Breadcrumbs

European Space Agency satellites used to diagnose health of Bay of Plenty lakes

14 October 2021

Satellite image of Lake Rotoehu
Satellite images showing algal bloom highlighted at Lake Rotoehu.

Satellite images from the European Space Agency are being used to diagnose the health of Bay of Plenty lakes, researchers using images from space to hunt out algal blooms and help manage them.

As we head into summer, which is peak algal bloom time, the health of New Zealand lakes is usually monitored by water samples taken at specific points from the lakes being tested. Now a collaborative study by New Zealand and German researchers has shown how satellite images can be used to track algal blooms in lakes over time.

The blooms are seen from space as patches and swirls of green and brown colours. Satellite images can support the ground management of the lakes by sending council staff to the perfect locations for water sampling.

“Using satellite imagery, we can pinpoint exactly where the blooms are and how they are spreading over time. This helps to ensure we get the best water samples, building a full picture of how healthy our lakes are, or not,” says Dr Moritz Lehmann from the Xerra Earth Observation Institute and the University of Waikato.

Dr Moritz Lehmann
Dr Moritz Lehmann

Moritz said New Zealand and Rotorua had both some of the most pristine lakes in the world and some of the most degraded but detailed data on the water quality of all New Zealand’s lakes was patchy at best.

“A 2019 report from the Parliamentary Commissioner for the Environment said New Zealand was lacking in environmental monitoring data, including the water quality of most of our lakes. We tend to focus on our big ones, the ones people live closest to, or the ones that are most polluted, but we don’t have a full picture,” he says.

With satellites flying over New Zealand constantly and access to the images from the European Space Agency provided free, the methods developed on the Rotorua lakes have potential to help manage the health of all New Zealand’s lakes and lakes worldwide.

This project was started by Eike Schütt, a student enrolled at the University of Kiel in Germany who wanted data to support his coursework.

“The Rotorua lakes boast some of the best water quality monitoring data sets in the world, so I sent Eike a decade of data from the Bay of Plenty Regional Council,” says Moritz.

With the support of Dr Martin Hieronymi and Dr Hajo Krasemann (Helmholtz-Zentrum Hereon, Germany), Eike calibrated an algorithm to detect algae in the Rotorua lakes with better accuracy than before. The team then wanted to demonstrate how satellites can be used in routine monitoring of lake health, so they teamed up with James Dare, environmental scientist at the Bay of Plenty Regional Council.

Over time the satellite maps show chlorophyll a concentration, (chlorophyll a is an indicator of algal biomass) and the team was able to describe these patches using statistics, says Moritz.

“This allows lake managers to understand how algae is distributed through the lakes without having to visit them and provides information on where the best monitoring sites are to test water quality.”

The collaborative work through this study and a recently awarded MBIE Smart Ideas project, will support further developments of the methodology.

The study was published on 22 September 2021 in the International Journal of Applied Earth Observation and Geoinformation and the article is free to download from  https://doi.org/10.1016/j.jag.2021.102547


This research aligns with the following United Nations Sustainable Development Goals:

Clean Water and Sanitation

Latest stories

Related stories

Indigenous birthing knowledge the focus of Fulbright research

Nikki Barrett is locking down the detail for her Fulbright-Ngā Pae o te Māramatanga Graduate…

Ahuroa Leach

Scholarship recipient researches affordable energy for impoverished communities

Unleashing the power of waves and wind to provide affordable electricity to New Zealand’s most…

Science alumna wins prestigious conservation award

Science alumna, wetlands expert and advocate Dr Beverley Clarkson has been awarded the Loder Cup…

Research shows oxytocin could be used as an appetite suppressant

Oxytocin, the drug sometimes called the love hormone, and which is used to bring on…

Tahu Kukutai and Margaret Carr

Waikato researchers recognised as Royal Society Te Apārangi Fellows

Two University of Waikato Professors have been named Fellows to the Academy of the Royal…

Engineering student’s drive to succeed

Tom Miller admits the decision to quit his job, move from Auckland to Hamilton and…

Summer research projects inspire students

Whoever thinks research is a dull and lonely occupation has got it wrong, says psychology…

University of Waikato Fulbright Scholar to study how kava can be used to reduce PTSD

Kava could be used as an alternative to mainstream medicines in the treatment of Post-Traumatic…

New study shows inequality in vaccine rollout for Māori and at risk communities

New Zealand’s rollout of the Covid-19 vaccine has failed Māori and at-risk communities as health…

Scholarship empowers women in STEM

Engineering student Isobella Nicholls and Computing and Mathematical Science student Courtney Wilson are the inaugural…

Medalists

2021 Hillary Medalists named

Two alumni, Courtney Richmond and Tim Neild, have been named as the 2021 Hillary Medalists…

Professor Taciano Milfont

Waikato appoints three new Professors

University of Waikato Vice-Chancellor Professor Neil Quigley has announced promotion to Professor for three academics,…