I was looking at a research paper by Thomas (1954) and came across a graph with ambient oxygen concentration plotted against oxygen consumption rate of a European lobster kept in water.


As we can see, this is a linear relationship, but I'm unable to figure out the reason behind this direct linear relationship.

I would be glad if anyone out there can suggest a possible reason, because just rote learning the graph is not something which should be done.

  • $\begingroup$ Did you read the summary? Given explanation seems legit to me: "6. Increase in oxygen uptake with temperature in sea water is mainly brought about by an increase in the gill ventilation rate. In addition, the degree of utilization increases. The relationship is a direct reflexion of the increased metabolic activity". $\endgroup$ – Maxim Kuleshov Jan 4 at 16:50
  • $\begingroup$ I read the summary and I understand why increase in temperature leads to higher oxygen consumption rate, but I can't figure out how oxygen consumption rate is dependent upon the ambient oxygen concentration. $\endgroup$ – Anonymous Jan 4 at 17:12
  • $\begingroup$ That's how blood flow works. Gills are not 100% effective and can absorb only certain percentage of oxygen. So the lower oxygen concentration is the lower amount of oxygen is absorbed. $\endgroup$ – Maxim Kuleshov Jan 4 at 17:27
  • $\begingroup$ Now I understand. Thank you very much Maxim Kuleshov. $\endgroup$ – Anonymous Jan 4 at 17:29

Increasing the ambient oxygen concentration increases diffusion of oxygen across the gills, thereby increasing the oxygen uptake by the lobster. This can be proven by the fick's law of diffusion-


L=thickness of diffusion membrane

D=diffusion coefficient

A=cross sectional area of diffusion membrane

P2-P1=pressure difference


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