Nutritional sources of meio- and macrofauna at hydrothermal vents and adjacent areas: natural-abundance radiocarbon and stable isotope analyses

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 622:49-65 (2019) - DOI: https://doi.org/10.3354/meps13053 Nutritional sources of meio- and macrofauna at hydrothermal vents and adjacent areas: natural-abundance radiocarbon and stable isotope analyses Hidetaka Nomaki1,*, Yuki Uejima2, Nanako O. Ogawa3, Masako Yamane4,7, Hiromi K. Watanabe1, Reina Senokuchi2, Joan M. Bernhard5, Tomo Kitahashi6, Yosuke Miyairi4, Yusuke Yokoyama3,4, Naohiko Ohkouchi3, Motohiro Shimanaga2 1Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-star), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka 237-0061, Japan 2Aitsu Marine Station, Kumamoto University, Kumamoto 861-6102, Japan 3Research Institute for Marine Resources Utilization (MRU), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka 237-0061, Japan 4Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba 277-8564, Japan 5Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA 6Research Institute for Global Change (RIGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka 237-0061, Japan 7Present address: Institute for Space-Earth Environmental Research, Nagoya University, Nagoya 464-8601, Japan *Corresponding author: nomakih@jamstec.go.jp ABSTRACT: Deep-sea hydrothermal vents host unique marine ecosystems that rely on organic matter produced by chemoautotrophic microbes together with phytodetritus. Although meiofauna can be abundant at such vents, the small size of meiofauna limits studies on nutritional sources. Here we investigated dietary sources of meio- and macrofauna at hydrothermal vent fields in the western North Pacific using stable carbon and nitrogen isotope ratios (δ13C, δ15N) and natural-abundance radiocarbon (Δ14C). Bacterial mats and Paralvinella spp. (polychaetes) collected from hydrothermal vent chimneys were enriched in 13C (up to -10‰) and depleted in 14C (-700 to -580‰). The δ13C and Δ14C values of dirivultid copepods, endemic to hydrothermal vent chimneys, were -11‰ and -661‰, respectively, and were similar to the values in the bacterial mats and Paralvinella spp. but distinct from those of nearby non-vent sediments (δ13C: ~-24‰) and water-column plankton (Δ14C: ~40‰). In contrast, δ13C values of nematodes from vent chimneys were similar to those of non-vent sites (ca. -25‰). Results suggest that dirivultids relied on vent chimney bacterial mats as their nutritional source, whereas vent nematodes did not obtain significant nutrient amounts from the chemolithoautotrophic microbes. The Δ14C values of Neoverruca intermedia (vent barnacle) suggest they gain nutrition from chemoautotrophic microbes, but the source of inorganic carbon was diluted with bottom water much more than those of the Paralvinella habitat, reflecting Neoverruca’s more distant distribution from active venting. The combination of stable and radioisotope analyses on hydrothermal vent organisms provides valuable information on their nutritional sources and, hence, their adaptive ecology to chemosynthesis-based ecosystems. KEY WORDS: Meiofauna · Dirivultid copepods · Nematodes · Paralvinella · Neoverruca · Nutrition · Natural-abundance radiocarbon · Stable carbon and nitrogen isotope ratios Full text in pdf format Supplementary material PreviousNextCite this article as: Nomaki H, Uejima Y, Ogawa NO, Yamane M and others (2019) Nutritional sources of meio- and macrofauna at hydrothermal vents and adjacent areas: natural-abundance radiocarbon and stable isotope analyses. Mar Ecol Prog Ser 622:49-65. https://doi.org/10.3354/meps13053 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 622. Online publication date: July 18, 2019 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2019 Inter-Research.