Document Type
Journal Article
Publication Title
Global and Planetary Change
Publisher
Elsevier
School
School of Science
RAS ID
27694
Funders
Australian Research Council
Grant Number
ARC Number : DE170101524
Abstract
Posidonia oceanica is a marine phanerogam that buries a significant part of its belowground production forming an organic bioconstruction known as mat. Despite Posidonia seagrass mats have proven to be reliable archives of long-term environmental change, palaeoecological studies using seagrass archives are still scarce. Here we reconstruct four millennia of environmental dynamics in the NE coast of Spain by analysing the carbon and nitrogen stable isotopic composition of P. oceanica sheaths, the proportion of different seagrass organs throughout the seagrass mat and other sedimentological proxies. The palaeoenvironmental reconstruction informs on long-term ecosystem productivity and nutrient loading, which have been linked to global (e.g., solar radiation) and local (e.g., land-use changes) factors. The long-term environmental records obtained are compared with previous palaeoecological records obtained for the area, showing a common environmental history. First, a relative seagrass ecosystem stability at ~ 4000 and 2000 cal. yr BP. Then, after a productivity peak at ~ 1400 – 800 cal. yr BP, productivity shows an abrupt decline to unprecedented low values. The fluctuations in ecosystem productivity are likely explained by increases in nutrient inputs related to human activities – mostly in the bay watershed – concomitantly with changes in total solar radiation. Cumulative anthropogenic stressors after Roman times may have started to affect ecosystem resilience, dynamics and productivity, with more abrupt regime shifts during the last millennium. These results add into recent research showing the potential of seagrass archives in reconstructing environmental change and seagrass post-disturbance dynamics, hence providing unvaluable information for improving the efficiency in managing these key coastal ecosystems.
DOI
10.1016/j.gloplacha.2018.07.011
Comments
This is the Author's Accepted Manuscript of: Leiva-Dueñas, C., López-Merino, L., Serrano, O., Cortizas, A. M., & Mateo, M. A. (2018). Millennial-scale trends and controls in Posidonia oceanica (L. Delile) ecosystem productivity. Global and Planetary Change. 169(October), 92-104.
https://doi.org/10.1016/j.gloplacha.2018.07.011