Articles | Volume 13, issue 21
Research article
01 Nov 2016
Research article |  | 01 Nov 2016

Anthropogenically induced environmental changes in the northeastern Adriatic Sea in the last 500 years (Panzano Bay, Gulf of Trieste)

Jelena Vidović, Rafał Nawrot, Ivo Gallmetzer, Alexandra Haselmair, Adam Tomašových, Michael Stachowitsch, Vlasta Ćosović, and Martin Zuschin

Abstract. Shallow and sheltered marine embayments in urbanized areas are prone to the accumulation of pollutants, but little is known about the historical baselines of such marine ecosystems. Here we study foraminiferal assemblages, geochemical proxies and sedimentological data from 1.6 m long sediment cores to uncover  ∼  500 years of anthropogenic pressure from mining, port and industrial activities in the Gulf of Trieste, Italy.

From 1600 to 1900 AD, normalized element concentrations and foraminiferal assemblages point to negligible effects of agricultural activities. The only significant anthropogenic activity during this period was mercury mining in the hinterlands of the gulf, releasing high amounts of mercury into the bay and significantly exceeding the standards on the effects of trace elements on benthic organisms. Nonetheless, the fluctuations in the concentrations of mercury do not correlate with changes in the composition and diversity of foraminiferal assemblages due to its non-bioavailability. Intensified agricultural and maricultural activities in the first half of the 20th century caused slight nutrient enrichment and a minor increase in foraminiferal diversity. Intensified port and industrial activities in the second half of 20th century increased the normalized trace element concentrations and persistent organic pollutants (PAH, PCB) in the topmost part of the core. This increase caused only minor changes in the foraminiferal community because foraminifera in Panzano Bay have a long history of adaptation to elevated trace element concentrations.

Our study underlines the importance of using an integrated, multidisciplinary approach in reconstructing the history of environmental and anthropogenic changes in marine systems. Given the prolonged human impacts in coastal areas like the Gulf of Trieste, such long-term baseline data are crucial for interpreting the present state of marine ecosystems.

Short summary
We studied the ecological history of the Gulf of Trieste. Before the 20th century, the only activity here was ore mining, releasing high amounts of mercury into its northern part, Panzano Bay. Mercury did not cause changes to microorganisms, as it is not bioavailable. In the 20th century, agriculture caused nutrient enrichment in the bay and increased diversity of microorganisms. Industrial activities increased the concentrations of pollutants, causing only minor changes to microorganisms.
Final-revised paper