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

Abstract. Hydrothermal vent sites along the Juan de Fuca Ridge in the north-east Pacific host dense populations of Ridgeia piscesae tubeworms that promote habitat heterogeneity and local diversity. A detailed description of the biodiversity and community structure is needed to help understand the ecological processes that underlie the distribution and dynamics of deep-sea vent communities. Here, we assessed the composition, abundance, diversity and trophic structure of six tubeworm samples, corresponding to different successional stages, collected on the Grotto hydrothermal edifice (Main Endeavour Field, Juan de Fuca Ridge) at 2196 m depth. Including R. piscesae, a total of 36 macrofaunal taxa were identified to the species level. Although polychaetes made up the most diverse taxon, faunal densities were dominated by gastropods. Most tubeworm aggregations were numerically dominated by the gastropods Lepetodrilus fucensis and Depressigyra globulus and polychaete Amphisamytha carldarei. The highest diversities were found in tubeworm aggregations characterised by the longest tubes (18.5 ± 3.3 cm). The high biomass of grazers and high resource partitioning at a small scale illustrates the importance of the diversity of free-living microbial communities in the maintenance of food webs. Although symbiont-bearing invertebrates R. piscesae represented a large part of the total biomass, the low number of specialised predators on this potential food source suggests that its primary role lies in community structuring. Vent food webs did not appear to be organised through predator–prey relationships. For example, although trophic structure complexity increased with ecological successional stages, showing a higher number of predators in the last stages, the food web structure itself did not change across assemblages. We suggest that environmental gradients provided by the biogenic structure of tubeworm bushes generate a multitude of ecological niches and contribute to the partitioning of nutritional resources, releasing communities from competition pressure for resources and thus allowing species to coexist.

Download Full-text

Trophic structure of a nektobenthic community exploited by a multispecific bottom trawling fishery in Northeastern Brazil

PLoS ONE ◽

10.1371/journal.pone.0246491 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0246491

Author(s):

Alex Souza Lira ◽

Flávia Lucena-Frédou ◽

Frédéric Ménard ◽

Thierry Frédou ◽

Júlio Guazzelli Gonzalez ◽

...

Keyword(s):

Stable Isotope ◽

Food Web ◽

Benthic Invertebrates ◽

Trophic Structure ◽

Fish Fauna ◽

Cumulative Effects ◽

Northeastern Brazil ◽

Population Parameters ◽

Bottom Trawling ◽

Trophic Pathways

We used complementary stable isotope (SIA) and stomach content (SCA) analyses to investigate feeding relationships among species of the nektobenthic communities and the potential ecological effects of the bottom trawling of a coastal ecosystem in northeastern Brazil. Carbon (δ13C) and nitrogen (δ15N) compositions were determined for five basal sources and 28 consumers, from zooplankton to shrimp and fish species. Fishes and basal sources showed a broad range of δ15N (fishes: 6.49–14.94‰; sources: 2.58–6.79‰) and δ13C values (fishes: -23.86 to -13.71‰; sources: -24.32 to -13.53‰), while shrimps and crabs exhibited similar nitrogen and carbon ratios. Six trophic consumer groups were determined among zooplankton, crustaceans and fishes by SIA, with trophic pathways associated mostly with benthic sources. SCA results indicated a preference for benthic invertebrates, mainly worms, crabs and shrimps, as prey for the fish fauna, highlighting their importance in the food web. In overall, differences between SCA and the SIA approaches were observed, except for groups composed mainly for shrimps and some species of high δ15N values, mostly piscivorous and zoobenthivores. Given the absence of regulation for bottom trawling activities in the area, the cumulative effects of trawling on population parameters, species composition, potentially decreasing the abundance of benthic preys (e.g., shrimps, worms and crabs) may lead to changes in the trophic structure potentially affect the food web and the sustainability of the fishery.

Download Full-text

The trophic structure of the pipefish community (Pisces: Syngnathidae) from a western Mediterranean seagrass meadow based on stable isotope analysis

Estuaries ◽

10.1007/bf02803388 ◽

2004 ◽

Vol 27 (2) ◽

pp. 325-333 ◽

Cited By ~ 13

Author(s):

S. Vizzini ◽

A. Mazzola

Keyword(s):

Stable Isotope ◽

Stable Isotope Analysis ◽

Trophic Structure ◽

Seagrass Meadow ◽

Isotope Analysis ◽

Western Mediterranean

Download Full-text

Vertebrate nutrition in a deep-sea hydrothermal vent ecosystem: Fatty acid and stable isotope evidence

Deep Sea Research Part I Oceanographic Research Papers ◽

10.1016/j.dsr.2008.07.006 ◽

2008 ◽

Vol 55 (12) ◽

pp. 1718-1726 ◽

Cited By ~ 14

Author(s):

D.W. Pond ◽

A.E. Fallick ◽

C.J. Stevens ◽

D.J. Morrison ◽

D.R. Dixon

Keyword(s):

Fatty Acid ◽

Stable Isotope ◽

Deep Sea ◽

Hydrothermal Vent ◽

Isotope Evidence

Download Full-text

Trophodynamics at the Longqi hydrothermal vent field and comparison with the East Scotia and Central Indian Ridges

Marine Biology ◽

10.1007/s00227-020-03755-1 ◽

2020 ◽

Vol 167 (10) ◽

Author(s):

W. D. K. Reid ◽

B. D. Wigham ◽

L. Marsh ◽

J. N. J. Weston ◽

Y. Zhu ◽

...

Keyword(s):

Stable Isotope ◽

Hydrothermal Vent ◽

Hydrothermal Vents ◽

Trophic Ecology ◽

Tricarboxylic Acid Cycle ◽

Isotope Analysis ◽

Southwest Indian Ridge ◽

Food Sources ◽

Model Based Clustering ◽

Indian Ridge

Abstract The Longqi vent field, situated on the Southwest Indian Ridge, is ecologically distinct among known hydrothermal vents fields. It hosts a combination of previously unknown species and those shared at species or genus level with other hydrothermal vents on the Central Indian Ridge (CIR) and East Scotia Ridge (ESR). We investigate the size-based and trophodynamics of consumers at Longqi vent field and compared these with ESR and CIR vent fields using stable isotope analysis. Intra-specific variability in δ13C and δ15N values in relationship to shell length was observed in Gigantopelta aegis but absent in Chrysomallon squamiferum. A model-based clustering approach identified four trophic groupings at Longqi: species with the lowest δ13C values being supported by carbon fixed via the Calvin–Benson–Bassham cycle, the highest δ13C values being supported by the reductive tricarboxylic acid cycle and intermediate values potentially supported by a mix of these primary production sources. These clusters were driven by potential differences in resource partitioning. There were also differences in the spread of stable isotope values at the vent field level when comparing Bayesian stable isotope ellipse areas among Longqi, CIR and ESR vent fields. This was driven by a combination of the range in δ13C value of macrofauna, and the negative δ15N values which were only observed at Longqi and CIR vent fields. Many of the shared species or genera showed inter-vent field differences in stable isotope values which may be related to site-specific differences in food sources, geochemistry or potential intra-field competition. This study provides important information on the trophic ecology of hydrothermal vent macrofauna found within an area of seabed that is licensed for seabed mining exploration.

Download Full-text