Orchids are one of the most widely distributed plant families. However, current research on the ecophysiology of terrestrial orchids is biased towards temperate species. Thus, it is currently unknown whether tropical terrestrial orchids belong to similar trophic guilds as their temperate relatives. To examine the ecophysiologies of two tropical terrestrial orchids, I analysed the carbon and nit...

High precision measurements of molecules containing more than one heavy isotope may provide novel constraints on element cycles in nature. These so-called clumped isotope signatures are reported relative to the random (stochastic) distribution of heavy isotopes over all available isotopocules of a molecule, which is the conventional reference. When multiple indistinguishable atoms of the same e...

Isotopic compositions of reactants affect the rates of chemical and biochemical reactions. Usually it is assumed that heavy stable isotope enrichment leads to progressively slower reactions. Yet the effect of stable isotopes may be nonlinear, as exemplified by the "isotopic resonance" phenomenon. Since the isotopic compositions of other planets of Solar system, including Mars and Venus, are mar...

[1] Longitudinal and diel measurements of dual isotope composition (dN and dO) in nitrate (NO3-N) were made in the Ichetucknee River, a large ( 8 m s ), entirely spring-fed river in North Florida, to determine whether isotopic variation can deconvolve assimilatory and dissimilatory removal. Comparing nitrate concentrations and isotope composition during the day and night we predicted (1) daytim...

The marine record of ocean lithium isotope composition may provide important information constraining the factors that control continental weathering and how they have varied in the past. However, the equations establishing links between the continental flux of Li to the ocean, the continental Li isotope composition and the ocean Li isotope composition are under-constrained, and their resolutio...

Bacteria grow and transform elements at different rates, and as yet, quantifying this variation in the environment is difficult. Determining isotope enrichment with fine taxonomic resolution after exposure to isotope tracers could help, but there are few suitable techniques. We propose a modification to stable isotope probing (SIP) that enables the isotopic composition of DNA from individual ba...

Isotope composition, in many cases, holds unique information on the sources, chemical modification and sinks of atmospheric trace gases. Vital to the interpretation and use of an increasing number of isotope analyses is appropriate modelling. However, the exact implementation of isotopic information in chemistry-climate models is a challenge, and often studies use simplifications which limit th...

Stable isotopes (Deuterium and Oxygen-18) have a broad application in many of water related sciences. Precipitation is the most important input to the water cycle which shows considrable spatial and temporal variability in its isotope content. To study the precipitation isotope content, 51 samples from August 2015 to July 2016 have been collected mainly on a monthly basis with few events based ...

[1] Recently, calcium isotope fractionation in the coccolithophore Emiliania huxleyi was shown to exhibit a significant temperature dependency. An important subsequent question in this context is whether the observed fractionation patterns are caused by temperature itself or related growth rate changes. In order to separate growth and calcification rate effects from direct temperature effects, ...

Introduction: We have recently characterized the mineralogy and petrography of ~ 100 CAIs from ~20 R chondrites [1]. Here we report O-isotope compositions of ten R CAIs and Mg-isotope composition of three hibonite-bearing CAIs: H030