First evidence of testate amoebae in Lago fagnano (54\ub0S), Tierra del Fuego (Argentina): Proxies to reconstruct environmental changes

We report here the first findings of testate amoebae at high southern latitudes (54 S) from four gravity cores recovered in the Lago Fagnano (Tierra del Fuego, Argentina), where twelve taxa have been recognized. Among them, Centropyxis constricta \u201cconstricta\u201d, Centropyxis elongata, Difflugia globulus, Difflugia oblonga \u201coblonga\u201d, and Difflugia protaeiformis \u201camphoralis\u201d are always present, while other taxa are randomly distributed. According to the sand/silt ratio in the different cores, the Total Organic Carbon content and the Carbon/Nitrogen ratio, as well as the presence/disappearance and abundance of testate amoebae from cluster analysis, we infer a correlation between major textural/granulometrical changes found in the cores and environmental changes. A seismic event occurred on 1949, which substantially modified the morphology of the eastern Lago Fagnano shoreline and the supply pattern from two main eastern tributaries of the lake, is recorded in the studied cores. This event has in part modified the distribution of testate amoebae taxa within the studied cores. Present results show that testate amoebae represent important indicators to detect changes occurring in the environment in which they live

Opažanja u obalnom području u okviru ADRICOSM projekta: Tršćanski zaljev

In the framework of the ADRICOSM project, from October 2002 to September 2003, a coastal observing system network was set up in the Gulf of Trieste. During this period, 36 CTD cruises were performed over a grid of 19 stations. An accurate data acquisition and quality check protocol was implemented for data decimation and smoothing. However, data analysis showed that conductivity/ salinity spikes were recorded at the depth of the very sharp thermocline observed in summer 2003. The exceptionally high salinity waters and the marked thermocline observed in the Gulf of Trieste in spring and summer 2003 directed us to compare the distributions of the temperature and salinity fields observed during ADRICOSM cruises with the available climatological values of the Gulf of Trieste, in order to assess whether the data collected during this research deviated significantly from the climatology.U okviru projekta ADRICOSM, od listopada 2002. do rujna 2003. godine, provedeno je 36 krstarenja tijekom kojih se uzorkovalo CTD sondom na 19 postaja u Tršćanskom zaljevu. Posebna pažnja je posvećena kvaliteti podataka. Tijekom ljeta 2003. godine opaženi su nagli skokovi vrijednosti saliniteta i gustoće (tzv. “spikes”) u području izražene termokline. U proljeće i ljeto 2003. godine vrijednosti saliniteta bile su izrazito visoke. Polja temperature i saliniteta određena za to razdoblje uspoređena su s postojećim podacima ne bi li se utvrdilo koliko odstupaju od prosjeka