We worked on samples from several peatlands and several seagrass meadows from Spain. Studying the palaeoecology of peatlands throughout the analysis of peat cores, we aimed to understand the long-term dynamics of terrestrial carbon sinks, while through analysing P. oceanica mat cores from seagrass meadows we wanted to do the same for marine carbon sinks.
In the case of peatlands, we selected two peat cores from north-western Spain covering most of the Holocene for which the host laboratory at the USC already had palynological and geochemical results, as well as chronological frameworks thanks to age-depth models. We complemented the available proxy records with new analyses of non-biological indicators that have been fundamental for the training of the fellow: colorimetry of solids and FTIR-ATR spectroscopy. The two peatlands comprised a bog and a fen, so two different types of peatlands with diverse hydrological dynamics and carbon contents. The results highlight the importance of analysing not only the elemental composition of the peat organic matter, but also its molecular composition. In this way, we can obtain both an overview of the total carbon accumulated and also information on the potential loss of carbon owing to mineralisation (as a function of the proportion of labile components of the organic matter). In addition, analysing the colour of the peat in a quantitative manner allowed us to link colour and organic matter content. This is important as a first, fast and inexpensive screening of large sets of samples in order to plan further analyses.
In the case of the seagrass meadows, we selected five P. oceanica mat cores form two bays at Cabrera Island (Balearic Islands) covering the last two millennia, in collaboration with the partner organisation CEAB-CSIC. We have performed magnetic susceptibility, charcoal and palynological analyses on the seagrass mat samples. Magnetic susceptibility analyses were performed in the five cores, showing a synchronous trend of increasing values during the last centuries. Palynological and charcoal analyses are still in progress, and preliminary data suggest that charcoal records show the same trend than magnetic susceptibility and that terrestrial pollen records agree with larger human impact on the terrestrial landscape during the last centuries. Finally, we have obtained, for the first time in seagrass cores, dinoflagellate cysts (dinocysts) records. Our preliminary dinocysts results allowed supporting a study of fossil pigments on the same cores published in collaboration with the CEAB-CSIC. In this study we demonstrated that fossil pigments can be used to reconstruct algal communities in seagrass meadows and how these communities were affected by local and global environmental factors.
Several activities have been done to disseminate and communicate parts of the action to academic and non-academic beneficiaries. First, a journal paper has been published so far while further manuscripts will be sent to journals in the future once the proxy analyses are completed and the numerical analyses performed. Second, the fellow was invited as speaker in a conference organised at the USC for master students in which she presented the importance of palynological analyses. Third, the fellow was invited in a workshop for the general public as an expert in the study of botanical remains from archives. Finally, during the duration of the project, the fellow engaged in activities such as teaching undergraduate and master students, supervising dissertations, and grant writing; valuable resources towards a fruitful career as independent researcher.
