Respirometry: VO2 in water
This routine will calculate oxygen depletion curves or rates of O2 consumption of aquatic organisms, based on changes O2 concentration. The latter can be expressed in a variety of units: oxygen partial pressure, i.e., pO2 (torr), percent saturation of oxygen (zero to 100%), parts per million O2 (by mass), or mg O2/Liter (note that the latter two units are identical).

Most of these parameters can be edited with the EDIT FILE DATA option, including flow rate, barometric pressure, temperature, and container volume (= effective volume).  Alternately, you can enter your own O2 content data (dissolved oxygen per unit volume) and click the 'net O2' button, or you can directly enter net O2 content (total dissolved oxygen).

If there are less than 40 channels in the file, you can store results in a new channel.

For closed-system measurements, there are three conversion options.  For any of these, you can generate absolute units or mass-specific units (per mg, per g, or per kg).  Note that all conversions are based on the value shown in the 'net O2 content' edit field.  If you know that oxygen content differs from the computed value in this edit field, you can enter your own value prior to doing the conversion. 

Here is an example showing conversion into consumption rate (ml O2 / [g .  min]):

The Open-system (flow-through) routine will only compute oxygen consumption rate, in your choice of units.  You can use either of two algorithms, selected with buttons in the initial window:

Deflections in O2 concentration in the excurrent stream may be either positive or negative (if the latter, click the 'negative deflection' button in the initial window).


Other links: