NIWA researchers Hamish Sutton and Leigh Tait are setting up a drone, equipped with a 6-band multispectral camera and a Sony a5100 mirrorless camera, to map a marine reserve near Wellington. [Photo: Rebekah Parsons-King / NIWA]
Aotearoa – New Zealand’s sea area of 167,650 km² presents an astonishing climatic distribution, ranging from subtropical to subantarctic waters, that needs to be understood and managed.
But we may know more about the Martian surface than we know about the ocean floor.
To fill this gap, NIWA marine ecologist Dr Leigh Tait is researching better use of satellites, drones and remotely operated vehicles (ROVs) to improve our understanding of life on the seafloor.
The research is part of the Monitoring Tools and Technologies project led by Christchurch-based Dr Tait.
His work with ROVs is dedicated to biosecurity purposes and is funded by NIWA’s Marine Biosecurity Program, while his research on satellites and drones is funded by other NIWA programs.
The purpose is to develop or optimize monitoring and surveillance technologies to protect the aquatic environment from invasive species and to measure the state of our marine environment.
Biosecurity monitoring involves monitoring the occurrence of specific events. The wider use of the tools being developed by the program is for monitoring, mapping and evaluation.
This is 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 affect the services and values New Zealand derives from land and sea.
“Currently, we don’t have a lot of baseline information about the state of our marine environment, let alone how much our marine ecosystems have changed,” Tate said.
“But the use of remote sensing provides a wide range of observations that will allow us to build a time series of data to determine what the main drivers of these changes are.”
drone
Tait presented his research on monitoring tools and technology projects at the Local Government Information Management Association conference in Wellington, under the theme “Ignite the Future”.
He spoke of NIWA’s innovative use of drones for the Department of Conservation on the South Island’s west coast to survey rocky shores where it’s too dangerous for people to go.
“These areas are remote, exposed and difficult to access, so this is an example of drones bridging the gap between satellite and ground-based observations.”
NIWA’s drones can be fitted with multispectral cameras to detect a range of light wavelengths, observe the seafloor and identify marine plants. Small drones with standard cameras are also used for field work.
Drones are largely autonomous and can be programmed to fly autonomously to provide detailed pictures of specific habitats. They have been recognized as powerful tools for ecological monitoring.
ROV
ROVs are on a similar trajectory to monitoring tools for subsea environments that are inaccessible or too dangerous for divers to access, Tait said.
“Satellites and drones provide a huge leap in coverage for ocean monitoring from above, but there is also a need to understand what’s happening below the ocean’s surface, which is why ROVs are important.”
NIWA’s ROV units are battery powered but are connected to operators on the ground via fiber optic cables.
The cable provides real-time data and images, and it allows operators to maneuver the ROV, which is critical when working in ports with underwater structures.
ROVs are already being used by contracted diving companies to detect biofouling on the hulls of ships sailing in international waters to prevent offshore hitchhikers from establishing in new environments.
NIWA has also played a role in biofouling research, focusing 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 Antarctica, equipped with a grabber as a collection tool to sample organisms.
“Our ROVs have also been used in Aotea – Great Barrier Island and Mercury Island to investigate an invasive weed called Caulerpa.
“Divers have been surveying the area for a year, but they have limited time in the water, especially diving below 20 meters.
“The last time we went to Mercury Island, we lowered the ROV by more than 30 meters to determine if invasive weeds could survive and spread in deeper waters with lower light levels.”
artificial intelligence
Tait said NIWA is pioneering the use of artificial intelligence and machine learning to automatically detect invasive species.
The concept is to run the ROV’s video through a probe to identify invasive species, eliminating the need for people to spend hours watching the video.
Satellites launched by NASA, the Geological Society of America and the European Space Agency have been in orbit for decades and continue to provide a wide range of data for scientific use.
NIWA is making better use of this resource in the sky by developing new algorithms to detect and map kelp forests across New Zealand, for example, using medium-resolution satellites.
“This allows us to provide a national approach to determining abundance cycles, regional trends and threats to kelp ecosystems.”
Kelp forests are important because they fix and store carbon dioxide, produce oxygen, provide habitat, and they are a source of food for ecosystems and humans.
But kelp is also vulnerable to climate change, overfishing and land disturbance.
Wetlands provide similar services by filtering agricultural runoff, sediment and nutrients, and NIWA is also developing remote sensing techniques to map wetland habitats to provide health assessments and time series to assess changes over the past few decades.
Many agencies use satellite data, drones and ROVs, but NIWA is leading the way in applying technology to coastal ecosystems, Tait said.
“We are combining this technology with traditional surveillance methods, so we combine the two to provide reliable findings.”
Traditional methods for detecting marine invasive species require resource-intensive surveys, as well as highly specialized personnel and equipment.
Remote sensing reduces the resources needed, but Tate says people are still key to getting the most out of drones, ROVs and satellite data.
“We are still a long way from fully hands-free drone operation, and the key factor is getting maximum coverage in the least human time.”