Ant Atoll was our final dive of this unforgettable trip. Our continual mission to document and collect deep-reef fish and gorgonian corals is peppered with the wonder of what else may be encountered during our brief sojourn into the depths. Caves and caverns adorn the shear, vertical wall on the western side of Ant Atoll, and at 120 m (394 ft) we scour a small cave to see perhaps what relictual delights we may encounter; coral, fish… we’re not sure! These ancient structures and the habitat they provide are enchanting geological sinks through time, filled with a wealth of knowledge as yet untapped. We descend into the cave to investigate.
The peace and baron rocks increase further into the cave with gorgonians, soft corals, zoanthids (very close coral relatives), small sponges, ascidians, bryozoans and hydroids sprinkled sparingly along the walls. I stop filming to ‘bag a gorg’ and return to the open reef wall from this taster back in time, we’ll be back!
As the fish frenzy ensues I select specific colonies of sea fans, time seems to stop somehow and I notice more of our little micro-fossils the forams (as Rich presents which may be Marginopora vertebralis or Cycloclypeus carpenteri) at the base of the fans. The concentric rings depict age, informing of temperature, carbon dioxide and nutrient levels; environmental variables that appear to work in synergy, having a greater effect than if considered alone. Therefore, these foram species act as informative archives of reef health as a consequence of the environment over time.
Whilst gorgonians dominate below, the scleractinians prevail readily in the shallows. Oceanic atolls and islands are extremely exposed to natural disturbances – the weather can be harsh and destructive. The shallow reefs of Ant and Pohnpei are particularly evident of this with dead stands of scleractinian corals liberally populated by reef-building corals, crustose coralline algae and numerous benthic invertebrates. The reef is in a constant state of repair, which is heartwarming to see in action without human intervention. Even more so as we spy no coral disease (infection).
As we venture further into the shallows of the reef flat towards the mangroves we encounter numerous microatolls. At first take you can see the analogous process with the accepted atoll paradigm whereby continental uplift leading to ocean-plate subsistence in conjunction with upward and lateral coral reef growth results in an circle of islands (Darwin 1842). With microatolls, the peripheral growth persists laterally whereas the centre, and typically highest point of the coral head, has died due to aerial exposure. Like all things in life it’s a matter of scale, with the majority of nature consisting of rings and branches – a thought to ponder!
The rings of these interconnected structures are also indicative of dynamic sea levels over time. The most striking however, is that of cultural knowledge and experience. This area of Micronesia – the Caroline Islands – was originally colonized by travelers from Papua New Guinea nearly 3 thousand years ago! Generations of sustainable living have passed yet only in recent decades has the alarming effects of sea level rise begun to emerge. As Brian (Greene) and myself travel to arrange permits, he tells of his youth having been raised on the atoll of Kwajalein. We discuss the evolution of languages, with new ones created by settlers on high islands as to mark a community’s territory and therefore protect the high land. Atoll settlers, on the other hand, need to travel for trade and therefore speak numerous languages. But the undisturbed tranquility of these low island dwellers are in peril, with sea level rising 2-3 feet (~1 m) in recent decades for the first time in history, their appeal for Someplace with a Mountain is essential to survive. Islanders and atoll-dwellers alike note the changes in the fruiting seasons and the falling of entire coconut stands into the ocean. These climatic refugee’s are the consequences of western excess.
Our research at the Bishop Museum extends the tropical Pacific, placing us in a highly unique position to document biodiversity in a multitude of interconnected disciplines over a wide geographic range. Mapping biodiversity and species distributions reveal the intricate branches of connectivity between islands in addition to the evolution of species differences over space and time (e.g. ring species). With this growing body of information we can assist in informed conservation management strategies and provide an invaluable library of biodiversity available to researchers and lay folk alike. Please excuse my seemingly digressive ramblings – when put in this context the value of what we do becomes even more motivating and compelling.
In closing, here at Pohnpei and Ant Atoll there is clear evidence for reef-building capacity supporting reef communities and biodiversity. However the primary concern is anthropogenically accelerated sea level rise with low-lying atolls being the most vulnerable. Nature will continuously persist irrespective of our presence, yet we hope that our work contributes to the growing body of awareness that we do a have choice as to which aspect of nature prevail.