-water nutrient fluxes and biogeochemical cycles. ; Diatomeen (Kieselalgen) bilden eine diverse Gruppe von Mikroalgen, die in aquatischen Systemen zu den dominanten Primärproduzenten zählen. Durch ihre große photosynthetische Aktivität tragen sie zu ca. einem Viertel der globalen Primärproduktion bei. Die einzigartige Morphologie der Diatomeen ist durch ihre biomineralisierten, silikatbasierten Zellwände geprägt. ...
Directed motility of benthic diatoms
Diatoms are a group of highly diverse microalgae dominating aquatic systems and contributing to a quarter of the global primary production. They have a unique morphology including a biomineralized silicate-based cell wall. This rigid cell wall leads to cell size reduction during mitosis followed by size restoration through sexual reproduction. I used the model pennate diatom Seminavis robusta to determine how benthic diatoms forage for nutrients and locate their mating partners across their life cycle. A combination of video monitoring, trajectory analysis, and statistical modelling was utilized to determine how nutrient-starved or sexually-induced cells responded to the signal gradients formed by hotspot sources. I observed that cells are attracted to specific stimuli depending on their physiological conditions and needs. Nutrient foraging is consistent across the life cycle, wherein starved cells are attracted to silicate and phosphate, but not for nitrogen, and ammonium. On the other hand, once sexual, cells will also exhibit a finding mechanism for the mating pheromone, diproline. S. robusta exhibited a simultaneous tactic and kinetic mechanism towards the stimuli gradients. Despite being unicellular, diatoms can clearly prioritize between nutrient foraging and mating. It is highly possible that there is a cross-talk between dSi- and mate-sensing where motility is being regulated by the cells. The active searching behaviour can potentially contribute in shaping the aquatic environment on a microscale by influencing patchiness of biofilm communities, and on a global scale by affecting sediment-water nutrient fluxes and biogeochemical cycles. ; Diatomeen (Kieselalgen) bilden eine diverse Gruppe von Mikroalgen, die in aquatischen Systemen zu den dominanten Primärproduzenten zählen. Durch ihre große photosynthetische Aktivität tragen sie zu ca. einem Viertel der globalen Primärproduktion bei. Die einzigartige Morphologie der Diatomeen ist durch ihre biomineralisierten, silikatbasierten Zellwände geprägt. ...
Directed motility of benthic diatoms
Bondoc, Karen Grace V. (author) / Pohnert, Georg / Boland, Wilhelm / Drescher, Knut
2017-01-01
Theses
Electronic Resource
English
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