At the National Sea Simulator, engineers use advanced automation, environmental modelling and industrial control systems to help safeguard the Great Barrier Reef from the impacts of climate change.
By Chris Sheedy and Joseph Harding
As soon as global environmental challenges become technically defined problems, engineers are able to step forward and solve them.
A timely example of that intersection between science and engineering is Australia’s National Sea Simulator, aka SeaSim.
One of the most advanced experimental marine research facilities in the world, SeaSim opened in 2013 and is operated by the Australian Institute of Marine Science (AIMS), using Siemens technology for industrial process automation.
“The impact of climate change on the reef is actually a science and an engineering challenge,” said Dr Eva Riesenhuber, Global Head of Sustainability at Siemens. “Once it’s defined, the first people who speak up and fix it are engineers.”
Located in Townsville, SeaSim has been designed to recreate specific ocean conditions with precision. This enables researchers to experiment around coral reef responses to changing environmental pressures.
“One of the reasons we went down the industrial process automation pathway is that we get better levels of control,” Craig Humphrey, National Sea Simulator Director, told create.
“We get more reliability out of the process and instrumentation than we would from traditional systems.”
But this also tosses up challenges for engineers.
“Standard industrial process automation is, to a certain extent, set up then left to sit,” Humphrey said. “If you’re manufacturing a product, you want that consistency. We have around 30 different experimental spaces, and those spaces are reconfigured continuously to meet the needs of our experiments. So, our industrial process automation system is dynamic.”
Engineers originally set up SeaSim with a centralised data system to control everything.
Then, because different areas of the facility required continual changes, a more distributed system with individual programmable logic controllers (PLCs) was added, enabling ongoing reconfiguration.
It is, in a way, the next logical step after the creation of a digital twin.
SeaSim is a testing area, a staging site where smaller tests can be run safely in a real-world environment.
“[At Siemens] we have digital twin technology where we design and simulate something first in the digital world, before it’s built,” Riesenhuber said. “First, you design and simulate it, then you build it much more efficiently and then you optimise. So, it’s a digital twin of the product, the production, the process. And then you close the loop afterwards.”
“That makes it so powerful for sustainability … to eliminate waste. Waste is a design flaw. It alleviates pressure on biodiversity. It reduces CO₂ in everything that we do. It alleviates pressure on climate change.”
The combination of these control systems, sensors and modelling tools to replicate natural environments with unprecedented levels of accuracy represents a new level of opportunity for environmental researchers and engineers.
At SeaSim, scientists simulate present and future ocean conditions under tightly controlled laboratory environments in seawater systems.
Most importantly, the seawater systems are able to introduce constant change, just as the ocean does.
The recreation of these natural environmental cycles, Humphrey said, is one of SeaSim’s most powerful capabilities.
“With the control we have now, we can get much better resolution. We can recreate daily variations we see on the reef.”
Replicating the reef
The technological limitations of earlier coral experiments meant many environmental conditions were kept constant.
Now, new technologies driven by data collected in the field of ocean science can ensure the water systems within SeaSim experience the same natural fluctuations that ocean environments do throughout each day.
The coral spawning system automatically harvests egg / sperm bundles and manages the fertilisation process using auto valves and feedback from turbidity sensors.
SeaSim is essentially a large-scale seawater processing and distribution system.
The coastal seawater brought into the facility – up to 800,000 L per day – is processed to ensure variability is reduced, then delivered as needed into various experimental rooms where the final experimental water quality parameters are established.
“We filter out the sediments and, as required, we will correct the salinity,” Humphrey said. “Then we’ll create different temperature streams, and that water is reticulated around the facility to a variety of experimental spaces.
“Within those experimental spaces there’s control of water quality parameters. In terms of process automation, there’s a central SCADA system that does the seawater processing, and then distributed PLCs do the experimental, finer-scale manipulation.”
Dynamic loads
Consistency of water quality at the start is vital to ensure outcomes at the end aren’t distorted.
“Variability is the worst thing we can have in research,” Humphrey said.
Temperature
The primary driver of coral bleaching events
Salinity
The concentration of salts in seawater
Nutrients
Which influence algae growth and coral health
Light intensity
Which affects photosynthesis in coral symbiotic algae
Water flow
Which replicates ecosystem water movement
Total suspended solids
The concentration of particles in water
In doing so, engineers have enabled SeaSim and researchers to simulate real ocean conditions to help develop an understanding of system behaviour on a coral reef under dynamic loads.
The resulting data contributes significantly to improving the accuracy of ecosystem models used to predict how coral reefs will respond to climate change.
“In SeaSim, it’s about data generation for decision-making,” Humphrey said. “Good-quality data, good-quality decisions. Poor-quality data, poor decisions.”
The science of coral bleaching
As an example of where this data will be useful, Humphrey explained the science behind coral bleaching.
“Corals are a partnership between a small algal cell and a host that live together, and they make a calcareous skeleton, which is their home. It’s what forms those complex reef structures where fish, snails and other organisms live to come up with this incredibly rich ecosystem.”
That partnership between algae and coral is vital. Through photosynthesis, the algae provides much of the energy requirements of the coral.
In return, the coral provides sugars, carbohydrates and protection for the algae.
The algae are colourful, so give the coral its hues.
Bleaching frequency
But this is a delicate balance, and when the sea-surface temperature increases above a certain threshold for a prolonged period of time, the partnership starts to break down.
The coral, sensing something is wrong, expels the algae out of its tissue and becomes transparent, revealing its white skeleton and looking bleached.
Of course, this creates a serious problem for the coral, as it is weak and stressed on its own, and can die if the ocean doesn’t cool down and the algae isn’t welcomed back.
If bleaching events occur too frequently, reefs can struggle to recover. That’s bad news as reefs are home to around 25 per cent of ocean species.
“If the bleaching events are widely spaced, coral reefs can recover,” Humphrey said. “But they’re becoming more regular.”
Global reach
Engineers have helped SeaSim to containerise versions of systems to share the research with other regions.
Professor Selina Stead, CEO of AIMS, said engineers have designed and developed portable, modular research systems that can be transported internationally in a shipping container.
“We have just recently done that and sent a mini SeaSim to the Maldives,” she said.
The unit is designed to operate in remote areas, and breed a large number of young corals for reef restoration.
“Two of the researchers from the Maldives came to SeaSim and learned about the technology behind how we do things.”
Virtual models
Riesenhuber said technological innovations currently emerging from facilities such as SeaSim, and from infrastructure builds around the globe, demonstrate the way engineering will play a central role in enabling global sustainability.
One such example, she said, is digital twin technology that involves virtual models of physical systems designed to simulate performance before construction or deployment.
“First you design and simulate it, then you build it much more efficiently, and then you optimise,” she said.
Designing for sustainability
By combining modelling with real operational data, engineers can identify inefficiencies, clashes and design improvements before those systems are built, reducing waste, resources required and energy consumption.
For Riesenhuber, this type of thinking is essential for tackling climate change which, like the rejuvenation of the Great Barrier Reef, is a challenge specifically for scientists and engineers. What it will take is greater attention paid to the maintenance of natural systems and environments.
“Nature has value. It’s an infrastructure,” she said.
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