Ökophysiologische Studien an der Kaltwasserkoralle Lophelia pertusa (Scleractinia)

• Main Author: Gutperlet, Ruth
• Format: Thesis
• Language: German
• Published: 2008
• Subjects: Lophelia pertusa
• Online Access: https://oceanrep.geomar.de/id/eprint/8144/; https://oceanrep.geomar.de/id/eprint/8144/1/Dipl.%202008%20Gutperlet,%20R.pdf; https://oceanrep.geomar.de/id/eprint/8144/2/Dipl.%202008%20Gutperlet,%20R_Anhang.7z

The aim of the present study was to investigate the effects of increased water temperatures on the physiology of Lophelia pertusa. It was tested which type of analysis is appropriate to measure physiological stress of this hermatypic cold water coral by means of two different experimental setups (11 °C and 18 °C). In each setup some fragments of L. pertusa were cultivated at 8 °C simulating habitat temperature. These fragments represented the control groups (KG I & KG II). During the first experiment stress group I (SG I) was cultured at an extreme temperature of 18 °C. In the second experiment, stress group II (SG II) was kept at 11 °C and the influence of this moderate stress level investigated right after temperature increase. This second stress induction followed an acclimatisation phase of 14 days. In both experiments the extension behaviour of L. pertusa was documented by cameras and analysed using a newly developed method. Additionally, respiration rates of the different fragments were measured using a Winkler titration technique. To determine natural variability of the single polyps, both SG measurements were undertaken at 8°C, before inducing high temperature stress. Considering the low sample size final respiration rates and polyp extensions were compared to pre-manipulated values. In simultaneous processes to both SG experiments, the extension and the respiration rate of the respective KGs were recorded. The RNA/DNA ratio of all examined polyps was determined, directly after each of the two experiments. The applicability of this method as a general indicator for the fitness of L. pertusa was assessed by means of an additional experiment, in which the ratios of polyps, which survived starvation for 152 days was measured.