Herz-Kreislaufphysiologie des Taschenkrebs Cancer pagurus unter Ozeanerwärmung und Ozeanversauerung Cardiovascular physiology of the edible crab Cancer pagurus under Ocean Warming and Acidification Dissertation zur Erlangung des akademischen Grads Dr. rer. nat. Bastian Maus Fachbereich 2 Biologie/Chemie Universität Bremen 2019 Title picture Nina Krah Photographs Bastian Maus Sebastian Gutsfeld Gutachter Prof. Dr. Hans-Otto Pörtner Alfred-Wegener-Institute, Helmholtz Zentrum für Polar- und Meeresforschung Integrative Ökophysiologie Am Handelhafen 12 27570 Bremerhaven PD Dr. Frank Melzner GEOMAR, Helmholtz Zentrum für Ozeanforschung Ökophysiologie Hohenbergstraße 2 24105 Kiel Weitere Prüfer Prof. Dr. Wilhelm Hagen Universität Bremen, Fachbereich 2 Leobener Str. 28359 Bremen PD Dr. Wolfgang Dreher Universität Bremen Universität Bremen, Fachbereich 2 Leobener Str. 28359 Bremen Termin des Kolloquiums: 20. Dezember 2019 I Ich widme diese Arbeit meinem Vater. II Table of contents Abbreviations ................................................................................................................................ IV List of figures and tables ............................................................................................................... V Summary ....................................................................................................................................... VII Zusammenfassung ........................................................................................................................ IX 1. Introduction ................................................................................................................................ 1 1.1 Climate change and ecophysiology ....................................................................................... 1 1.2 The cardiovascular and respiratory systems of a decapod crustacean ................................. 4 1.3 Non-invasive measurements and a multi-modal approach .................................................... 8 1.4 Research questions ............................................................................................................... 9 2. Material and methods .............................................................................................................. 11 2.1 The edible crab, Cancer pagurus ......................................................................................... 11 2.2 Manipulation of water temperature, CO2 and O2 ................................................................. 12 2.3 In vivo magnetic resonance imaging .................................................................................... 13 2.3.1 Experimental setup ........................................................................................................ 13 2.3.2 Imaging protocols ........................................................................................................... 14 2.4 Infra-red photoplethysmography .......................................................................................... 16 2.5 Respirometry ........................................................................................................................ 18 2.6 Statistics ............................................................................................................................... 18 3. Manuscripts .............................................................................................................................. 20 3.1 Manuscript 1 ......................................................................................................................... 20 3.2 Manuscript 2 ......................................................................................................................... 34 3.3 Manuscript 3 ......................................................................................................................... 59 4. Discussion ................................................................................................................................ 85 4.1 Methods and experimental approach ................................................................................... 85 4.2 Interplay between respiration and the cardiovascular system ............................................. 88 4.2.1 Functional links .............................................................................................................. 89 4.2.2 The roles of ventilation and cardiac performance at temperature thresholds................ 93 4.2.3 Cardiac work under hypoxemia ..................................................................................... 99 4.2.4 Proposal for mechanistic action of OWA on thermal tolerance ................................... 101 4.3 Conclusions and perspectives ........................................................................................... 103 4.4 Annex to the discussion ..................................................................................................... 106 5. References .............................................................................................................................. 111 6. Appendix ................................................................................................................................. 117 6.1 Figures ............................................................................................................................... 117 6.2 Calculations ........................................................................................................................ 120 Acknowledgments ......................................................................................................................... XI Versicherung an Eides statt ........................................................................................................ XII III Abbreviations AA ............................................. anterior aorta OWA ........... ocean warming and acidification ALA ............................... anterolateral arteries PA .......................................... posterior artery BF .................................................. blood flow PC ........................................... phase contrast bpm ..................................... beats per minute PCO2 .......................... partial pressure of CO2 BPV ....................... branchio-pericardial veins PO2 .............................. partial pressure of O2 BV .......................................... branchial veins pHe ........................................ extracellular pH CINE ..................................... cinematography pHi .......................................... intracellular pH CNS .......................... central nervous system RF ......................................... radio frequency CO ........................................... cardiac output ROI ..................................... region of interest CVS ............................ cardiovascular system SA .................. sternal artery, arteria sternalis DIC ...................... dissolved inorganic carbon SUC .................... surface radiofrequency coil EDV .............................. end-diastolic volume SV ............................................ stroke volume EF ......................................... ejection fraction SVP ................................ stroke volume proxy ESV ................................. end-systolic volume TA ......................... total alkalinity of seawater FLASH ............................. fast low-angle shot Tc .....................................critical temperature FOV ............................................ field of view TE ................................................... echo time FR ..................................................... flow rate Tp ...................................... pejus temperature HA .......................................... hepatic arteries TR ............................................ repetition time HL .............................................. haemolymph Tw ...................................... water temperature HR ................................................... heart rate wf ................................................. fresh weight Ig .................................................... Intragate© IR-PPG ........ infrared photoplethysmography MIP .................. maximum intensity projection ̇ MO2 ........ whole-animal oxygen consumption ................................................................ rate MOTSA ........... multiple overlapping thin-slice ..................................................... acquisition MRI .................. magnetic resonance imaging NMR .................. nuclear magnetic resonance OA ..................................... ocean acidification OCLTT ............... oxygen and capacity limited .......................................... thermal tolerance IV List of figures and tables Figures Fig. 1 Cardiovascular system of Cancer pagurus ......................................................................... 5 Fig. 2 Geographical distribution of Cancer pagurus .................................................................... 11 Fig. 3 In situ water temperature record from the North Sea seafloor .......................................... 12 Fig. 4 Experimental setup for MRI experiments .......................................................................... 14 Fig. 5 Localizer MRI scan of Cancer pagurus in experimental chamber....................................