Hydrothermal vent fauna of the western Pacific Ocean: Distribution patterns and biogeographic networks

Abstract

AimDeep‐sea hydrothermal vent habitats support a low‐diversity fauna in which most species are unique to the ecosystem. To inform conservation planning around this vulnerable marine ecosystem, we examine species distributions over a wide area to assess the underlying beta‐diversity components and to examine biogeographic patterns. We assess the concept of a highly connected fauna that would repopulate areas of local extinction from distal locations.LocationWestern Pacific Ocean from Japan to New Zealand.MethodsWe assemble a database of 295 confirmed species records for 11 western Pacific vent systems. The SET beta‐diversity framework supports query of the distribution of pairwise pattern components in comparisons among vent systems. We build a network based in graph theory to examine connectivity among vent systems based on shared species similarity. A bipartite network revealed the relative role of each species in linkages among vent system nodes. We assess the importance of sampling bias and distance between systems.ResultsOverall, two‐thirds of the taxa are restricted to a single basin or arc. The Mariana Trough system has the highest corrected weighted endemism for vent‐specific species, followed by that of the Okinawa Trough. Species replacement is the dominant feature of beta‐diversity. Eleven vent systems form seven network modules with stronger connectivity in the Southwest than Northwest Pacific. The Manus Basin vent system emerges as a network ‘hub’ reflecting its central geographic near the equator.Main ConclusionTwo western Pacific biogeographic provinces arise, north and south of the equator that few species transcend. Local and regional conservation plans should consider the low network connectivity and high system endemism in management of hydrothermal vent ecosystems in the event of seabed mining. Species recruitment is unlikely to transcend vent system boundaries. We identify Okinawa Trough, Mariana Trough, Manus Basin, Feni‐Tabar Arc and Kermadec Arc for development of conservation plans that initiate or expand protection.

Comparative population genomics unveils congruent secondary suture zone in Southwest Pacific Hydrothermal Vents

“…Nevertheless, the Manus Basin appears more diversified in terms of species (Poitrimol et al, 2022) and could have served as a source of biodiversity for part of the Western Pacific hydrothermal fauna, suggesting a possible “out of Manus” hypothesis. In line with this idea, recent work on taxa network analysis redescribes the Western Pacific region for hydrothermal fauna not as a single biogeographic province, as suggested by Moalic et al (2012), but as two distinct provinces, the North West Pacific and the South West Pacific, with the Manus Basin as a possible hub connecting both (Tunnicliffe et al, 2024).…”

“…The vent fauna and communities inhabiting these Southwest Pacific BABs appear as a single biogeographic unit (Bachraty et al, 2009; Moalic et al, 2012; Tunnicliffe et al, 2024). In contrast to other hydrothermal communities, which are mainly composed of tubeworms, mussels and shrimps, the BAB fauna is mainly composed of large symbiotic Provannidae gastropods, such as Ifremeria nautilei or Alviniconcha spp ., and deep-sea Bathymodiolus mussels.…”

Hydrothermal vent fauna of the Galápagos Rift: Updated species list with new records

“…Currently, at least 14 species (not including nomen dubium ) are known only from the Galápagos Rift (Table 1), an endemism proportion of 15%; another five species whose endemism is uncertain. While not high compared to the endemism among western Pacific vent systems (Tunnicliffe et al 2023), as there are no geographic barriers separating the Rift from EPR, specific environmental conditions may foster the endemics. For example, sustained venting over numerous large chimneys may foster population maintenance compared to the high turnover at EPR vents (Gollner et al 2017).…”