Foraminifers and ostracods were studied in a gravity-core recovered near Cape Adare (Ross Sea, Antarctica) with the aim of identifying the climatic and oceanographic variations during the last 30 ka. The sedimentary sequence represents conditions of a cool-water carbonate factory, which evidences that during the Marine Isotope Stage 2 (MIS2) the area was ice-free and very productive. The overall preservation of delicate skeletal remains such as bryozoans and molluscs indicated moderate bottom currents. This carbonate factory was interrupted by some terrigenous levels, representing conditions of instability/retreat of the ice shelves southward. The younger levels were referred to the meltwater pulse (MWP)-1A and 1B events. The Holocene sequence comprised more terrigenous sediments, reflecting high bottom-currents similar to the present-day conditions. Very abundant and well preserved foraminifers and ostracods, representative of shelf-upper slope paleoenvironments, were recovered. Epistominella exigua, among the foraminifers, suggested the influence of the Circumpolar Deep Water during some periods of the late Quaternary. Heavy-test taxa, such as Cibicides refulgens, indicated strengthening bottom hydrodynamics. As for the ostracods, peaks in the presence of Australicythere devexa, Bairdoppilata simplex and Pseudocythere aff. caudata together with significant values of Polycope spp. allowed us to identify environments rich in nutrients with the influence of cold and deep water upwelling phenomena.
For the first time, the distribution and modifications of living ostracod associations present in the Gulf of Trieste (GoT) in relation to alterations caused by human activity in the last 20 years were investigated. The results were compared with the main physicochemical parameters (especially nitrogen and phosphorus) measured over the same period, which can lead to a general decrease in environmental quality. For a more in-depth analysis of the changes recorded by ostracods in the last 50 years, a period in which eutrophication and anoxia increased, we revisited the study carried out by Masoli in the GoT in 1967. The results obtained made it possible to verify how, over the last 20 years, ostracod assemblages have suffered a decrease both qualitatively and quantitatively. Most of the species recovered show characteristics of opportunism and tolerance to environmentally stressful conditions, high organic matter concentrations, and oxygen deficiency. The ostracods analyzed in 1967 showed similar results with few dominant opportunistic species. We verified how ostracods recorded in GoT, similar to Mollusks and Foraminifera, have been impaired by the possible environmental crisis linked to the recurrence of mucilage and hypoxic events documented for the GoT in the last 50 years. Finally, a comparison with the best environmental conditions found in the Marine Nature Reserve of Miramare (MPA) allowed us to emphasize the important role of protected areas to avoid loss of biodiversity due to urbanization.
For the first time the distribution and modifications of living ostracod associations present in the Gulf of Trieste (GoT) in relation to the alterations caused by human activity in the last 20 years were investigated. The results were compared with the main chemico-physical parameters (especially nitrogen and phosphorus) measured over the same period, which can lead to a general decrease in environmental quality. For a more in-depth analysis of the changes recorded by ostracods in the last 50 years, a period in which eutrophication and anoxia increased, we revisited the study carried out by Masoli in the GoT in 1967. The results obtained made it possible to verify how over the last 20 years, ostracod assemblages have suffered a decrease both qualitatively and quantitatively. Most of the species recovered show characteristics of opportunism and tolerance to environmentally stressful conditions, high organic matter concentrations and oxygen deficiency. The ostracods analyzed in 1967 showed similar results with few dominant opportunistic species. We verified how ostracods recorded in GoT, similar to Mollusks and Foraminifera, the possible environmental crisis linked to the recurrence of mucilage and hypoxic events documented for the Gulf of Trieste in the last 50 years. Finally, a comparison with the best environmental conditions found in the Marine Nature Reserve of Miramare (MPA) allowed us to emphasize the important role of protected areas to avoid the loss of biodiversity due to urbanization.
The ancient city of Elaiussa Sebaste, currently Ayaş, is located on the southeastern coast of Turkey. It was one of the main trading Mediterranean harbours from the Augustan period until the early Byzantine era. The Arab invasion in the 7th century ce marked its definitive abandonment. A significant historical topic concerns the palaeoenvironmental evolution of the northern and southern harbours of Elaiussa Sebaste, including their decline and burial. An interdisciplinary study analysed six cores drilled in the current plains corresponding to the former harbour basins. A geoelectrical study, integrated with borehole stratigraphy, reconstructed the geometry of the carbonate bedrock that forms the accumulation base of the marine sediments. Sediments deposited from the 8th century bce to the 6th century ce include the development phases of the ancient city from the 3rd century bce onwards. Sedimentology, micropalaeontology (foraminifers, ostracods), palaeobotany (pollen, non‐pollen palynomorphs, microcharcoals, plant macroremains) and Pb isotopes provided a model of the environmental evolution in both harbour basins. The main harbour expansion phase, marked by a change in Pb concentration, is hypothesized to have occurred between 140 and 220 ce, which is consistent with the historical sources indicating the development of the city during the mid‐Roman Imperial period.
Ostracoda are a minor but recurrent component of Southern Ocean marine carbonate factories, and their low-Mg calcitic skeletal mineralogy helps in ensuring a noteworthy post-mortem resilience. Our study, based upon surface sediment occurrences, contributes to the better definition of their distribution vs. potential controlling factors in Antarctic waters. The ostracod fauna from the Western Ross Sea Shelf appears dominated by Australicythere polylyca, Australicythere devexa, Xestoleberis rigusa, Loxoreticulatum fallax, Cativella bensoni, Austrotrachyleberis antarctica and Patagonacythere longiducta, colonizing a variety of shelf environments along a wide bathymetric range. The abundance and richness values correlate well to nutrient distribution and sediment supply, primarily related to the circulation of different oceanographic regimes affecting the floor of the Ross Sea Shelf. Circumpolar Deep Water could represent the main factor controlling the distribution of ostracods. Similar results (high abundance and richness in ostracod values) were also recorded in the Terra Nova Bay and in a nearby area characterized by warm water rich in nutrients and composed of water of circumpolar origin flowing from the open ocean southwards onto the continental shelf. Particulate Fe (pFe), in suspended particulate matter (SPM), and other particulate trace metals in TNB could support the hypothesis that biogenic iron may significantly contribute to the bioavailable iron pool, sustaining both primary production and ostracod fauna richness in this area.