Stables Isotopes

1. The structure of food webs provides important insight into biodiversity, organic matter (OM) pathways, and ecosystem functioning. 2. Stable isotope analysis (δ 13 C and δ 15 N) was used to characterize the trophic structure and the main OM pathways supporting food webs in the Rapa Nui

Isotopic proxies have been employed within archaeological research since decades; however, their use has surged in recent years. Together with the increase in the number of published case studies, there have also been significant technical developments that improved greatly on available analytical techniques. Throughout the years, the introduction of novel isotopic proxies refined and expanded the existing knowledge on past environments and human activities. Such developments allowed for and were motivated by a growth of archaeological research topics. These have included, among others, climatic and environmental reconstruction, studies of past human diet, nutrition, and mobility, building accurate chronologies, past animal and crop management practices, pottery use, etc. Thus, an attempt at offering a complete overview of the applications and methodologies involved in isotopic analyses applied to archaeological research would represent an undertaking well beyond the limited scope of this special issue. Instead, this issue is aimed at highlighting a selection of special themes that represent a mix of well-established and recent topics within isotopic studies applied to archaeological research.

— The arid and semi-arid regions constitute roughly one third of the total earth's surface. In these regions water scarcity is one of the main limiting factors for economic growth. The impact of such water scarcity is amplified by inefficient irrigation practices, especially since about 85% of available water is used for irrigation in these regions. Therefore, a sound and efficient irrigation practice is an important step for achieving sustainable management of water resources in these regions. In this regard, a better understanding of the water balance is essential to explore water-saving techniques. In the context CRP project, experimental setups were conceived to monitor seasonal water consumption on the wheat crop irrigated by flood irrigation in Sidi Rahal station (middle of morocco. The partitioning of evapotranspiration compounds shows that transpiration dominates the evaporation about 68 % for three days (22, 23 and 24 February 2012). In addition the wheat absorbs the soil water from 10 cm to 20 cm (90%) at this growing stage according to the multiple-source mass balance assessment.