Turbitidy Sensor Upskilling- Kawerau students @ Massey University
Kawerau students were full of enthusiasm as they attempted to solder their components together. Using the arduino open-source electronics platform, students were taught how to use this easy-to-use hardware and software which included:uno boards; usb cables; jumper wires; phototransistor; LEDs; pin strips; resistors and sensors. Dr Mercer and his team demonstrated how students can send a set of instructions to the microcontroller on the board Arduino boards are able to read inputs - light on a sensor, a finger on a button, or a Twitter message - and turn it into an output - activating a motor, turning on an LED, publishing something online. They also began to appreciate the Arduino programming language (based on Wiring), and the Arduino Software (IDE), based on Processing.
Building their own turbidity meters is an useful step toward youth engaging the challenge of managing turbidity levels of our rivers. In June 2002, for example, Rowe et al (2002) delivered a paper on Lethal Turbidity Levels for Common Fish and Invertebrates in Auckland Streams for the Auckland Regional Council.
The paper examined the effects of acute (24 h) exposure to high turbidity levels on the survival of 6 species of aquatic invertebrate and 4 species of fish commonly encountered in Auckland region streams. These species were likely to be more sensitive to increases in turbidity than others. The invertebrates tested included the larvae of 2 caddisflies, 1 damselfly, 2 mayflies, and adult freshwater crayfish (koura). The fish tested were smelt, inanga, redfinned bully and banded kokopu.
Results revealed that there was no significant difference between the percentage survival of any of the aquatic insect larvae, crayfish, banded kokopu and redfinned bullies and their respective control groups at turbidities up to c. 20,000 NTU.
However, the common smelt -Retropinna-retropinna -was the most sensitive taxa to high turbidity levels in Auckland streams. NIWA reports that 'Smelt are very sensitive to handling and stress and prefer low levels of sedimentation with lower smelt populations in lakes that have high levels of siltation'.
The results from the Auckland Regional Council tests has provided guidelines for both its protection, as well as for predicting the effects of high turbidity events on its survival.
Examples of crayfish, banded kokopu, redfinned bullies and smelt fish that can be affected by turbidity levels