Warmer seas tracked by Lyttelton Port Company monitoring project
If you’ve been feeling like the sea is warmer than usual, you’re right. Lyttelton Port Company (LPC) has 14 monitoring buoys around the Lyttelton Harbour and the wider coastal area, measuring water clarity, currents, wave height, salinity, dissolved oxygen and temperature. The data showed December water temperatures were about five degrees warmer than the same time last year.
Dr Leonie Andersen from Vision Environment installed the buoys in September 2016 to provide baseline data on the harbour’s natural fluctuations before channel deepening dredging begins this year.
Dr Andersen said the inshore sites are always warmer and fluctuate more than the offshore sites, which are in deeper water and exposed to oceanic currents. The buoys send data via 3G networks every 30 minutes. The real time data is publicly available on the LPC website.
“The water temperatures within the harbour itself strongly respond to air temperatures and it was a pretty hot December. We can see the water temperature cycling during the day – heating during the day and cooling at night. Sometimes it can vary up to five degrees in 24 hours,” Dr Andersen says.
She says this variation is more radical than other harbours she has studied because Lyttelton is relatively shallow in the inner and upper harbour. The shallow areas are easily heated during the day and cooled at night.
The monitoring system will help Dr Andersen and other scientists understand more about the harbour’s natural variations.
“The system was commissioned so that LPC can manage its dredging in real time, but what we’re learning about the harbour is amazing for science. Prior to this, the harbour had only a few data points, but we’ve been gathering so much information on currents, water chemistry and sedimentation.”
The buoys have been custom-designed by Dr Andersen’s company and lathe manufactured in England. They have solar panels on the outside, a bundle of electronic “brains” inside and sensors below the water.
“These little buoys are just amazing,” she says. “Imagine someone trying to physically collect this amount of information. It would be impossible. And the times when we learn the most – like during a storm – it would be impossible to send people out onto the harbour.”
The data has also proven to be a resource for divers (who can check water clarity), surfers (who can check wave heights and direction) and also maybe for swimmers looking for balmy temps for a swim at Corsair Bay.
LPC Environment Manager Kim Kelleher hopes that giving the public access to the data will stimulate interest in the local marine environment.
“We’re learning a lot about how the harbour functions and what the natural variations look like. Data is able to be viewed by the public in real time on a custom built viewing platform at the same time as LPC, without a delay. It’s really interesting when there’s some sort of event going on, such as a big southerly or a pumping swell.”
LPC Strategic Communications Manager
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