CODAMAT: a modern analogue techinque for compositional data

The quantitative estimation of Sea Surface Temperatures from fossils assemblages is a fundamental issue in palaeoclimatic and paleooceanographic investigations. The Modern Analogue Technique, a widely adopted method based on direct comparison of fossil assemblages with modern coretop samples, was revised with the aim of conforming it to compositional data analysis. The new CODAMAT method was developed by adopting the Aitchison metric as distance measure. Modern coretop datasets are characterised by a large amount of zeros. The zero replacement was carried out by adopting a Bayesian approach to the zero replacement, based on a posterior estimation of the parameter of the multinomial distribution. The number of modern analogues from which reconstructing the SST was determined by means of a multiple approach by considering the Proxies correlation matrix, Standardized Residual Sum of Squares and Mean Squared Distance. This new CODAMAT method was applied to the planktonic foraminiferal assemblages of a core recovered in the Tyrrhenian Sea. Kew words: Modern analogues, Aitchison distance, Proxies correlation matrix, Standardized Residual Sum of Squares

Vegetative and reproductive morphology of Kallymenia patens (Kallymeniaceae, Rhodophyta) in the Mediterranean Sea

Reproductive morphology of the Mediterranean red alga Kallymenia patens is described for the first time, confirming its position in the genus. K. patens is characterized by a non-procarpic female reproductive apparatus, carpogonial branch systems consisting of supporting cells bearing both three-celled carpogonial branches and subsidiary cells that lack a hypogynous cell and carpogonium; fusion cells develop numerous connecting filaments, and tetrasporangia are scattered over the thallus and are probably cruciately divided. Old fertile spathulate specimens of K. patens are morphologically similar to K. spathulata, but they can be distinguished by the length of spathulated proliferations (up to 0.6 cm and 6 cm, respectively), the length of inner cortical cells (up to 70 and 30 μm, respectively), and the gonimoblast location (in proliferations from the perennial part of the blade and over all the thallus surface, respectively)

Cystoseira-dominated assemblages from sheltered areas in the Mediterranean sea : diversity, distribution and effects of pollution

Les algues del gènere Cystoseira són els principals organismes formadors d'estructura en fons rocosos ben il·luminats del Mar Mediterrani. Formen unes comunitats molt estructurades que s'assemblen ecològicament als boscos terrestres i que són sensibles als impactes antròpics. Aquesta tesi s'ha centrat en l'estudi de les espècies i comunitats dominades per Cystoseira que es troben en ambients calmats, és a dir, en petites cales i/o badies. S'han abordat diversos aspectes com són la distribució, composició, estructura i biogeografia d'aquestes comunitats, així com els efectes de la contaminació sobre les mateixes. Per una banda, s'ha documentat l'estat actual de les comunitats dominades per C. crinita a nombrosos llocs al llarg de tot el Mediterrani, aportant informació sobre la seva composició, estructura, variació biogeogràfica i dinàmica de la comunitat a llarg termini. S'ha documentat la desaparició de diverses espècies de Cystoseira en zones afectades per impactes antròpics diversos i s'ha proporcionat la primera evidència experimental de la desaparició d'espècies de Cystoseira a causa de la contaminació.