Life Science Mass Spectrometry Facility
Stable isotopes are most often utilised in ecological studies to elucidate trophic relationships within food webs, and indeed this is the most common request we receive. Nitrogen and carbon isotope ratios are the most useful for this type of study: the ratio of 15N to 14N (ɗ 15N) increases with each trophic level, whereas the effect on ɗ 13C is much less pronounced and reflects more the source of carbon, and hence is used to discriminate between different biomes. Thus we have received pertinent proposals to investigate the foodwebs and carbon flow in fluvial, estuarine, and offshore and deep-sea marine environments. Such studies may attempt to answer broad questions about an entire foodweb, or may try to explain dietary differences at species level.
There is growing interest in the use of stable isotope ratios to elucidate migration pathways. We have had one successful proposal to look at the carbon and oxygen isotopes in fish otoliths ("ear-stones") to investigate the importance of mangroves as fish nurseries (and hence follow the migration from estuarine to the open-sea environment). Another proposal has investigated the migration of sperm whales using the carbon and nitrogen isotope ratios in their teeth. Over the past few years we have also seen an explosion in the number of ornithologists wanting to use hydrogen isotope ratios in feather keratin to map the migration routes of birds. Hydrogen isotope ratios broadly reflect the ɗ 2H of the local precipitation, hence this can be a powerful tool to source where feathers are moulted. Furthermore, this involves non-destructive sampling, and for further clarification, other isotope systems can also be used on the same feather. More recently this methodology has been extended to investigate the migration of bats.
The examples above all involve natural abundance isotope ratios. We also offer the analysis of 13C-labelled samples. 13C can be used to investigate biogeochemical cycling in environments which are otherwise difficult to assess, e.g. the deep ocean floor.
Our commitment to training and our keenness to introduce new technologies to stable isotope ecology is reflected in the LSMSF's high scores in previous Service Reviews. We will therefore continue this winning approach to support the UK science community.
Also, check out our blog for current projects
The linked projects listed below typify research undertaken by the UK scientific community using the Life Sciences Mass Spectrometry Facility (see also the Facility publication list and the 6th IsoEcol conference):