No abstract

The short sediment core EMB201/7-4 retrieved from the East Gotland Basin, central Baltic Sea, is explored here as a candidate to host the stratigraphical basis for the Anthropocene series and its equivalent Anthropocene epoch, still to be formalized in the Geological Time Scale. The core has been accurately dated back to 1840 CE using a well-established event stratigraphy approach. A pronounced and significant change occurs at 26.5 cm (dated 1956 ± 4 CE) for a range of geochemical markers including 239+240Pu, 241Am, fly-ash particles, DDT (organochlorine insecticide), total organic carbon, and bulk organic carbon stable isotopes. This stratigraphic level, which corresponds to a change in both lithology and sediment colour related to early anthropogenic-triggered eutrophication of the central Baltic Sea, is proposed as a Global Boundary Stratotype Section and Point for the Anthropocene series.

No abstract

Extraction of heavy metals (e.g. silver, gold) through the formation of amalgams with mercury has been utilized in jewellery production [1] and mining [2] for over 2500 years. This has been contemporarily applied in a nanoformulation for the opposite process with the abstraction of mercury from waste sources using zero-valent nanoparticles of noble metals.[3] The interaction of metal nanoparticles with other species has shown great promise for a number of applications [4] and in particular silver nanoparticles (AgNPs) have been used as an anti-microbial agent in textiles and composites [5] and also (less frequently) for the destruction of pesticides or the removal of mercury from industrial effluents and other waters.[6] With the formation of silver through a silicon hydride reduction, we expect that as the size of the particle is reduced to the nanoscale its interaction with aqueous mercury will be dominated by surface forces.It is well known that at the bulk scale, aqueous mercury(II) interacts with silver metal(0) with a stoichiometric ratio of 1:2 [Eq. (1)], resulting in zero-valent mercury.

The extensive array of mid‐20th century stratigraphic event signals associated with the ‘Great Acceleration’ enables precise and unambiguous recognition of the Anthropocene as an epoch/series within the Geological Time Scale. A mid‐20th century inception is consistent with Earth System science analysis in which the Anthropocene term and concept arose, and would reflect the reality that our planet has sharply exited the range of natural variability characterizing the Holocene Epoch/Series, which the Anthropocene would therefore terminate. An alternative, recently proposed ‘geological event’ approach to the Anthropocene is primarily an interdisciplinary concept, encompassing historical and socio‐cultural processes and their global environmental impacts over a diachronous timeframe that extends back at least many millennia. Resembling more closely a geological episode than an event, it would decouple the Anthropocene from its chronostratigraphic delineation and association with an abrupt planetary perturbation; but separately defined and differently named it might be usefully complementary. We recommend a clear separation of epochs, events and episodes. An epoch is a formal subdivision of the Geological Time Scale, and its correlation may be assisted by one or more events; an event is usually, and particularly in the Quaternary, a brief incident or perturbation with a sedimentary expression; and an episode is a longer, internally complex time interval that may include several events and even extend across several epochs.