United States

Nowadays, given their fundamental importance, the application of coastal sand dunes’ restoration plans is widespread and they are usually aimed at reactivating the natural dynamics of two main components, often compromised: the morphological integrity and the vegetation growth. The aim of this work is to propose a relevant and low-cost methodology for monitoring this kind of restoration projects, which contemplates a simultaneous survey of the geomorphological component as well as the vegetational one. An Unmanned Aerial Vehicle (UAV) was applied to survey these two components’ trend, by means of building high‐resolution Digital Surfaces Models (DSMs) and RGB orthophotos, in an area in the North Adriatic Sea (Punta Marina, Ravenna, Italy): the local coastal environment is particularly suitable because it includes a residual coastal dune system, damaged by decades of erosion and fragmentation by human intervention. The are was recently the subject of a restoration project aimed at limiting its deterioration as well as enhancing dune stability by the construction of walkways and the introduction of vegetation. RGB data from the drone’s photographs were used to identify the spectral signature of vegetation in the visible part of the spectrum as well as that of bare sand. This allowed to monitor changes in the relative cover area extension (vegetated Vs not vegetated) in time. Elevation data from high‐resolution DSMs were used to identify and monitor changes (considering every source of error) of the principal morphological features, such as the Dune Foot Line (DFL), the Dune Crest Line (DCL), the Dune seaward Crest Line (DsCL) and the Stable Vegetation Line (SVL). Both morphological data, as well as orthophotos analysis, confirmed a constant and progressive increase of the vegetated cover area and consolidation of the dune system following the restoration project. The proposed survey protocol resulted to be rapid, low‐cost and easily replicable by coastal managers to quantify the effectiveness of restoration projects.

SGI 2021

High resolution and automated monitoring methodology (UAV) for vegetation and morphological dynamics involved in restoration projects in coastal sand dunes environments.

Welcome Seabirders!  

Welcome to Virtual World Seabird Conference 3 - vWSC3! Whether you are in your office or lab, at home, in a coffee shop or bar poaching some wifi, or at a remote field site or research vessel – we are very excited to welcome you to the third ever World Seabird Conference. 

We would like to thank ALL of you for being so patient as WSC3 was scheduled, postponed, rescheduled, revised to virtual, and scheduled again. Throughout all those iterations there was one message that remained perfectly clear – seabirders were eager to meet and share their science. If we could not meet in person then virtual it would have to be, but a 3rd WSC was something everyone wanted. That support and commitment helped the WSU Board of Directors and Member Societies sort through all of the challenges they faced to plan and hold this conference. 

The list of those that need to be thanked is long and, while we plan on recognizing many during the live closing plenary, it is important to do so here in writing as well. 

The Australasian Seabird Group was our Local Host for our plan to meet in Hobart, Tasmania. They invested substantial time and effort to find venues and plan events that we unfortunately were not able to visit. Nonetheless we appreciate their work on behalf of WSC3 and encourage all of you to thank them when you see their members in Gathertown or elsewhere during our virtual meeting. Their willingness to host created the initial excitement for WSC3 and without that our vWSC would not have been possible.

We also wish to thank the Science Program Committee, the Virtual Committee, and the Early Career Scientist Committee for their hard work planning the logistics, events, and schedule for vWSC3. These committees also had to deal with changing parameters and short timelines that made what is always a challenging task even more challenging. The Travel Awards Committee also invested time and effort in developing procedures for awarding travel funds that ultimately would not be implemented. 

Our ability to shift from an in-person to a virtual meeting, and to do so in a way that would be financially feasible, was due to the effective efforts of The International Fundraising Committee and to our financial sponsors. The IFC raised funds to support WSC3 and then, through the good relationships they built with sponsors, ensured we could re-envision how those funds could be used to support a virtual conference that would be affordable and high-quality.

We all owe the WSU Board of Directors and the Representatives of the Member Societies a great deal of thanks. They are the ones who manage the WSU and, for the past 18 months, have had to have a series of challenging meetings and conversations, have had to make a series of difficult choices, have had to do all of that while considering the short- and long-term health of WSU and the World Seabird Conferences, and did this while also managing their own challenges at their day jobs. We are grateful for their diligence, patience, foresight, and throughout all of the meetings, their collegiality. Also – a 6-year term is quite a commitment!

There would not be a WSC3 without a successful WSC1 and WSC2. Thanks go to the Pacific Seabird Group for their support of WSC1 in Victoria, Canada, and to the African Seabird Group for their support of WSC2 in Cape Town, South Africa. In each of these endeavors and for our current conference we were fortunate to work with a dependable and trustworthy partner in Podium Conferences. Michelle Smith and Marischal de Armond have become valued members of our team and have not only helped us plan conferences but have assisted and advised the WSU Chairs and Board on issues above and beyond conference planning. 

As we embark on our vWSC3 week we extend to all of you our thanks for showing up, for being patient, and most importantly for the work you do with seabirds. We are all part of a unique, global community that shares an interest, a fascination, and a passion for birds that make a living in our world’s oceans. We have advanced the science, conservation, and management of seabirds as well the ecosystems they inhabit. We are consistently impressed and motivated by the work you do. 

The WSU formed in 2010 because we saw the need for a global organization to address challenges at a global level. Over the past 11 years WSU has grown, adapted, and evolved to become the community that this week is making vWSC3 a reality. Enjoy the week, appreciate and support the friends and colleagues you have made in the community, and if you see us in a virtual hallway please stop and say hello! 

Thank you for the opportunity to serve all of you and the WSU over the past few years,

Nicholas Carlile, Interim Chair, WSU<br>
Patrick Jodice, 2nd Chair of the WSU<br><br>

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3rd World Seabird Conference

Join us for four days of science, networking and virtual engagement with delegates from around the world!

technical paper

**Attenzione, gli orari riportati nel PROGRAMMA (icona calendario) si riferiscono al fuso orario locale dell’utente. Il fuso orario ufficiale del Congresso è Central European Time (CET).**

L'Istituto Nazionale di Oceanografia e Geofisica Sperimentale - OGS e il Dipartimento di Matematica e Geoscienze dell'Università di Trieste sono orgogliosi di ospitare il 90° Congresso della Società Geologica Italiana a Trieste dal 14 al 16 settembre 2021. La modalità del congresso è interamente online.

Con il motto "Geologia senza frontiere" questo evento mira a promuovere le Scienze della Terra come disciplina scientifica proiettata nel futuro, oltre i confini geografici, politici e disciplinari, per comprendere meglio l'interno del Pianeta Terra e la struttura del sottosuolo, difendere la società da pericolosi eventi geologici, comprendere meglio la variabilità climatica, pianificare l'utilizzo delle georisorse in modo etico e nel rispetto dell'ambiente.


**Please note, times listed in the SCHEDULE tab (calendar icon) reflect YOUR LOCAL TIME ZONE. The main timezone for this conference will be Central European Summer Time.**

The National Institute of Oceanography and Experimental Geophysics - OGS and the Department of Mathematics and Geosciences of the University of Trieste are proud to host the 90th Congress of the Italian Geological Society in Trieste on 14-16 September 2021.  The Congress will be held entirely online.

With the motto "Geology Without Borders" this event aims to promote Earth Sciences as a scientific discipline projected into the future, beyond geographical, political and disciplinary boundaries, to better understand the interior of Planet Earth and the structure of the subsurface, defend society from dangerous geological events, better understand climatic variability, plan the use of geo-resources in an ethical way and respecting the environment.


Welcome to the SGI2021 virtual conference.  In order to access the conference and content, [please register for the meeting here](https://www.geoscienze.org/trieste2021/index.php/registrazioni/registrati)

Please register for the SGI conference to join the event.

Earth Sciences should be understood not only as necessary for a better understanding of the interior of the planet Earth, but also as a defense of society from dangerous geological events, for the understanding of climatic variations, for the planning and use of georesources in a ethical and respecting and protecting the environment.

The Siele mine and its smelting plant are part of the world class Monte Amiata mining district (MAMD – Tuscany, Italy). The mine is located close to the Siele creek (c.), which drains the mining area, then flows to the Paglia River (R.), which in turn is an affluent of Tiber River, flowing through the city of Rome to the Mediterranean Sea. After closure in 1981, the mining area was subjected to the first reclamation in the district (and at the worldwide scale), completed in 2001. In this study, we present new data on Hg concentrations in soils, stream sediments, and air in the Siele mining area and along the Siele c., and we review all previously available data, with the aim of quantifying the Hg contribution from the Siele c. into the Paglia R., and of documenting the evolution of the system following mine reclamation. Hg concentrations (up to 5400 mg/kg) in stream sediments are comparable to pre-reclamation values in the first 500 m downstream the mine site. They decrease downstream to the confluence with the Paglia R., but remain anomalous (i.e., above the 1 mg/kg Italian law limit for residential soil). Comparison of pre- and post-remediation data of gaseous elemental mercury (GEM) in air shows that Hg0 emissions in most of the sites within the Siele mining area are lower than pre-reclamation values, but in few outdoor sites, levels are still high (up to 9500 ng/m3), exceeding the existing regulatory limits (“Norma Amiata”: 300 ng/m3 in outdoor sites). On the other hand, Hg mobility, determined by leaching tests, is mostly below the limits defined by pending regulations (1 μg/L), and methyl-Hg concentrations are mostly below 1 ng/kg (with a single value of 6 ng/kg). Results show the Siele c. plays a role by no means negligible in the general picture of the contributions of Hg in the Paglia R. basin, proving to be one of the most critical areas of the entire MAMD. Indeed, concentrations of Hg in sediments and soils in the Siele c. are comparable to those of the Pagliola c., draining the Abbadia S.S. mine (the main site of the MAMD), where reclamation is still under way. Moreover, despite remediation works, Hg emissions from contaminated soil will represent a significant contribution to the atmospheric load of Hg in the future, if no further remediation action is taken. The Siele system has a low resilience and natural recovery will take many years (probably decades), during which the area will remain an important source of Hg for the Paglia and Tiber River systems, and eventually for the Mediterranean Sea. This study provides important background data for local authorities to implement monitoring strategies and find new remediation plans based on the identified critical area. Further, at a global scale, this work contributes additional data to the assessment of the global Hg budget to the atmosphere and the hydrosphere.

Low resilience of a mercury mining area after reclamation: the case of the Siele mine (Mt. Amiata Mining District, Italy)

Video cameras has been widely used in coastal engineering since their first applications in the late Eighties. The main advantages of the video monitoring techniques are a continuous monitoring of the observed region in time, an adequate spatial resolution, and a relatively simple technology to acquire and transfer data. Many studies applied video monitoring techniques to evaluate the shoreline evolution of a littoral (Archetti and Romagnoli, 2011), to reconstruct the intertidal beach or even to extrapolate the whole nearshore (Aarninkhof et al., 2005), thanks to the wave transformation which occurs when waves approach the shore. However, several limits are still present in the current applications. For instance, video cameras are usually quite expensive, produce a huge amount of data and are not always easily managed in near-real time from remote users. Furthermore, current instrumentation and software are mostly commercial. Here, we present a new tool which uses a Raspberry Pi for the development of a smart camera at very low costs. The software scripts, originally realized in MATLAB (Archetti et al. 2020), are also available in Python and OpenCV for open access implementations. At the current state, the low-cost smart camera (LCC) can acquire images, transfer data, perform on-line rectification and off-line post-processing (e.g., shoreline extrapolation and intertidal bathymetry reconstruction) with a minimum human intervention, which is practically limited to a validation of the results. For coastal video monitoring purposes, next future implementations aim to completely automate on-line analyses, and to implement further scripts (e.g., cBathy, see Holman et al., 2013) on Python. Possible evolutions of the video station include the development of machine learning for several environmental applications.

A low-cost camera for coastal video monitoring

Sediment transfer in mountain streams occurs via processes classified as debris flows, debris floods, and water flows. The analysis of the sediment-water flows occurring during high-magnitude floods is currently a scarcely explored issue. This knowledge gap is particularly striking for the debris floods, a water-driven flood flow with extremely high bedload transport that has been rarely investigated. This study investigates how the transport mechanisms activated in a mountain stream during a high-magnitude flood differ from those triggered during ordinary floods, focusing on the controlling factors and conditions required for debris flood occurrence. The study area is the Tegnas catchment (drainage area 51 km2), a mountain basin of the Dolomites (northeastern Italy) affected in October 2018 by a severe flood (Vaia Storm), whose recurrence interval has been estimated to approximately 200 years. We developed a post-flood survey protocol for distinguishing various flow types based on the features of the flood deposits. The transport processes typifying the stream network during ordinary floods and those occurred during the Vaia Storm were determined through the field survey of the deposits. We observed water flow as a response to ordinary events occurring along the entire Tegnas main stem. During the Vaia Storm, water flow still dominated, although debris floods were documented at several sub-reaches. The unit stream power induced by the Vaia Storm was calculated based on the peak discharge computed at the sub-reach scale using a rainfall-runoff model, and channel widening was determined measuring the pre- and post-Vaia channel width. The comparison between the high-magnitude and the ordinary flows allowed us to infer the existence of relationships between the transport mechanisms, the hydraulic forcing, and channel dynamics. The upheaval of the ordinary flow types did not occur along the entire stream network: water flows transitioned into debris floods only under unit stream powers exceeding the threshold of 5500 Wm–2 or downstream of sediment-injection sites. Debris floods occurrence appears to be facilitated by tributaries prone to debris flow and connected to the receiving stream, the injection of fine material into the flows (which can occur as consequence of channel-bank erosion or overbank floodwater re-entering the channel), and channels characterized by high slope and relative narrow section. The occurrence of debris floods caused higher channel widening than that induced by water flows. The complex relationships found between flow types and a range of controlling factors reveal that a detailed characterization that includes field observations is necessary to understand the transport mechanisms that can affect a specific channel site during high-magnitude hydrological events for an accurate and reliable definition of flood hazard at the local (e.g., sub-reach) scale.

Debris floods in mountain streams: Insights from the Vaia Storm (October 2018) in the Tegnas catchment (Dolomites, Italy)

Several heavy precipitation events causing flash floods, debris flows, landslides, and morphological channel changes have occurred in Europe over the last years. In mountain environments, mass movements along the hillslopes are important sources of sediment supply to the rivers, and may enhance the geomorphic effects of floods. The Stolla creek (catchment area: 40 km2) is a confined/partly confined channel of the Dolomites (Easter Italian Alps), that was affected by an extreme flood in August 2017, and by a moderate flood in August 2020. The geomorphic effects of the two floods were investigated in the main channel and along the hillslopes with the aims: to compare the channel changes induced by the two events; to assess the impacts of the lateral sediment connectivity to the channel response. A multi-methodical approach was applied, including radar rainfall estimation, rainfall-runoff modeling, field surveys, remote sensing, geomorphological and statistical analysis. Hillslope and channel processes were mapped by comparing multitemporal orthophotos and Digital Terrain Models. Debris-flow connectivity to the main channel was derived by combining field evidence and geomorphometric analysis. The 2017 flood was caused by rainfall with a short duration (6 hrs) and a rain rate exceeding 45 mm in one hour. More than 600 debris flows were triggered along the hillslopes, among which 23 were connected to the Stolla. Important discontinuities for the sediment flux were represented by the floodplains. The Stolla channel experienced channel widening occurred through bank erosion, and overbank depositions. With ratio (ratio between the channel width after and before the flood) was between 1.3 and 4.9. Widening was accompanied by channel bed aggradation up to 1.2 m or incision up to -2.2 m. Widening through bank erosion was more common in narrower reaches, affected by higher flood power, and presenting higher connectivity with debris flows. Although 294,000 m3 of sediments were eroded in the connected debris flows and 12,380 m3 were transferred to channel from toe erosion processes, limited volumes of sediments (< 1000 m3) were exported to the catchment outlet. The 2020 flood event was characterized by a lower rain rate (max 17 mm h-1) and a long duration (48 hrs) and did not trigger debris flows. The moderate magnitude of the flood peak did not lead to channel widening, but only bed incision (up to -1.4 m) in the reaches where the 2017 event had caused channel-bed aggradation occurred. 

Catchment response to different severity storm floods: channel variations and hillslope sediment coupling dynamics

The Apuan Alps are a mountain range in northern Tuscany exploited for the famous Carrara marble since the Roman age. The Apuan quarrying district currently comprises about 150 quarries and most of them are located at high elevations. Marble blocks are cut and re-squared by means of line drilling and various sawing techniques, diamond wire and chain saw being the most used. Such quarrying activities produce a fine marble powder that frequently mixes up with meteoric water, producing a slurry that can easily infiltrate into the karst aquifers through solution-enlarged fractures. Depending on the aquifer hydrodynamics, the marble slurry can eventually reach the karst springs, thus contaminating high quality waters generally used for the human consumption. Several samples of marble powder, karst spring deposits, and stream sediments were collected and analyzed for their mineralogical, morphological and sedimentological characterization, to evaluate the degree of pollution of the Apuan karst aquifers. Quarry powder samples are mainly made up of calcite crystals, whereas spring and stream sediment samples have variable proportions of calcite, silicates, and dolomite grains. The clasts from marble powder produced by diamond wire and chain sawing have constant morphological features, whereas the sediments collected in filtering tanks and disposal bags exhibit more heterogeneous characteristics. The quarry powders are generally finer than the sediments, although some overlap occurs probably because of marble powder contamination in the sediments themselves. The most polluted spring samples are characterized by a predominant calcite component that is finer than the silicate one. The same occurs also for the stream samples. Spring samples also show homogeneous morphometric features that are probably related to both marble powder contamination and the transport mechanisms through the karst aquifers. Marble powder pollution appears to be widespread in most of the Apuan karst springs, thus affecting the aquifer hydrodynamics and water quality.

Physical pollution of karst aquifers caused by marble quarrying: the case of the Apuan Alps, Italy

River waters may respond gradually or suddenly to natural or anthropic disturbances by varying their chemical composition. Understanding the nature of these complex interactions plays a crucial role in our fast-changing planet threatened by climatic and human-induced changes. In this work, water chemistry is analyzed as a whole by focusing on its interconnections with hydro-litho-morphologic and anthropic pressures at a basin-wide scale. This implies the introduction of the concept of regime shift, which has been widely applied to study the resilience of ecological systems to environmental perturbations. We propose to transpose this idea to geochemistry by considering Geochemical Regime Shifts (GRSs) as abrupt and permanent changes in the system state (composition) of a given environmental media, triggered by external or inner perturbations (Gozzi et al., 2021). From this perspective, river water composition represents a response variable resulting from the synergic action of environmental drivers and catchment properties. The aim of this study is to detect potential spatial GRSs in the water chemistry of the Tiber River, the third-longest Italian river. To reach this aim potential forcing variables (e.g. land use, terrain slope, human impact and lithology) were considered and estimated for all nested watersheds. Compositional Data Analysis, Robust Principal Component Analysis and score-distance graphs were used to explore data variability and the nature of driver-system state relationships. In the lower reaches, a potential regime shift was identified for major species suddenly changing the water composition from a relative prevalence of N-bearing species to that of Na+ and Cl-. The regime shift scenarios described by Andersen et al. (2008) suggest that the observed shift might represent a threshold-like state response triggered by lithological forcing. Conversely, no abrupt changes were detected for trace elements which instead seem to respond gradually to environmental pressures. The research offers new perspectives for future studies and for a deeper understanding of the circumstances controlling river system’s self-restoring capability.

Detecting Geochemical Regime Shifts in the compositional dynamics of the Tiber River waters (Italy)

Mercury (Hg) contamination in the Gulf of Trieste (GT, northern Adriatic Sea) is due to historical mining activity at Idrija (Slovenia) and still represents an environmental issue of great concern (Covelli et al., 2001; Covelli et al., 2021). Indeed, the freshwater inputs from the Isonzo/Soča River have been identified as the main source of Hg into the GT. At the river mouth, the element was found to be mainly associated with the suspended particulate matter, especially following periods of medium-high river discharge and river plume events in the GT (Covelli et al., 2006; 2007) The primary aim of this research is to evaluate the occurrence and distribution of both dissolved (DHg) and particulate (PHg) Hg along the water column in the northernmost sector of the GT, a shallow and sheltered embayment suitable for the accumulation of fine sediments and contaminants. In order to achieve this objective, sediment and water samples were collected at six sites which were representative of different targets, such as mussel farming and tourism activities. Moreover, different environmental conditions including unperturbed and perturbed hydrological conditions, induced by both natural and anthropogenic factors, were taken into account. The amount of Hg in the surface sediments (0.77–6.39 µg g-1) as well as the relationship between the Hg concentration and the percentage of the 2-16 µm grain size fraction from this study were found to be consistent with previous research focused on the whole Gulf, thus testifying the common origin of the sediment. Results showed a notable variability of DHg (0.07–149 ng L-1) and PHg (0.39–12.5 ng L-1) depending on the interaction between riverine and meteo-marine hydrological conditions at the time of sampling. Mercury was found to be mainly partitioned in the suspended particles and elevated values of PHg were observed following periods of high discharge from the Isonzo/Soča River confirming that the river discharge may represent an important factor in regulating the amount of PHg in the GT.

Mercury in the water column of the Gulf of Trieste is still an environmental issue: the legacy of the Idrija mine twentyfive years after its closure

The gaseous exchange of mercury (Hg) at the water-air interface represents an important aspect of the biogeochemical cycle of this element in the environment. Particularly at sites impacted by Hg due to anthropogenic activities, evasion can contribute to reduce the amount of this metal in the water column, but also to widen its spreading in the environment due to the long-range atmospheric transport of the element (Driscoll et al., 2013). However, dynamics of gaseous elemental Hg emissions from the water-air interface at Hg contaminated sites are still poorly characterised. In this work, Hg evasion fluxes were monitored by means of a flux chamber coupled with a real-time gaseous Hg analyzer (Lumex RA915M) in 3 freshwater environments characterized by different contamination legacy: the artificial reservoir of Solkan (SK-Slovenia) along the Isonzo River, where Hg contaminated sediments due to cinnabar extraction activities at the Idrija Hg mine have been accumulated since 1984, date of the dam construction; the dock near a chlor-alkali plant at Torviscosa (TR-Italy); the Cavazzo Lake (CV-Italy), chosen as pristine environment with no known Hg sources. At each site, 6 distinct sets of flux measurements were performed at regular time intervals during the diurnal period in 3 different seasons (spring, summer, and autumn). Moreover, the concentrations of dissolved gaseous mercury (DGM) were monitored during the sampling period together with total dissolved Hg, incoming UV radiation and main water physico-chemical parameters. As expected, at all sites the highest Hg fluxes were found in summer, due to higher irradiation, which favours the formation of volatile DGM through photoreduction, and higher water temperatures, which decrease the solubility of Hg. On average, Hg evasion fluxes found in this study were higher than those reported in literature for other background freshwater environments. Surprisingly, Hg fluxes at CV site were comparable to those of the other sites, likely due to re-emission of Hg of atmospheric origin, but further research is needed to confirm this hypothesis. The widest diurnal variability of Hg fluxes was observed at TR site, located inside an industrial complex, and likely related to irregular supplies of Hg through atmospheric depositions and water circulation. Conversely, SK and CV showed a more regular trend, confirming that Hg fluxes are strongly influenced by local conditions and site-specific interaction of different factors. Based on these results, the investigated sites can be considered as secondary sources of Hg for the atmosphere, underlining the importance of direct Hg fluxes monitoring to understand its fate in the environment.

Gaseous mercury evasion from the water-air interface at freshwater environments impacted by different anthropogenic sources

Research studies and numerical models in coastal geomorphology often rely on short to medium-term datasets (months to years), normally depending on available financial resources to enrol employees or adopt up-to-date surveying technologies. Lately, satellite images have largely benefit long-term analyses of coastal change, extending the temporal investigation up to few decades, but limitations related to temporal coverage and spatial resolution remain. An unexploited source of information is represented by historical data, but modern coastal geomorphologists do not take advantage of them due to their poor reliability and accuracy, especially if compared to modern technologies. The keynote will explore a new chance to build long-term datasets of coastal change through the revalue of historical data with modern techniques of Structure-from-Motion (SfM), GIS analyses and reliable estimation of spatial errors. Reliable geographic data were extracted from different sources available from historical archives (i.e., aerial photos, maps, bathymetric charts, topographic data pre-DGNSS era, military reports, newspapers, etc.) for the coastal site of Dundrum Bay in the Irish Sea (Northern Ireland, UK). Historical maps and aerial photographs were analysed to extrapolate 23 shorelines and quantify almost 200 years of shoreline change (1833 to 2020). Vertical aerial photographs were processed thorough SfM techniques to build 3D models and calculate volumetric change of the extensive local coastal dune for the last six decades (1963 to 2020). Geomorphic changes were discussed considering local forcing parameters (wave, wind, water level) from historical or hindcasted datasets available (1901 to 2020). Advantages and limitations of each ‘revaluation’ technique of the historical data were considered. Several potential errors are associated with historical coastal data; however, their advantage is to provide a quantifiable record when other (more accurate) data sources are not available. In the pre-satellite era (pre-1970’s), historical geographic data are the only available source, and they have also the advantage to be coeval with the increase of human pressure on the coast (post Industrial Revolution and post WWII). Long-term datasets are crucial for decision makers, often divided between warnings from the scientific community and the will to give effective and immediate response to concerns from the coastal communities. Adaptation strategies for coastal environments are often conceived without a long-term perspective which is partially caused by the lack of reliable long-term data. In a current situation of rapidly improving machine learning techniques, reliable long-term datasets are crucial to feed algorithms and better refine models of future coastal behaviour, especially in a context of sea level rise and climate change.

Revalue historical data to overcome the persistent lack of long-term datasets in coastal geomorphology: examples from Northern Ireland.

The foreseen global sea level rise threatens the most vulnerable coastal morphotypes, as the barrier islands. Their resilience is linked to processes of sediment deposition, mostly where a high sediment supply occurs, via a source-sink pathway or through cannibalization. Along the barrier islands of the Grado Lagoon (North Adriatic Sea), a system of submerged sand banks (called Mula di Muggia Bank, MMB) extends up to 2 km seawards and their rapid evolution induces conflicts with the touristic uses of the adjacent beaches. In order to quantify the past and present morphological changes and obtain the sediment budget, this work compared the aerial photographs from 1954 to 2019 and topo-bathymetric data (1968, 1985, 2007 and 2019). The temporal morpho-evolutionary analysis shows the preservation of a wide succession of intertidal and subtidal sandy bars, which migrate toward southwest. The migration follows the main littoral drift generated by waves along the sedimentary pathway of the only fluvial source, the Isonzo River. Down-drift, on the western terminus, the bank curves abruptly, inducing bars to shift landward toward the touristic beaches. Therein, sediment tends to accumulate over time, and the area is currently the final sedimentary sink for the entire coastal compartment. The sediment budget from 1968 to 2019 confirms two markedly positive budget sectors: the eastern one, adjacent to the sedimentary source of the Isonzo River, and the westernmost sector, as the trap of the longshore littoral path. Conversely, in the central tract a stable budget would indicate an area of sediment bypass. Here, the deposition prevails on the shallow zone, whereas beyond the -2.5m depth an erosive dynamics occurs with an increase in the steepness of the bank’s outer limit. The causes of these complex dynamics are still unknown, but the role of a bimodal wave regime must be considered: it acts in the opposite way on the seabed at different depths. Moreover, the bimodal wave regime explains the landward shift of the sandy bars in the western area where the influence of the southern swell waves is greater. Despite the cannibalization of the central tract, the very high positive budget resulting in the western sink area of the MMB (about 3 million m3 in 51 years) is difficult to explain in the regional context. In the lack of direct measurements, our hypothesis suggests the effect of climate changes in hydrological and solid regime of the fluvial source could exert a main role in the sedimentary dynamics. Longer summer drought and subsequent greater intensity of late autumn/winter precipitation likely lead to an increase of the Isonzo River solid discharge. Moreover, part of the sediments eroded by the deeper seabed could supply the sedimentary source of the Isonzo river delta, thus increasing the littoral drift.

High resolution and automated monitoring methodology (UAV) for vegetation and morphological dynamics involved in restoration projects in coastal sand dunes environments.

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Low resilience of a mercury mining area after reclamation: the case of the Siele mine (Mt. Amiata Mining District, Italy)

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High resolution and automated monitoring methodology (UAV) for vegetation and morphological dynamics involved in restoration projects in coastal sand dunes environments.

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Next from SGI 2021

Low resilience of a mercury mining area after reclamation: the case of the Siele mine (Mt. Amiata Mining District, Italy)

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