Technology provides insights into life in remote habitats

NIWA researchers Hamish Sutton and Lee Tait set up a drone with a 6-band multispectral camera and a Sony a5100 mirrorless camera to map marine reserves near Wellington. [Photo: Rebekah Parsons-King / NIWA]

The Aotearoa-New Zealand marine area covers 167,650 square kilometres, presenting a stunning range of climates, from subtropical to subantarctic waters, to understand and manage.

But we likely know more about the surface of Mars than we do about the seafloor of our marine environment.

To fill this gap, Dr Lee Tate, a marine ecologist at NIWA, is exploring better use of satellites, drones and remotely operated vehicles (ROVs) to improve our understanding of life under the ocean.

The research is part of the Monitoring Instruments and Technologies project led by Dr Tate, which is based in Christchurch.

His ROV work 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 goal is to develop or optimize monitoring and surveillance technology to protect the aquatic environment from invasive species and to measure the state of our marine environment.

Biosecurity surveillance is concerned with monitoring the occurrence of specific events. A wider use of the tools 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 to our marine environment are affecting the services and values ​​New Zealand receives from land and oceans.

“Right now, we don’t have a lot of basic information about the current state of our marine environment, let alone the extent to which our marine ecosystems have changed,” Tate said.

“But using remote sensing provides a broad scale of observations that will allow us to establish a time series of data to determine what the main drivers of these changes are.”

The drones

Tait presented his research on the Monitoring Tools and Technologies project at the Local Government Information Management Association 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 shores where it is too dangerous for humans.

“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 has drones that can be fitted with multispectral cameras to detect a range of light wavelengths, to monitor the seabed 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 been accepted as a robust environmental monitoring tool.

ROVs

Tate said ROVs are on a similar trajectory as monitoring tools for underwater environments where divers can’t reach or are too dangerous to visit.

“Satellites and drones provide huge leaps in marine monitoring coverage from above, but it’s also necessary to understand the changes happening deep below the ocean’s surface, which is why ROVs are important.”

NIWA’s ROVs are battery-powered but connected to the operator on the surface via a fiber optic cable.

The cable provides real-time data and images and allows the operator to maneuver the ROV, which is critical when working in ports with submerged structures.

ROVs are already used by diving companies contracted to detect biofouling on the hulls of ships traveling in international waters to prevent marine hitchhikers from establishing in new environments.

NIWA also has a role in biofouling research, focusing on the development and testing of new platforms and sensors and ensuring that these tools are fit for purpose and cost effective.

NIWA has used ROVs under the ice in Antarctica equipped with a grapple as a tool to collect samples of organisms.

“Our ROVs have also been used in Aotea – Great Barrier Island and Mercury Island to survey an invasive weed called Caulerpa.

“Divers have been exploring this area for a year, but are limited in terms of the time they can spend in the water, especially when diving below 20 meters.

“The last time we went to Mercury Island, we took the ROV down over 30 meters to determine if the invasive weed was able to survive and spread into deeper water with lower light levels.”

AI

Tate said NIWA is a pioneer in artificial intelligence and machine learning to automatically detect invasive species.

The concept is to run video from ROVs through a detector to identify invasive species, eliminating the need for humans to spend hours viewing the footage.

Satellites launched by NASA, the American Geological Society and the European Space Agency have been in orbit for decades and continue to provide large-scale 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 in New Zealand, as one example, using moderate-resolution satellites.

“This allows us to provide a national approach to identify cycles of abundance, regional trends and threats to algal ecosystems.”

Algal forests are important because they can fix and store carbon dioxide, produce oxygen, provide habitat, they are a source of food for ecosystems and people.

But the algae are also vulnerable to climate change, overfishing and terrestrial disturbance.

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 changes over the past few decades.

Tate said many agencies have used satellite data, drones and ROVs, but NIWA is leading the way in applying the technology to coastal ecosystems.

“We align this technology with traditional monitoring methods, so we get a cross between the two to provide reliable survey results.”

Traditional methods used to detect marine invasive species require resource-intensive surveys as well as highly specialized personnel and equipment.

Remote sensing has reduced the resources required, but Tate said people are still the key to getting the most out of drones, ROVs and satellite data.

“We’re still a long way from being completely hands-free with a drone, and the critical factor is getting the most coverage in the least human time.”

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