Lower-impact seafloor polymetallic nodules battery metals explorer The Metals Company (TMC) reports that it has completed its latest offshore research campaign – Environmental Expedition 5E.

TMC’s NORI-D nodule project is the first in the company’s project development pipeline.

This project is a targeted sampling campaign of both benthic and pelagic fauna with wider investigations to characterise ecosystem function on the abyssal seafloor.

The completion of the six-week expedition – the company’s fifth environmental campaign in the last 12 months – is the latest offshore campaign required to develop an environmental baseline of TMC’s proposed operating environment in the Clarion Clipperton Zone (CCZ) of the Pacific Ocean.

It also serves to characterise the potential impacts of its proposed nodule collection operations to source critical battery metals from deep-sea polymetallic nodules.

Later this year, TMC will conduct an initial prototype collector vehicle manoeuvrability test in the Atlantic Ocean, followed by pilot collection system trials in the CCZ.

Aboard the ship Maersk Launcher, were researchers from some of the world’s leading marine science institutions including the UK National Oceanography Centre (NOC), Japan Agency for Marine-Earth Science & Marine Technology (Jamstec), Natural History Museum (London), Heriot-Watt University and the University of Gothenburg.

On the ship, they deployed a range of modern technologies including a remote operated vehicle (ROV) and an array of seafloor landers.

Over the course of more than 390 ROV operational hours, researchers from the UK National Oceanography Centre conducted visual observations of over 30 km² of seafloor, capturing more than 35 000 high-resolution images and extensive video data, which will be used to identify megafauna at depths of 4 km.

Whereas prior campaigns used randomised boxcore sampling to obtain macrofaunal samples, the technologies used for Expedition 5E enabled the team to conduct highly targeted sampling of benthic macro and megafauna and to focus on species of particular scientific interest.

To explore the gelatinous communities that occupy the midwater column, the pelagic team, led by Jamstec, supplemented traditional sampling methods such as nets with ROV-mounted video to conduct 130 video transects at various depths, and used specialised D-samplers and the ROV’s suction sampler to collect specimens.

A team led by Heriot-Watt University used an array of seafloor landers, including seabed respirometers and baited traps and cameras, to collect a range of data to assess ecosystem function on the abyssal seafloor.

In total, just under 1 200 tissue and specimen samples were collected throughout the campaign, contributing to a variety of baseline studies including deoxyribonucleic acid and morphological taxonomy, population genetics, ecotoxicology and ecosystem function.

TMC CEO and chairperson Gerard Barron says that, with five research campaigns conducted by TMC in the last 12 months, the experienced research teams brought together are helping build a high-resolution picture of the potential impacts of collecting nodules. “This data will enable our engineering and project teams to [enhance] our activities for low impact and ensure we lift the nodules to the surface with the lightest possible touch.”

Meanwhile, in January 2021, TMC published an upward revision to the nodule resource reported within the NORI-D area held by its subsidiary, Nauru Ocean Resources, improving resource confidence from inferred to indicated status.

As a result, resource tonnage increased by 7% over the reported area from 320-million tonnes inferred, to 341-million tonnes indicated.

The positive conversion rates arising from infill sampling grid with quality box core sample data are high compared to the typical outcomes from infill sampling of terrestrial mineral deposits, TMC says in a statement.