Sediment Dynamics of the Neretva Channel (Croatia Coast) Inferred by Chemical and Physical Proxies

Abstract

We examined the transport of sediments and their surficial pathways from the mouth of Neretva River, through the Neretva Channel, toward the Adriatic Sea. This research was based on twelve box-cores and five grab samples collected within the Neretva Channel. Sediment dynamics were evaluated using several proxies, such as organic matter, radiochemical isotopes and select metal concentrations and physical parameters. The data analysis showed that the influence of the river on particle distribution along the Neretva Channel decreases northward, with an estimated sediment accumulation rate ranging from 1.9 to 8.5 mm/yr. The lowest accumulation rate was found in the sector not influenced by river inflow, whereas the preferential sediment accumulation area is in the center of the basin. We speculate that dispersion and accumulation of sediments are both driven by an eddy in the waters of the Neretva Channel triggered/or intensified seasonally by the interaction of karstic springs, river input and Adriatic Sea waters. Our results indicate that the anthropogenic factor does not affect the concentration of metals within the channel and that the river particles dynamics determine the Pb areal distribution, while Cr and Ni have a possible source located to the northwest of the river-mouth.