MEPS 418:25-45 (2010)  -  DOI: https://doi.org/10.3354/meps08797

Biotic and abiotic factors affecting distributions of megafauna in diffuse flow on andesite and basalt along the Eastern Lau Spreading Center, Tonga

Elizabeth L. Podowski1, Shufen Ma3,4, George W. Luther III3, Denice Wardrop2, Charles R. Fisher1,*

1Biology Department and 2Geography Department, Pennsylvania State University, University Park, Pennsylvania 16802, USA
3College of Marine and Earth Studies, University of Delaware, Lewes, Delaware 19958, USA
4Present address: Department of Earth and Planetary Sciences, University of California, Berkeley, California 94720, USA
*Corresponding author. Email:

ABSTRACT: Imagery and environmental data from 7 diffuse flow hydrothermal vent sites along the Eastern Lau Spreading Center (ELSC) are used to constrain the effects of lava type, temperature, chemistry, and biological interactions on faunal distributions. Of the species with chemoautotrophic endosymbionts, the snail Alviniconcha spp. occupies habitats with the greatest exposure to vent fluids. Temperatures exceeding 45°C define its upper limit of exposure to vent flow, and minimum sulfide requirements constrain its lower limits. The mussel Bathymodiolus brevior experiences the least exposure to vent flow; temperatures of about 20°C determine its upper limit, while its lower limit is defined by its minimum sulfide requirements. The snail Ifremeria nautilei inhabits areas with intermediate exposure to vent fluids and biological interactions are likely the most important factor shaping this snail’s realized niche. Microhabitats of non-symbiont-containing fauna were defined in terms of symbiont-containing faunal distributions. The crab Austinograea spp. occupies areas with the greatest exposure to vent flow; shrimp, the snail Eosipho desbruyeresi, and anemones inhabit intermediate zones of vent flow; and the squat lobster Munidopsis lauensis dominates the periphery of diffuse flow areas, with little exposure to vent fluids. The physical structure of different lava types along the ELSC differentially affects the diffusion of vent fluids, which has a variety of implications for fauna, particularly distributions of zoanthids, anemones, and mixed communities of I. nautilei and B. brevior.


KEY WORDS: Lau back-arc basin · Faunal distributions · Diffuse flow · Lava type · In situ voltammetry · GIS


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Cite this article as: Podowski EL, Ma S, Luther III GW, Wardrop D, Fisher CR (2010) Biotic and abiotic factors affecting distributions of megafauna in diffuse flow on andesite and basalt along the Eastern Lau Spreading Center, Tonga. Mar Ecol Prog Ser 418:25-45. https://doi.org/10.3354/meps08797

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