...—base variables and regulation. Accordingly, the sediment-dwelling worm Sipunculus nudus was used as an experimental model to investigate the correlation of acid—base-induced metabolic depression and protein/amino acid catabolism, by determining the rates of oxygen consumption, ammonia excretion and O/N...

...I. Hardewig; A. D. F. Addink; M. K. Grieshaber; H. O. Pörtner; G. Van Den Thillart ABSTRACT Oxygen uptake and the mode of energy production in Sipunculus nudus L. were determined at different oxygen levels by means of direct and indirect calorimetry. Oxygen consumption declined linearly...

...H. O. Pörtner; N. A. Andersen; N. Heisler ABSTRACT Proton-equivalent ion transfer processes between animals and ambient water were determined under normoxic control conditions during anaerobiosis and the subsequent recovery period in the marine worm Sipunculus nudus L. During anaerobiosis...

...Hans-Otto Pörtner ABSTRACT The quantitative influence of anaerobic metabolism on acid-base status and on acid-base regulation is investigated in Sipunculus nudus L. Proton generation by metabolism is calculated from theoretical predictions. The quantitative comparison of metabolic protons with non...

...H. O. Pörtner; S. Vogeler; M. K. Grieshaber ABSTRACT Recovery from 24 h of anaerobiosis was investigated in Sipunculus nudus L. by monitoring changes in the concentrations of anaerobic metabolites in the musculature and in the coelomic plasma. The metabolic events in animals collected during March...

...H. O. Pörtner; S. Vogeler; M. K. Grieshaber ABSTRACT Intra- and extracellular acid-base status and changes of coelomic were investigated during recovery following 24 h of anaerobiosis in Sipunculus nudus L. Metabolism, gas exchange and acid-base status were compared in animals collected during...