Source: NIWA – National Institute of Water and Atmospheric Research
Aotearoa-New Zealand’s marine area covers 167,650 square kilometres presenting a staggering distribution of climates, from subtropical to subantarctic waters, to understand and manage.
But it’s likely we know more about the surface of Mars than we do about the seafloor of our marine environment.
To fill that void, Dr Leigh Tait, a marine ecologist at NIWA, is investigating better use of satellites, drones and remote operated vehicles (ROVs) to improve our understanding of life under the ocean.
The research is part of the Surveillance Tools and Technologies Project led by Dr Tait who is based in Christchurch.
His work with ROVs is specifically for biosecurity purposes and is funded by NIWA’s Marine Biosecurity Programme while his research with satellites and drones is funded by other NIWA programmes.
The aim is to develop or optimise monitoring and surveillance technology to protect aquatic environments from invasive species and to measure the state of our marine environment.
Biosecurity surveillance relates to monitoring the occurrence of specific events. The broader use of the tools being developed by the programme is for monitoring, mapping and assessment.
It’s important because New Zealand’s marine ecosystems face threats from climate change, habitat loss, land-use change and invasive species.
There is an urgent need to understand how changes in our marine environment influence the services and values New Zealand receives from the land and oceans.
“At the moment we don’t have a lot of baseline information about the current state of our marine environment, let alone the extent to which our marine ecosystems have changed,” Tait said.
“But the use of remote sensing provides the broad-scale of observations that will enable us to establish a time series of data to determine what the main drivers of those changes are.”
Drones
Tait presented his research on Surveillance Tools and Technologies Project to the Association of Local Government Information Management conference in Wellington where the theme was “Ignite The Future”.
He spoke about NIWA’s innovative use of drones for the Department of Conservation on the West Coast of the South Island, to survey rocky coasts where it was too dangerous for people to go.
“These areas are remote, exposed and difficult to access and so this is an example where drones fill the gap between satellites and ground observations.”
NIWA has drones which can be mounted with multispectral cameras to detect an array of light wavelengths, to view the sea floor and identify marine plants. Smaller drones carrying standard cameras are also used for field work.
Drones are largely autonomous and can be programmed to fly an automated path to provide a detailed picture of a particular habitat. They have become accepted as a robust tool for ecological monitoring.
ROVs
Tait said ROVs are on a similar trajectory as monitoring tools for undersea environments where divers cannot reach or are too dangerous to visit.
“Satellites and drones provide enormous leaps in the coverage of marine monitoring from above but there is also a need to understand the changes that are occurring well beneath the surface of the ocean, that’s why ROVs are important.”
NIWA’s ROV units are battery powered but tethered to the operator at the surface via a fibre optic cable.
The cable provides real time data and images, and it allows the operator to manoeuvre the ROV which is crucial when working in harbours with submerged structures.
ROVs are already being used by dive companies contracted to detect biofouling on the hulls of ships traveling international waters, to prevent marine hitchhikers establishing in new environments.
NIWA has a role in biofouling research too, focused on developing and testing novel platforms and sensors and ensuring that these instruments are fit for purpose and cost-effective.
NIWA has used ROVs under the ice in Antartica, fitted with a grabber as a collection tool to sample organisms.
“Our ROVs have also been used at Aotea – Great Barrier Island and Mercury Island surveying for an invasive weed called Caulerpa.
“Divers have been surveying this area for one year but are limited in terms of the time they can spend in the water, especially when diving below 20 metres.
“Last time we went to Mercury Island we took the ROV down 30-plus metres, to determine whether the invasive weed was able to survive and spread and in deeper water with lower levels of light.”
Artificial intelligence
Tait said NIWA is pioneering artificial intelligence and machine learning to detect invasive species automatically.
The concept is to run video from ROVs through a detector to identify invasive species, eliminating the need for people to spend hours watching the footage.
Satellites launched by NASA, US Geological Society and European Space Agency have been in orbit for decades and continued to provide broad scale data for scientific use.
NIWA is making better use of this resource in the sky by developing novel algorithms to detect and map kelp forests across New Zealand, as one example, using moderate resolution satellites.
“This allows us to provide a national approach to identifying cycles of abundance, regional trends and threats to kelp ecosystems.”
Kelp forests are important because they can fix and store carbon dioxide, produce oxygen, provide habitat, they are a food source for ecosystems and people.
But kelp is also vulnerable to climate change, overfishing and land-based disturbances.
Wetlands provide similar services by filtering agricultural runoff, sediments and nutrients and NIWA is also developing remote sensing techniques to map wetland habitats to provide health assessments and time series to assess change over the past couple of decades.
Tait said many agencies used satellite data, drones and ROVs but NIWA is leading the way in the application of the technology to coastal ecosystems.
“We’re aligning this technology with traditional surveillance methods, so we get a crossover of the two, to provide robust survey results.”
Traditional methods used to detect marine invasive species require resource intensive surveys, as well as highly specialised personnel and equipment.
Remote sensing has reduced the resources needed but Tait said people were still the key to making the most out of drones, ROVs and satellite data.
“We are still a long way off from being completely hands-free for drone operation and the critical factor is getting the greatest coverage for the least amount of human time.”
