Figure - available from: Diversity and Distributions
This content is subject to copyright. Terms and conditions apply.
Vents on the Carlsberg Ridge. (a) Daxi, tall black smokers; (b) Daxi, dense aggregations of the vent shrimp Rimicaris kairei; (c) Daxi, peripheral actinostolid anemone field; (d) Wocan, high wall with numerous black smokers on a hydrothermal mound; (e) Wocan, dense aggregations of Alviniconcha snails with associated bathymodioline mussels, bythograeid crabs, and limpets in diffusing flow; (f) Wocan, indeterminate tube‐dwelling worms in peripheral hydrothermal sediments, red arrow enlarged in (g); (h) Tianxiu, black smokers with dense aggregations of R. kairei; (i) Tianxiu, inactive chimneys with anemones; (j) Tianxiu, field of indeterminate tube‐dwelling worms in periphery covered by hydrothermal sediments and chimney debris. Scale bars (b, f, h–j) are 10 cm
Source publication
Aim
The pattern of biodiversity and biogeography is crucial to informing management and conservation strategy. But a lack of study across multiple ridge systems, especially for the Carlsberg Ridge, has hampered the conception of the overall picture for the Indian Ocean vents, a top target for deep-sea exploration of massive sulphides. Here, we aim...
Citations
... Continuous investigation has led to the discovery of over 30 active and inactive hydrothermal fields at Indian Ocean ridges as well as numerous hydrothermal anomalies (Tao et al., 2013;Son et al., 2014;Jiang et al., 2015;Nakamura and Takai, 2015;Chen et al., 2018;Kim et al., 2020;Wang et al., 2021;Choi et al., 2021;Noowong et al., 2021). These fields are controlled by different geologic settings, and they undergo diverse processes of hydrothermal circulation and host unique ecosystems (Van Dover et al., 2001;Copley et al., 2016;Zhou et al., 2022;Jang et al., 2023;van der Most et al., 2023). In addition, they form sulfide structures with various morphologies, some of which could contain mineral resources of great economic potential . ...
... For a long time, there are considerable attention to the hydrothermal organisms attached to active hydrothermal fields, although research on hydrothermal fields in the Indian Ocean has been limited relative to research on other oceans Van Dover et al., 2001). Over the past 20 years, there are numerous studies revealing various types of hydrothermal fields leading to the identification of multiple biological provinces (Zhou et al., 2018(Zhou et al., , 2022Jang et al., 2023). Beyond that, the most important thing is that active hydrothermal fields undergoing minimal alteration, and that are not covered by sediment serve as natural laboratories for observing the formation of sulfide structures. ...
... Ocean vent fauna emerges as a separate biogeographic entity (Zhou et al., 2022). Our data assembly forms a strong basis to define regional species pools that underlie biogeographic provinces through F I G U R E 9 Variance Partitioning of vent system dissimilarity (Sorensen's coefficient) against sampling effort for the western Pacific, in the form of the number of cruises and sites sampled, as well as geographical distance in the form of a distance-based Moran's Eigenvector Map (dbMEM). ...
Aim
Deep‐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.
Location
Western Pacific Ocean from Japan to New Zealand.
Methods
We 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.
Results
Overall, 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 Conclusion
Two 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.
... Tianxiu is the only ultramafic-hosted hydrothermal site currently known on the Carlsberg Ridge, situated on the rift wall at water depths of 3200-3500 m, approximately 5 km from the ridge axis ( Fig. 1b; Qiu et al., 2023a). Five active chimney clusters were observed at Tianxiu, with the tallest chimney up to 10 m and vent-endemic fauna similar to that at Wocan-1 (Zhou et al., 2022). Fluid temperatures of up to 307°C were measured in the vent orifices. ...
... Comprehensively analyze the gradients of plume anomalies (e.g., turbidity, temperature, and Such as Alvinocaridid shrimps, actinostlid anemones, bythograeid crabs, alviniconcha snails, bathymodiolin mussels, limpets, tube-dwelling worms, and microbial mats. Qiu et al., 2021;Zhou et al., 2022 CH 4 ), as well as the mineralogical (sulfides, sulfates, Fe-oxides, and Fe-oxyhydroxides) and geochemical (e.g., Fe, Cu, Zn, and element ratios, such as (Fe + Mn)/Al, Fe/Ti, and Al/(Al + Fe + Mn)) anomalies of sediments, combined with bottom currents, to determine the potential position of hydrothermal sources, and further restrict the anomaly area. ...
As the most widespread hydrothermal products in the oceans, metalliferous sediments are particularly useful in prospecting for seafloor massive sulfide (SMS) deposits. A comparative study of metalliferous sediments from two types of hydrothermal fields and the background sediments along the Carlsberg Ridge has been performed to reveal their hydrothermal signatures and to determine the prospecting indicators for SMS deposits. Cu-Fe-Zn sulfides, sulfates, Fe-oxides, and Fe-oxyhydroxides are dominant in the near-vent sediments from the basalt-hosted hydrothermal fields. The near-vent sediments from the ultramafic-hosted field are abundant in detrital minerals of ultramafic source in addition to the minerals mentioned above in the basalt-hosted fields. Sulfide minerals with large grains are mainly deposited close to the vent, and as the distance from the vent increases, the grain size and abundance of the minerals rapidly decrease. Geochemically, the near-vent sediments in the basalt-hosted hydrothermal fields are abundant in Fe, Cu, Zn, Ag, Pb, Mo, Co, U, V, and P, whereas the sediments from the ultramafic-hosted system are enriched in Fe, Mn, Cu, Zn, Ag, Pb, Mo, Co, Mg, Ni, Cr, U, V, and P. The enrichment of these elements and element ratios, such as (Fe + Mn)/Al, Fe/Ti, Al/(Al + Fe + Mn), Cu/Fe, Zn/Fe, U/Fe, and V/Fe, can be indicators of the intensity of the hydrothermal inputs and the distance to the SMS deposits. Temporal and spatial variations of hydrothermally derived elements (e.g., Fe, Cu, Zn, and Pb) in sediment cores can serve as effective tools for reconstructing the hydrothermal history, evaluating the mineralization potential, and tracing inactive/buried SMS deposits. Finally, a prospecting model and method for SMS deposits is proposed based on the prospecting indicators revealed by the sediment study, combined with other prospecting indicators generally used during marine exploration. The results can provide guidance for the prospecting of hydrothermal fields and SMS deposits.
... Widely distributed in vents and seeps across the globe, shrimps in the family Alvinocarididae are restricted to chemosynthesis-based ecosystems (Lunina and Vereshchaka 2014;Zbinden and Cambon-Bonavita 2020), often dominating faunal assemblages (Nye et al. 2013;Hernández-Ávila et al. 2022;Methou et al. 2022a). In most studied cases, these species exhibit high connectivity across large distances along mid-oceanic ridges (Teixeira et al. 2012(Teixeira et al. , 2013Beedessee et al. 2013;Zhou et al. 2022) or between back-arc basins (Thaler et al. 2014;Yahagi et al. 2015) indicating possible high realized dispersal potentials. In characterizing lifehistory traits linked to dispersal capability, observations of first zoea stages in four alvinocaridid species have revealed an atypical combination of morphological characteristics suggesting an early lecithotrophic phase with an extended larval development (Hernández-Ávila et al. 2015). ...
Alvinocaridid shrimps are endemic and globally widespread in chemosynthetic ecosystems such as hydrothermal vents and hydrocarbon seeps. Though the biology of Atlantic alvinocaridid species have received considerable attention, little is known about their Pacific relatives. Here we described population structures and reproductive biology of three Pacific alvinocaridid species—Shinkaicaris leurokolos, Opaepele loihi, Alvinocaris longirostris—with notes on a fourth species—A. dissimilis—from several chemosynthetic ecosystems around Japan and compared their size frequency distributions and reproductive outputs. We showed that population demographics differ among these species, including a significantly larger proportion of juveniles in O. loihi and spatial variation of sex ratio in S. leurokolos, but all shared sex ratios biased toward females. The three shrimp species were characterized by relatively small sizes at onset of maturity, although this varied among sites for A. longirostris. Overall, size-specific fecundities and egg volumes of A. longirostris, O. loihi and S. leurokolos were in a similar range to Atlantic alvinocaridids. In addition, we performed egg incubation experiments of O. loihi under different temperature conditions to characterize thermal physiology during its brooding period. This confirmed a strong influence of temperature on both brooding duration and hatching rate, with a thermal preference that differs from previously published data for A. longirostris and S. leurokolos. Finally, our results indicated that these alvinocaridid species from the northwestern Pacific likely differ in reproductive timing, either through distinct brooding durations and/or distinct brooding periodicity, although further investigations are required to confirm these patterns.
... To date, six species of Ophryotrocha from hydrothermal vents have been formally described, including O. akessoni Blake, 1985 from the Galapagos Rift, O. platykephale Blake, 1985 from the Guaymas Basin (Gulf of California), O. globopalpata Blake & Hilbig, 1990 Zhang, Zhou, Wang & Rouse, 2017 from the Southwest and Central Indian Ridges (Blake 1985;Blake & Hilbig 1990;Solis Weiss & Hilbig 1992;Miura 1997;Paxton & Morineaux 2009;Zhang et al. 2017;Zhou et al. 2022). Also, several undescribed species of Ophryotrocha have been reported from hydrothermal vents in the western Pacific, southern Gulf of California (Watanabe & Kojima 2015;Goffredi et al. 2017). ...
... Bold values represent maximum intraspecific variation when known. Values for O. jiaolongi based on GenBank data reported inZhou et al. (2022). The smallest interspecific distance found was between O. jiaolongi (Indian Ocean vents) and O. marinae sp. ...
Dorvilleids belonging to Ophryotrocha Claparède & Mecznikow, 1869 are known from deep-sea hydrothermal vents in the Pacific, Atlantic, Indian and Southern Oceans. However, how they colonized and diversified in these ecosystems has not been assessed in detail. Here, a collection of Pacific hydrothermal vent Ophryotrocha was examined using morphology and DNA markers (COI, 16S and H3). Five new species were revealed, largely expanding the diversity of the group at this habitat type. They are Ophryotrocha charlottae sp. nov., O. kailae sp. nov., O. marinae sp. nov., O. pruittae sp. nov. from eastern Pacific, and O. bohnorum sp. nov. from the western Pacific. Phylogenetic analyses based on the concatenated alignments of all three genes suggest vent habitants have been colonized several times independently within Ophryotrocha. One clade of six vent species was recovered, indicative of diversification following a colonization of hydrothermal vents, likely in the eastern Pacific. An Indian Ocean species, O. jiaolongi, was nested inside this clade and was closely related to one of the new species from the Gulf of California, diverging from it by less than 4% on COI.
... Yellow symbols are additional sites at which this species occurs. Indian Ocean sites extended from records in Zhou et al. (2022). ...
Mussels of the genus Bathymodiolus Kenk & Wilson belong to the foundation fauna at hydrothermal vents in the global deep sea. In the western Pacific and Indian oceans, the three nominal taxa B. septemdierum Hashimoto and Okutani, B. brevior Cosel, Métivier & Okutani and B. marisindicus Hashimoto are currently recognized as separate species despite morphological and genetic evidence for their conspecificity. All three are listed with the International Union for Conservation of Nature Red List based on highly restricted ranges. We compile and supplement existing morphometric and molecular data to revise the Bathymodiolus septemdierum species group. We redescribe B. septemdierum as a single species with B. brevior and B. marisindicus recognized as junior synonyms. Given the exceptionally broad range of B. septemdierum, we propose removal of these three taxa from the IUCN Red List.
Mao et al. (2024) recently published an article comparing the mitochondrial genome and transcriptome of the deep-sea hydrothermal vent barnacle Vulcanolepas fijiensis and the relatively shallower barnacle Scalpellum stearnsi (contradictory to the title, no new species was described). This paper concluded that the mitogenomes and key genes found in the transcriptomic analysis were subjected to positive selection related to high-temperature and high-pressure conditions, allowing V. fijiensis to adapt to the deep-sea environment. However, the neolepadid hydrothermal vent barnacle used in their study was misidentified and actually represents a different species, Neolepas marisindica. We present our evidence and reasoning for this below. Although the main conclusions presented by Mao et al. (2024) still stand because N. marisindica is also a deep-sea vent species, their misidentification has connotations on the context, interpretation, and of course future use of their data.
The recently discovered deep-sea Capelinhos hydrothermal edifice, ~ 1.5 km of the main Lucky Strike (LS) vent field (northern Mid-Atlantic Ridge), contrasts with the other LS edifices in having poorly-altered end-member hydrothermal fluids with low pH and chlorine, and high metal concentrations. Capelinhos unique chemistry and location offer the opportunity to test the effects of local abiotic filters on faunal community structure while avoiding the often-correlated influence of dispersal limitation and depth. In this paper, we characterize for the first time the distribution patterns of the Capelinhos faunal communities, and analyze the benthic invertebrates (> 250 µm) inhabiting diffusive-flow areas and their trophic structures (δ¹³C, δ¹⁵N and δ³⁴S). We hypothesized that faunal communities would differ from those of the nearest LS vent edifices, showing an impoverished species subset due to the potential toxicity of the chemical environment. Conversely, our results show that: (1) community distribution resembles that of other LS edifices, with assemblages visually dominated by shrimps (close to high-temperature focused-fluid areas) and mussels (at low-temperature diffuse flow areas); (2) most species from diffuse flow areas are well-known LS inhabitants, including the bed-forming and chemosymbiotic mussel Bathymodiolus azoricus and (3) communities are as diverse as those of the most diverse LS edifices. On the contrary, stable isotopes suggest different trophodynamics at Capelinhos. The high δ¹⁵N and, especially, δ¹³C and δ³⁴S values suggest an important role of methane oxidation (i.e., methanotrophy), rather than the sulfide oxidation (i.e., thiotrophy) that predominates at most LS edifices. Our results indicate that Capelinhos shows unique environmental conditions, trophic structure and trophodynamics, yet similar fauna, compared to other LS edifices, which suggest a great environmental and trophic plasticity of the vent faunal communities at the LS.
The Tianxiu hydrothermal field (TXHF) located on Carlsberg Ridge is one of the few active ultramafic-hosted venting systems known in the Indian Ocean. Despite numerous investigations, there is limited understanding of its sulfide structure morphology, and the factors controlling the formation of TXHF are poorly understood. In this study, we conducted detailed seafloor mapping using visual data obtained by dives using the human-occupied vehicle (HOV) Jiaolong. The TXHF is found to be an active, off-axis, ultramafic-hosted, high-temperature hydrothermal area in which serpentine peridotite is exposed. Two main hydrothermal sites were identified, i.e., P and Y, both of which feature a complex of chimneys and beehive diffusers constituting a “chimney jungle” and isolated large steep-sided structures developed on flat-lying sulfide mounds. In addition, some sporadic inactive chimneys and outcrops of hydrothermal deposits were noted. The chimneys are rich in Fe and Zn sulfide, and lack the central fluid channel formed by focused high-temperature fluid flow. Hydrothermal venting at TXHF is likely related to low-angle detachment faults that focus and transport hydrothermal fluids away from a heat source along the valley wall. Our results complement and expand upon previous works concerning sulfide chimney morphology and their corresponding mineral paragenesis in ultramafic-hosted hydrothermal systems in the Indian Ocean and further our understanding of modern seafloor hydrothermal systems.
Lepidonotopodinae is a subfamily of Polynoidae endemic to deep-sea chemosynthetic ecosystems around the world. Nevertheless, their species composition and phylogeny have only been systematically studied in hydrothermal vents of the Eastern and Western Pacific. Here, we morphologically and genetically examined worms in Lepidonotopodinae from vents across three Indian Ocean ridges, revealing two new Branchinotogluma species (B. jiaolongae sp. nov. and B. kaireiensis sp. nov.) and two new Levensteiniella species (L. pettiboneae sp. nov. and L. longqiensis sp. nov.). Primary morphological characters distinguishing them from other congeners include the number and arrangement of both pharyngeal papillae and ventral papillae. The reconstructed molecular phylogeny of Lepidonotopodinae supports a monophyletic Levensteiniella, with the two new Indian Ocean species recovered as sisters. As revealed in previous studies, a paraphyletic Branchinotogluma was also found, with the three Indian Ocean species separated into distinct clades with sister-relationships to species from the Mid-Atlantic, Alarcon Rise, and Manus Basin, respectively. This indicates three separate historical invasions to Indian Ocean vents. Our findings increase the number of Indian Ocean Lepidonotopodinae worms to seven, now the most diverse annelid group there, and help to elucidate the biodiversity, distribution, and biogeography of this subfamily in the Indian Ocean.
