Time capsules of misfortune, and fine capsules of swift fortune

For us, as a Pacific-based organisation, the exploration of these deep-sea environments is fuel for a twofold opportunity. Firstly, it allows us to advance our collective comprehension of natural hydrogen as a clean source of energy. Secondly, it enables the recovery of submerged artefacts that could reshape the history tensors of maritime forces and extensive exchange networks of early Pacific Islanders. This pursuit enriches our understanding of our past and, by extension, contributes to the broader narrative of human expansion. For, the settlement of the Pacific marks one of the final significant chapters, a narrative characterised by extraordinary courage and exceptional navigational aptitude.

While the general eastward migrations from Island Southeast Asia (think Taiwan, Philippines) into Remote Oceania are well-documented, the specific intricacies of inter-island connections, especially concerning those Polynesian societies that established communities considerably west of the so-called primary "Polynesian" triangle — the Polynesian "Outliers" — have, until fairly recently, remained somewhat less defined. These communities, dispersed across Melanesia and Micronesia, are distinguished by their distinct forms of Polynesian languages and cultural practices, which suggest extensive voyages and sustained interactions across substantial oceanic distances.

This historical backdrop of movement and cultural exchange forms a core area of interest for understanding the region's linguistic relationship. From this complex past, recent advancements in the geochemical sourcing of stone artefacts are beginning to provide new clarity on the true scale of these ancient maritime routes. Consider the adze, the stone flake, or even discarded oven stones. When excavated from archaeological sites on islands such as Emae in Vanuatu, Taumako in the Solomon Islands, and Kapingamarangi in the Caroline Islands, and subjected to detailed elemental analysis, they point to unambiguous evidence of the long-distance shipping of manufactured materials.

Some of these stone tools once a staple to their daily existence and cultural expression have been traced back to their geological origins, in some cases as far as 2,500 kilometres from their eventual point of use and discharge. Adzes unearthed in Emae and Taumako have been geochemically linked to the Tātaga-Matau quarry complex on Tutuila Island, in present-day American Sāmoa. This quarry was an industrious centre of stone tool production, and its distinctive basalt implements were disseminated widely, reaching Tonga and the Cook Islands, with particular intensity between the late 13th and 16th centuries CE.

The presence of these Toʻi (adzes in Samoan), some of which were substantial ceremonial items likely passed from one generation to the next as heirlooms, strongly indicates meticulously planned voyages and not accidental landfalls. This organised movement of socially valued goods traded across such vast stretches of ocean gives us an idea of the high degree of mobility that characterised the Western Pacific during the last millennium. These time capsules provide us with clearer patterns into the mechanisms by which social ties and political alliances were forged and maintained between interconnected communities.

In a similar vein, obsidian flakes discovered on Emae, dated to the 16th century, have been sourced to Vanua Lava in the Banks Islands of northern Vanuatu. This discovery is concrete proof of established trade networks operating within and between different archipelagos. Furthermore, artefacts from Kapingamarangi suggest connections with other Caroline Islands, such as Kosrae and Pohnpei, and even more distant links reaching towards New Britain, possibly facilitated through intermediary islands like Luangiua (Ontong Java).

With such a trade network, these discoveries naturally lead us to consider the prospects of the deep ocean floor itself, which is transforming in our perception into an inestimable, albeit challenging, historical repository. Shipwrecks, whether they are the remnants of purposeful trading expeditions or vessels tragically overcome by the elements, may lie preserved in the cold, anoxic, hyperbaric conditions of the abyssal depths. These submerged sites could hold caches of goods, direct material evidence of the economic interactions and material cultures of past Pacific societies. The rich oral traditions of Polynesian Outliers frequently recount extensive overseas voyages and sustained interactions with neighbouring populations. This is a narrative that is now increasingly being corroborated by tangible archaeological findings.

While the direct discovery of ancient Chinese or other distant Asian vessels in the prehistoric Pacific remains a subject of ongoing scholarly investigation — with much of the purported evidence for such early contacts often being circumstantial or linked to later, well-documented historical periods — the established prehistoric trade in items such as iron across the Bering Strait by AD 200-500 clearly highlights a long and dynamic history of rudimentary trade across the North Pacific Rim. The appearance of Chinese coins on the Northwest Coast of America in the late 18th century, for example, is largely attributed to the activities of European traders and, subsequently, Chinese immigrants, though the possibility of earlier, indirect diffusion or accidental voyages carrying such items cannot be entirely dismissed.

Systematic exploration of the Pacific seabed, therefore, holds the potential to yield artefacts that will further refine our understanding of these extensive ancient networks and showcase the true reach and dynamism of ancient Pacific peoples as accomplished traders and seafarers. Our own work of facilitating communication through our Pacific Island language services aims to support the communities whose heritage is so intrinsically linked to these ancestral voyages and the ongoing efforts to understand them. This exploration of the Pacific's depths, however, is not solely a journey into the past.

Astonishingly, the same environments that may hold the secrets of ancient sailing misfortunes could also prove a key to our planet's energy future. As the global community grapples with the imperative to transition away from fossil fuels and mitigate the impacts of climate change, hydrogen is increasingly recognised as a versatile and clean energy carrier. Currently, a significant portion of commercially produced hydrogen is derived from natural gas or coal. These processes, unless integrated with carbon capture and storage technologies, imply a substantial carbon footprint. "Green" hydrogen, produced via the electrolysis of water using renewable electricity, offers a low-emission alternative, but its production cost often remains a barrier to its widespread adoption.

Yet, it is a noteworthy scientific reality that substantial quantities of hydrogen are also generated naturally within the Earth's crust through ongoing geological processes. Two primary mechanisms are principally responsible for this natural hydrogen production. The first involves specific water-rock reactions, most notably the oxidation of iron-bearing minerals (Fe2+) contained within so-called "ultramafic rocks" (silica < 45%). The second key mechanism is the radiolysis of water. In this process, naturally occurring radioactive elements such as uranium, thorium, and potassium — which are ubiquitous in crustal rocks and found in higher concentrations in formations like granites and certain types of sediment — emit ionising particles. These particles possess sufficient energy to split water molecules (H2O) upon impact, thereby producing free hydrogen (H2).

In fact, the Earth's continental crust, particularly its ancient Precambrian formations, has been a site of continuous hydrogen generation through these combined processes for billions of years. It has been estimated with some confidence that over the past billion years, the Precambrian continental crust alone could have generated volumes of hydrogen possessing an energy equivalent to approximately 170,000 years of current global oil consumption.

While it is understood that a large proportion of this naturally produced hydrogen would have been consumed by subsurface microbial communities or escaped to the atmosphere over geological time, the sheer scale of this natural generation capacity suggests that economically viable accumulations might exist where the conditions for trapping and long-term preservation are favourable. This is the case for the Bourakébougou gas field in Mali, which is already producing hydrogen with a purity reported to be greater than 97% from such a geological accumulation.

This understanding of terrestrial hydrogen generation brings the deep Pacific Ocean floor into sharp focus as an area of considerable interest. Its extensive mid-ocean spreading ridges, numerous fracture zones, and areas where ultramafic rocks are exposed to seawater are all ingredients for the prolific generation of natural hydrogen, particularly through water-rock reactions like serpentinisation. Like the East Pacific Rise, mid-ocean ridges are the sites where new oceanic crust is continually formed and are characterised by intense hydrothermal activity and associated chemical transformations.

While much of the hydrogen produced in these highly dynamic, high-temperature, high-pressure settings may be vented directly into the overlying ocean, conditions in off-axis areas — within older, more fractured oceanic crust, or beneath substantial layers of overlying sediment — might allow for hydrogen to become effectively trapped and accumulate over time. The timescales for these natural hydrogen generation processes vary considerably, going from thousands to millions of years for active water-rock reactions in highly fractured zones, to tens or even hundreds of millions of years for water-limited reactions and for the slower, steady production of hydrogen via radiolysis.

Now, for natural hydrogen to become a recoverable resource, a specific confluence of geological conditions must be met. These include the presence of a productive source rock, an adequate supply of water to participate in the reactions, established pathways for gas migration from the source to a reservoir, and, fundamentally, an operative geological trap — such as impermeable cap rocks or suitable structural enclosures — to retain the hydrogen and allow it to accumulate as a free gas phase.

Furthermore, any accumulated hydrogen must be preserved from subsequent chemical reactions or microbial consumption that could otherwise deplete the reservoir. Geoscientists are also investigating the utility of helium, which is often co-produced with hydrogen from radiolytic sources, as a potential pathfinder element in exploration, as its presence may indicate regions with active deep gas generation and the existence of competent trapping structures.

So, the focused exploration for natural hydrogen is still in its relative infancy, particularly within the challenging deep marine environments of the Pacific and beyond. However, the potential environmental benefit is a strong motivator. The carbon footprint associated with the extraction and production of high-purity natural hydrogen is expected to be very low, possibly even negative in certain scenarios where co-produced greenhouse gases like methane are not present in substantial quantities. These fine capsules make the prospect of finding and developing natural hydrogen resources highly attractive in the context of the global transition towards cleaner and more sustainable energy systems.

Thus, our big, beautiful Pacific beckons us with a distinct and compelling dual allure. The recovery and detailed analysis of artefacts retrieved from the seabed can mean direct, tangible evidence of ancient trade routes, material exchanges, etc. that will force our societies to rewrite history books. As an organisation rooted in the linguistic heritage of our region, we recognise and honour the great connection that exists between language, culture, and the ancestral journeys that have so definitively shaped our island nations.

So, yes indeed, these ocean depths may also harbour a major component of our planet's future energy landscape as we explore the tantalising possibility of accessing a clean, naturally occurring source of fuel. Advancing our scientific understanding of the complex and interacting geological systems that generate, allow for the migration of, and ultimately trap this hydrogen is a significant scientific frontier with transformative implications for a sustainable global future.

The journey into the Pacific's depths is, without question, a demanding scientific and technological endeavour. It calls for the continued development and deployment of advanced underwater technologies and close, interdisciplinary collaboration across a broad range of scientific fields. Yet, the endeavours to unlock its manifold secrets — be they sleeping ancient adzes or newly forming hydrogen reservoirs — may remind us of our pioneering tradespeople. Both pursuits expand our fundamental knowledge of our planet and our evolving place within its long and ruthless history. They give us perspectives that span from the dawn of established human societies to the urgent energy requirements of the 21st century and beyond. The path ahead is one of continued exploration, diligent discovery, and potential overnight fortunes, a journey where the echoes of our shared past may well illuminate the way toward a more sustainable and comprehensively understood future.