Monitoring climate change induced desertification of Antarctica using stable isotopic signatures - species list

Metadata record for data from AAS (ASAC) project 3219.Public SummaryWe will use mosses to investigate the changing climate in Antarctica and the implications this has for terrestrial biodiversity. Mosses grow incrementally from the tip, thus shoot sections contain a record of atmospheric carbon corresponding to each growing season, in a similar fashion to tree rings. This method has been used to age East Antarctic mosses and indicates that some individuals are more than 60 years old. Analysing stable isotopes of carbon and oxygen in cell walls tells us how climate has changed around these mosses over time and allows us to determine which sites are drying and becoming inhospitable.Project ObjectivesOur hypothesis is that the carbon and oxygen isotope composition of bryophytes can be used as a proxy for desertification, inundation and precipitation regimes in Antarctica.We will determine whether stable isotopes of carbon and oxygen in plant tissues can be used as a surrogate for changes in effective growing season by determining whether they provide an accurate record of water availability to moss beds through time. To do this we will:1) determine if long term water availability is accurately recorded in cell wall delta13C and delta18O signatures of moss, and if2) short term, within/between season changes in moss submergence are reflected in the delta13C of sugars. In addition we will3) measure instantaneous fractionation of carbon isotopes during photosynthesis in moss under different water availabilities.Taken from the 2010-2011 Progress ReportProgress against objectives:Moss, snow and water samples for Objectives 1 and 3 were collected in February 2011. These were from ASPA136 (Stevenson's Cove and a ridge site near Whitney Pt), on Bailey Peninsula (ASPA135, Science and Red Shed locations) and from Robinson RidgeThese samples have all been identified.Objective 2 requires a longer season and was not possible in the time available at Casey.Laboratory activity/analysis:These samples have all been identified at WollongongStable isotope analysis is planned for September-October 2011 in Vienna (Bramley-Alves and Robinson).An experiment to investigate the fractionation of mosses under different water availabilities is planned with some of the samples that were collected and transferred to ANU (Bramley-Alves, Robinson and Ball).Jess Bramley-Alves has applied for a 2011 AINSE Postgraduate Research Award, which would provide research funding and access to radiocarbon dating facilities at ANSTO. This will allow us to date the samples and track stable isotope changes over time.Transplant experiment will be conducted and additional samples will be collected in 2011/12These will be analysed in 2012.Progress to date is excellent given the short season at Casey.