Summary #
Dissolved oxygen (DO) is essential for aquatic life. AMD impacts, algal blooms, and other pollution sources can reduce DO levels. This page explains what dissolved oxygen measures, why it fluctuates, and what levels indicate healthy or stressed conditions.
Dissolved Oxygen (DO) is absolutely essential for the health of organisms in aquatic environments. The macro invertebrates depend on this to breathe, as they cannot produce their own oxygen. It usually ranges from 0 to 20 g/L, with higher values indicating better water quality. Colder water typically has a higher DO capacity than warmer water. Once the level of DO has been determined, as well as the temperature, you can use a percent saturation chart to find out if your stream has all the oxygen it can hold. Though a level of 13mg/L DO might not sound high, it may mean that your stream is at 100% saturation: the best level possible. Lower saturation levels may be due to pollution affects.
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·E #
This picture is an example of a dissolved oxygen test kit from HACH. These are relatively easy to use and accurate. Clear directions are included with the kit. It is very important when using this test kit, however, to be sure that no air bubbles are introduced to the sample. Any air bubbles that are in the sample or that enter the sample during the testing may alter the results.
Dissolved oxygen meters are also commonly used for testing. These meters are very similar to pH meters, a wand is inserted into the water after the meter has been calibrated to compensate for temperature and altitude. The dissolved oxygen content is then recorded from the readout.
HACH Company provides a catalogue of chemical water testing kits and supplies
Other tests, including and/or in addition to those described above, may be appropriate for the watershed in your area. The indicators that were chosen as points of study while making your monitoring plan are a good way to decide what tests need to be performed.
Sources/Links (as provided in the source text):
Related Pages #
- Developing a Monitoring Plan — Structuring your monitoring program
Source and Last Reviewed #
Source: AMR Clearinghouse (amrclearinghouse.org). Migrated to AML-Connect. Last Reviewed: 2026-03-13.
[Admin note: Some external links in this article may be outdated. Verify before relying on them. Flag dead links for removal or replacement.]
Tags: monitoring, sampling, education
