Critical Processes of Trace Metals Mobility in Transitional Waters: Implications from the Remote, Antinioti Lagoon, Corfu Island, Greece

Abstract

The Antinioti Lagoon is a karstified, rather pristine, and shallow coastal lagoon located in the northern part of Corfu Island in NW Greece. The present study examines the levels of metals (Al, Fe, Mn, Cd, Cu, Pb, and Zn) in the dissolved and particulate phase, as well as in surface and core sediments, and identifies the critical processes that define their behavior. The major transport pathway of dissolved Mn, Cd, and Pb, and particulate Mn, Cd, and Zn into the lagoon is through freshwater springs, whereas surface runoff dominates the transport of particulate Al, Fe, and Cu. Interestingly, large particles (>8 μm) contain higher amounts of Al, Fe and Mn than the finer ones (<8 μm), due to flocculation of oxyhydroxides that, eventually, scavenge other metals, as well. Cadmium and Zn bound to the large particles were found to be less prone to desorption than the smaller ones and were effectively captured within the lagoon. In the sediments, diagenetic processes are responsible for post-depositional changes in the forms of metals (particularly Fe, Mn and Cd). Enrichment factors (EFs) based on local background showed that sediments are enriched in restricted areas in Cd and Pb by maximum factors 4.8 and 10, respectively. These metals were predominantly found in potentially labile forms. Thus, any interventions introducing changes in the physico-chemical conditions may result in the release of metals, with negative implications on the lagoon’s ecological quality.

Marine Sediments: Processes, Transport and Environmental Aspects

“…Botsou et al [12] analyzed the aspects related to metals' mobility in the water column, focusing their attention on Antinioti Lagoon and Corfu Island. In particular, they investigated the processes responsible for the mobility of metals both in and beyond the transitional fresh-saline water interface.…”

“…The issue collected five papers that cover different aspects of coastal and ocean engineering, chemical oceanography, geology, and geomorphology using different approaches and instruments. Some of the studies used numerical models [10,11], others acquired and analyzed field data regarding chemical [12] or geomorphological aspects of the ocean [13] while Lisi et al [14] suggested a mathematical modeling framework to analyze the effects of sediment handling operations.…”

Transboundary Transitional Waters: Arenas for Cross-Border Cooperation or Confrontation?

“…The ever-increasing attention paid by researchers from diverse research fields to TW is primarily related to the inclusion of TW into the regulations imposed by the WFD on the EU Member States with regard to a good ecological status, its criteria, and its indicators [15]. The majority of papers on these issues have been published by authors from Mediterranean countries, i.e., Italy [16][17][18], Greece [19][20][21], and Spain [22][23][24] in particular. The investigated and assessed good ecological status indicators range from invertebrates [25][26][27] to fish [28][29][30] and aquatic macrophytes [31][32][33].…”

Exchangeable form of potentially toxic elements in floodplain soils along the river-marine systems of Southern Russia

“…Deltas of large rivers and adjacent coastal areas are transitional environments, where parameters of the media and element mobility change significantly at rather short distances, and interactions between fluvial and marine processes significantly affect their geochemistry (Dada et al, 2016;Botsou et al, 2019). Chemical and physical gradients typical for such systems lead to the partial removal of both suspended and dissolved matter, which sequentially results in the formation of barrier zones (Chen et al, 2020;Savenko and Pokrovsky, 2020).…”