Trophic structure of the bathyal benthos at an area with evidence of methane seep activity off southern Chile (~45°S)

2014 ◽  
Vol 94 (4) ◽  
pp. 659-669 ◽  
Author(s):  
Germán Zapata-Hernández ◽  
Javier Sellanes ◽  
Andrew R. Thurber ◽  
Lisa A. Levin
Keyword(s):  
Trophic Structure ◽  
Trophic Position ◽  
Demersal Fish ◽  
Trophic Levels ◽  
Food Sources ◽  
Isotopic Niche ◽  
Methane Seep ◽  
Southern Chile ◽  
Close Proximity ◽  
Third Trophic Level

Through application of carbon (C) and nitrogen (N) stable isotope analyses, we investigated the benthic trophic structure of the upper-slope off southern Chile (~45°S) including a recent methane seep area discovered as part of this study. The observed fauna comprised 53 invertebrates and seven fish taxa, including remains of chemosymbiotic fauna (e.g. chemosymbiotic bivalves and siboglinid polychaetes), which are typical of methane seep environments. While in close-proximity to a seep, the heterotrophic fauna had a nutrition derived predominantly from photosynthetic sources (δ13C > –21‰). The absence of chemosynthesis-based nutrition in the consumers was likely a result of using an Agassiz trawl to sample the benthos, a method that is likely to collect a mix of fauna including individuals from adjacent non-seep bathyal environments. While four trophic levels were estimated for invertebrates, the fish assemblage was positioned within the third trophic level of the food web. Differences in corrected standard ellipse area (SEAC), which is a proxy of the isotopic niche width, yielded differences for the demersal fish Notophycis marginata (SEAC = 5.1‰) and Coelorinchus fasciatus (SEAC = 1.1‰), suggesting distinct trophic behaviours. No ontogenic changes were detected in C. fasciatus regarding food sources and trophic position. The present study contributes the first basic trophic data for the bathyal area off southern Chile, including the identification of a new methane seep area, among the furthest south ever discovered. Such information provides the basis for the proper sustainable management of the benthic environments present along the vast Chilean continental margin.

Trophic ecology of the chihuil sea catfish (Bagre panamensis) in the south-east Gulf of California, México

2017 ◽  
Vol 98 (4) ◽  
pp. 885-893 ◽  
Author(s):  
Víctor M. Muro-Torres ◽  
Felipe Amezcua ◽  
Raul E. Lara-Mendoza ◽  
John T. Buszkiewicz ◽  
Felipe Amezcua-Linares
Keyword(s):  
Gulf Of California ◽  
Trophic Ecology ◽  
Trophic Position ◽  
Feeding Habits ◽  
Isotope Analysis ◽  
Demersal Fish ◽  
Trophic Levels ◽  
High Plasticity ◽  
Combined Use ◽  
Ecosystem Based Fisheries Management

The trophic ecology of the chihuil sea catfish Bagre panamensis was studied through high-resolution variations in its feeding habits and trophic position (TP) in the SE Gulf of California, relevant to sex, size and season. The combined use of stomach content (SCA) and stable isotope analysis (SIA) allowed us to perform these analyses and also estimate the TP of its preys. Results of this study show that the chihuil sea catfish is a generalist and opportunistic omnivore predator that consumes primarily demersal fish and peneid shrimps. Its diet did not vary with climatic season (rainy or dry), size or sex. Results from the SIA indicated high plasticity in habitat use and prey species. The estimated TP value was 4.19, which indicates a tertiary consumer from the soft bottom demersal community in the SE Gulf of California, preying on lower trophic levels, which aids in understanding the species' trophic role in the food web. Because this species and its prey are important to artisanal and industrial fisheries in the Gulf of California, diet assimilation information is useful for the potential establishment of an ecosystem-based fisheries management in the area.

The trophic role of Octopus insularis at a pristine tropical atoll in southwest Atlantic: a potential keystone predator?

2019 ◽  
Author(s):  
Renato Junqueira de Souza Dantas ◽  
Tatiana Silva Leite ◽  
Cristiano Queiroz de Albuquerque
Keyword(s):  
Food Web ◽  
Trophic Position ◽  
Feeding Strategy ◽  
Isotope Analysis ◽  
Carbon Sources ◽  
Trophic Levels ◽  
Isotopic Niche ◽  
Southwest Atlantic ◽  
Trophic Role

In the present study, we evaluated the trophic role of Octopus insularis Leite and Haimovici, 2008 in the food web of Rocas Atoll, a preserved insular territory in the southwest Atlantic. Using stable isotope analysis of C and N, we showed that the local trophic web comprises at least four trophic levels, where the octopus presents d13C values from -12.1 to -6.1‰, d15N values from 6.4 to 11.0‰ and occupies a trophic position (TP) between the second and third trophic levels (mean ± SD TPadditive = 3.08 ± 0.36; TPBayesian = 3.12 ± 0.17). Among other benthic/reef-associated consumers, this cephalopod stood out for its much wider isotopic niche (SEAB = 4.7890), pointing to a diet diversified in carbon sources, but focused on prey in lower TPs. Time-minimizing feeding strategy seemed almost permanent throughout the life cycle, given the great niche overlap between small and large octopuses (large: SEAB = 4.59, small: SEAB = 4.03) and their very similar trophic positions (TPadditive/TPBayesian: large = 3.27/3.26; small = 2.89/2.99). Also, as a prey, O. insularis composed 16%-24% of the diet of some benthic/demersal predators. Overall, exerting great predatory pressure on bottom-associated organisms and serving as a relevant food source for top and mesopredators, O. insularis represented a top consumer of the benthic portion of the food web and an important link between its benthic and demersal strata with potential for keystone species.

Flexible diet and trophic position of dreissenid mussels as inferred from stable isotopes of carbon and nitrogen

2005 ◽  
Vol 62 (5) ◽  
pp. 1119-1129 ◽  
Author(s):  
David W Garton ◽  
Christopher D Payne ◽  
Joseph P Montoya
Keyword(s):  
Stable Isotope ◽  
Dreissena Polymorpha ◽  
Lake Erie ◽  
Trophic Position ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Trophic Levels ◽  
Food Sources ◽  
Stable Isotope Ratios ◽  
Western Lake

In this study, the trophic position and food-web impacts of invading zebra mussels (Dreissena polymorpha) were investigated by sampling mussels, seston (= phytoplankton), macrophytes, zooplankton, and surficial sediment in two small inland lakes (1999–2002) and similarly in western Lake Erie (1999 only). Tissues from quagga mussels (Dreissena bugensis) from Lake Erie were also analyzed. Stable-isotope ratios (15N/14N and 13C/12C) were used to identify likely food sources and estimate relative trophic position. For Lake Erie, stable-isotope ratios indicated no diet differences between the two mussel species. For all lakes, zooplankton δ13C was indicative of phytoplanktivory. The 13C stable isotope ratios indicated that seston comprised ~50% of food sources for mussels in Lake Erie, but 73%–97% and 52%–100% of the diet of mussel populations in Lake Wawasee and Clark Lake, respectively. Stable nitrogen isotope ratios placed zooplankton at trophic levels equal to or higher than those of mussels in seven of eight comparisons. Dreissena polymorpha and D. bugensis are able to exploit suspended detritus as a significant energy source, as well as compete directly with zooplankton for seston as a food source and with each other in areas of sympatry.

scholarly journals Dual stable isotope abundances unravel trophic position of estuarine nematodes

2005 ◽  
Vol 85 (6) ◽  
pp. 1401-1407 ◽  
Author(s):  
Tom Moens ◽  
Steven Bouillon ◽  
Fabiane Gallucci
Keyword(s):  
Empirical Evidence ◽  
Trophic Level ◽  
Trophic Position ◽  
Feeding Habits ◽  
Nematode Species ◽  
Trophic Levels ◽  
Food Sources ◽  
Feeding Mode ◽  
Nematode Communities ◽  
Carbon And Nitrogen

The role and quantitative importance of free-living nematodes in marine and estuarine soft sediments remain enigmatic for lack of empirical evidence on the feeding habits and trophic position of most nematode species. Here we use natural abundances of carbon and nitrogen stable isotopes of some abundant nematode species/genera from estuarine intertidal sediments to assess their trophic level and major food sources. In all stations, δ15N of different dominant nematode species/genera spanned a range of 3.6 to 6.3 ppt, indicating that at least two trophic levels were represented. The large nematodes Enoplus brevis, Enoploides longispiculosus and Adoncholaimus fuscus consistently had high δ15N, in line with mouth-morphology based predictions and empirical evidence on their predacious feeding modes. Daptonema sp., Metachromadora remanei, Praeacanthonchus punctatus and ‘Chromadoridae’ (dominated by Ptycholaimellus ponticus) had comparatively lower δ15N, and δ13C suggesting that microphytobenthos (MPB) is their major carbon source, although freshly sedimented particulate organic matter may also contribute to their nutrition in silty sediments. The trophic position of Sphaerolaimus sp., a genus with documented predacious feeding mode, was ambiguous. Ascolaimus elongatus had δ15N signatures indicating a predacious ecology, which is at variance with expectations from existing feeding type classifications. Our study shows that—despite limitations imposed by the biomass requirements for EA-IRMS (elemental analyser—isotope ratio mass spectrometry)—natural isotope abundances of carbon and nitrogen are powerful tools to unravel trophic structure within nematode communities. At the same time, the prominence of different trophic levels results in a large span of δ15N, largely invalidating the use of nitrogen isotope abundances to assess food sources and trophic level of whole nematode communities.

scholarly journals Not all jellyfish are equal: isotopic evidence for inter- and intraspecific variation in jellyfish trophic ecology

2015 ◽  
Author(s):  
Nicholas E.C. Fleming ◽  
Chris Harrod ◽  
Jason Newton ◽  
Jonathan D.R. Houghton
Keyword(s):  
Trophic Ecology ◽  
Functional Group ◽  
Trophic Position ◽  
Seasonal Succession ◽  
Deep Ocean ◽  
Trophic Levels ◽  
Foraging Strategies ◽  
Isotopic Niche ◽  
Ecosystem Models ◽  
Temporal Shifts

Jellyfish are highly topical within studies of pelagic food-webs and there is a growing realisation that their role is more complex than once thought. Efforts being made to include jellyfish within fisheries and ecosystem models are an important step forward, but our present understanding of their underlying trophic ecology can lead to their over-simplification in these models. Gelatinous zooplankton represent a polyphyletic assemblage spanning >1,400 species that inhabit coastal seas to the deep-ocean and employ a wide variety of foraging strategies. Despite this diversity, many contemporary modelling approaches include jellyfish as a single functional group feeding at one or two trophic levels at most. Recent reviews have drawn attention to this issue and highlighted the need for improved communication between biologists and theoreticians if this problem is to be overcome. We used stable isotopes to investigate the trophic ecology of three co-occurring scyphozoan jellyfish species (Aurelia aurita, Cyanea lamarckii and C. capillata) within a temperate, coastal food-web in the NE Atlantic. Using information on individual size, time of year and δ13C and δ15N stable isotope values we examined: (1) whether all jellyfish could be considered as a single functional group, or showed distinct inter-specific differences in trophic ecology; (2) Were size-based shifts in trophic position, found previously in A. aurita, a common trait across species?; (3) When considered collectively, did the trophic position of three sympatric species remain constant over time? Differences in δ15N (trophic position) were evident between all three species, with size-based and temporal shifts in δ15N apparent in A. aurita and C. capillata. The isotopic niche width for all species combined increased throughout the season, reflecting temporal shifts in trophic position and seasonal succession in these gelatinous species. Taken together, these findings support previous assertions that jellyfish require more robust inclusion in marine fisheries or ecosystem models.

Stable carbon and nitrogen isotope analysis of Nephrops norvegicus / Merluccius merluccius fishing grounds in the Bay of Biscay (Northeast Atlantic)

2005 ◽  
Vol 62 (1) ◽  
pp. 123-132 ◽  
Author(s):  
François Le Loc'h ◽  
Christian Hily
Keyword(s):  
Trophic Structure ◽  
Isotope Analysis ◽  
Nitrogen Isotope ◽  
Trophic Levels ◽  
Food Sources ◽  
Bay Of Biscay ◽  
Stable Carbon ◽  
Merluccius Merluccius ◽  
Nephrops Norvegicus ◽  
Primary Consumers

The trophic structure of the benthic ecosystem of the Grande Vasière (Great Mud Bank), a heavily trawled area in the Bay of Biscay, is largely unknown. To better understand the biotic interactions between exploited species (mainly Norway lobster, Nephrops norvegicus, and European hake, Merluccius merluccius) and their competitors and prey, we applied a dual stable carbon (13C/12C) and nitrogen (15N/14N) isotope analysis to determine trophic levels and differences in the potential food sources of species in the benthic and demersal communities. Five main groups of species constitute the basis of the trophic structure. They are distributed in three main trophic levels: primary consumers; secondary consumers including N. norvegicus and juvenile M. merluccius; and top predators including adult M. merluccius (δ15N = 14.5‰). The large differences in δ13C values within the primary consumers attest to two different food components: a pelagic component composed of fresh sedimenting particulate organic matter, which mainly supplies supra- and epi-benthic suspension feeders, and zooplankton, and a benthic component, which mainly supplies deposit feeders. For the predators, the target species, and their competitors, diet changes during the life-span are reflected by differences in isotope values for the size classes.

scholarly journals Reconstructing the diet, trophic level, and migration pattern of Mysticete whales based on baleen isotopic composition

2020 ◽  
Author(s):  
Philip M. Riekenberg ◽  
Jaime Camalich ◽  
Elisabeth Svensson ◽  
Lonneke L. IJsseldijk ◽  
Sophie M.J.M. Brasseur ◽  
...  
Keyword(s):  
Trophic Level ◽  
Trophic Position ◽  
Feeding Habits ◽  
Trophic Levels ◽  
Isotopic Niche ◽  
Physiological Changes ◽  
Temporal Sampling ◽  
Fin Whales ◽  
And Migration ◽  
Migration Pathways

AbstractBaleen from mysticete whales is a well-preserved proteinaceous material that can be used to identify migrations and feeding habits for species whose migration pathways are unknown. Analysis of δ13C and δ15N from bulk baleen has been used to infer migration patterns for individuals. However, this approach has fallen short of identifying migrations between regions as it is difficult to determine variations in isotopic shifts without temporal sampling of prey items. Here we apply analysis of δ15N values of amino acids to five baleen plates belonging to three species, revealing novel insights on trophic position, metabolic state, and migration between regions. Humpback and minke whales had higher reconstructed trophic levels than fin whales (3.4-3.5 versus 2.7-2.9, respectively) as expected due to different feeding specialization. Isotopic niche areas between baleen minima and maxima were well separated, indicating regional resource use for individuals during migration that aligned with isotopic gradients in Atlantic Ocean particulate organic matter. δ15N values from phenylalanine confirmed regional separation between the niche areas for two fin whales as migrations occurred and elevated glycine and threonine δ15N values revealed physiological changes due to fasting. Simultaneous resolution of trophic level and physiological changes allow for identification of regional migrations in mysticetes.

scholarly journals Trophic structure of a floodplain fish assemblage in the upper Amazon basin, Bolivia.

2018 ◽  
Vol 66 (3) ◽  
pp. 1258
Author(s):  
Danny César Rejas Alurralde
Keyword(s):  
Aquatic Macrophytes ◽  
Amazon Basin ◽  
Trophic Structure ◽  
Fish Assemblages ◽  
Trophic Position ◽  
Carbon Sources ◽  
Trophic Group ◽  
Food Sources ◽  
Oxbow Lakes ◽  
Terrestrial Plants

Amazonian fish assemblages are typically high in species diversity and trophic complexity. Stable isotopes are valuable tools to describe the trophic structure of such assemblages, providing useful information for conservation and ecological management. This study aimed at estimating the relative contribution of the different basal carbon sources to the diet of primary consumer fishes (herbivores and detritivores), and determining the trophic position (TP) of the dominant fishes from each trophic guild (herbivores, detritivores, invertivores and piscivores). For this purpose we analyzed stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in potential food sources, and muscle tissue of fishes in five oxbow lakes located in the floodplain of River Ichilo, Bolivia. Terrestrial plants and C3 aquatic macrophytes were the major carbon source contributing to the diet of herbivorous fishes, whereas particulate organic matter (POM) contributed more to the diet of detritivore fishes. In general, C4 aquatic macrophytes contributed little to the diet of herbivores and detritivores. However, we found a relatively high contribution of C4 macrophytes (28 %) to the diet of the herbivores Mylossoma duriventre and Schizodon fasciatus. We found a good agreement between our estimated TP values and the trophic group assigned based on diet composition from literature. The herbivore M. duriventre was at the bottom of the food web, being the baseline organism (TP = 2). The remaining primary consumers (herbivores and algivore/detritivores) exhibited relatively high TP values (2.3 - 2.9), probably due to their opportunistic feeding behavior. Omnivore/invertivore species studied displayed TP values near the 3.0 value expected for secondary consumers. Piscivore fishes were at the top TP, with TP values varying from 3.3 (Serrasalmus spilopleura and Serrasalmus rhombeus) to 3.8 (Pseudoplatystoma fasciatum). The fact that detritivore fishes, the most abundant food source for piscivores, occupy relatively high TPs determines that food chains in these particular Amazonian floodplains are longer than previously thought.

Isotopic niche of two coastal dolphins in a tropical marine area: specific and age class comparisons

2015 ◽  
Vol 96 (4) ◽  
pp. 853-858 ◽  
Author(s):  
Ana Paula Madeira Di Beneditto ◽  
Leandro Rabello Monteiro
Keyword(s):  
Stomach Contents ◽  
Niche Overlap ◽  
Niche Differentiation ◽  
Trophic Levels ◽  
Food Sources ◽  
Isotopic Niche ◽  
Marine Area ◽  
Age Class ◽  
Niche Metrics ◽  
Pontoporia Blainvillei

Niche differentiation is the process by which species evolve different forms of resource use, and is used to explain the co-occurrence in a variety of habitats. The Bayesian framework of isotopic niche through quantitative niche metrics was applied to estimate and compare the niche breadth of two sympatric coastal dolphinsPontoporia blainvilleiandSotalia guianensisin a tropical marine area. The standard ellipse areas (SEAs) based on species were quite similar, but the SEAs based on age class showed that the matures’ niche space is larger than the immatures’ for both dolphins. A probabilistic comparison of SEAs indicated that specific differences are negligible compared with age class differences. Trophic level measures (δ15N range) indicated that the dolphins are comparable as top predators, and that immature specimens have a lower range of trophic levels than mature ones. In terms of variability of food sources (δ13C range),S. guianensisshowed a larger value thanP. blainvilleiand mature specimens had larger δ13C range than immatures for both species. In general,P. blainvilleiandS. guianensiswere similar in the niche metrics, with SEAs overlap of 52.1 and 39.7%. The immature specimens showed reduced isotopic niche overlap between species (<3%). In conclusion,Pontoporia blainvilleiandS. guianensisspecimens have similar isotopic niches, but pronounced differences between immature and mature specimens, both intraspecific and interspecific. Isotopic niche and quantitative metrics along with previous data on stomach contents provide a strong representation of species niche and their relationships.

scholarly journals Isotopic profile and mercury concentration in fish of the lower portion of the rio Paraíba do Sul watershed, southeastern Brazil

2015 ◽  
Vol 13 (4) ◽  
pp. 723-732 ◽  
Author(s):  
Adélia R. M. Rocha ◽  
Ana Paula M. Di Beneditto ◽  
Inácio A. Pestana ◽  
Cristina Maria M. de Souza
Keyword(s):  
Trophic Position ◽  
Dry Weight ◽  
Food Sources ◽  
Lower Portion ◽  
Southeastern Brazil ◽  
Isotopic Niche ◽  
Carnivorous Fish ◽  
Omnivorous Fish ◽  
Wet Weight ◽  
Isotopic Profile

ABSTRACT The aim of this study was to evaluate the isotopic profile and mercury (Hg) concentrations in fish (carnivores, omnivores and detritivores) in the lower portion of the rio Paraíba do Sul watershed, southeastern Brazil. Carbon (δ13C) isotopic analyses revealed that pelagic and benthonic sources are part of the feeding of the fish from the different guilds (-14.0 to -24.8 ‰). The benthic sources are usually enriched in δ13C (-16.9‰, from watershed runoff) compared to pelagic sources because the phytoplankton, important primary producer that supports several pelagic chains, has δ13C signature lighter (-23.9‰). The nitrogen (δ15N) isotopic signatures indicated that most guilds were at the same trophic position (10.0 to 15.5 ‰), except for pelagic omnivorous fish, which had a lower trophic position. Niche overlap was observed among pelagic and demersal carnivorous fish, demersal omnivorous fish, and demersal detritivorous fish. The lower isotopic niche breadth of pelagic carnivorous fish reveals the specialized resource use by this guild. Hg concentrations (ng g-1 dry weight) differed significantly between demersal carnivorous fish (185.3 dry weight; 27.8 wet weight) and demersal omnivorous fish (277.9 dry weight; 41.7 wet weight) and between pelagic omnivorous fish (197.2 dry weight; 29.6 wet weight) and demersal omnivorous fish due to (1) differences in food sources: guilds that fed on bottom resources were more affected by contamination because the sediment is an important Hg accumulator in the study area, and (2) because of its trophic positions. Considering that the fish consumed prey of similar trophic positions, the guilds did not show a well-defined food hierarchy. Therefore, in this study, there was no clear relationship between Hg and δ15N.

Sign in / Sign up

Export Citation Format

Share Document