Search results for "ISOTOPES"

and variability in Posidonia oceanica associated with seasonality and plant fraction

2003

Abstract The carbon and nitrogen isotopic compositions of fractions of the seagrass Posidonia oceanica (L.) Delile in a Mediterranean shallow environment (Stagnone di Marsala, western Sicily) were investigated seasonally throughout 1998. The stable isotope ratios of seagrass leaves (intermediate and adult), rhizomes, leaf litter and aegagropiles were compared over 1 year in order to distinguish between seasonal and plant part variability. Significant differences in the isotopic composition tested using ANOVA were observed as a function of both plant fraction and season. There was an overall trend towards less discrimination against 13 C in summer (average δ 13 C ∼ −10‰) than in winter (aver…

Trophic habits of Muscardinus avellanarius (Mammalia Gliridae) as revealed by multiple stable isotope analysis

2007

Multiple stable isotope analysis was used to investigate the diet of the common dormouse Muscardinus avellanarius in a mixed Mediterranean forest. δ13C and δ15N values of dormouse tissues compared to those of the vegetal and animal sources available in the area showed that the isotopic composition of both adult and juvenile M. avellanarius could be explained by a mixture of vegetal and animal organic matter. The isotopic composition of the assimilated nitrogen was mostly explained by the organic matter from flora. Among the vegetal components, flowers of Fagus silvatica, Quercus robur, and the rarer Crataegus oxyacantha, berries of Ilex aquifolium and acorns of Q. robur were found in the ad…

Oxygen isotope analysis of human bone phosphate evidences weaning age in archaeological populations

2015

Here we report bone phosphate oxygen (δ(18)Op) values from perinates/neonates and infants ( 50 years), have δ(18)Op values consistent with the consumption of local modern drinking water. The implications of this study for the reconstruction of weaning practices in archaeological populations are discussed, including variations observed with bone δ(15)Ncoll and δ(18)Op co-analysis and the influence of culturally-modified drinking water and seasonality. The use of this method to explore human mobility and palaeoclimatic conditions are also discussed with reference to the data presented.

Oxygen isotopes in mammal bone phosphate: A new tool for paleohydrological and paleoclimatological research?

1984

Abstract Oxygen isotope analyses of water in blood of humans and domestic pigs indicate that the oxygen isotope fractionation effects between ingested water and body water are the same in all specimens of the same species. The δ 18 O of body water has been shown to vary linearly with the mean δ 18 O of local meteoric water. This conclusion also holds for the bone phosphate. Thus, δ 18 O ( PO 3− 4 ) values of unaltered fossil bones from humans and domestic pigs can be used to reconstruct the δ 18 O values of local meteoric waters during the life-times of the mammals. Such data can be used for paleohydrological and paleoclimatological studies both on land and at sea.

Depth profiling of Pu, 241Am and 137Cs in soils from southern Belarus measured by ICP-MS and alpha- and gamma-spectrometry

2003

The depth distribution of plutonium, americium, and Cs-137 originating front the 1986 accident at the Chernobyl Nuclear Power Plant (NPP) was investigated in several soil profiles in the vicinity from Belarus. The vertical migration of transuranic elements in soils typical of the 30 km relocation area around Chernobyl NPP was studied using inductively coupled plasma mass spectrometry (ICP-MS), alpha spectrometry, and gamma spectrometry. Transuranic concentrations in upper soil layers ranged from 6 x 10(-12) g g(-1) to 6 x 10(-10) g g(-1) for plutonium and from 1.8 x 10(-13) g g(-1) to 1.6 x 10(-11) g g(-1) for americium. These concentrations correspond to specific activities of Pu239+240 of…

Maturation of a Key Resource – The Germanium-68/Gallium-68 Generator: Development and New Insights

2011

(68)Ge/(68)Ga radionuclide generators have been investigated for almost fifty years, since the cyclotron-independent availability of positron emitting (68)Ga via the (68)Ge/(68)Ga system had always attracted researches working in basic nuclear chemistry as well as radiopharmaceutical chemistry. However, it took decades and generations of research (and researchers) to finally reach a level of (68)Ge/(68)Ga radionuclide generator designs adequate to the modern requirements of radiometal labelling chemistry. Nevertheless, most of the existing commercial generator systems address aspects of (68)Ge breakthrough and safe synthesis of (68)Ga radiopharmaceuticals by adopting eluate post-processing …

Long-term decrease in Asian monsoon rainfall and abrupt climate change events over the past 6,700 years

2021

Significance The variability of the Asian summer monsoon (ASM) is important for the functioning of ecological and societal systems at regional to continental scales, but the long-term evolution and interannual variability of this system is not well understood. Here, we present a stable isotope–based reconstruction of ASM variability covering 4680 BCE to 2011 CE. Superimposed on a gradual drying trend, a rapid drop in mean annual precipitation (>40%) toward persistently drier conditions occurred in ∼1675 BCE. This megadrought caused regional forest deterioration and enhanced aeolian activity affecting Chinese ecosystems. We argue that this abrupt aridification starting ∼2000 BCE triggered wa…

Variazioni climatiche ed ambientali degli ultimi 10.000 anni: studio preliminare di una carota prelevata nel Golfo di Termini Imerese (Sicilia Setten…

2009

Stable isotopes in monitoring terrestrial arthropods

2022

Monitoring of arthropods focuses typically on changes in population and range size over time. Yet, there are a myriad of other aspects that could and should be monitored under the ongoing global and local environmental change. Stable isotope analysis, widely employed in short-term ecological studies, has potential in long-term monitoring of arthropods. Here we discuss the use of stable isotopes in monitoring terrestrial arthropods, provide some empirical examples of the use of bulk tissue samples in stable isotope analysis, and outline future directions in using compound-specific stable isotope analysis in monitoring. We performed a literature search for 2012–2021 to see if stable isotopes …

Simulated eutrophication and browning alters zooplankton nutritional quality and determines juvenile fish growth and survival

2018

Source at https://doi.org/10.1002/ece3.3832. The first few months of life is the most vulnerable period for fish and their optimal hatching time with zooplankton prey is favored by natural selection. Traditionally, however, prey abundance (i.e., zooplankton density) has been considered important, whereas prey nutritional composition has been largely neglected in natural settings. High‐quality zooplankton, rich in both essential amino acids (EAAs) and fatty acids (FAs), are required as starting prey to initiate development and fast juvenile growth. Prey quality is dependent on environmental conditions, and, for example, eutrophication and browning are two major factors defining primary produ…