THE RESILIENCE OF A MEDITERRANEAN LAGOON THROUGH PAST AND FUTURE THREATS

Lagoonal systems represent some of the most important yet endangered transitional environments worldwide. The Grado-Marano lagoon (northern Adriatic Sea-eastern Mediterranean Sea) is a hotspot of biodiversity and a source of ecosystem services but it is historically polluted by mercury (Hg). This element exerts neurotoxic and genotoxic effects on animals once organized into the bioaccumulable monomethylmercury (MeHg). As the water temperature increases, the lagoon experiences occasional hypoxia/anoxia as consequences of high organic matter loads and water stratification. Under these conditions, the benthic MeHg production and release through the water column is stimulated. To test the resilience capacity of the lagoon system subjected to the synergistic effect of high temperature and contamination, we performed a field experiment, where we enclosed portions of the water column and surface sediments to simulate a plausible climate change scenario, i.e., high temperature in an organic-enriched shallow area. The short-term (few hours) and long-term (few days) effects on composition, abundance and structure of planktonic and benthic communities at different trophic levels (prokaryotes, microalgae, consumers) were investigated, together with physical-chemical changes in both the water column and in the sediments. To assess the effect of the combined stressors on the overall pelagic-benthic coupling, the main biological processes (respiration, primary production and prokaryotic heterotrophic production) rates were quantified in the enclosed water and sediments.

Presentation Preference: Either

Primary Presenter: Laura Baldassarre, National Institute of Oceanography and Applied Geophysics - OGS (lbaldassarre@ogs.it)

Authors:

Laura Baldassarre, National Institute of Oceanography and Applied Geophysics - OGS  (lbaldassarre@ogs.it)

Margherita Burini, National Institute of Oceanography and Applied Geophysics - OGS  (mburini@ogs.it)

Federica Nasi, National Institute of Oceanography and Applied Geophysics - OGS  (fnasi@ogs.it)

Tamara Cibic, National Institute of Oceanography and Applied Geophysics - OGS  (tcibic@ogs.it)

Lisa Sandri, National Institute of Oceanography and Applied Geophysics - OGS  (lsandri@ogs.it)

Annamaria Albanese, National Institute of Oceanography and Applied Geophysics - OGS  (aalbanese@ogs.it)

Sonia Manzo, ENEA  (sonia.manzo@enea.it)