Vailulu'u Seamount, Samoa: Life and death on an active submarine volcano - PubMed (original) (raw)

. 2006 Apr 25;103(17):6448-53.

doi: 10.1073/pnas.0600830103. Epub 2006 Apr 13.

Stanley R Hart, Adele Pile, Bradley E Bailey, Edward T Baker, Sandra Brooke, Douglas P Connelly, Lisa Haucke, Christopher R German, Ian Hudson, Daniel Jones, Anthony A P Koppers, Jasper Konter, Ray Lee, Theodore W Pietsch, Bradley M Tebo, Alexis S Templeton, Robert Zierenberg, Craig M Young

Affiliations

Vailulu'u Seamount, Samoa: Life and death on an active submarine volcano

Hubert Staudigel et al. Proc Natl Acad Sci U S A. 2006.

Abstract

Submersible exploration of the Samoan hotspot revealed a new, 300-m-tall, volcanic cone, named Nafanua, in the summit crater of Vailulu'u seamount. Nafanua grew from the 1,000-m-deep crater floor in <4 years and could reach the sea surface within decades. Vents fill Vailulu'u crater with a thick suspension of particulates and apparently toxic fluids that mix with seawater entering from the crater breaches. Low-temperature vents form Fe oxide chimneys in many locations and up to 1-m-thick layers of hydrothermal Fe floc on Nafanua. High-temperature (81 degrees C) hydrothermal vents in the northern moat (945-m water depth) produce acidic fluids (pH 2.7) with rising droplets of (probably) liquid CO(2). The Nafanua summit vent area is inhabited by a thriving population of eels (Dysommina rugosa) that feed on midwater shrimp probably concentrated by anticyclonic currents at the volcano summit and rim. The moat and crater floor around the new volcano are littered with dead metazoans that apparently died from exposure to hydrothermal emissions. Acid-tolerant polychaetes (Polynoidae) live in this environment, apparently feeding on bacteria from decaying fish carcasses. Vailulu'u is an unpredictable and very active underwater volcano presenting a potential long-term volcanic hazard. Although eels thrive in hydrothermal vents at the summit of Nafanua, venting elsewhere in the crater causes mass mortality. Paradoxically, the same anticyclonic currents that deliver food to the eels may also concentrate a wide variety of nektonic animals in a death trap of toxic hydrothermal fluids.

PubMed Disclaimer

Conflict of interest statement

Conflict of interest statement: No conflicts declared.

Figures

Fig. 1.

Fig. 1.

Bathymetric map of Nafanua and the summit crater of Vailulu’u. Inset indicates the location of Vailulu’u east of the Samoa archipelago. Hydrothermal sites include the NMHC, the summit of Nafanua, and the South Wall Hydrothermal Complex (SWHC). The region colored green within the crater at depths >800 m indicates the Moat of Death, where the ocean floor is littered with fish and invertebrate carcasses. Note that all data coverage is indicated by submersible and ROV tracks. Monitoring locations include temperature recorders, exposure experiments, and/or light back-scattering sensors (nephelometers). Time series conductivity–temperature–depth measurements were made at the NMHC site and NW of the crater.

Fig. 2.

Fig. 2.

Vertical profiles of light back-scattering sensor (LBSS−) data at the NMHC site showing variability over a 14-h time period (Left). Salinity (Center) and temperature (Right) data are given for hydrocasts outside of the crater (NW of the NW breach, in blue) and the crater at the NMHC site (orange/yellow). Only three representative casts are shown for deployments inside the crater, together with the total range observed outside. Note the temperature inversion and the low salinities at the bottom of the crater site, indicating injection of (“vapor-like”) hydrothermal fluids from a phase-separating reaction zone. Potential temperature is well correlated negatively with potential density, and temperature inversions are mirrored by corresponding low density spikes (data not shown).

Fig. 3.

Fig. 3.

Photographs taken from Pisces V. (A) Rock pillar on Nafanua Summit (1-m diameter; 700-m water depth) coated with microbial mats. (B) Pencil-sized Fe chimneys from low-temperature hydrothermal vent west of Lefa Summit (760 m). (C) Meter-sized Fe oxide chimneys of the South Wall Hydrothermal Complex (SWHC; 720 m). (D) NMHC vent field (940 m). (E) Eels (≈30 cm and smaller; Dysommina rugosa) swarming near Nafanua Summit (710 m). (F and G) Polychaetes of unknown genus and species in the family Polynoidae, feeding near a meter-sized fish (930 m). (H) Pillow lavas from the western rift. (I) Octocorals, Anthomastus sp., and an unidentified crab on Lefa Summit (580 m). Carapace width on the crab is ≈10 cm. (J) An abundant demosponge, Abyssocladia brunei, on the inside of the crater, downslope from the SW breach (745 m). The sponges are ≈1 cm in diameter and stand on stalks ≈2 cm long. (K) Large isocrinid crinoid, unidentified, from the western rift. (L) Euryalid ophiuroids on a gorgonian from the western rift (1,670 m). (M) Unidentified octopus from Lefa summit (580 m). The diameter is ≈1m, arm tip to arm tip. (N) Large, unidentified hexactinellid sponges, ≈20 cm in diameter, from the western rift (1,650 m).

Fig. 4.

Fig. 4.

Current meter data from Lefa Summit for the time period from April 4 to 11, 2005. Note that the current directions display an anticlockwise rotation. Five major rotation periods are indicated by vertical lines over a time period of 6 days. Some complete rotations may be accomplished in <2 h, close to the resolution limit imposed by the 20-min sampling frequency of the instrument.

Fig. 5.

Fig. 5.

Scanning electron microscope images of Fe floc from Nafanua volcano, Vailulu’u Seamount. (A) Long, hollow filamentous iron oxide tubes interspersed with amorphous iron oxide. (B) Twisted stalks (arrow) resembling structures formed by the Fe(II)-oxidizing bacterium Gallionella.

Similar articles

Cited by

References

    1. Morgan W. J. Am. Assoc. Petrol. Geol. Bull. 1972;56:42–43.
    1. Watts A. B., Ribe N. M. J. Geophys. Res. 1984;89:11152–11170.
    1. Sandwell D. T., Winterer E. L., Mammerickx J., Duncan R. A., Lynch M. A., Levitt D. A., Johnson C. L. J. Geophys. Res. 1995;100:15087–15100.
    1. Zindler A., Hart S. R. Annu. Rev. Earth Planet. Sci. 1986;14:493–571.
    1. Wishner K., Levin L. A., Gowing M., Mullineaux L. Nature. 1990;346:57–59.

Publication types

MeSH terms

Substances

LinkOut - more resources