Ostracods represent valuable proxies in palaeoenvironmental reconstructions and environmental monitoring, yet their ecological response to organic enrichment remains poorly quantified compared to other benthic groups such as macrofauna and benthic foraminifera. Here, we propose the first large-scale assessment of ostracod species' tolerance to total organic carbon (TOC) in the Adriatic Sea (western Mediterranean), based on a previously published, extensive dataset of 298 samples analyzed using a weighted-averaging approach. Ninety marine species are assigned into five canonical Ecological Groups (EGs): twenty-six sensitive (EG I), thirty-one indifferent (EG II), twenty third-order opportunists (EG III), ten second-order (EG IV), and three first-order opportunists (EG V). This classification allowed the development of a novel Ostra-AMBI index, a modified version of the AZTI Marine Biotic Index (AMBI), based on species-specific tolerance to organic matter enrichment. The reliability of species assignment is supported by significant positive correlations between Ostra-AMBI and both TOC (R2 = 0.59) and Foram-AMBI (R2 = 0.75), calculated on an independent testing dataset. Besides promoting ostracods as reliable marine (palaeo)ecological indicators, results reveal a clear link between ostracod EGs distribution and the Adriatic sediment routing system, reflecting the interplay between river plumes, current-driven sediment dispersal, and organic matter accumulation. Sensitive and indifferent species dominate the coastal belt and north-central shelf, whereas opportunistic taxa prevail in TOC-enriched deposits (i.e., Adriatic Mud Wedge and deep basins). Although further studies are needed to refine the Ostra-AMBI index, this work highlights the importance of integrating biological and sedimentological processes for both environmental and stratigraphic studies.

The Mediterranean Sea is considered a hotspot for bioinvaders. Nonetheless, information on non-indigenous benthic foraminifera is still fragmented. This study documents for the first time the presence along the northwestern Adriatic coast of the non-indigenous benthic foraminifera species Virgulinella fragilis, Grindell and Collen (1976). Due to the low abundance recorded in the study area, the presence of this species may represent an early colonization phase. We discuss the temporal and spatial patterns of V. fragilis arrival in the Mediterranean and Adriatic Seas, and we hypothesize stowaway transport (via ship fouling or ballast water) as the main introduction pathway. Morphological test analyses suggest that V. fragilis prefers a low oxygen content, consistent with the ecological requirements reported for this taxon in the literature. The application of Maximum Entropy (MaxEnt) modeling indicates that the key factor influencing the presence of V. fragilis in the Mediterranean basin is the bacterial concentration expressed as NO3. Projections under future climate scenarios (RCP 4.5) point to a decline of habitat suitability conditions, making widespread invasion unlikely in the Mediterranean. We emphasize the importance of continuous biomonitoring for early detection of alien species, improving our understanding of invasion dynamics and enabling prompt conservation actions, especially in regions impacted by anthropogenic activities.

Combined natural processes and human activities shaped the late Holocene landscape history in many Mediterranean regions. This is especially true with areas subjected to specific human interest, such as coastal areas morphologically suitable to the establishment of harbours. Here, we test the hypothesis on the location of the Roman harbour Portus Trajectus in Peloro Cape (NE Sicily, Italy) and describe the evolution of the area over the last 3700 years through lithostratigraphic, geochemical, meiofauna and microfossil analyses performed on a new sediment core recovered from the coastal salt marsh Pantano Grande (aka Lago di Ganzirri). The age-depth model was developed on radiocarbon dates and geochemical fingerprinting of two tephra layers. Results indicate that the area underwent dramatic changes ca. 650 bce. The anthropogenic impact of Greek colonies may have contributed to modifying the coastal environment of Peloro Cape due to their widespread impact on natural resources. This happened at many localities in the Mediterranean, indicating the magnitude of impact of the Greek colonies over the landscape. According to our results, it is unlikely that the current Pantano Grande basin was used as a harbour in Roman times, although the presence of a harbour in the nearby Pantano Piccolo marsh cannot be excluded. Pantano Grande had been isolated from the sea for more than 2000 years. Human intervention in the 19th century halted that isolation and provided the background for the ecological, economic and social functions the salt marsh performs today.

ABSTRACT Depositional processes recorded by shelf deposits may vary widely along‐strike, depending largely on the mode of delivery and deposition of sediments to the basin. In fine‐grained systems in particular, depositional processes are difficult to reconstruct with standard facies analysis of sediment cores due to the ostensibly featureless and homogenous appearance of muds. In this study, sedimentological, palaeontological, geochemical, and oceanographic data were combined in a detailed characterization of depositional conditions via sedimentary structures, type of organic matter, trace‐metal geochemistry, and benthic fauna assemblages (foraminifera and ostracods) along the 600 km long shelf delta clinothems of the West Adriatic shelf (Italy). Processes inferred from sedimentary facies and micro‐structures were then considered in the context of the modern Adriatic oceanographic regime. Specific attention was given to the Little Ice Age stratigraphic unit (1500–1850 ce ), which contains a continuum of genetically related fine‐grained strata. The Little Ice Age deposit offers the opportunity to examine a source‐to‐sink system with the high resolution typical of modern analogues, at a time interval when Apennine rivers were not yet hydraulically engineered with man‐made sediment traps along their trunks. Individual beds within the Little Ice Age muddy prodelta form hectometre to kilometre‐wide bedsets that reflect the interplay between energetic meteo‐ocean conditions (storm‐dominated beds), flood supply (river‐dominated beds or hyperpycnites) and along‐shelf bottom‐current dispersion (drift‐dominated beds). The multidisciplinary approach applied at different scales of observations helped in understanding sediment provenance and the relative timing of sediment transport before final burial that strongly promoted organic matter oxygen exposure and the loss of carbon by microbial degradation. Overall, the distinctive depositional processes that acted in concert along the prodelta slope produced a subtle lateral heterogeneity of preserved sedimentary structures, faunal associations, and organic matter composition in a laterally‐continuous lithostratigraphic unit deposited at centennial scale. These findings have implications on the forcing conditions that ultimately control the location and nature of fine‐grained beds in both modern and ancient, mud‐dominated depositional systems.

The combined use of the meiofauna (benthic foraminifers and ostracods) and geochemical data from three cores, recovered in distinct bathymetric sectors of the southern Adriatic shelf (Apulia, SE Italy), provides new insights on the relationships between shallow-marine environments, sediment fluxes and eutrophication trends over the last ~7000 years. The stratigraphic distribution of meiofauna assemblages allows distinguishing a variety of facies associations, accumulated at proximal (Manfredonia Gulf), intermediate and distal shelf sectors. Spatial-temporal facies trajectories mainly reflect changes in fluxes of fine-grained, inorganic and organic particles at the seafloor. Major palaeoenvironmental shifts are paralleled by stratigraphic variations of Cr-Ni values, which represent effective provenance tracers for the Adriatic region. The correlation between the meiofauna content and trace-metal concentrations documents the link between the type of substrate (organic matter-OM and grain-size) and sediment provenance along the bathymetric profile and through time. After 6000 yr B.P., the gulf, partly sheltered by the Gargano Promontory, experienced the first increase in OM fluxes (transition from open-bay to prodelta). This turnaround occurred under the progressive change in sediment supply from southern Apennine source-rocks, poor in trace metals, to a mixed contribution including northern sources, enriched in chromium and nickel (mafic/ultramafic rocks of the Po River catchment) via the SSE-directed longshore drift. Alongside, prodelta clays in lateral transition to mud-belt deposits accumulated in the adjacent open shelf under the steady influence of the longshore drift. Finally, since ~2000 yr B.P. a pervasive subaqueous delta system developed across the study area in response to increased sediment load by Po + Apennine rivers, likely induced by enhanced anthropic pressure during Roman times. This study highlights the key role played by the sediment routing system, coastal morphology and human land-use on shelf facies patterns and eutrophication trends, even in areas hundreds of km away from the main fluvial mouths.

Holocene prodelta lobes are key sedimentary archives of environmental change that can be used effectively for high-resolution palynological investigations, as they: (i) consist almost entirely of mud, (ii) represent stratigraphically expanded successions, and (iii) are strictly related to river dynamics, thus reflecting vegetation changes in river catchments. In this study, we focussed on the ~20 m-thick prodelta succession of the modern Po Delta (NE Italy), fed by two river branches (Volano and Goro) that were mostly active during the past two millennia, a period of rapid acceleration of natural resources’ exploitation and climate variability. Forty-eight samples with mean temporal resolution of 50 years were analysed. Eleven ecological groups and four pollen zones were identified, with distinct peaks of the secondary-primary pollen ratio marking major floods during the Volano-Goro lobe switching and the Little Ice Age. Five vegetation phases were detected since the 1 st century AD. In the framework of a patchy natural-cultural landscape, patterns of wetland expansion/contraction reflect the combined effect of cool-wet oscillations (LALIA – Late Antique Little Ice Age), land management (reclamations) and river avulsion. Forest dynamics document warm conditions during the so-called ‘Roman Climate Optimum’ and ‘Medieval Warm Period’, although minor cool-wet episodes occurred in tune with solar minima, and bipartite climate conditions (cool-moist followed by cool-dry) characterized the LALIA. Since the 14 th century, despite human-induced forest shrinking, peaks of montane vegetation followed a centennial-scale cyclicity likely influenced by solar minima and major plagues.

The Middle and Late Pleistocene were characterized by high-amplitude climate and sea-level oscillations that deeply influenced the evolution of alluvial and coastal systems worldwide. Through the correlation of 43 cores and 168 well data, with the aid of pollen, meiofauna, 14 C, ESR and IRSL data, this work provides a detailed reconstruction of the Middle Pleistocene to Holocene stratigraphy of the Po Basin and explores the sedimentary response of the Po-Adriatic alluvial-coastal system to glacio-eustatic oscillations and other concomitant forcing factors. The Middle Pleistocene to Holocene sedimentary succession of the Po Basin is composed of alluvial, paralic, coastal and shallow-marine facies associations arranged in an overall shallowing-upward trend. This general trend is punctuated by the rhythmical alternation of progradationally stacked coastal wedges with thick alluvial deposits. At landward locations, where the coastal facies wedge out, the depositional cyclicity records alternating paralic and alluvial facies associations. The overall shallowing-upward trend documents the longer-term, progressive filling of the basin driven by high sediment supply which overcame the rate of creation of accommodation induced by subsidence. The cyclic arrangement of facies, paralleled by rhythmical changes in vegetation, reflects Milankovitch-scale, glacio-eustatic oscillations in the 100 ka band. Increasing subsidence towards the sea and the activity of selected sectors of the buried Apennine thrust front, might have enhanced the seaward migration of coastal wedges. This study provides clues on the sedimentary response of a low-gradient coastal system to dramatic climatic and eustatic changes. The model of basin evolution presented here may help predict the environmental modifications of coastal areas in near future scenarios of climate and sea-level change.

Multiple paleovalley systems of late Quaternary age have been widely explored in previous research from the Gulf of Manfredonia on the basis of seismic data, but only limited information is available on their proximal (onshore) segments. Through an integration of sedimentary, paleoecological (mollusks, benthic foraminifers, ostracods), and geochemical analyses from three 30-50 m-long onshore cores and a sequence-stratigraphic framework chronologically constrained by 25 radiocarbon data, we document the stratigraphic architecture of three contiguous paleovalley systems (Candelaro, Cervaro and Carapelle rivers) and their sedimentary response to Late Pleistocene valley excavation, Holocene filling and basinwide interfluve flooding. Above a prominent sequence boundary formed during the Late Pleistocene relative sea-level fall, fluvial-channel gravels and sands (lowstand systems tract) are overlain by a deepening-upward, valley-fill succession of inner-estuarine (fresh-water) to outer-estuarine (brackish) muds (lower transgressive systems tract - TST). The individual valley fills are overlain by laterally extensive bay deposits (upper TST) and by a progradational succession of prodelta/delta front and offshore/shoreface deposits that reflect normal regression under highstand conditions (HST). The transition from fluvial to inner-estuary (fluvial-dominated) and outer-estuary (wave-influenced) deposits records the progressive shift in sediment provenance from Southern Apennine source rocks to a mixed composition that reflects increasing alongshore sediment contribution from northern sources via the SE-directed Western Adriatic Current. The stratigraphic surface that demarcates the transition from estuarine to bay depositional systems (lower/upper TST boundary) represents the physical prolongation of interfluvial terrace surfaces, as valley margins were flooded during the Early Holocene transgression. This surface, typically recognizable on seismic profiles at the boundary between low-amplitude and overlying high-amplitude reflectors, has no obvious lith-ologic signature in core. However, it can be readily identified on the basis of paleoecologic features (sharp in-crease in species diversity and in the proportion of marine taxa) that reveal the abrupt transition from laterally confined to unconfined settings.

In order to explore the relationship between the coastal zone and the urban layout of the ancient city of Nora (Sardinia, Italy), in 2011 the Department of Cultural Heritage of the University of Padua launched an interdisciplinary research project that currently involves the Universities of Pisa and Bologna. The processing of the archaeological and geological data collected during the fieldworks has provided a suite of new proxies to estimate the rates of sea-level evolution in Nora from the mid-2nd century B.C. to the 5th century A.D. This paper presents the results of the project, exposing some reconstructive proposals of the urban extent and layout of Nora between the Nuragic Age and the Late Antiquity. Since coping with the sea level rise is a matter of increasingly urgency, some strategies against the erosional risk affecting the archaeological heritage are finally reported.

The Makgadikgadi Basin in Botswana hosts a system of salt lakes, which developed from the Upper Pleistocene onward due to the gradual shrinking of the giant Lake Palaeo-Makgadikgadi. Stratigraphic and palaeoclimatic studies of this area are difficult due to the influence of several factors, such as a complex history of regional tectonic activities, as well as climatic changes coupled with dryland diagenetic processes. This lake, in the central Kalahari, is the key to understanding the climatic variability in the southern part of Africa in the Quaternary and has played an important role in the evolution of numerous taxa, including our own. In this study, detailed sedimentological analyses (grain size and major elements distribution) of shallow sediments from the Makgadikgadi Pans were combined with the first comprehensive study of the encountered ostracod fauna to establish trends in the environmental changes in the area from the late Quaternary. Ostracod fossil assemblages from the cores of the Makgadikgadi Pans are dominated by the Limnocythere ssp., an opportunistic taxa commonly colonizing the littoral areas of shallow evaporative, ephemeral lakes, together with the subordinate occurrences of Sarcypridopsis ochracea , Sclerocypris cf. bicornis, Candonopsis spp., and Ilyocypris spp. The sediments from the pans show fluctuations in the Cl/K and Ca/Cl ratios, often in phase with the relative abundance of Limnocythere suggesting a cyclicity induced by changes of salinity and alkalinity in the water. This multi-proxy study of the cores collected from the pans suggests a Late Pleistocene shallow, playa lake environment with strongly alkaline water, interrupted by a prolonged drought with sustained aeolian conditions between ∼16 and 2 ka BP. Increasing diversity of ostracod fauna in the top 20–30 cm of the cores indicates that a temporary shift toward higher humidity occurred around 2–1.5 ka BP and lasted through the Medieval Warm Period. This humid period was followed by an overall desiccation trend that started with the Little Ice Age and continues until the present day.

The fluvial harbour of Aquileia (Italy), one of the most important Roman trading centres in the Mediterranean, was abandoned after the city's destruction in 452 AD. The deserted harbour evolved into a swamp surrounded by a floodplain that has recorded the anthropogenic, environmental and climatic pressures that have occurred during the last 1500 years in the northern Adriatic. Focusing on the period since 500 AD, we here reconstruct the area's long-term ecosystem dynamics. We show that ecosystem dynamics mainly mirror the climate phases of the pre-industrial era. After the Roman era, anthropogenic activities (agriculture, pasture and fire activity) declined in scope and amplitude and are chronologically limited (from the late 7th to the early 13th centuries AD), acting as a background pressure on ecosystems. The main non-human impacts recorded by ecosystems correspond to the Late Antique Little Ice Age, defined by an average temperature anomaly of -2.04 ?? 0.17 ??C, exceeding the Pre-industrial Little Ice Age by -1.26 ?? 0.16 ??C in severity. The temperatures reconstructed for the Medieval Climate Anomaly are close to those recorded for the 20th century AD (average anomaly of 0.08 ?? 0.15 ??C) but they differ from the 21st century AD, according to the CRUTEM4 data. Aquileia shows that ancient harbours are key areas to understand how climate and human societies have shaped northern Adriatic environments since the post-Roman period.

Full quantitative benthic foraminiferal data of samples from cores M1 (Arno delta) and R2 (Rhone delta) including >300 tests.

The definition of reference conditions has a major role for the understanding of the present-day and paleoecological quality status on transitional environments. The estuarine quality paradox and the paucity of unimpacted sites make the definition of reference conditions a challenging task. In this context, the integration of biological indicators with stratigraphic data is essential, as the vertical stacking pattern of facies composing the shallow subsurface of modern coastal plains reflects changes in physical-chemical parameters which, in turn, affect (paleo-)biotic communities. In the Po coastal plain (N Italy), the mid to late Holocene back-barrier succession of the Mezzano Lowland and the adjacent present-day Bellocchio Lagoon offer a unique example of pristine paralic system for comparing reference conditions defined in fossil and modern settings, respectively. Benthic foraminifers and ostracods from the Mezzano succession allowed us to investigate vertical (i.e., temporal) and lateral (i.e., spatial) changes in (paleo-)environmental conditions, in analogy to the lateral variations recorded at the Bellocchio Lagoon. Both sites present subtidal channel sands almost barren in autochthonous meiofauna and fine-grained lagoon sediments with abundant benthic foraminifers and ostracods mostly represented by euryhaline taxa recording the highest diversity. Intertidal muddy deposits are also recorded, including mud flat clays with abundant oligotypic assemblages dominated by highly-confined benthic foraminifers. In the present study, we demonstrate that changes in modern benthic foraminifer assemblages diversity and composition often interpreted as perturbations of ecological conditions in response to anthropogenic pressures also occur under natural state, as confirmed by paleoenvironmental conditions recorded by ostracods. This reflects the effects of authogenic processes at short time and geographic scales.

The Gulf of La Spezia (GLS) in Northwest Italy is a rocky embayment with low fluvial influence facing the Mediterranean Sea. Past landscape dynamics were investigated through a multi-proxy, facies-based analysis down to a core depth of 30 m. The integration of quantitative ostracod, foraminifera, and pollen analyses, supported by radiocarbon ages, proved to be a powerful tool to unravel the late Quaternary palaeoenvironmental evolution and its forcing factors. The complex interplay between relative sea-level (RSL), climatic changes, and geomorphological features of the embayment drove four main evolution phases. A barrier–lagoon system developed in response to the rising RSL of the Late Pleistocene (likely the Last Interglacial). The establishment of glacial conditions then promoted the development of an alluvial environment, with generalised erosion of the underlying succession and subsequent accumulation of fluvial strata. The Holocene transgression (dated ca. 9000 cal year BP) caused GLS inundation and the formation of a low-confined lagoon basin, which rapidly turned into a coastal bay from ca. 8000 cal year BP onwards. This latter environmental change occurred in response to the last Holocene stage of global sea-level acceleration, which submerged a morphological relief currently forming a drowned barrier-island complex in the embayment.

Understanding Quaternary dynamics of delta-coastal plains across multiple glacial-interglacial cycles in the Milankovitch band (~100 kyrs) is crucial to achieve a robust evaluation of possible environmental response to future climate-change scenarios. In this work, we document the long-term bio-sedimentary record of core 204 S16 (~205 m long), which covers a wide portion of the post-MPR (Mid-Pleistocene Revolution) interval, taking advantage of the highly subsiding context of the SE Po Plain (NE Italy). Detailed facies characterization through an integrated sedimentological and meiofauna (benthic foraminifers and ostracods) approach allowed for the identification of a repetitive pattern of alluvial deposits alternating with four fossiliferous, paralic to shallow-marine units (Units 1–4). The transgressive surfaces identified at the base of these units mark major flooding events, forced by Holocene (Unit 4), Late Pleistocene (Unit 3) and Middle Pleistocene (Units 1, 2) interglacials. Distinct stratigraphic patterns typify the Middle Pleistocene interval, which includes coastal-marine (tidal inlet and bay) deposits. In contrast, lagoonal sediments record the maximum marine influence in the Late Pleistocene-Holocene succession. As a whole, the meiofauna tracks a regressive trend, with the deepest conditions recorded by the oldest Unit 1 (MIS 9/11 age?).

Coastal-transitional areas, including delta plains, strandplains, lagoons, embayments, salt marshes, and mangroves, are some of the most valuable global resources in terms of both socioeconomic interest and cultural–natural heritage [...]

Large volumes of peatland deposits characterise the Holocene stratigraphy of the Po Plain. A combination of sedimentological and pollen-based paleoenvironmental analyses enables recognition and stratigraphic correlation of small-scale (2-5 m thick) packages of peat-bearing strata, stacked rhythmically in a retrogradational to progradational set and bounded by chronostratigraphically significant surfaces. Across these repetitive lithofacies successions, the proportion of facies-controlled palynomorphs is used as a diagnostic signature to characterise marine flooding surface equivalents (helophytes and hydrophytes) and shoaling-upward (terrestrialization) trends (trees and mesophilous herbs) that record systematic variations in groundwater table associated with increasing/decreasing accommodation. Paludification surfaces at the base of peats delineate the updip (freshwater) equivalents of brackish/marine flooding surfaces recognized at seaward locations atop peat layers (give-up transgressive surfaces). Peat beds exhibit maximum thickness in aggradational strata of the lowermost highstand systems tract, above the maximum flooding surface (MFS). An extrinsic control due to eustatic rise can be inferred for peat development in transgressive deposits: peats, in particular, reveal warmer climates at flooding surfaces (specifically around the MFS) that invariably coincide with rapid shifts to deeper depositional environments. Under highstand conditions, autogenic mechanisms affected base-level changes in the paralic swamps. At this stratigraphic level, peat-bearing strata primarily reflect subtle changes in accommodation due to distributary-channel avulsion, subsidence, and peat autocompaction. Detailed patterns of Holocene peat distribution on millennial timescales can help decipher multiple high-resolution accommodation cycles developed in the rock record on sub-seismic scales, resulting in an improved stratigraphic analysis and prediction of chronologically less constrained non-marine successions.

Benthic ostracods and foraminifers are commonly applied as paleoenvironmental indicators in shallow marine successions, ignoring that individual meiofaunal groups could provide distinct information. We aim to shed light on the distinct paleoecological record of benthic ostracods and foraminifers by analyzing the shallow marine Holocene succession of the Po Delta (Italy) in a sequence stratigraphic fashion. Multivariate elaborations connecting the modern North Adriatic reference set to fossil data allowed to investigate community dynamics, obtain quantitative estimates of (paleo-)environmental drivers and assess the meiofaunal response to coastal and delta dynamics through time and space under the influence of allogenic and autogenic factors. Benthic ostracods and foraminifers easily discern transgressive (TST) and highstand (HST) systems tract, and also discriminate between locations at different distance from paleo-river mouths under highstand conditions. Specifically, community changes reflecting shifts in delta regimes at distal locations suggest that lobe-fringe deposits are more indicated for paleoenvironmental purposes. We emphasize that a deep knowledge of the analyzed datasets should drive the interpretation of multivariate outputs, as reconstructed values from significantly similar deposits could be inappropriate, and the lack of true modern analogs could reflect authentic differences in community composition, or either pitfalls in the modern reference set. Our results show that ostracods evidence depositional regimes determined by the interplay of sediment supply and hydrodynamic energy in relationship with the position from main river outlets; on the other hand, foraminifers highlight changes in riverine inputs in terms of organic matter. Our findings demonstrate that shallow marine benthic ostracods and foraminifers provide distinct but complementary paleoecological information, and their integration allows to achieve high-resolution reconstructions.

ABSTRACTFramed into a robust stratigraphic context, multivariate analyses on the Holocene palaeobiological record (pollen, benthic foraminifers, ostracods) of the Po coastal plain (NE Italy) allowed the investigation of microtidal ecosystems variability and driving parameters along a 35‐km‐long land–sea transect. Millennial‐scale ecosystem shifts are documented by coeval changes in the meiofauna, reflecting variations in organic matter–water depth (shallow‐marine environments) and degree of confinement‐salinity (back‐barrier settings). In‐phase shifts of vegetation communities track unsteady water‐table levels and river dynamics in freshwater palustrine areas. Five environmental–ecological stages followed one another crossing four tipping points that mark changes in relative sea level (RSL), climate and/or fluvial regime. At the culmination of Mediterranean RSL rise, after the 8200 event, remarkable growth of peatlands took place in the Po estuary, while low accumulation rates typified the shelf. At the transgressive–regressive turnaround (~7000 cal a bp), the estuary turned into a delta plain with tidally influenced interdistributary embayments. River flow regime oscillations after the Climate Optimum (post‐5000 cal a bp) favoured isolation of the bays and the development of brackish wetlands surrounded by wooded peatlands. The youngest threshold (~800 cal a bp), which led to the establishment of the modern delta, reflects a major avulsion of the Po River.