Nikoleta Zisi

Clastic sedimentary features of beachrocks and their palaeo-environmental significance: comparison of past and modern coastal regimes

Clastic sedimentary features of beachrocks and unconsolidated deposits of parent beaches were investigated along the northern Aegean coastline (Greece) to assess their suitability in palaeo-environmental reconstruction. Twelve paired datasets were collected in the Thermaikos, Toroneos, Siggitikos and Ierissos gulfs of the Chalkidiki Peninsula, the adjoining Kavala Gulf and Thassos Island, comprising beachrock cores and companion beach subsurface sediments. Particle size analyses based on univariate and bivariate statistics suggest that, during the time period of beachrock formation, depositional conditions differed distinctly from those of the modern parent beaches. The results imply difference of maturity level of beach evolution from the time of cementation (coarser materials-early stage of beach formation) to modern situation (finer materials-reworked and ‘mature’ beach sediments). Furthermore, the findings indicate increasing coastal protection due to beachrock exposure in the modern swash zone. In conclusion, it is suggested that textural analysis of beachrocks in comparison with unconsolidated sediments of the parent beach might provide information regarding differences of coastal depositional regimes and future research could focus on specific-layer analysis and comparison.

Sugar-specific carbon isotope ratio analysis of coconut waters for authentication purposes

The application of sugar-specific carbon isotope analysis by combining high performance liquid chromatography and isotope ratio mass spectrometry is described, for investigating the detection of added C4-plant sugars in coconut waters. Authenticity of coconut waters gains more importance since the product is considered a juice by the European Fruit Juice Association (AIJN), while it holds an increasing consumer preference as healthy, low-carb beverage. The detection potential was compared with the conventional total sugar carbon isotope analysis and it is demonstrated that the isotopic profile of individual sugars substantially improves the limit of detection of added C4-plant sugars in coconut water. The study includes 30 authentic coconut waters (extracted from coconuts in the lab), which provide the authentic carbon isotope range of pulp, total sugars, sucrose, glucose and fructose, and 24 commercial coconut waters (bottled) purchased from grocery stores. The market scan revealed that 38% of the tested samples contain undeclared added C4-sugars.