Teleost and elasmobranch eye lenses as a target for life-history stable isotope analyses.

Incrementally grown, metabolically inert tissues such as fish otoliths provide biochemical records that can used to infer behavior and physiology throughout the lifetime of the individual. Organic tissues are particularly useful as the stable isotope composition of the organic component can provide information about diet, trophic level and location. Unfortunately, inert, incrementally grown organic tissues are relatively uncommon.

Rapid recovery of life at ground zero of the end-Cretaceous mass extinction.

The Cretaceous/Palaeogene mass extinction eradicated 76% of species on Earth. It was caused by the impact of an asteroid on the Yucatán carbonate platform in the southern Gulf of Mexico 66 million years ago , forming the Chicxulub impact crater. After the mass extinction, the recovery of the global marine ecosystem-measured as primary productivity-was geographically heterogeneous ; export production in the Gulf of Mexico and North Atlantic-western Tethys was slower than in most other regions, taking 300 thousand years (kyr) to return to levels similar to those of the Late Cretaceous period.

Chronology of martian breccia NWA 7034 and the formation of the martian crustal dichotomy.

Martian meteorite Northwest Africa (NWA) 7034 and its paired stones are the only brecciated regolith samples from Mars with compositions that are representative of the average martian crust. These samples therefore provide a unique opportunity to constrain the processes of metamorphism and alteration in the martian crust, which we have investigated via U-Pu/Xe, Ar/Ar, and U-Th-Sm/He chronometry. U-Pu/Xe ages are comparable to previously reported Sm-Nd and U-Pb ages obtained from NWA 7034 and confirm an ancient (>4.

Measurement of protein digestibility in humans by a dual-tracer method.

Background: Recent evaluations of the risk of dietary protein deficiency have indicated that protein digestibility may be a key limiting factor in the provision of indispensable amino acids (IAAs), particularly for vulnerable populations living in challenging environments where intestinal dysfunction may exist. Since the digestion of protein occurs only in the small intestine, and the metabolic activity of colonic bacteria confounds measurements at the fecal level, there is a need to develop noninvasive protein digestibility measurements at the ileal level.

Objective: We used a dual-tracer method with stable isotopes to characterize the digestibility of uniformly labeled [13C]-spirulina protein as a standard protein, in comparison to a mixture of 2H-labeled crystalline amino acids, and then demonstrated the use of this standard protein to measure the digestibility of selected legumes (chick pea and mung bean) through the use of proteins that were intrinsically labeled with 2H.

Macronutrient and carbon supply, uptake and cycling across the Antarctic Peninsula shelf during summer.

The West Antarctic Peninsula shelf is a region of high seasonal primary production which supports a large and productive food web, where macronutrients and inorganic carbon are sourced primarily from intrusions of warm saline Circumpolar Deep Water. We examined the cross-shelf modification of this water mass during mid-summer 2015 to understand the supply of nutrients and carbon to the productive surface ocean, and their subsequent uptake and cycling. We show that nitrate, phosphate, silicic acid and inorganic carbon are progressively enriched in subsurface waters across the shelf, contrary to cross-shelf reductions in heat, salinity and density.

Dietary divergence is associated with increased intra-specific competition in a marine predator.

Optimal foraging theory predicts that when food is plentiful all individuals should take a small range of preferred prey types, but as competition increases less preferred prey will be included in the diet. This dietary switching may not be uniform among individuals, which produces discrete dietary clusters. We tested this hypothesis for gentoo penguins at Bird Island, South Georgia, using stable isotope analysis and biologging.

The resilience of postglacial hunter-gatherers to abrupt climate change.

Understanding the resilience of early societies to climate change is an essential part of exploring the environmental sensitivity of human populations. There is significant interest in the role of abrupt climate events as a driver of early Holocene human activity, but there are very few well-dated records directly compared with local climate archives. Here, we present evidence from the internationally important Mesolithic site of Star Carr showing occupation during the early Holocene, which is directly compared with a high-resolution palaeoclimate record from neighbouring lake beds.

Collision activity during training increases total energy expenditure measured via doubly labelled water.

Purpose: Collision sports are characterised by frequent high-intensity collisions that induce substantial muscle damage, potentially increasing the energetic cost of recovery. Therefore, this study investigated the energetic cost of collision-based activity for the first time across any sport.

Methods: Using a randomised crossover design, six professional young male rugby league players completed two different 5-day pre-season training microcycles.

The Beaker phenomenon and the genomic transformation of northwest Europe.

From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts.

Energy expenditure of rugby players during a 14-day in-season period, measured using doubly labelled water.

Criterion data for total energy expenditure (TEE) in elite rugby are lacking, which prediction equations may not reflect accurately. This study quantified TEE of 27 elite male rugby league (RL) and rugby union (RU) players (U16, U20, U24 age groups) during a 14-day in-season period using doubly labelled water (DLW). Measured TEE was also compared to estimated, using prediction equations.

Carbohydrate dose influences liver and muscle glycogen oxidation and performance during prolonged exercise.

This study investigated the effect of carbohydrate (CHO) dose and composition on fuel selection during exercise, specifically exogenous and endogenous (liver and muscle) CHO oxidation. Ten trained males cycled in a double-blind randomized order on 5 occasions at 77% V˙O2max for 2 h, followed by a 30-min time-trial (TT) while ingesting either 60 g·h (LG) or 75 g·h C-glucose (HG), 90 g·h (LGF) or 112.5 g·h C-glucose- C-fructose ([2:1] HGF) or placebo.

Tectonically-triggered sediment and carbon export to the Hadal zone.

Sediments in deep ocean trenches may contain crucial information on past earthquake history and constitute important sites of carbon burial. Here we present C data on bulk organic carbon (OC) and its thermal decomposition fractions produced by ramped pyrolysis/oxidation for a core retrieved from the >7.5 km-deep Japan Trench.

Environmental differences between sites control the diet and nutrition of the carnivorous plant .

Background And Aims: Carnivorous plants are sensitive to small changes in resource availability, but few previous studies have examined how differences in nutrient and prey availability affect investment in and the benefit of carnivory. We studied the impact of site-level differences in resource availability on ecophysiological traits of carnivory for L.

Methods: We measured prey availability, investment in carnivory (leaf stickiness), prey capture and diet of plants growing in two bogs with differences in N deposition and plant available N: Cors Fochno (0.

Determination of chlorpropham (CIPC) residues, in the concrete flooring of potato stores, using quantitative (HPLC UV/VIS) and qualitative (GCMS) methods.

Isopropyl-N-(3-chlorophenyl) carbamate (CIPC, common name Chlorpropham) is commonly used for post-harvest sprout inhibition in stored potatoes. It is applied as a thermal fog which results in loss to the fabric of the store and the atmosphere. Recently, there have been concerns in the United Kingdom because of cross contamination of other crop commodities that were stored in buildings with a history of CIPC usage.

Counter-intuitive influence of Himalayan river morphodynamics on Indus Civilisation urban settlements.

Urbanism in the Bronze-age Indus Civilisation (~4.6-3.9 thousand years before the present, ka) has been linked to water resources provided by large Himalayan river systems, although the largest concentrations of urban-scale Indus settlements are located far from extant Himalayan rivers.

Acute oral sodium propionate supplementation raises resting energy expenditure and lipid oxidation in fasted humans.

Short-chain fatty acids (SCFAs), produced from fermentation of dietary fibre by the gut microbiota, have been suggested to modulate energy metabolism. Previous work using rodent models has demonstrated that oral supplementation of the SCFA propionate raises resting energy expenditure (REE) by promoting lipid oxidation. The objective of the present study was to investigate the effects of oral sodium propionate on REE and substrate metabolism in humans.

Local variance of atmospheric C concentrations around Fukushima Dai-ichi Nuclear Power Plant from 2010 to 2012.

Radiocarbon (C) has been measured in single tree ring samples collected from the southwest of the Fukushima Dai-ichi Nuclear Power Plant. Our data indicate south-westwards dispersion of radiocarbon and the highest C activity observed so far in the local environment during the 2011 accident. The abnormally high C activity in the late wood of 2011 ring may imply an unknown source of radiocarbon nearby after the accident.

Assessment of the calibration of gamma spectrometry systems in forest environments.

A Monte Carlo simulation was used to develop a model of the response of a portable gamma spectrometry system in forest environments. This model was used to evaluate any corrections needed to measurements of Cs activity per unit area calibrated assuming an open field geometry. These were shown to be less than 20% for most forest environments.

Journey to the east: Diverse routes and variable flowering times for wheat and barley en route to prehistoric China.

Today, farmers in many regions of eastern Asia sow their barley grains in the spring and harvest them in the autumn of the same year (spring barley). However, when it was first domesticated in southwest Asia, barley was grown between the autumn and subsequent spring (winter barley), to complete their life cycles before the summer drought. The question of when the eastern barley shifted from the original winter habit to flexible growing schedules is of significance in terms of understanding its spread.

Kleptopredation: a mechanism to facilitate planktivory in a benthic mollusc.

Predation occurs when an organism completely or partially consumes its prey. Partial consumption is typical of herbivores but is also common in some marine microbenthic carnivores that feed on colonial organisms. Associations between nudibranch molluscs and colonial hydroids have long been assumed to be simple predator-prey relationships.

What on Earth Have We Been Burning? Deciphering Sedimentary Records of Pyrogenic Carbon.

Humans have interacted with fire for thousands of years, yet the utilization of fossil fuels marked the beginning of a new era. Ubiquitous in the environment, pyrogenic carbon (PyC) arises from incomplete combustion of biomass and fossil fuels, forming a continuum of condensed aromatic structures. Here, we develop and evaluate C records for two complementary PyC molecular markers, benzene polycarboxylic acids (BPCAs) and polycyclic aromatic hydrocarbons (PAHs), preserved in aquatic sediments from a suburban and a remote catchment in the United States (U.

Taking the pulse of Mars via dating of a plume-fed volcano.

Mars hosts the solar system's largest volcanoes. Although their size and impact crater density indicate continued activity over billions of years, their formation rates are poorly understood. Here we quantify the growth rate of a Martian volcano by Ar/Ar and cosmogenic exposure dating of six nakhlites, meteorites that were ejected from Mars by a single impact event at 10.

Rapid global ocean-atmosphere response to Southern Ocean freshening during the last glacial.

Contrasting Greenland and Antarctic temperatures during the last glacial period (115,000 to 11,650 years ago) are thought to have been driven by imbalances in the rates of formation of North Atlantic and Antarctic Deep Water (the 'bipolar seesaw'). Here we exploit a bidecadally resolved C data set obtained from New Zealand kauri (Agathis australis) to undertake high-precision alignment of key climate data sets spanning iceberg-rafted debris event Heinrich 3 and Greenland Interstadial (GI) 5.1 in the North Atlantic (~30,400 to 28,400 years ago).

Carbon sequestration potential and physicochemical properties differ between wildfire charcoals and slow-pyrolysis biochars.

Pyrogenic carbon (PyC), produced naturally (wildfire charcoal) and anthropogenically (biochar), is extensively studied due to its importance in several disciplines, including global climate dynamics, agronomy and paleosciences. Charcoal and biochar are commonly used as analogues for each other to infer respective carbon sequestration potentials, production conditions, and environmental roles and fates. The direct comparability of corresponding natural and anthropogenic PyC, however, has never been tested.