نتایج جستجو برای: δ13c

تعداد نتایج: 1653  

2010
Hillary S. Young Douglas J. McCauley Rodolfo Dirzo Robert B. Dunbar Scott A. Shaffer

The low productivity and unpredictable nature of resources in tropical waters would appear to make resource partitioning among predators difficult. Yet, stable isotope data from the present study suggest that substantial resource partitioning occurs among tropical seabird communities, both between and within species. In the present study, we compared δ13C and δ15N levels among 8 sympatric tropi...

Journal: :The Science of the total environment 2016
Fang Cao Shi-Chun Zhang Kimitaka Kawamura Yan-Lin Zhang

To better characterize the chemical compositions and sources of fine particulate matter (i.e. PM2.5) in Sanjiang Plain, Northeast China, total carbon (TC), organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and inorganic ions as well as stable carbon isotopic composition (δ13C) were measured in this study. Intensively open biomass burning episodes are identified fr...

2013
Michael Grant

1. For the first time, diet and isotopic niche overlap among males and two female-specific colour morphs of a damselfly were quantified to test whether sexual conflict could cause intra-sexual diet variation. 2. Relative to the green female morph, blue females, similar in coloration to the blue males, may be more likely overlooked by mate-searching males. If so, blue females should be more like...

Journal: :Marine environmental research 2017
Krishna Das Ophélie Holleville Conor Ryan Simon Berrow Anita Gilles Denis Ody Loïc N Michel

The fin whale (Balaenoptera physalus) is the most abundant and widespread mysticete species in the Mediterranean Sea, found mostly in deep, offshore waters of the western and central portion of the region. In the Mediterranean, this species is known to feed mainly on krill, in contrast to its Atlantic counterpart, which displays a more diversified diet. The International Whaling Commission reco...

2016
Vikash Kumar Manish Tiwari Siddhesh Nagoji Shubham Tripathi

Accurate estimation of relative carbon deposition (marine vs. terrestrial) is required for understanding the global carbon budget, particularly in the Arctic region, which holds disproportionate importance with respect to global carbon cycling. Although the sedimentary organic matter (SOM) concentration and its isotopic composition are important tools for such calculations, uncertainties loom o...

2018
Agnes M L Karlson Martin Reutgard Andrius Garbaras Elena Gorokhova

The isotopic niche has become an established concept in trophic ecology. However, the assumptions behind this approach have rarely been evaluated. Evidence is accumulating that physiological stress can affect both magnitude and inter-individual variability of the isotopic signature in consumers via alterations in metabolic pathways. We hypothesized that stress factors (inadequate nutrition, par...

Journal: :Water, air, and soil pollution 2016
Barbara M Sensuła

In this study, stable carbon isotope ratios in the glucose samples were extracted from annual pine tree rings as bio-indicators of contemporary environmental changes in heavily urbanized areas. The sampling sites were located in close proximity to point source pollution emitters, such as a heat and power plant "Łaziska" and steelworks "Huta Katowice" in Silesia (Poland). The analysed samples co...

2016
L. Menviel J. Yu F. Joos A. Mouchet K. J. Meissner H. England

Atmospheric CO2 was ∼90 ppmv lower at the Last Glacial Maximum (LGM) compared to the late Holocene, but the mechanisms responsible for this change remain elusive. Here we employ a carbon isotope-enabled Earth System Model to investigate the role of ocean circulation in setting the LGM oceanic δ 13C distribution, thereby improving our understanding of glacial/interglacial atmospheric CO2 variati...

2015
Nina Siebers Christopher Martius Kai-Uwe Eckhardt Marcos V. B. Garcia Peter Leinweber Wulf Amelung

The impact of termites on nutrient cycling and tropical soil formation depends on their feeding habits and related material transformation. The identification of food sources, however, is difficult, because they are variable and changed by termite activity and nest construction. Here, we related the sources and alteration of organic matter in nests from seven different termite genera and feedin...

2016
Christoph A. Lehmeier Ford Ballantyne IV Kyungjin Min Sharon A. Billings

Understanding how carbon dioxide (CO2) flux from ecosystems feeds back to climate warming depends in part on our ability to quantify the efficiency with which microorganisms convert organic carbon (C) into either biomass or CO2. Quantifying ecosystem-level respiratory CO2 losses often also requires assumptions about stable C isotope fractionations associated with the microbial transformation of...

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