scholarly journals Spatio–temporal variation in stable isotope signatures (δ13C and δ15N) of sponges on the Saba Bank

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5460 ◽  
Author(s):  
Fleur C. Van Duyl ◽  
Benjamin Mueller ◽  
Erik H. Meesters
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
Environmental Changes ◽  
Food Sources ◽  
Sponge Species ◽  
Isotopic Niche ◽  
Δ13c And Δ15n ◽  
Spatio Temporal ◽  
Species Specific ◽  
Potential Food

Sponges are ubiquitous on coral reefs, mostly long lived and therefore adaptive to changing environmental conditions. They feed on organic matter withdrawn from the passing water and they may harbor microorganisms (endosymbionts), which contribute to their nutrition. Their diets and stable isotope (SI) fractionation determine the SI signature of the sponge holobiont. Little is known of spatio–temporal variations in SI signatures of δ13C and δ15N in tropical sponges and whether they reflect variations in the environment. We investigated the SI signatures of seven common sponge species with different functional traits and their potential food sources between 15 and 32 m depth along the S-SE and E-NE side of the Saba Bank, Eastern Caribbean, in October 2011 and October 2013. SI signatures differed significantly between most sponge species, both in mean values and in variation, indicating different food preferences and/or fractionation, inferring sponge species-specific isotopic niche spaces. In 2011, all sponge species at the S-SE side were enriched in d13C compared to the E-NE side. In 2013, SI signatures of sponges did not differ between the two sides and were overall lighter in δ13C and δ15N than in 2011. Observed spatio–temporal changes in SI in sponges could not be attributed to changes in the SI signatures of their potential food sources, which remained stable with different SI signatures of pelagic (particulate organic matter (POM): δ13C −24.9‰, δ15N +4.3‰) and benthic-derived food (macroalgae: δ13C −15.4‰, δ15N +0.8‰). Enriched δ13C signatures in sponges at the S-SE side in 2011 are proposed to be attributed to predominantly feeding on benthic-derived C. This interpretation was supported by significant differences in water mass constituents between sides in October 2011. Elevated NO3 and dissolved organic matter concentrations point toward a stronger reef signal in reef overlying water at the S-SE than N-NE side of the Bank in 2011. The depletions of δ13C and δ15N in sponges in October 2013 compared to October 2011 concurred with significantly elevated POM concentrations. The contemporaneous decrease in δ15N suggests that sponges obtain their N mostly from benthic-derived food with a lower δ15N than pelagic food. Average proportional feeding on available sources varied between sponge species and ranged from 20% to 50% for benthic and 50% to 80% for pelagic-derived food, assuming trophic enrichment factors of 0.5‰ ± sd 0.5 for δ13C and 3‰ ± sd 0.5 for δ15N for sponges. We suggest that observed variation of SI in sponges between sides and years were the result of shifts in the proportion of ingested benthic- and pelagic-derived organic matter driven by environmental changes. We show that sponge SI signatures reflect environmental variability in space and time on the Saba Bank and that SI of sponges irrespective of their species-specific traits move in a similar direction in response to these environmental changes.

Tracing sewage-derived organic matter into a shallow groundwater food web using stable isotope and fluorescence signatures

2011 ◽  
Vol 62 (2) ◽  
pp. 119 ◽  
Author(s):  
Adam Hartland ◽  
Graham D. Fenwick ◽  
Sarah J. Bury
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
Food Web ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Shallow Groundwater ◽  
Organic Pollution ◽  
Food Sources ◽  
Δ13c And Δ15n

Little is known about the feeding modes of groundwater invertebrates (stygofauna). Incorporation of sewage-derived organic matter (OM) into a shallow groundwater food web was studied using fluorescence and stable isotope signatures (δ13C and δ15N). Organic pollution was hypothesised to limit sensitive species’ abundances along the contamination gradient and isotope signatures of stygofauna consuming sewage-derived OM were expected to be enriched in δ15N. Stygofauna communities near a sewage treatment plant in New Zealand were sampled over 4 months and microbial biofilms were incubated in situ on native gravel for 1 month. As anticipated, OM stress-subsidy gradients altered stygofauna composition: the biomass of oligochaetes and Paraleptamphopus amphipods increased in OM-enriched groundwater (higher dissolved organic carbon (DOC) and tryptophan-like fluorescence), whereas other, probably less-tolerant taxa (e.g. ostracods, Dytiscidae) were absent. Isotopic signatures for stygofauna from polluted groundwater were consistent with assimilation of isotopically enriched sewage-N (δ15N values of 7–16‰), but highly depleted in δ13C relative to sewage. Negative 13C discriminations probably occur in Paraleptamphopus amphipods, and may also occur in oligochaetes and Dytiscidae, a finding with implications for the application of δ13C for determining food sources in groundwaters. Organic pollution of groundwaters may have serious repercussions for stygofauna community structure with potentially irreversible consequences.

scholarly journals Arsenic speciation in food chains from mid-Atlantic hydrothermal vents

2012 ◽  
Vol 9 (2) ◽  
pp. 130 ◽  
Author(s):  
Vivien F. Taylor ◽  
Brian P. Jackson ◽  
Matthew R. Siegfried ◽  
Jana Navratilova ◽  
Kevin A. Francesconi ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Deep Sea ◽  
Hydrothermal Vents ◽  
Arsenic Speciation ◽  
Inorganic Arsenic ◽  
Food Sources ◽  
Arsenic Compounds ◽  
Marine Animals ◽  
Δ13c And Δ15n ◽  
Organic Arsenic

Environmental contextArsenic occurs in marine organisms at high levels and in many chemical forms. A common explanation of this phenomenon is that algae play the central role in accumulating arsenic by producing arsenic-containing sugars that are then converted into simpler organic arsenic compounds found in fish and other marine animals. We show that animals in deep-sea vent ecosystems, which are uninhabited by algae, contain the same organic arsenic compounds as do pelagic animals, indicating that algae are not the only source of these compounds. AbstractArsenic concentration and speciation were determined in benthic fauna collected from the Mid-Atlantic Ridge hydrothermal vents. The shrimp species, Rimicaris exoculata, the vent chimney-dwelling mussel, Bathymodiolus azoricus, Branchipolynoe seepensis, a commensal worm of B. azoricus and the gastropod Peltospira smaragdina showed variations in As concentration and in stable isotope (δ13C and δ15N) signature between species, suggesting different sources of As uptake. Arsenic speciation showed arsenobetaine to be the dominant species in R. exoculata, whereas in B. azoricus and B. seepensis arsenosugars were most abundant, although arsenobetaine, dimethylarsinate and inorganic arsenic were also observed, along with several unidentified species. Scrape samples from outside the vent chimneys covered with microbial mat, which is a presumed food source for many vent organisms, contained high levels of total As, but organic species were not detectable. The formation of arsenosugars in pelagic environments is typically attributed to marine algae, and the pathway to arsenobetaine is still unknown. The occurrence of arsenosugars and arsenobetaine in these deep sea organisms, where primary production is chemolithoautotrophic and stable isotope analyses indicate food sources are of vent origin, suggests that organic arsenicals can occur in a foodweb without algae or other photosynthetic life.

Stable isotope analysis reveals partitioning in prey use by Kajikia audax (Istiophoridae), Thunnus albacares, Katsuwonus pelamis, and Auxis spp. (Scombridae) in the Eastern Tropical Pacific of Ecuador

2021 ◽  
Vol 19 (4) ◽  
Author(s):  
Rigoberto Rosas-Luis ◽  
Nancy Cabanillas-Terán ◽  
Carmen A. Villegas-Sánchez
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Stable Isotope Analysis ◽  
Trophic Ecology ◽  
Isotope Analysis ◽  
Middle Level ◽  
Food Sources ◽  
Thunnus Albacares ◽  
Katsuwonus Pelamis ◽  
Δ13c And Δ15n

Abstract Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size.

scholarly journals Seasonal Variation in Stable Isotope Ratios of Cow Milk in Vilnius Region, Lithuania

Animals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 69 ◽  
Author(s):  
Andrius Garbaras ◽  
Raminta Skipitytė ◽  
Justina Šapolaitė ◽  
Žilvinas Ežerinskis ◽  
Vidmantas Remeikis
Keyword(s):  
Stable Isotope ◽  
Dairy Products ◽  
Geographic Origin ◽  
Isotope Ratios ◽  
Food Sources ◽  
Cow Milk ◽  
Ratio Method ◽  
Stable Isotope Ratios ◽  
Δ13c And Δ15n ◽  
Artesian Water

Various studies have shown that stable isotope analysis has the potential to verify the geographic origin of foods and drinks. However, stable isotope composition is not always constant in the environment and can even change in the same area. Dairy products are of particular interest as a group of foods that play an important role in feeding the population. The composition of milk is fundamentally dependent on the feeding of the cows, and thereby on a particular environment. To better understand the amount of variation in δ18O, δ13C, and δ15N values in the milk from the same area, we measured stable isotope ratios in cow milk water, artesian water, and precipitation (δ18O) as well as in bulk milk samples (δ13C and δ15N) collected in 2014–2016. Different water and food sources were available during the winter (artesian water only and dry grass) and summer (artesian water and fresh grass), and spring and autumn seasons reflected transitional periods. Oxygen stable isotope ratios in milk water were relatively lower in winter and transitional seasons and higher in summer, showing the dependence on the main water source. δ13C values reflected particular food sources. This study shows the applicability of the stable isotope ratio method in linking cow milk to specific environments and reveals the amount of variation in stable isotope ratios in the same area. These results could be valuable for other studies on geographical origin determination of dairy products.

scholarly journals CONSUMO DE RESÍDUOS AGRÍCOLAS E URBANOS PELO DIPLÓPODE Trigoniulus corallinus

Nativa ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 162
Author(s):  
Luiz Fernando De Sousa Antunes ◽  
Rafael Nogueira Scoriza ◽  
Dione Galvão da Silva ◽  
Maria Elizabeth Fernandes Correia
Keyword(s):  
Organic Matter ◽  
Organic Agriculture ◽  
Food Preferences ◽  
Dry Mass ◽  
Food Sources ◽  
Banana Tree ◽  
Consumption Rates ◽  
Potential Food

Os diplópodes são capazes de ingerir serapilheira parcialmente decomposta, transformando-a em matéria orgânica que enriquece o solo. Este trabalho objetivou avaliar potenciais fontes alimentares dos diplópodes da espécie Trigoniulus corallinus em laboratório fornecendo diferentes resíduos na forma de serrapilheira não decomposta, por um período de dez dias. Os resíduos utilizados neste experimento (todos senescentes) foram: aparas de grama batatais; folhas de gliricídia; de flemingia; de pata de vaca; de bananeira, além de um resíduo industrializado, neste caso, pedaços de papelão picado. O delineamento utilizado foi inteiramente casualizado, com dez repetições. Ao final de dez dias foram avaliados os seguintes parâmetros: massa seca do resíduo restante da alimentação dos diplópodes, massa seca dos coprólitos e mortalidade dos diplópodes. A mensuração das taxas de consumo dos diplópodes mostraram-se diferentes entre os tratamentos, sendo as maiores taxas observadas para as folhas de flemingia (25,4 %) seguido pelas folhas de gliricídia (21,2 %). A massa de coprólitos gerados foi maior a partir dos resíduos de flemingia (0,214 g) e foi ausente na presença de papelão e gliricídia. Observou-se 100% de mortalidade dos diplópodes após o consumo de folhas de gliricídia. Depreende-se dos resultados que diplópodes da espécie T. corallinus são capazes de ingerir resíduos pobres em nutrientes, porém exibem nitidamente preferência alimentar por resíduos que contenham maiores teores de nutrientes.Palavras-chave: gongolos, compostagem, agricultura orgânica. CONSUMPTION OF AGRICULTURAL AND URBAN WASTES BY THE DIPLOPODA Trigoniulus corallinus  ABSTRACT: Diplopods are able to ingest litter partially decomposed, transforming them into organic matter that enrich the soil. This work aimed to evaluate potential food sources of the dipropods of the specie Trigoniulus corallinus in the laboratory providing different residues in the form of non - decomposed litter for a period of ten days. The residues used in this experiment (all senescent) were: batatais grass cuttings; Gliricidia leaves; of Flemingia; of cow's foot; of banana tree, in addition to an industrialized residue, in this case pieces of cardboard. The design was completely randomized, with ten replications. At the end of ten days, the following parameters were evaluated: dry mass of the remaining diplopods feed, dry mass of coprolites and mortality of diplopods. The measurement of the consumption rates of the diplopods were different among the treatments, with the highest rates observed for the leaves of flemingia (25.4%) followed by the leaves of gliricidia (21.2%). The mass of generated coprolites was higher from the flemingia residues (0.214 g) and was absent in the presence of cardboard and gliricidia. It was observed 100% mortality of the diplopods after consumption of gliricidia leaves. It appears from the results that dipropods of T. corallinus species are able to ingest nutrient-poor residues, but clearly exhibit their food preferences for residues containing higher nutrient contents.Keywords: millipedes, composting, organic agriculture. 

Zoobenthos are minor dietary components of small omnivorous fishes in a shallow eutrophic lake

2016 ◽  
Vol 67 (10) ◽  
pp. 1562 ◽  
Author(s):  
Natsuru Yasuno ◽  
Yuki Chiba ◽  
Yasufumi Fujimoto ◽  
Kentaro Shindo ◽  
Tetsuo Shimada ◽  
...  
Keyword(s):  
Isotope Analysis ◽  
Fish Tissue ◽  
Eutrophic Lake ◽  
Food Sources ◽  
Epiphytic Algae ◽  
Δ13c And Δ15n ◽  
Chironomid Larvae ◽  
Dietary Components ◽  
Shallow Eutrophic Lake ◽  
Potential Food

We examined whether small omnivorous fishes (smaller than ~100mm long) integrate littoral, pelagic and benthic pathways in a shallow, eutrophic lake (Lake Izunuma, Japan). The surface of the lake was covered by a dense vegetation of floating-leaved macrophytes, and small species dominated the icthyofauna. We determined the δ13C and δ15N ratios of five dominant species of small omnivorous fishes. Using a stable isotope analysis in the R mixing model, we determined the possible contribution of three potential food sources (epiphytic algae, zooplankton and zoobenthos (larval chironomids)) to omnivorous fish tissue compositions. Four omnivorous fishes (Gnathopogon elongatus elongatus, Pseudorasbora parva, Biwia zezera and Tridentiger obscurus) subsisted largely on epiphytic algae and zooplankton, whereas zoobenthos contributed little to their diets. Acheilognathus rhombeus subsisted mostly on epiphytic algae. Thus, in this shallow, eutrophic lake, omnivorous fishes incorporated both littoral and pelagic production into the food web, but rarely benthic production. The dominant benthic chironomid larvae often burrow several centimetres into the sediment, and the low dietary contribution of zoobenthos to small fishes may be due to inefficiency at foraging on buried benthos associated with fish body size.

Diet of the intertidal callianassid shrimps Biffarius arenosus and Trypea australiensis (Decapoda:Thalassinidea) in Western Port (southern Australia), determined with multiple stable-isotope analyses

1997 ◽  
Vol 48 (6) ◽  
pp. 503 ◽  
Author(s):  
Paul I. Boon ◽  
Fiona L. Bird ◽  
Stuart E. Bunn
Keyword(s):  
Stable Isotope ◽  
Organic Carbon ◽  
Food Source ◽  
Avicennia Marina ◽  
Benthic Microalgae ◽  
Food Sources ◽  
Mangrove Species ◽  
Δ13c And Δ15n ◽  
Green Macroalgae ◽  
Isotope Analyses

Biffarius arenosus had a mean δ13C of –15·4 ± 0·2‰ and a mean δ15N of 5·9 ± 0·1‰ (n = 38), and Trypea australiensis had a mean δ13C of –16·3 ± 0·3 and a mean δ15N of 7·6 ± 0·1 (n = 20). The δ13C signatures of the only mangrove species present (Avicennia marina) and the most abundant saltmarsh plant (Sarcocornia quinqueflora) indicated that they were not major food sources. Seagrasses, predominantly Heterozostera tasmanica, had mean δ13C and δ15N values of –11·7 ± 0·2‰ (n = 65) and 3·9 ± 0·2‰ (n = 62), respectively. Seagrass epiphytes had mean δ13C and δ15N values of –17·9 ± 0·4‰ and 4·6 ± 0·3‰ (n = 27), respectively. A mixture of seagrasses and their epiphytes was the most likely source of organic carbon for B. arenosus. Benthic microalgae, such as diatoms, were a possible food source, but phospholipid biomarkers indicated a meagre abundance of diatoms in the sediments, and microscopy of shrimp guts revealed few or no diatom frustules. For T. australiensis, food sources were less easily distinguished than for B. arenosus, but they could include seagrass epiphytes plus the green macroalgae Enteromorpha spp. and/or the brown alga Chordaria cladisiphon.

scholarly journals Trophic diversity of seagrass detritus copepods: A consequence of species-specific specialization or a random diet?

2016 ◽  
Author(s):  
Thibaud Mascart ◽  
Marleen De Troch ◽  
François Remy ◽  
Loïc Michel ◽  
Gilles Lepoint
Keyword(s):  
Organic Matter ◽  
Trophic Ecology ◽  
Harpacticoid Copepod ◽  
Food Sources ◽  
Calanoid Copepods ◽  
Copepod Community ◽  
Suspended Organic Matter ◽  
Trophic Diversity ◽  
Seagrass Meadows ◽  
Species Specific

One of the major ecological research questions is understanding how biodiversity influences ecosystem functioning. Unravelling interspecific feeding preferences of organisms with overlapping trophic niches will give part of the answer. Subsequently, the present study displays the trophic diversity of a benthic copepod community in a North-Western Corsican Posidonia oceanica seagrass ecosystem. These seagrass meadows are often interrupted by bare sand patches serving as deposition area for loose detritus. The accumulated macrophytodetritus, mainly derived from senescent macrophytes, harbour a diverse community of Harpacticoida (Crustacea, Copepoda). The most abundant copepods (i.e. three harpacticoids and one calanoid, belonging to different eco-morphological types) and their potential food sources (i.e. macrophytodetritus, epiphytic biofilm and suspended organic matter) were analysed for stable isotope ratios (δ13C, δ15N) and total lipids content. The results revealed a harpacticoid copepod feeding preference towards the epiphytic biofilm, while calanoid copepods preferred suspended organic matter. Additionally, a species-specific composition variation revealed finer partitioning of food resources (e.g. different micro-organisms present in the biofilm like bacteria, diatoms, fungi) over time.In conclusion, results showed species-specific food preferences, resulting in trophic niche and resource partitioning. Every eco-morphological type seems to cope in different ways with temporal fluctuations of food sources to comply with their nutritional needs. This illustrates the high resilience of the copepod community present in macrophytodetritus accumulations. Moreover, our results underlined the importance of multiple biomarker species-specific analysis in trophic ecology studies, especially in complex and dynamic environments offering numerous food items to consumers.

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