Respiratory adaptations to a combination of oxygen deprivation and extreme carbon dioxide concentration in nematodes.
To examine physiological adaptations to the two combined stressors O2deprivation and extreme CO2concentrations, we compared respiratory responses of two nematode species occurring in natural CO2springs. The minimum O2concentration allowing maintenance of respiration in both species was 0.0176μmol O2ml-1(corresponds to 1.4% O2in air). After exposure to anoxia, individuals resumed respiration immediately when O2was added, but on a lower level compared to control and without showing a respiratory overshoot. A species-specific response was found in respiration rate during 20% CO2: the more tolerant species maintained respiration rates, whereas the sensitive species showed a decreased respiration rate as low as after anoxia. The results indicate that during 20% CO2the sensitive species undergo a survival state. We conclude, that the ability to maintain respiration even under low oxygen and high CO2concentrations may allow the better adapted species to occupy an ecological niche in the field, where others cannot exist.
Senckenberg Museum of Natural History Görlitz, Am Museum 1, 02826 Görlitz, Germany. Electronic address: maria.pilz@senckenberg.de.
Maria
M
Pilz
Senckenberg Museum of Natural History Görlitz, Am Museum 1, 02826 Görlitz, Germany. Electronic address: karin.hohberg@senckenberg.de.
Karin
K
Hohberg
Institute of Applied Botany and Volcano Biology, University Duisburg Essen, Universitätsstraße 5, 45141 Essen, Germany. Electronic address: hardy.pfanz@uni-due.de.
Hardy
H
Pfanz
Institute of Applied Botany and Volcano Biology, University Duisburg Essen, Universitätsstraße 5, 45141 Essen, Germany. Electronic address: christiane.wittmann@uni-due.de.
Christiane
C
Wittmann
Senckenberg Museum of Natural History Görlitz, Am Museum 1, 02826 Görlitz, Germany. Electronic address: willi.xylander@senckenberg.de.
Willi E R
WER
Xylander
D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D002245:Carbon Dioxide / Q000009:adverse effects / Q000378:metabolism*; D000860:Hypoxia / Q000503:physiopathology*; D009348:Nematoda / Q000502:physiology*; D012119:Respiration / Q000187:drug effects; D013045:Species Specificity; D013312:Stress, Physiological
D002245:Carbon Dioxide
Anoxia; Carbon dioxide; Cryptobiosis; Environmental stress; Hypoxia; Mofette field