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Understanding past seasonal temperature variability in the ocean is essential to evaluate the effects of future climate change on marine ecosystems. Here, we estimate seasonal water temperature amplitudes from stable oxygen isotope (δ18Oshell) values of fossil shells of Arctica islandica (assuming δ18Owater= + 0.9 ± 0.1‰ V-SMOW). Specimens were collected from three Pleistocene successions (Emilian and Sicilian substages of the Calabrian) in Central and Southern Italy (i.e., Rome, Lecce and Sicily). Biostratigraphic analyses from Rome Quarry deposits indicate an age between 1.6 and 1.2 Ma, whereas Sicily and Lecce successions are slightly more recent (between 1.1 and 0.62 Ma). Prior to carbonate geochemical analysis, we checked the shells for potential diagenetic alterations (e.g., from aragonite to calcite) using confocal Raman microscopy. δ18Oshelltransects indicate an annual temperature amplitude of about 3 °C during the Early Pleistocene. This is in sharp contrast to reconstructions based on faunal assemblages, according to which the simultaneous occurrence of boreal and warm-water species in the Calabrian Mediterranean Sea suggests a much higher seasonality (ca. 10 °C). The low seasonality and the relatively cold water (9–10 °C) indicate the outcrops represent colder climatic conditions compared to modern times, and suggest the occurrence of a maximum glacial phase.

In siliciclastic marine settings, skeletal concentrations are a characteristic feature of transgressive intervals that provide insights into biological and sequence-stratigraphic processes. To investigate taphonomic signatures of transgressive intervals, we analysed three cores along a depositional profile from the high resolution chrono- and stratigraphic framework of the Holocene Po coastal plain, in northern Italy. Coupled multivariate taphonomic and bathymetric trends delineated spatial and temporal gradients in sediment starvation/bypassing, suggesting that quality and resolution of the fossil record vary predictably along the studied depositional profile. Moreover, integration of taphonomic, bathymetric, and fossil density trends across the study area reveals distinctive signatures useful in characterizing facies associations and determining surfaces and intervals of sequence-stratigraphic significance. Within the southern Po plain succession, taphonomic degradation of macroskeletal remains increases from proximal/nearshore to distal/offshore locations. This trend is discernible for both biologically-driven (bioerosion) and physically-driven (e.g., dissolution, abrasion) shell alterations. Compared to the up-dip (most proximal) core, the down-dip core is distinguished by shell-rich lithosomes affected by ecological condensation (co-occurrence of environmentally non-overlapping taxa) and by higher taphonomic alteration. The onshore-offshore taphonomic trend likely reflects variation in sediment-accumulation along the depositional profile of the Holocene Northern Adriatic shelf, with surface/near-surface residence-time of macroskeletal remains increasing down dip due to lower accumulation rates. These results indicate that, during transgressive phases, changes in sea level (base level) are likely to produce down-dip taphonomic gradients across shelves, where the quality and resolution of the fossil record both deteriorate distally. Radiocarbon-calibrated amino acid racemisation dates on individual bivalve specimens and the chronostratigraphic framework for this profile suggest jointly that the high levels of taphonomic degradation observed distally developed over millennial time scales (∼8ky). Whereas in proximal setting overall low taphonomic degradation and geochronologic constrains point to centennial-scale time-averaging during the late transgression phase. Patterns documented in the Holocene transgressive (and lowermost regressive) deposits of the southern Po Plain may be characteristic of siliciclastic-dominated depositional systems that experience high-frequency, base-level fluctuations.

Previous work in Late Pleistocene–Holocene sequences from the Po plain revealed significant long-term fluctuations in trematode prevalence in marine environments: higher prevalence in retrogradational environments (TST) and negligible prevalence in progradational environments (HST). Here we expand upon this work by investigating traces of trematode parasitism among bivalves within parasequence sets from the Holocene brackish deposits of the Po Plain. The investigated portion of core 204-S7 is 24 m long and, from bottom to top, includes 5 m of amalgamated fluvial channel sands (latest Pleistocene) followed upwards by alternating packages of swamp and poorly drained floodplain deposits. The middle part of the core includes brackish deposits (inner to outer lagoon) accumulated through the Holocene. Using dense sampling (32 bulk samples and >1,550 specimens) of wetland and lagoonal strata from core 204-S7, we documented trematode occurrences in Abra segmentum, Loripes orbiculatus, and Cerastoderma glaucum. A randomization (10,000 iterations) at the level of individual specimens was conducted to investigate the statistical significance of the observed variability in trematode frequency. Frequencies of trematode infestation of A. segmentum were significantly elevated (p < 0.01) in samples associated with flooding surfaces and significantly depressed (p < 0.01) in samples collected from in-between flooding surfaces. Frequencies of termatode occurrences were similarly elevated around flooding surfaces in the case of L. orbiculatus. However, frequencies of trematode infestations in C. glaucum did not vary signinficantly across samples likely refelcting their low abundance. These results, documented at a much finer scale of observation within the sequence stratigraphic framework (dissecting parasequences) than in our previous studies (comparing data pooled by systems tracts), further support the hypothesis that increasing trematode prevalence is linked to transgressive cycles, a pattern now documented in shallow marine and estuarine settings, on two continents, and in both modern and fossil taxa.

Ecological systems vary in their responses to long-term climate changes that occur naturally on our planet. Preliminary analyses of the late Quaternary mollusk communities of the Adriatic Sea tentatively suggest that benthic ecosystems of the Po Delta displayed a remarkably resilient response to major long-term environmental changes associated with glacial cycles. The Po Delta was located in an approximately present-day location during the previous interglacial (isotope stage 5.5, ~125ka). During the subsequent glacial phase, the regional sea-level dropped by ~120 meters and the Po Delta migrated ~200km southeastward and resided close to the Mid-Adriatic Deep. The Po Delta returned back to its current location with the onset of the current interglacial phase. We compared core samples from the proximal Po Delta (the previous and current interglacial time intervals) with the distal core samples from the Mid-Adriatic Deep (the last glacial interval). The multivariate ordination (NMDS) and regional diversity analyses suggests that mollusk associations are indistinguishable between the two interglacial deltas. In contrast, the glacial Po Delta located distally represented distinct faunal associations and was dominated regionally by a different suite of species. These preliminary results tentatively suggest that Po Delta ecosystems have responded resiliently to major climate perturbations. When Po Delta migrated offshore during the glacial lowstand the delta communities changed significantly in composition and regional diversity patterns. However, when Po Delta returned to its previous location, the mollusk communities reverted back to their previous state. Whereas this progress report is based on a still limited number of glacial core samples, the reported results suggest that marine benthic communities may be highly resilient to natural, long-term environmental changes that are driven by global climatic processes. This outcome underscores the unique threat of ongoing anthropogenic changes that are altering many marine communities, including contemporary ecosystems of the Po Delta.

During the late Miocene, reef complexes characterised by poorly diversified coral associations (mainly Porites, occasionally associated with Tarbellastraea and/or Siderastraea), became widespread in the Mediterranean area. One of these complexes crops out at Vigoleno (Castell'Arquato, Piacenza, Northern Italy). According to the regional palaeogeographic and palinspastic reconstructions, it can be considered up to now the northernmost late Miocene (Tortonian-Messinian) reef of the Mediterranean area. Despite the limited outcropping and the faulting, the multidisciplinary investigations reveal the anatomy of this reef complex along two reference sections. In addition, a marked cyclicity characterises both carbonate and siliciclastic deposits of the Vigoleno wedge-top basin. At present, the lack of reliable geochronological markers and unsuitability of the material for stable isotope analyses are not sufficient to constrain the time-span and the main controlling environmental factors of these depositional cycles.

Parasitic trematode worms leave characteristic pits in their bivalve mollusk hosts and represent an ideal system for analyzing parasite-host interactions through space and time with statistically meaningful sample sizes. Previous work in Late Pleistocene–Holocene sequences from the Po plain revealed significant long-term fluctuations in trematode prevalence values: higher prevalence in retrogradational environments (TST) and negligible prevalence in progradational environments (HST). Here we expand upon this work by investigating traces of parasitism, kleptoparasitism, and predation on mollusk death assemblages from two domains along the northern Adriatic coastline. The domain north of the Po delta (TST-like) and the southern domain (including the Po delta; HST-like) comprise environments comparable to those recovered in late Holocene (

The Valle di Manche (VdM) section represents one of the best-documented on-land marine records of the Early to Middle (E/M) Pleistocene transition available to date. Accordingly, the VdM succession is among the few appropriate candidates to host the GSSP of the Middle Pleistocene (“Ionian”) Stage. In particular, the VdM section uniquely documents the Matuyama–Brunhes magnetic reversal (mid-MIS 19), which is agreed to be the main criterion for defining the chronostratigraphic position of the base of the Middle Pleistocene. The section also yields a wide range of chronological, paleoclimatic and stratigraphic data sets that allow long-distance correlation with both marine and terrestrial reference records. Notably, the stratigraphy across the MIS 19 interglacial is greatly expanded, permitting a precise and detailed investigation of this critical interval. The section is also easy to reach, and fortunately the exposure is destined to persist. Therefore, the section fulfills the essential requirements to host the GSSP for the “Ionian” Stage and Middle Pleistocene Subseries. We suggest that the GSSP be placed at the base of the “Pitagora ash”, a prominent bed that occurs in mid-MIS 19, close to the Matuyama–Brunhes magnetic reversal. Here, we present and discuss scientific information gathered in the past two decades, and give a preliminary account of the work to which we are presently committed, that aims at improving our knowledge on the VdM section.

Responses of ecosystems to environmental changes vary greatly across habitats, organisms and observational scales. The Quaternary fossil record of the Po Basin demonstrates that marine communities of the northern Adriatic re-emerged unchanged following the most recent glaciation, which lasted approximately 100 000 years. The Late Pleistocene and Holocene interglacial ecosystems were both dominated by the same species, species turnover rates approximated predictions of resampling models of a homogeneous system, and comparable bathymetric gradients in species composition, sample-level diversity, dominance and specimen abundance were observed in both time intervals. The interglacial Adriatic ecosystems appear to have been impervious to natural climate change either owing to their persistence during those long-term perturbations or their resilient recovery during interglacial phases of climate oscillations. By contrast, present-day communities of the northern Adriatic differ notably from their Holocene counterparts. The recent ecosystem shift stands in contrast to the long-term endurance of interglacial communities in face of climate-driven environmental changes.