Dissolved oxygen levels indicate health of reefs

Dissolved oxygen is vital to support life and on coral reefs it is especially important. The concentration of dissolved oxygen is one of the best indicators of the health of an ecosystem. When oxygen levels drop, life can no longer be supported and fish can die.

Measuring dissolved oxygen (DO) can be performed using titrations, just like in chemistry classes, or by using a specialized probe.

We are making a DO probe that will be fully submersible and can be carried around by a diver to measure DO levels on reefs. The one we are using is made by Global Water. Now we just need to make a datalogger from an arduino and then waterproof the whole thing!

Connectors

Finding waterproof electrical connectors is a difficult task - Teledyne has some

Learning about conductance

Specific Conductance (SC) is a measure of how well water can conduct an electrical current. Conductivity increases with increasing amount and mobility of ions.

SC is usually reported in microsiemens (1/1,000,000 siemen) per centimeter, or µS/cm. SC is affected by temperature, so for consistency SC values are converted to what they would be at room temperature (25° C).



How can we measure this in the ocean. Well there are many "probes" that you can buy, or it is possible to make a probe using a few electronic chips and a microcontroller.
A microcontroller is essentially a small computer, and I personally like the open source arduino.
There is a very active group of hobbyists, scientists, artists, and very clever people using the arduino.

Benthic flux

How much of the material coming from the seafloor is used to help corals grow?
This summer we plan to measure the rates of chemicals (good ones) coming out of the sediment. We will use specially designed chambers to do this, called benthic flux chambers.


Initial sketch of a benthic flux chamber.

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