Ontogenetic profiles of dentine isotopes (δ15N and δ13C) reveal variable narwhal Monodon monoceros nursing duration

2021 ◽  
Author(s):  
ST Zhao ◽  
CJD Matthews ◽  
GK Davoren ◽  
SH Ferguson ◽  
CA Watt
Keyword(s):  
Monodon Monoceros ◽  
Δ15n And Δ13c

scholarly journals Tracing the Trophic Plasticity of the Coral–Dinoflagellate Symbiosis Using Amino Acid Compound-Specific Stable Isotope Analysis

2021 ◽  
Vol 9 (1) ◽  
pp. 182
Author(s):  
Christine Ferrier-Pagès ◽  
Stephane Martinez ◽  
Renaud Grover ◽  
Jonathan Cybulski ◽  
Eli Shemesh ◽  
...  
Keyword(s):  
Amino Acids ◽  
Essential Role ◽  
Isotope Analysis ◽  
Diagnostic Tools ◽  
Global Changes ◽  
Biosynthetic Pathways ◽  
Trophic Plasticity ◽  
Trophic Index ◽  
Δ15n And Δ13c ◽  
Acid Compound

The association between corals and photosynthetic dinoflagellates is one of the most well-known nutritional symbioses, but nowadays it is threatened by global changes. Nutritional exchanges are critical to understanding the performance of this symbiosis under stress conditions. Here, compound-specific δ15N and δ13C values of amino acids (δ15NAA and δ13CAA) were assessed in autotrophic, mixotrophic and heterotrophic holobionts as diagnostic tools to follow nutritional interactions between the partners. Contrary to what was expected, heterotrophy was mainly traced through the δ15N of the symbiont’s amino acids (AAs), suggesting that symbionts directly profit from host heterotrophy. The trophic index (TP) ranged from 1.1 to 2.3 from autotrophic to heterotrophic symbionts. In addition, changes in TP across conditions were more significant in the symbionts than in the host. The similar δ13C-AAs signatures of host and symbionts further suggests that symbiont-derived photosynthates are the main source of carbon for AAs synthesis. Symbionts, therefore, appear to be a key component in the AAs biosynthetic pathways, and might, via this obligatory function, play an essential role in the capacity of corals to withstand environmental stress. These novel findings highlight important aspects of the nutritional exchanges in the coral–dinoflagellates symbiosis. In addition, they feature δ15NAA as a useful tool for studies regarding the nutritional exchanges within the coral–symbiodiniaceae symbiosis.

scholarly journals Phylogenetic Community Structure and Niche Differentiation in Termites of the Tropical Dry Forests of Colombia

Insects ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 103
Author(s):  
Robin Casalla Daza ◽  
Judith Korb
Keyword(s):  
Niche Differentiation ◽  
Environmental Data ◽  
Tropical Dry Forests ◽  
Diet Shift ◽  
Dry Forests ◽  
Phylogenetic Community Structure ◽  
Phylogenetic Overdispersion ◽  
Δ15n And Δ13c ◽  
Increasing Temperature ◽  
The Tropics

The mechanisms that structure species communities are still debated. We addressed this question for termite assemblages from tropical dry forests in Colombia. These forests are endangered and poorly understood ecosystems and termites are important ecosystem engineers in the tropics. Using biodiversity and environmental data, combined with phylogenetic community analyses, trait mapping, and stable isotopes studies, we investigated the termite community composition of three protected dry forests in Colombia. Our data suggest that the structuring mechanisms differed between sites. Phylogenetic overdispersion of termite assemblages correlated with decreasing rainfall and elevation and increasing temperature. Food niche traits—classified as feeding groups and quantified by δ15N‰ and δ13C‰ isotope signatures—were phylogenetically conserved. Hence, the overdispersion pattern implies increasing interspecific competition with decreasing drier and warmer conditions, which is also supported by fewer species occurring at the driest site. Our results are in line with a hypothesis that decreased biomass production limits resource availability for termites, which leads to competition. Along with this comes a diet shift: termites from drier plots had higher δ13C signatures, reflecting higher δ13C values in the litter and more C4 plants. Our study shows how a phylogenetic community approach combined with trait analyses can contribute to gaining the first insights into mechanisms structuring whole termite assemblages.

scholarly journals Long-term Carbon and Nitrogen Dynamics at SPRUCE Revealed through Stable Isotopes in Peat Profiles

2016 ◽  
Author(s):  
Erik A. Hobbie ◽  
Janet Chen ◽  
Paul J. Hanson ◽  
Colleen M. Iversen ◽  
Karis J. Mcfarlane ◽  
...  
Keyword(s):  
Industrial Revolution ◽  
Continuous Variables ◽  
Carbon And Nitrogen ◽  
Carbon And Nitrogen Dynamics ◽  
Aerobic Decomposition ◽  
C And N ◽  
C And N Cycling ◽  
Δ15n And Δ13c ◽  
Forested Bog

Abstract. We used δ15N and δ13C patterns from 16 peat depth profiles to interpret changes in C and N cycling in the Marcell S1 forested bog in northern Minnesota over the past ~ 10 000 years. In multiple regression analyses, δ15N and δ13C correlated strongly with depth, plot location, C / N, %N, and each other. Continuous variables in the regression model mainly reflected 13C and 15N fractionation accompanying N and C losses, with an estimated 40 % of fractionations involving C-N bonds. In contrast, nominal variables such as plot, depth, and vegetation cover reflected peatland successional history and climate. Higher δ15N and lower δ13C in plots closer to uplands may reflect distinct hydrology and accompanying shifts in C and N dynamics in the lagg drainage area surrounding the bog. The Suess effect (declining δ13CO2 since the Industrial Revolution) and aerobic decomposition lowered δ13C in recent surficial samples. A decrease of 1 ‰ in the depth coefficient for δ15N from −35 cm to −25 cm probably indicated the depth of ectomycorrhizal activity after tree colonization of the peatland. Low δ13C at −213 cm and −225 cm (~ 8500 years BP) corresponded to a warm period during a sedge-dominated rich fen stage, whereas higher δ13C thereafter reflected subsequent cooling. Because of multiple potential mechanisms influencing δ13C, there was no clear evidence for the influence of methanogenesis or methane oxidation on bulk δ13C.

Compound-Specific δ15N and δ13C Analyses of Amino Acids for Potential Discrimination between Organically and Conventionally Grown Wheat

2015 ◽  
Vol 63 (25) ◽  
pp. 5841-5850 ◽  
Author(s):  
Mauro Paolini ◽  
Luca Ziller ◽  
Kristian Holst Laursen ◽  
Søren Husted ◽  
Federica Camin
Keyword(s):  
Amino Acids ◽  
Δ15n And Δ13c

The migratory behaviour of narwhals (Monodon monoceros)

2003 ◽  
Vol 81 (8) ◽  
pp. 1298-1305 ◽  
Author(s):  
Mads Peter Heide-Jørgensen ◽  
Rune Dietz ◽  
Kristin L Laidre ◽  
Pierre Richard ◽  
Jack Orr ◽  
...  
Keyword(s):  
Open Water ◽  
High Arctic ◽  
Early Summer ◽  
Canadian High Arctic ◽  
Baffin Bay ◽  
Bay Area ◽  
Monodon Monoceros ◽  
Migratory Routes ◽  
Somerset Island ◽  
Wintering Ground

Sixteen female narwhals (Monodon monoceros) were tracked by satellite in 2000 and 2001 from their summering ground near Somerset Island in the Canadian High Arctic to their wintering ground in central Baffin Bay. The wintering ground location was spatially discrete from another narwhal wintering ground in southern Baffin Bay. Area extent of the summering ground was approximately 9464 km2 and area extent of the wintering ground was 25 846 km2. Two of the narwhals were tracked for more than 12 consecutive months. These whales used three focal areas between their spring and autumn migration: a coastal area in the open-water season in August in the Canadian High Arctic, a wintering area from November through April in the consolidated pack ice of Baffin Bay, and an early summer area in front of the receding fast ice edge in Lancaster Sound. The whales showed remarkable site fidelity to summering grounds and had specific migratory routes that followed sea ice formation and recession.

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