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Aims

The project is based on the hypothesis that the presence, formation and the type of naturally occurring nanominerals characterize the physico-chemical state of the recent sediments and soils and govern the main biogeochemical processes that occur in these environments. The separation and structural and chemical characterization of these nanosolids shed light on the mechanisms of their formation (authigenesis), phase transformation, their geochemical and surface physico-chemical properties and the role in the cycling of inorganic and organic compounds in modern sediments and soils. The primary objectives of this project are:

  1. to identify the size, mineral composition, the morphological, geochemical and surface physico-chemical properties of the naturally occurring inorganic nanomineral fraction separated from different modern marine and lacustrine sediments of the Adriatic region and soils developed on carbonate rocks along the Adriatic coast. Accordingly, the unique structural and surface properties and the role of the nanomineral phases in the cycling of trace elements in modern sediments and soils will be determined.
  2. to determine the early diageneticaly driven formation and phase transformation of nanosized carbonate, sulfide and iron (hydr)oxide particles in modern lacrustine and marine sediments at the nanoscale. Specifically, recently reaffirmed non-classical crystal-growth mechanisms, especially the particle-mediated, nanoscale aggregation route will be studied. Namely, according to this path, submicron-sized carbonate and sulfide solids are formed through the aggregation of preformed nanosized particles.
  3. to resolve the pedogeneticaly driven formation of nanosized clay mineral and iron and manganese (hydr)oxide particles in soils at the nanoscale. The role of iron (hydr)oxides and humic materials on nanoscale agglomeration processes in soils will also be evaluated. Furthermore, the role of microbial activity in the dissolution and precipitation of metal (hydr)oxides will be studied.
  4. to elucidate the transfer of CO2 between organic (sedimentary organic matter) and inorganic (carbonate) pools in the sediment. The origin of the bulk and molecularly uncharacterized sedimentary organic matter, as well as the dissolved inorganic carbon (DIC) and carbonate, will be determined using stable isotope ratios (13C/12C and 15N/14N) as the natural tracers. Sources of DIC (carbonate dissolution vs. decomposition of sedimentary organic matter) in the pore water and in the DIC flux across the sediment–water interface, as well as in the sedimentary carbonate fraction will be chosen, so as to estimate the contribution of organically derived CO2 to the formation of authigenic nanocarbonate solids (cements). This will further allow an indirect estimation of the capacity of the sediment system for the fixation of CO2 in sedimentary organic and inorganic carbon pools.
  5. to introduce and incorporate the findings from “NanoMin” into the domain of Croatian and international geosciences.

The results of this project will address a number of issues that are important to the modern geochemistry (nanogeochemistry), particularly to the authigenic formation of nanominerals, their structural and surface properties and processes at the nanoscale, and finally, to their role in transport of trace elements and organics in modern sediments and soils. A shift of the research boundaries to the nanometre scale will shed light on the complex nanoprocesses in geochemistry.

NAVIGATION