Protocols for the ACT Verification of In Situ Dissolved Oxygen Sensors.

Abstract

As part of our service to the coastal community, ACT Partner Institutions and Stakeholder Council has chosen the perform ance verification of commercially available in situ dissolved oxygen sensors as the first ACT Technology Evaluation. There are a variety of dissolved oxygen sensors/electr odes currently available, many of which use polargraphic membrane measuring techniques. Recently, however, new optical luminescence dissolved oxygen sensors have been developed and are now on the market. Precise and reliable measurements of dissolved oxygen concentration (DO) with effective and reliable in situ sensors are critical for understanding many physiological and ecological processes and are required for a variety of coastal science and manage ment activities. For example, many coastal resource managers and scientists are interested in regions of very low levels of dissolved oxygen (hypoxia) in bottom-water or "dead zones". These areas of seas onally-depleted oxygen levels are natural phenom ena, but can be intensified spatially and temporally as a result of human activities (i.e., nutrient over-over enrichment). ACT has performed a customer needs and use assessment for in situ dissolved oxygen sensors. Scientists, resource managers, and other users of these technologies were asked to 1 ACT Verification Protocols ACT TV04-01 respond to a questionnaire regarding their curren t use or application of these instruments, limitations or problems with their current dissolved oxygen sensors, and the important parameters they use when selecting a dissolved oxygen sensor. The results of this assessment were used to identify the main applications and key parameters that ACT will evaluate in this Technology Verificatication.