The Anthropocene is characterized by dramatic ecosystem changes driven by human activities. The impact of these activities can be assessed by different geochemical and paleontological proxies. However, each of these proxies provides only a fragmentary insight into the effects of anthropogenic impacts. It is highly challenging to reconstruct, with a holistic view, the state of the ecosystems from the preindustrial period to the present day, covering all biological components, from prokaryotes to multicellular eukaryotes. Here, we used sedimentary ancient DNA (sedaDNA) archives encompassing all trophic levels of biodiversity to reconstruct the two century-natural history in Bagnoli-Coroglio (Gulf of Pozzuoli, Tyrrhenian Sea), one of the most polluted marine-coastal sites in Europe. The site was characterized by seagrass meadows and high eukaryotic diversity until the beginning of the 20th century. Then, the ecosystem completely changed, with seagrasses and associated fauna as well as diverse groups of planktonic and benthic protists being replaced by low diversity biota dominated by dinophyceans and infaunal metazoan species. The sedaDNA analysis revealed a five-phase evolution of the area, where changes appear as the result of a multi-level cascade effect of impacts associated with industrial activities, urbanization, water circulation and land-use changes. The sedaDNA allowed to infer reference conditions that must be considered when restoration actions are to be implemented.
1 February 2020 in Journal of Environmental Radioactivity
Current measurements in the open sea are generally acquired by Acoustic Doppler Current Profilers (ADCPs). In the case of ADCPs mounted on spar buoy, current profiles require to be post-processed, to properly take into account the buoy influence: in fact, ADCP compass may reflect alterations induced by the metal structure of the buoy and apparent currents can occur due to the large displacement of the platform. Uncertainty analysis is finally required to properly consider both these effects and to compute robust velocity estimates. A new methodology is tested for a measurement station in the Ligurian Sea, where an ADCP was mounted on the surface buoy of the W1-M3A (Western 1 Mediterranean Moored Multisensor Array) oceanographic observatory, facing upwards at the depth of about 40 m. Marine current numerical models and historical data in the area have been used as a basis for comparison to test the consistency of the proposed method. A very good agreement is obtained. Only minor discrepancies are reported (e.g., monthly averages from the reference model slightly underestimate the west-east current component along the entire profile), but, in general, the application of the proposed methodology ensures that the spar buoy-mounted ADCP system is able to provide reliable measurements for oceanographic studies and validation of 3D hydrodynamic models.
Marine coastal areas are highly dynamic and fragile environments characterised by a complex interplay of biological, physical, and chemical factors. These areas are also affected by anthropogenic activities with the discharge of organic and inorganic contaminants that alters the quality of the environment. In this work, the effects of anthropogenic activities (i.e., urban and industrial development) on benthic foraminifera have been investigated along the A2TM core collected from the Sant’Elia-Foxi Canyon (Gulf of Cagliari, Sardinia—western Tyrrhenian Sea). The Gulf of Cagliari has experienced intense urbanisation since the beginning of the twentieth century with the establishment of petrochemical complexes and harbour activities. The A2TM core, dating from 1907 to 2013, was analysed with an integrated approach that includes grain size, organic matter, and benthic foraminifera characterisation compared with geochemical characterisation. The variations in the composition of the benthic foraminiferal assemblages and the Margalef diversity index are related to the altered environmental conditions that reflect the historical development of the area and to the land-based activities surrounding the Gulf of Cagliari. The statistical analysis identifies two main intervals (i.e., the years 1907–1986 and 1986–2013) that are typified by different benthic foraminiferal assemblages and diversity values. Accordingly, the increases in organic matter content and both organic and inorganic contaminants are well mirrored by a major drop in foraminiferal diversity after 1973 and a major foraminiferal turnover after 1989. The composition of the benthic foraminiferal assemblages in the uppermost part of the core (i.e., 1989–2013) might suggest a lowering of the oxygen availability at the seafloor. These changes might be related to the increase in organic matter and the silty fraction in the same interval likely triggered by damming on land and wetland reclamation.