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Electrochemical measurements of microparticles in seawater samples taken in the Gulf of Trieste (northern Adriatic Sea)

Summer periods of dense marine snow aggregates have been observed more frequently in recent years in the northern Adriatic. Several hypothesis have been proposed to explain the process and to understand the origin and pathway of the formation of the marine snow and the mucus aggregates. Current views leave no doubt on phytoplankton production and bacterial transformation of the main constituents of the gel matrix. Although the term "gel" has frequently been used to describe the appearance of newly discovered marine particles such as transparent exopolymeric particles, TEPs, the particles were not approached as a gel state of matter experimentally or conceptually. In our study the electrochemical detection of marine gel microparticles using the dropping mercury electrode (DME) as a sensor were used to detect surface-active microparticles. Electrochemical adhesion sensor enable direct and simple recording of reactive microparticles and to follow the transition to the gel phase in seawater. The monitoring of basic chemical and biological parameters, surface-active particles and transparent exopolymeric particles were performed at the stations in the eastern part of the Gulf of Trieste (northern Adriatic). The average abundance of surface-active microparticles was 1-2 x 106/l, while the maximum value up to 3x107/l was measured in macroaggregates. Preliminary results of the abundance of surface-active microparticles showed a correlation with the abundance of alcian blue staining transparent exopolymeric particles (TEP), yellow stained DAPI particles and bacterial abundance.

exopolymeric particles; eleectrochemical particle detection; alcian blue staining; macroaggregates; Northern Adriatic

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