Global change effects on zooplankton body size: a range of experimental approaches

• Main Author: Garzke, Jessica
• Other Authors: Sommer, Ulrich, Ismar, Stefanie M.H.
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2014
• Subjects: thesis; ddc:570; marine copepods; metabolic theory of ecology; abundance; mesocosm experiments; Ocean acidification; Copepods
• Online Access: https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-157160; https://macau.uni-kiel.de/receive/diss_mods_00015716; https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00005715/Diss_JGarzke.pdf

It is a major challenge to understand the impacts of recent climate change on zooplankton communities. The impacts of global warming are manifold and multiple factors, which drive ecological changes in zooplankton communities have to be understood. Increasing sea surface temperature is likely to alter zooplankton phenology and community structure. Recent studies on the global scale showed a decline in size and productivity of zooplankton, which was related to climate change. Reorganization of zooplankton community with warming can change community interactions and energy flow through whole aquatic food webs. The aim of this thesis was to examine the effects of temperature, phosphorus limitation and acidification on copepods and disentangle direct and indirect effects of warming on zooplankton and how the observed changes can alter the metabolic fluxes in food webs. In the first chapter, I tested the effect of three temperatures on copepod communities in a mesocosm experiment. The second chapter presents results of a monoculture experiment with the copepod species Acartia tonsa, where phosphorus concentration in food algae and temperature effects were combined. In my third experiment, a second mesocosm study, I show effects of the combined factors temperature and ocean acidification, to understand single and interactive effects on the copepod community. With respect to trophic chain length, I demonstrate in chapter 4, that total and mass-specific ecosystem primary production and respiration are differently temperature sensitive, and that bloom dynamics and non- bloom dynamics act differently on ecosystem oxygen fluxes. In the first chapter of this thesis, I describe the results of a performed mesocosm experiment, which allowed me to identify copepod responses to temperature. Body size of adult copepods and of all Acartia sp. developmental stages was smaller at higher temperatures. Total zooplankton, nauplii and adult copepod abundance was lower at higher temperatures. Additionally, a stage shift from older, at ...