The recent Women in Science at sea biological research expedition (WISE) wrapped up earlier this week. Organised by the Cook Islands Seabed Minerals Authority, a collective group of mostly females from the Pacific were invited to take part in at sea research surveys that focused on training and capacity building in collecting biological data.

The sites surveyed included an area between Aitutaki and Rarotonga, around 3500 metres below sea level. This is not an area of interest for deep seabed mining, as no polymetallic nodules are found there. The second site was just outside the Moana Minerals licensed exploration area, and outside the Cook Islands waters, in what is known as a high seas pocket. This is an area where we know polymetallic nodules are present.

It is an environment where the surface layer of the seabed consists of fine sediment and potato sized nodules that have taken millions of years to form, 5000m below sea level, in a cold, dark, extremely high-pressure environment.

Te Ipukarea Society had no prior knowledge on what life might be living in these polymetallic nodule environments close to our waters, so this site was going to be of great interest.

Through box core samples it became evident that there was life present. Although small in size and low in numbers, it was not a biological desert, as it had been described only a few short years ago in Cook Islands Seabed Minerals Authority consultations. 

We found that in some cases life apparently relied on hard surfaces like polymetallic nodules to survive. For example, the Nausithoe, a baby jellyfish which begins its initial phases of life nestled on a nodule before budding off into its jellyfish form. There are also deep sea sponges (Pyrenoid) which also rely on hard surfaces like the nodules to attach to. Some unidentified sponges, which will be further investigated at the Natural History Museum in the United Kingdom, were also found on the nodules.

The life span, and reproductive cycle of these animals are among the unknowns to science. If we could have looked deeper into the area of bacteria found in the surrounding sediment, and the role they play as food, or for other functions, in the deep sea ecosystem, there would have been a whole new layer of knowledge that could be added to the information gathered.

Investigating what larger lifeforms might be present within polymetallic nodule areas involved using an anchored post baited with parrot fish, bacon and sardines. There was a video camera attached to it to record what larger scavenger species might be attracted. As far as we are aware, this was the first ever attempt at surveying larger scavenger species in our waters, though we are currently in the third year of the initial five-year exploration phase. We had the assistance of Dr Fanny Girard, a Professor in Oceanography from the University of Hawaii, who took the lead on this survey.

Due to time constraints, the baited post could only sit on the ocean floor for six hours. On average, baited lander studies are usually left for 15 hours to provide a good representation of the slow moving biological community present at these depths. Because of the shorter surveying time, we were not necessarily expecting to find anything. Captured video recordings however revealed that four cusk eel, one rattail fish and a deep sea shrimp, had made their way to the baited lander. To see megafauna (bigger life visible to the human eye) within six hours suggested that we could have captured more individuals and more diversity if left longer.

Based on our brief introduction to deep sea biological surveys it was evident that despite deep sea exploration being in its third year, there was still little knowledge regarding what animals might be living in these polymetallic nodule environments and how these populations might be connected and their relationship with other marine species. We need key baseline figures to build our understanding of the potential risks involved with deep seabed mining and to determine if these risks can be responsibly managed.

Our engagement in deep ocean biodiversity research is not because we support industrial deep sea mining. It is because we are key stakeholders and an important part of the decision making process. We are helping to ensure the right questions are being asked and researched as well as making sure the environmental impacts of this industry are being fairly assessed.