Inherent variation in carbon and nitrogen isotopic assimilation in the freshwater macro-invertebrate Cherax destructor

2016 ◽  
Vol 67 (12) ◽  
pp. 1928 ◽  
Author(s):  
Debashish Mazumder ◽  
Li Wen ◽  
Mathew P. Johansen ◽  
Tsuyoshi Kobayashi ◽  
Neil Saintilan
Keyword(s):  
Trophic Ecology ◽  
Individual Variability ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Source Selection ◽  
Cherax Destructor ◽  
Specific Variation ◽  
The Individual ◽  
Diet Source

Individual variability in diet source selection has often been cited as the main factor for intra-specific variation of isotopic signatures among food-web consumers. We conducted a laboratory study to test how well the individual variability of the δ13C and δ15N ratios in the muscle of an omnivore consumer (yabby: Cherax destructor) corresponded to the variability of various diet types and diet combinations. We found that C. destructor muscle isotope signatures varied in concert with the composition of single-source diets, and that this variability was low. However, when fed the same proportional mixture of multiple diet sources, comparatively high isotopic variability was observed among specimens. Results suggest that a substantial component of isotopic variability in wild populations may be owing to inherent differences in uptake, absorption, and sequestration among individuals, which is distinct from behaviourally driven individualised diet selection. Considering the potential of such individual variability in assimilation to be present in many different consumer populations, we suggest further testing for a range of species and inclusion of this source of variation, for interpretation of isotopic data for trophic ecology.

scholarly journals C / N ratio, stable isotope (δ<sup>13</sup>C, δ<sup>15</sup>N), and <i>n</i>-alkane patterns of bryophytes along hydrological gradients of low-centred polygon of the Siberian Arctic

2016 ◽  
Author(s):  
Romy Zibulski ◽  
Felix Wesener ◽  
Heinz Wilkes ◽  
Birgit Plessen ◽  
Luidmila A. Pestryakova ◽  
...  
Keyword(s):  
Water Level ◽  
Isotopic Signature ◽  
The Arctic ◽  
Specific Level ◽  
Δ13c And Δ15n ◽  
Lena River ◽  
Isotopic Signatures ◽  
Microbial Symbiosis ◽  
The Stability ◽  
The Individual

Abstract. Mosses are a major component of the arctic vegetation, particularly of wetlands. We present C / N ratio, δ13C and δ15N data of 400 moss samples belonging to 10 species that were collected along hydrological gradients within polygonal mires located on the southern Taymyr Peninsula and the Lena River delta in northern Siberia. Additionally, n alkane patterns of six of these taxa were investigated. The aim of the study is to see whether the inter- and intra-specific differences in biochemical and isotopic signatures are indicative of habitat with particular respect to water-level. Overall, we find high variability in all investigated parameters. The C / N ratios range between 15.4 and 70.4 (median: 42.9) and show large variations at intra-specific level. However, species preferring a dry habitat (xero-mesophilic mosses) show higher C / N ratios than those preferring a wet habitat (meso-hygrophilic mosses). We assume that this mainly originates from the association of mosses from wet habitats with microorganisms which supply them with nitrogen. Furthermore, because of the stability provided by water, they do not need to invest in a sturdy stem-structure and accordingly have lower C contents in their biomass. The δ13C values range between −37.0 and 22.5 ‰ (median = −27.8 ‰). The δ15N values range between −6.59 and +1.69 ‰ (median = 2.17 ‰).We find differences in δ13C and δ15N signatures between both habitat types and, for some species of the meso-hygrophilic group, a significant relation between the individual habitat water-level and isotopic signature was inferred as a function of microbial symbiosis. The n alkane distribution also shows differences primarily between xero-mesophilic and meso-hygrophilic mosses, i.e. having a dominance of n-alkanes with long (n-C29, n-C31) and intermediate chain lengths (n-C25), respectively. Overall, our results reveal that biochemical and isotopic signals of certain moss taxa from polygonal wetlands are characteristic of their habitat and can thus be used in (palaeo-)environmental studies.

THE STUDY OF THE INDIVIDUAL VARIABILITY OF THE LINEAR DIMENSIONS OF THE SPHENOID SINUS

2019 ◽  
Vol 21 (1) ◽  
pp. 64-70
Author(s):  
O.V. Mareev ◽  
◽  
G.O. Mareev ◽  
M.E. Gutynina ◽  
D.A. Maksimova ◽  
...  
Keyword(s):  
Sphenoid Sinus ◽  
Individual Variability ◽  
Linear Dimensions ◽  
The Individual

Stabilization of Organic Carbon and Nitrogen in Consolidating Benthal Deposits

1985 ◽  
Vol 17 (6-7) ◽  
pp. 929-940 ◽  
Author(s):  
C. W. Bryant ◽  
L. G. Rich
Keyword(s):  
Organic Carbon ◽  
Model Verification ◽  
Volatile Acid ◽  
Free Energies ◽  
Organic Loading ◽  
Carbon And Nitrogen ◽  
Loading Rates ◽  
Degradation Reactions ◽  
The Individual ◽  
Organic Deposits

The objective of this research was to develop and validate a predictive model of the benthal stabilization of organic carbon and nitrogen in deposits of waste activated sludge solids formed at the bottom of an aerated water column, under conditions of continual deposition. A benthal model was developed from a one-dimensional, generalized transport equation and a set of first-order biological reactions. For model verification, depth profiles of the major interstitial carbon and nitrogen components were measured from a set of deposits formed in the laboratory at 20°C and a controlled loading rate. The observed sequence of volatile acid utilization in each benthal deposit was that which would be predicted by the Gibbs free energies of the individual degradation reactions and would be controlled by the reduction in interstitial hydrogen partial pressure with time. Biodegradable solids were solubilized rapidly during the first three weeks of benthal retention, but subsequent solubilization occurred much more slowly. The benthal simulation effectively predicted the dynamics of consolidating, organic deposits. Simulation of organic loading rates up to 250 g BVSS/(m2 day) indicated that the stabilization capacity of benthal deposits was far above the range of organic loading rates currently used in lagoon design.

Temperature affects carbon and nitrogen stable isotopic signatures of aquatic plants

2021 ◽  
Vol 83 (2) ◽  
Author(s):  
Peiyu Zhang ◽  
Xianghong Kong ◽  
Elisabeth S. Bakker ◽  
Jun Xu ◽  
Min Zhang
Keyword(s):  
Aquatic Plants ◽  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Stable Isotopic

scholarly journals Diversity and Diet Differences of Small Mammals in Commensal Habitats

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 346
Author(s):  
Linas Balčiauskas ◽  
Laima Balčiauskienė ◽  
Andrius Garbaras ◽  
Vitalijus Stirkė
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Trophic Ecology ◽  
Mammal Species ◽  
Additional Food ◽  
Δ13c And Δ15n ◽  
Degree Of Separation ◽  
Kitchen Gardens ◽  
Dietary Plasticity ◽  
The Stability

The stability of diversity of syntopic (inhabiting the same habitat in the same time) small mammals in commensal habitats, such as farmsteads and kitchen gardens, and, as a proxy of their diet, their isotopic niches, was investigated in Lithuania in 2019–2020. We tested whether the separation of species corresponds to the trophic guilds, whether their diets are related to possibilities of getting additional food from humans, and whether their diets are subject to seasonal trends. We analyzed diversity, dominance and distribution of hair δ13C and δ15N values. Diversity and dominance was not stable and differed according to human influence. The highest small mammal species richness occurred in commensal habitats that provided additional food. The degree of separation of species was higher in homestead habitats than in kitchen gardens, where a 1.27 to 35.97% overlap of isotopic niches was observed between pairs of species. Temporal changes in δ13C and δ15N values in the hair of the mammals were not equally expressed in different species. The isotopic overlap may depend on dietary plasticity, minimizing interspecific competition and allowing co-existence of syntopic species. Thus, small mammal trophic ecology is likely related to intensity of agricultural activities in the limited space of commensal habitats.

Soil organic carbon and nitrogen sequestration and turnover in aggregates under subtropical leucaena–grass pastures

Soil Research ◽  
2018 ◽  
Vol 56 (6) ◽  
pp. 632 ◽  
Author(s):  
Kathryn Conrad ◽  
Ram C. Dalal ◽  
Ryosuke Fujinuma ◽  
Neal W. Menzies
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Soil Mass ◽  
Δ13c And Δ15n ◽  
Organic C ◽  
Carbon And Nitrogen ◽  
Nitrogen Sequestration ◽  
C And N

Stabilisation and protection of soil organic carbon (SOC) in macroaggregates and microaggregates represents an important mechanism for the sequestration of SOC. Legume-based grass pastures have the potential to contribute to aggregate formation and stabilisation, thereby leading to SOC sequestration. However, there is limited research on the C and N dynamics of soil organic matter (SOM) fractions in deep-rooted legume leucaena (Leucaena leucocephala)–grass pastures. We assessed the potential of leucaena to sequester carbon (C) and nitrogen (N) in soil aggregates by estimating the origin, quantity and distribution in the soil profile. We utilised a chronosequence (0–40 years) of seasonally grazed leucaena stands (3–6 m rows), which were sampled to a depth of 0.3 m at 0.1-m intervals. The soil was wet-sieved for different aggregate sizes (large macroaggregates, >2000 µm; small macroaggregates, 250–2000 µm; microaggregates, 53–250 µm; and <53 µm), including occluded particulate organic matter (oPOM) within macroaggregates (>250 µm), and then analysed for organic C, N and δ13C and δ15N. Leucaena promoted aggregation, which increased with the age of the leucaena stands, and in particular the formation of large macroaggregates compared with grass in the upper 0.2 m. Macroaggregates contained a greater SOC stock than microaggregates, principally as a function of the soil mass distribution. The oPOM-C and -N concentrations were highest in macroaggregates at all depths. The acid nonhydrolysable C and N distribution (recalcitrant SOM) provided no clear distinction in stabilisation of SOM between pastures. Leucaena- and possibly other legume-based grass pastures have potential to sequester SOC through stabilisation and protection of oPOM within macroaggregates in soil.

scholarly journals Mycorrhizal Communities and Isotope Signatures in Two Partially Mycoheterotrophic Orchids

2021 ◽  
Vol 12 ◽  
Author(s):  
Hans Jacquemyn ◽  
Rein Brys ◽  
Michael Waud ◽  
Alexandra Evans ◽  
Tomáš Figura ◽  
...  
Keyword(s):  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Wide Range ◽  
Terrestrial Orchids ◽  
Significant Enrichment ◽  
Mycoheterotrophic Plants ◽  
C And N ◽  
Species Specific ◽  
Epipactis Helleborine ◽  
Isotope Analyses

Partial mycoheterotrophy, the ability of plants to obtain carbon from fungi throughout their life cycle in combination with photosynthesis, appears to be more common within the Plant Kingdom than previously anticipated. Recent studies using stable isotope analyses have indicated that isotope signatures in partially mycoheterotrophic plants vary widely among species, but the relative contributions of family- or species-specific characteristics and the identity of the fungal symbionts to the observed differences remain unclear. Here, we investigated in detail mycorrhizal communities and isotopic signatures in four co-occurring terrestrial orchids (Platanthera chlorantha, Epipactis helleborine, E. neglecta and the mycoheterotrophic Neottia nidus-avis). All investigated species were mycorrhizal generalists (i.e., associated with a large number of fungi simultaneously), but mycorrhizal communities differed significantly between species. Mycorrhizal communities associating with the two Epipactis species consisted of a wide range of fungi belonging to different families, whereas P. chlorantha and N. nidus-avis associated mainly with Ceratobasidiaceae and Sebacinaceae species, respectively. Isotopic signatures differed significantly between both Epipactis species, with E. helleborine showing near autotrophic behavior and E. neglecta showing significant enrichment in both carbon and nitrogen. No significant differences in photosynthesis and stomatal conductance were observed between the two partially mycoheterotrophic orchids, despite significant differences in isotopic signatures. Our results demonstrate that partially mycoheterotrophic orchids of the genus Epipactis formed mycorrhizas with a wide diversity of fungi from different fungal families, but variation in mycorrhizal community composition was not related to isotope signatures and thus transfer of C and N to the plant. We conclude that the observed differences in isotope signatures between E. helleborine and E. neglecta cannot solely be explained by differences in mycorrhizal communities, but most likely reflect a combination of inherent physiological differences and differences in mycorrhizal communities.

scholarly journals Individual variation of the masticatory system dominates 3D skull shape in the herbivory-adapted marsupial wombats

2019 ◽  
Author(s):  
Vera Weisbecker ◽  
Thomas Guillerme ◽  
Cruise Speck ◽  
Emma Sherratt ◽  
Hyab Mehari Abraha ◽  
...  
Keyword(s):  
Individual Variation ◽  
Principal Component ◽  
Individual Variability ◽  
Shape Variation ◽  
Mandibular Ramus ◽  
Geometric Morphometric ◽  
Skull Shape ◽  
Marsupial Species ◽  
Masticatory System ◽  
The Individual

AbstractBackgroundWithin-species skull shape variation of marsupial mammals is widely considered low and strongly size-dependent (allometric), possibly due to developmental constraints arising from the altricial birth of marsupials. However, species whose skulls are impacted by strong muscular stresses – particularly those produced through mastication of tough food items – may not display such intrinsic patterns very clearly because of the known plastic response of bone to muscle activity of the individual. In such cases, shape variation should not be dominated by allometry; ordination of shape in a geometric morphometric context through principal component analysis (PCA) should reveal main variation in areas under masticatory stress (incisor region/zygomatic arches/mandibular ramus); but this main variation should emerge from high individual variability and thus have low eigenvalues.ResultsWe assessed the evidence for high individual variation through 3D geometric morphometric shape analysis of crania and mandibles of thre species of grazing-specialized wombats, whose diet of tough grasses puts considerable strain on their masticatory system. As expected, we found little allometry and low Principal Component 1 (PC1) eigenvalues within crania and mandibles of all three species. Also as expected, the main variation was in the muzzle, zygomatic arches, and masticatory muscle attachments of the mandibular ramus. We then implemented a new test to ask if the landmark variation reflected on PC1 was reflected in individuals with opposite PC1 scores and with opposite shapes in Procrustes space. This showed that correspondence between individual and ordinated shape variation was limited, indicating high levels of individual variability in the masticatory apparatus.DiscussionOur results are inconsistent with hypotheses that skull shape variation within marsupial species reflects a constraint pattern. Rather, they support suggestions that individual plasticity can be an important determinant of within-species shape variation in marsupials (and possibly other mammals) with high masticatory stresses, making it difficult to understand the degree to which intrinsic constraint act on shape variation at the within-species level. We conclude that studies that link micro- and macroevolutionary patterns of shape variation might benefit from a focus on species with low-impact mastication, such as carnivorous or frugivorous species.

scholarly journals Phylogenetic comparative analyses of the determinants of anti-predator distraction behavior in shorebirds

2020 ◽  
Author(s):  
Miki Saijo ◽  
Nobuyuki Kutsukake
Keyword(s):  
Nest Site ◽  
Selective Pressure ◽  
Large Species ◽  
Behavioral Repertoire ◽  
Comparative Analyses ◽  
Colonial Nesting ◽  
Specific Variation ◽  
The Individual ◽  
Solitary Species ◽  
Predator Behavior

AbstractPredation risk exerts a strong selective pressure on anti-predator behavior, resulting in behaviors to achieve defense of offspring and the individual. In shorebirds, some species perform distraction behavior that is attracting the attention of a predator. This behavior evolved, and were lost multiple times, independently and the behavioral repertoire varies among species. Although defense of offspring is critical for parents, the determinants of inter-specific variation in the distraction behavior remain unstudied. We surveyed the literature and conducted phylogenetic comparative analyses (n = 169 species) to test predictions regarding nest site, body mass, and coloniality. We found that small species were more likely to perform distraction behavior than large species. Solitary species were more likely to perform distraction behavior than colonial nesting species. Previous studies suggested that colonial nesting and large species commonly perform aggressive anti-predator behavior, implying that distraction behavior is an alternative anti-predator strategy to aggressive ones.

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