Seasonal Fluctuations of Trace Elements from Different Habitats of Orbetello Lagoon (Thyrrenian Sea, Italy)

Abstract

This study evaluated seasonal fluctuations of trace elements of major ecotoxicological concern in sediments and their uptakes by the aquatic vegetation indifferent undisturbed habitats from the Orbetello lagoon, correlating measured levels to abiotic and biotic drivers to scale the significant of their effect on observed seasonal variability of trace elements. Results show that under natural undisturbed conditions, observed seasonal fluctuations in different habitats are statistically correlated to temperature, salinity, and turbidity of water and total nutrients in sediments. These variables and the habitat type dominated by macroalgae (C. linum) play a significant role as drivers of variability for measured trace elements in sediments. This study represents a reference undisturbed condition of natural seasonal trends of trace elements in different habitat types before the occurrence of numerous impacting activities on sediments and could represent a useful baseline for further management evaluations after the occurrence of sediment disturbance actions planned for the near future.

Production of methylmercury by sulphate-reducing bacteria in sediments from the orbetello lagoon in presence of high macroalgal loads

“…The study area was the Orbetello Lagoon (Italy; Figure 1, Table S1), located in Tuscany, west coast of Italy (42° 26′ 34′' N, 11° 13′ 29′' E). The lagoon covers an area of ~ 2,300 ha with average water depth of ~ 1 m. The Orbetello lagoon was selected as perfect study area for our purposes due to the large scientific knowledge developed on natural and human pressures by scientific studies developed on this ecosystem (Porrello et al, 2005;Renzi et al, 2009;Perra et al, 2010;Renzi and Guerranti, 2018) that allow us a better localization of sampling stations. It is a coastal lagoon characterized by eutrophication (Specchiulli et al, 2008) and by a critical coexistence of differing submerged vegetation forms (Renzi et al, 2007;Giovani et al, 2010), with an uneven accumulation of decomposing biomass and phanerogams seed dispersal (Giusti et al, 2010).…”