scholarly journals Extreme bill dimorphism leads to different but overlapping isotopic niches and similar trophic positions in sexes of the charismatic extinct huia

Oecologia ◽  
2021 ◽  
Author(s):  
Barbara M. Tomotani ◽  
Rodrigo B. Salvador ◽  
Amandine J. M. Sabadel ◽  
Colin M. Miskelly ◽  
Julie C. S. Brown ◽  
...  
Keyword(s):  
Amino Acids ◽  
Stable Isotopes ◽  
Geometric Morphometrics ◽  
Foraging Behaviour ◽  
Trophic Position ◽  
Female Competition ◽  
Museum Specimens ◽  
Foraging Habitat ◽  
Isotopic Analyses ◽  
Trophic Niches

AbstractThe New Zealand huia (Heteralocha acutirostris) had the most extreme bill sexual dimorphism among modern birds. Given the quick extinction of the species, the cause of the dimorphism could only be hypothesised to reflect different trophic niches and reduce male/female competition. We tested that hypothesis by combining museum specimens, geometric morphometrics, and isotopic analyses. We used geometric morphometrics to describe bill shape; measured bulk (δ15Nbulk) and (δ13Cbulk) values from feather as proxies of the birds’ foraging habitat and diet; and compared compound-specific stable isotopes analyses (CSIA) of nitrogen in amino acids (δ15NAA) in male–female pairs to estimate their trophic position. Sexes had significantly different, but overlapping feather δ15Nbulk and δ13Cbulk values, but δ15NAA indicated identical trophic positions and δ15Nbulk was not related to bill shape. Trophic position was less variable among females, consistent with a specialised foraging behaviour and, thus, supporting a partial male/female foraging segregation.

scholarly journals Isotope data from amino acids indicate Darwin’s ground sloth was not an herbivore

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Julia V. Tejada ◽  
John J. Flynn ◽  
Ross MacPhee ◽  
Tamsin C. O’Connell ◽  
Thure E. Cerling ◽  
...  
Keyword(s):  
Amino Acids ◽  
Direct Evidence ◽  
Nitrogen Isotopes ◽  
Trophic Position ◽  
South American ◽  
Isotope Data ◽  
The Past ◽  
Isotopic Analyses ◽  
Reliable Interpretation ◽  
Ground Sloth

AbstractFossil sloths are regarded as obligate herbivores for reasons including peculiarities of their craniodental morphology and that all living sloths feed exclusively on plants. We challenge this view based on isotopic analyses of nitrogen of specific amino acids, which show that Darwin’s ground sloth Mylodon darwinii was an opportunistic omnivore. This direct evidence of omnivory in an ancient sloth requires reevaluation of the ecological structure of South American Cenozoic mammalian communities, as sloths represented a major component of these ecosystems across the past 34 Myr. Furthermore, by analyzing modern mammals with known diets, we provide a basis for reliable interpretation of nitrogen isotopes of amino acids of fossils. We argue that a widely used equation to determine trophic position is unnecessary, and that the relative isotopic values of the amino acids glutamate and phenylalanine alone permit reliable reconstructions of trophic positions of extant and extinct mammals.

Assessment of indigeneity in fossil organic matter: amino acids and stable isotopes

1991 ◽  
Vol 333 (1268) ◽  
pp. 367-374 ◽  
Keyword(s):  
Amino Acids ◽  
Stable Isotopes ◽  
Organic Matter ◽  
New Technologies ◽  
Trophic Position ◽  
Stable Carbon Isotope ◽  
Nitrogen Isotope ◽  
Alternative Methods ◽  
Stable Carbon ◽  
Residual Organic Matter

Whereas the presence of amino acids in fossil materials is clearly related to biosynthesis, an indigenous relationship with the fossil may be suspect. At present, attempts to establish the indigeneity of amino acids in fossils are based on distribution and stereochemistry. However, fossil systems are not closed and racemization may be retarded in organic materials within a fossil matrix. The advent of new technologies has resulted in alternative methods for evaluating the authenticity of fossil organic matter. A comparison of the stable carbon isotope compositions of the D- and L-enantiomers of individual amino acids facilitates the evaluation of indigeneity. Here we report the application of this method for determining the origin(s) of amino acids in fossils and extraterrestrial samples. Further, nitrogen isotope compositions of fossil materials should reflect trophic order, with increasing enrichment in 515N with progression up the food chain. Establishment of the trophic position of a fossil would further reinforce the appraisal of indigeneity based on the isotopic composition of its residual organic matter. Results of initial studies on Cretaceous age vertebrates which are consistent with the suggested feeding morphologies of these organisms are also presented.

scholarly journals Effect of different derivatization protocols on the calculation of trophic position using amino acids compound-specific stable isotopes

2020 ◽  
Author(s):  
Stephane Martinez ◽  
Maya Lalzer ◽  
Eli Shemesh ◽  
Shai Einbinder ◽  
Beverly Goodman Tchernov ◽  
...  
Keyword(s):  
Amino Acids ◽  
Stable Isotopes ◽  
Amino Acid ◽  
Nitrogen Atom ◽  
Stable Isotope ◽  
System Dynamics ◽  
Trophic Position ◽  
Nitrogen Stable Isotope ◽  
Exogenous Nitrogen ◽  
Research Studies

AbstractAmino acids compound-specific nitrogen stable isotope (AA-CSIA) is an emerging tool in ecology for understanding trophic system dynamics. While it has been successfully used for several independent studies across a range of environments and study locations, researchers have encountered calculation issues for determining trophic position values. Most studies introduce modifications to the constants of trophic position equation calculations, but then fail to account for the equation variations when comparing the results of separate research studies. The acceptance of this approach is related to the underlying presumption that no addition of the exogenous nitrogen atom occurs in the different methods and, therefore, such variations should not affect the outcome. In this paper, we evaluate the use of the EZfaast amino acid derivatization kit (chloroformate) and compare it to the isotopic results of two other derivatization methods. We highlight new considerations for working with AA-CSIA that might account for some of the variations in the results and lead researchers to modify constants in the equation. This likely requires developing the unique constants per derivatization method in order to be able to compare the trophic position results across different studies.

scholarly journals Effect of Different Derivatization Protocols on the Calculation of Trophic Position Using Amino Acids Compound-Specific Stable Isotopes

2020 ◽  
Vol 7 ◽  
Author(s):  
Stephane Martinez ◽  
Maya Lalzar ◽  
Eli Shemesh ◽  
Shai Einbinder ◽  
Beverly Goodman Tchernov ◽  
...  
Keyword(s):  
Amino Acids ◽  
Stable Isotopes ◽  
Amino Acid ◽  
Nitrogen Atom ◽  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Nitrogen Stable Isotope ◽  
Exogenous Nitrogen

Amino acids compound-specific nitrogen stable isotope analysis (AA-CSIA) is an emerging tool in ecology for understanding trophic system dynamics. While it has been successfully used for several independent studies across a range of environments and study locations, researchers have encountered calculation issues for determining trophic position values. Most studies introduce modifications to the constants of trophic position equation calculations, but then fail to account for the equation variations when comparing across separate research studies. The broad acceptance of this approach is anchored in an underlying presumption that no addition of the exogenous nitrogen atom occurs in the different methods; and therefore, such variations should not affect the outcome. In this paper, we evaluate the use of the EZfaast amino acid derivatization kit (chloroformate) and compare it to the isotopic results of two other derivatization methods. We highlight new considerations for working with AA-CSIA that might account for some of the variations in the results and lead researchers to modify constants in the equation. This study concludes that developing unique constants per derivatization method is required to have more accurate cross-study comparisons of trophic positions.

scholarly journals Determination of kinetic parameters of apolipoprotein B metabolism using amino acids labeled with stable isotopes.

1991 ◽  
Vol 32 (8) ◽  
pp. 1311-1323
Author(s):  
KG Parhofer ◽  
P Hugh ◽  
R Barrett ◽  
DM Bier ◽  
G Schonfeld
Keyword(s):  
Amino Acids ◽  
Stable Isotopes ◽  
Kinetic Parameters ◽  
Apolipoprotein B

scholarly journals Formation processes of basal ice at Hamna Glacier, Sôya Coast, East Antarctica, inferred by detailed co-isotopic analyses

2001 ◽  
Vol 47 (157) ◽  
pp. 223-231 ◽  
Author(s):  
Yoshinori Iizuka ◽  
Hiroshi Satake ◽  
Takayuki Shiraiwa ◽  
Renji Naruse
Keyword(s):  
Stable Isotopes ◽  
Standard Deviation ◽  
Open System ◽  
Ice Sheet ◽  
East Antarctica ◽  
Formation Processes ◽  
Basal Ice ◽  
Isotopic Analyses

AbstractDebris-laden basal ice is exposed along an ice cliff near Hamna Glacier, Sôya Coast, East Antarctica. The basal ice is about 6.8 m thick and shows conspicuous stratigraphic features. The upper 5.5 m consists of alternating layers of bubble-free and bubbly ice. δ values of the bubble-free ice layers are enriched by 2.4 ±1.0‰ (standard deviation) for δ18O compared to values of neighboring bubbly ice layers above, and slopes of δ18O vs δD are close to 8. Such layers are suggested to have been formed by refreezing of meltwater in an open system. In contrast, part of the bubbly ice layers shows neutral profiles for stable isotopes, suggesting that these ice masses are undisturbed ice-sheet ice which was not affected by melting and freezing. The massive alternating layers are thus considered to have been formed by folding of refrozen and non-melted layers. The lower 1.3 m consists predominantly of bubble-free massive ice. The profile of co-isotopic values shows a change of about 3.0‰ for δ18O at the interface between bubble-free and bubbly ice. Since the isotopic change occurred over a wider thickness than the upper 5.5 m, the basal ice is suggested to have been formed by refreezing of meltwater on a larger scale than the upper 5.5 m.

scholarly journals X-RAY FLUORESCENCE AND STABLE ISOTOPES ANALYSES OF IKPESHI MARBLE, SOUTH SOUTHERN NIGERIA

2020 ◽  
Vol 10 ◽  
pp. 102
Author(s):  
Phillips Reuben Ikhane ◽  
Olalekan Olayiwola Oyebolu ◽  
Afolabi Omotayo Alaka
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Precipitation Process ◽  
Dolomitic Marble ◽  
X Ray ◽  
Humid Condition ◽  
Major Oxides ◽  
Chemical Index ◽  
Isotopic Analyses ◽  
Chemical Index Of Alteration

Integration of X-ray fluor escence and stable isotope spectrometric techniques for quality assessment and provenance study of exposed marble deposit at Fakunle Quarry, Ikpeshi, South Western Nigeria constitute the fundamental aims of this research. Fourteen fresh (14) marble samples obtained at different localities within the quarry were subjected to geochemical and isotopic analyses to ascertain the quantitative abundance of major oxides and stable isotopes using X-Ray Fluorescence and Thermo Fisher mass spectrometer respectively. The major oxides revealed by XRF analysis of the marble samples are CaO, MgO, SiO2, Al2O3, Fe2O3 and Na2O with percentage composition ranging between 11.66 – 13.25, 7.75 – 9.65, 41.36 – 47.55, 12.36 – 15.23, 7.79 – 10.55 and 1.44 – 1.75respectively. Na2O + K2O value ranges between 1.48 and 1.78.The classification of marble in relation to percentage of calcite-dolomite indicate a percentage range of -5 to 4% and 93-103% for Calcite and Dolomite respectively. Chemical Index of Alteration (CIA) ranges from 45.16 to 51.59 % and Chemical Index of Weathering (CIW) ranges from 46.19 to 52.30 %. Stable isotope ( ? –180) of marble ranges from -10.50 to -7.00 with a corresponding value from 25.50 to 55.33.Interpretation of the overall results indicates an impure quartz-rich dolomitic marble; metamorphosed from a low carbonate sedimentary/meta sedimentary protolith which shallowly precipitated within a passive marginal marine environment under humid condition. The high silica impurity can however be attributed to the inordinate influx of terrigenous sediments during the precipitation process. Weathering effect is minimal on the marble deposit. Conclusively, strong correlation is apparent between the obtained geochemical result and the basement geology of the study area.

scholarly journals Preliminary study into the trophic position of symbiotic palaemonid shrimps (Decapoda, Palaemonidae) using stable isotopes

Crustaceana ◽  
2021 ◽  
Vol 94 (9) ◽  
pp. 1145-1153
Author(s):  
Sammy De Grave ◽  
Ulrich Struck ◽  
Magnus L. Johnson
Keyword(s):  
Stable Isotopes ◽  
Trophic Position ◽  
Preliminary Study
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