Journal Article

Trophic structure and energy flow in a shallow-water hydrothermal vent: Insights from a stable isotope approach

Chikaraishi, Yoshito, Chang, Ni-Na, Tu, Tzu-Hsuan, Jeng, Ming-Shiou, Lin, Li-Hung, Wang, Pei-Ling

2018

Overview

Shallow-water hydrothermal vent ecosystems are distinct from the deep-sea counterparts, because they are in receipt of sustenance from both chemosynthetic and photosynthetic production and have a lack of symbiosis. The trophic linkage and energy flow in these ecosystems, however remain elusive, which allows us poor understanding of the whole spectrum of biological components distributed across such environmental gradients. In this study, a thorough isotopic survey was conducted on various biological specimens and suspended particulates collected along four transects across the venting features of a shallow-water hydrothermal field off Kueishan Island, Taiwan. The isotope data combined with a Bayesian-based mixing model indicate that the vent-associated particulate organic matter (vent POM), as primary contribution of chemoautotrophic populations, has a high δ13C value (-18.2 ± 1.1‰) and a low δ15N value (-1.7 ± 0.4‰). Zooplankton and epibenthic crustaceans, as the fundamental consumers, exhibit δ13C and δ15N values ranging from -21.3 to -19.8‰ and +5.1 to +7.5‰, respectively, and can utilize the vent POM for 38-53% of their diets. The vent-obligate crab Xenograpsus testudinatus shows a large variation in δ13C (from -18.8 to -13.9‰) and δ15N values (from 1.1 to 9.8‰), although an omnivorous trophic level (2.5) is identified for it using δ15N values of amino acids, and it can utilize the vent POM for 6-87% of its diet. The consistently low (< 10.0‰) and overlapping δ15N values for most of the analyzed macroinvertebrates suggest extensive ingestion of chemosynthetic production complementing the photosynthetic production, a weak prey-predator relationship and low trophic complexity possibly imposed by the extreme environmental contexts of shallow-water hydrothermal ecosystems.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Amino acids / Analysis / Animals / Bayes Theorem / Bayesian analysis / Biology and Life Sciences / Brachyura - metabolism / Carbon / Carbon Isotopes - metabolism / Chemoautotrophic Growth / Chlorophyta - metabolism / Crabs / Crustaceans / Deep sea / Deep sea environments / Diet / Earth Sciences / Ecology and Environmental Sciences / Ecosystem / Ecosystems / Energy / Energy flow / Energy Metabolism / Energy transfer (Ecology) / Environmental gradient / Food / Food Chain / Hydrothermal plumes / Hydrothermal vent ecosystems / Hydrothermal Vents / Ingestion / Macroinvertebrates / Medicine and Health Sciences / Metabolism / Models, Biological / Nitrogen / Nitrogen Isotopes - metabolism / Nutrient deficiency / Oceanography / Organic matter / Particulate organic matter / Particulates / Photosynthesis / Prey / Sea Anemones / Shallow water / Stable isotopes / Structure / Studies / Surveys / Suspended particulate matter / Symbiosis / Taiwan / Trophic levels / Zooplankton / Zooplankton - metabolism