000K utf8 1100 $c2018 1500 eng 2050 urn:nbn:de:gbv:8-diss-224864 3000 Boxhammer, Tim 4000 Influence of ocean acidification on elemental mass balances and particulate organic matter stoichiometry in natural plankton communities$hChristian-Albrechts-Universität zu Kiel [Boxhammer, Tim] 4030 Kiel$nChristian-Albrechts-Universität zu Kiel 4209 The oceanic uptake of anthropogenic CO2 leads to a gradual acidification of the ocean. Ocean acidification (OA) is known to affect marine biota from the organism to the ecosystem level but with largely unknown consequences for the cycling of key elements such as carbon, nitrogen, and phosphorus. However, the ocean’s ability to absorb anthropogenic carbon or to provide sufficient food for humankind depends on these oceanic material cycles. This doctoral dissertation thus aimed to assess the influence of OA on biogeochemical cycles of elements in natural pelagic food webs of several trophic levels (up to fish larvae) over extended time scales of weeks to months. Large-scale pelagic mesocosms (up to 75 m3 per unit) were deployed in different marine ecosystems and new methods were developed to quantify the downward flux of particulate organic matter under simulated OA. This thesis reports on the potential influence of OA on element pool partitioning and particulate organic matter stoichiometry with consequences for biogeochemical cycling of elements in the ocean. Furthermore the potential and limitations of biogeochemical measurements inside pelagic mesocosms that host entire plankton communities are elucidated. 4950 https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-224864$xR$3Volltext$534 4961 https://macau.uni-kiel.de/receive/diss_mods_00022486 5051 570 5550 biogeochemistry 5550 elemental mass balance 5550 mesocosm 5550 ocean acidification 5550 plankton community 5550 POM stoichiometry