Maroon Lagoon from Algal Bloom 

Monday 27th February 2017

IB students join with other Dunedin schools to monitor water quality at Tomahawk Lagoon.

IB Students measure water quality at Tomahawk Lagoon
IB Students measure water quality at Tomahawk Lagoon

McGlashan students have had a long history with this body of water.  It has been the focus of the IB Diploma 3- day science project run in November over many years.  Last year however, ECOtago began a longitudinal monitoring study of the lagoon, looking at it's biodiversity and water quality and this provided our students an excellent opportunity to become involved in environmental science in a real-world context.

On a perfect February morning, around 25 students from across Dunedin were trained in a wide range of techniques, enabling them to collect water samples, measure oxygen concentration, water salinity, temperature, depth, nitrogen & phosphate concentration, and eColi contamination.  Bird counts, and biodiversity observations of plant and animal life are also made of the lagoon.  All data is logged and analysed to help create a meaningful story about the health of this important local waterway.

Students were intrigued to discover that the overall health of the lagoon tends to go in 2-3 year cycles.  Currently, there are two different algal blooms occurring in the two arms of the lagoon - one causing a green tinge and the other a reddish tinge (OK - not quite maroon, but I wasn't about to pass up a rhyming opportunity like that!)  Hopefully our monitoring will uncover the reasons for this interesting phenomenon.

Andrew Innes instructs IB Students about sampling techniques
Young scientists of tomorrow (and a few not so young).
Bird watching at Tomahawk Lagoon