Coping with a changing world: adaptive mechanisms in marine three-spined stickleback Gasterosteus aculeatus

• Main Author: Schade, Franziska Maria
• Other Authors: Wegner, K. Mathias, Hinrich Schulenburg
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2014
• Subjects: thesis; ddc:000; Climate change; fish; parasites; adaptation; phenotypic plasticity; transgenerational acclimation; Klimawandel; Fische; Parasiten; Phänotypische Plastizität; Transgenerationale Akklimatisierung; Wandel; Ocean acidification
• Online Access: https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-143928; https://macau.uni-kiel.de/receive/diss_mods_00014392; https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00005395/diss_schade.pdf

Due to ongoing increases in carbon dioxide (CO2) concentrations in the atmosphere, the world’s climate is changing at an unprecedented rate, leading to rising global mean air and water temperatures. When atmospheric CO2 dissolves in seawater, ocean pH declines, causing an acidification of the ocean. These altered environmental conditions are highly probable to have severe impacts on marine organisms by affecting their performance and survival. When environmental stress is increasing, some species can migrate to habitats with more favourable conditions, others have to adapt to changing conditions. Whether species will be able to adapt fast enough to keep pace with changing environments will be one decisive factor for population persistence. In this thesis, a prime model organism, the three-spined stickleback Gasterosteus aculeatus, was used to study ecological and evolutionary effects of rising water temperatures and ocean acidification on marine fish populations. Rising temperatures are likely to stress marine species, dependent on their thermal tolerance. Thermal stress can alter immune functions of organisms, thereby increasing the susceptibility to infectious diseases. By combining the effects of elevated temperature and bacterial infection in a common garden experiment, the influence of thermal stress on evolutionary trajectories of disease resistance in three-spined stickleback populations could be investigated (chapter II). Environmental stress negatively impacted life-history traits and pathogen resistance of sticklebacks. Furthermore, thermal stress reduced genetic differentiation between populations by releasing cryptic within-population variation. While life-history traits showed positive genetic correlations between temperatures and genotype by environment interactions (GxE), thermal stress led to negative genetic correlations in disease resistance, showing that evolutionary responses in altered environments can be hard to predict from prevailing conditions. Rising temperatures, on the other hand, ...