Special Issue "Coastal and Continental Shelf Dynamics in a Changing Climate"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Oceans and Coastal Zones".

Deadline for manuscript submissions: 31 July 2021.

Special Issue Editors

Dr. Serafeim E. Poulos
E-Mail Website
Guest Editor
Department of Geography and Climatology, Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, 15772 Athens, Greece
Interests: environmental oceanography; physical geography; coastal landforms; nearshore morphodynamics; coastal erosion
Dr. Vasilios Kapsimalis
E-Mail Website
Guest Editor
Institute of Oceanography, Hellenic Centre for Marine Research, 46.7 km Athens-Sounio Ave., 19013 Anavyssos, Greece
Interests: marine geology; coastal geomorphology; sediment quality assessment; dredged material management; coastal erosion; underwater geoarchaeology
Dr. Ioannis P. Panagiotopoulos
E-Mail Website
Guest Editor
Institute of Oceanography, Hellenic Centre for Marine Research, 46.7 km Athens-Sounio Ave., 19013 Anavyssos, Greece
Interests: marine sedimentology; marine geology; seabed morphology; sediment dynamics; environmental oceanography

Special Issue Information

Dear Colleagues,

In an ever changing Earth, coastal areas and continental shelves represent the dynamic transition zone between the land and ocean, including a variety of geomorphic features as well as rich living and non-living natural resources. They are also extremely important systems that enhance prosperity in many societies by integrating ecosystem services and several uses (e.g., agriculture, tourism, fishing, aquaculture, maritime transport). In particular, shelf seas contribute to climate amelioration and absorption of atmospheric gases including climatically-crucial greenhouse gases.

However, anthropogenic activities affect the natural evolution and, in many cases, even the connectivity of vulnerable coastal landforms (e.g., river deltas, estuaries, lagoons and beaches) by changing the availability and transport of sediments (either terrestrial or marine) and by intervening in the nearshore hydrodynamics through "hard" engineering constructions. Moreover, modification of freshwater influxes in association with climate variability (i.e., solar radiation, wind field) change the seawater temperature, shelf waters stratification and circulation patterns, while acidification enhancement poses a great risk to marine biota.

Based on the above, the research on coastal areas and shelf seas has to be increasingly focused on producing data and information to promote a science-based understanding of the changes in these environments with their consequences and to enable realistic assessments of the potential benefits and risks of human activities. Hence, the ambition of this Special Issue is to draw the attention of all environmental scientists in order to fill significant knowledge gaps related to pressures, impacts and trends in coastal areas and shelf seas, configured by the climate change and increased human presence.

We welcome innovative contributions, including collection and analysis of field observations or simulations with physical and numerical models, focusing on the topics (although provisional) referred to below:

  • Changes in hydrodynamics and sediment dynamics in relation (for example) to the impacts of sea level rise and modified storm intensities, coastal defence measures, dredging operations, offshore constructions, long-term coastal evolution and interactions of shelf seas with the ocean.
  • Anthropogenic impacts on shelf water’s biogeochemical cycles derived, for example, from changes in agriculture practices, dam operations, urban and industrial sewages, etc.
  • Biological changes (e.g., benthic biodiversity, food webs under the influence of new invasive species and climate change).

Prof. Dr. Serafeim E. Poulos
Dr. Vasilios Kapsimalis
Dr. Ioannis P. Panagiotopoulos
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access semimonthly journal published by MDPI.

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Keywords

  • Coastal landforms
  • Coastline evolution
  • Submarine geomorphology
  • Environmental oceanography
  • Marine sedimentology
  • Fluvial fluxes
  • Biodiversity
  • Biogeochemical cycles
  • Sea level rise
  • Seawater Stratification intensity
  • Coastal zone management

Published Papers (3 papers)

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Research

Open AccessFeature PaperArticle
Pre-Messinian Deposits of the Mediterranean Ridge: Biostratigraphic and Geochemical Evidence from the Olimpi Mud Volcano Field
Water 2021, 13(10), 1367; https://doi.org/10.3390/w13101367 - 14 May 2021
Viewed by 287
Abstract
This study presents the results derived from micropaleontological and organic geochemical analyses of mud breccia samples obtained (through gravity coring) from five mud volcanoes (Gelendzhik, Heraklion, Moscow, Milano, Leipzig) located at the Olimpi mud volcano field on the Mediterranean Ridge accretionary complex. A [...] Read more.
This study presents the results derived from micropaleontological and organic geochemical analyses of mud breccia samples obtained (through gravity coring) from five mud volcanoes (Gelendzhik, Heraklion, Moscow, Milano, Leipzig) located at the Olimpi mud volcano field on the Mediterranean Ridge accretionary complex. A thorough calcareous nannofossil semi-quantitative analysis was performed to determine the biostratigraphic assignment of the deep-seated source strata. Mudstone/shale clasts of different stratigraphic levels were identified and assigned to the Miocene nannofossil biozones CNM10, CNM8–9, CNM7, CNM6–7, and Oligocene CNO4/CNO5. A single mudstone clast from the Gelendzhik plateau, assigned to the biozone CNM10, demonstrated unique micropaleontological and geochemical characteristics, suggesting a sapropelic origin. Subsequently, the total organic carbon (TOC) content and thermal maturity of the collected mud breccias was evaluated using the Rock-Eval pyrolysis technique, and their oil and gas potential was estimated. The pyrolyzed sediments were both organic rich and organic poor (TOC >0.5% or <0.5%, respectively), with their organic matter showing characteristics of the type III kerogen that consists of adequate hydrogen to be gas generative, but insufficient hydrogen to be oil prone. However, the organic matter of the late Serravallian (CNM10) sapropelic mudstone was found to consist of a mixed type II/III kerogen, implying an oil-prone source rock. Full article
(This article belongs to the Special Issue Coastal and Continental Shelf Dynamics in a Changing Climate)
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Open AccessArticle
Potential Sources of Particulate Iron in Surface and Deep Waters of the Terra Nova Bay (Ross Sea, Antarctica)
Water 2020, 12(12), 3517; https://doi.org/10.3390/w12123517 - 14 Dec 2020
Viewed by 550
Abstract
The distribution of particulate Fe (pFe), suspended particulate matter (SPM), and other particulate trace metals were investigated in Terra Nova Bay as part of CDW Effects on glaciaL mElting and on Bulk of Fe in the Western Ross sea (CELEBeR) and Plankton biodiversity [...] Read more.
The distribution of particulate Fe (pFe), suspended particulate matter (SPM), and other particulate trace metals were investigated in Terra Nova Bay as part of CDW Effects on glaciaL mElting and on Bulk of Fe in the Western Ross sea (CELEBeR) and Plankton biodiversity and functioning of the Ross Sea ecosystems in a changing Southern Ocean (P-ROSE) projects. Variable concentrations of SPM (0.09–97 mg L−1), pFe (0.51–8.70 nM) and other trace metals were found in the Antarctic Surface waters (AASW) layer, where the addition of meltwater contributed to the pool with both lithogenic and biogenic forms. The deeper layer of the water column was occupied by High Salinity Shelf Water (HSSW) and Terra Nova Bay Ice Shelf Water (TISW) encompassing glacial water as confirmed by the lightest δ18O measured values. The concentration of pFe in TISW (11.7 ± 9.2 nM) was higher than in HSSW samples (5.55 ± 4.43 nM), suggesting that the drainage of material released from glaciers surrounding the area is relevant in terms of pFe contribution. Particulate Fe/Al and Mn/Al ratios were substantially in excess compared with the mean crustal ratios. Microscopic analyses confirmed that more labile Fe oxyhydroxides and authigenic MnO2 phases were present together with biogenic sinking material. Future expected increasing melt rates of these glaciers enlarge Fe input, thus having a greater role in supplying iron and counteracting the reductions in sea ice cover around Terra Nova Bay. Full article
(This article belongs to the Special Issue Coastal and Continental Shelf Dynamics in a Changing Climate)
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Figure 1

Open AccessArticle
Tidally Forced Saltwater Intrusions might Impact the Quality of Drinking Water, the Valdivia River (40° S), Chile Estuary Case
Water 2020, 12(9), 2387; https://doi.org/10.3390/w12092387 - 26 Aug 2020
Viewed by 884
Abstract
The Valdivia River estuary (VRE) located in south-central Chile is known as one of the largest estuarine ecosystems on the Pacific coast. This research aims to determine the intra-tidal and sub-tidal variability of saline intrusions into the VRE between November 2017 and March [...] Read more.
The Valdivia River estuary (VRE) located in south-central Chile is known as one of the largest estuarine ecosystems on the Pacific coast. This research aims to determine the intra-tidal and sub-tidal variability of saline intrusions into the VRE between November 2017 and March 2019 derived from salinity sensors located along the VRE. Complementary hydrographic measurements were conducted during flood and ebb conditions of the spring and neap tides for each of the four seasons of the year along the central axis of the VRE. The results of the salinity time series showed that saline intrusions (values greater than 0.5 Practical Salinity Units) occurred ~20 km from the estuary mouth, when the total flow of the Cruces and Calle-Calle rivers (main tributaries of the estuary) was low, around 280–300 m3 s−1. During the same period, the best co-variability was observed between the saline intrusions and the mixed-semidiurnal tide and the fortnightly and monthly periods of the tide. Regression analyses indicated that salinity intrusion length (L) is best correlated to discharge (D) with a fractional power model L α D−1/2.64 (R2 = 0.88). The decreasing discharge trend, found between 2008–2019, implies that saline water intrusions would negatively impact the Valdivia’s main drinking water intake during the low rainfall season under future climate conditions. Full article
(This article belongs to the Special Issue Coastal and Continental Shelf Dynamics in a Changing Climate)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

1. Quality assessment of the sediments in the Lake Butrint and the adjacent coastal area of SW Albania

Vasilios Kapsimalis 1,*, Lavdie Moisiu 4, Ioannis P. Panagiotopoulos 1,3, Çerçis Durmishi 4, Georgios-Angelos Hatiris 1,2 and Ioannis Hatzianestis 1

1    Hellenic Centre for Marine Research, Institute of Oceanography, 46.7 km Athens-Sounio Ave., 19013 Anavyssos, Greece;

2    Hydrobiological Station of Rhodes, Cos Street, 85131 Rhodes, Greece;

3    National and Kapodistrian University of Athens, School of Science, Faculty of Geology and Geoenvironment, University Campus, 15784 Zografou, Greece

4    Polytechnic University of Tirana, Faculty of Geology and Mining, Rruga Elbasanit, 1000 Tirana, Albania;

Abstract: The Lake Butrint is a salty ~23-m-deep elongated lagoon of tectonic origin (~6.8 km long and ~3.3 km wide, with the volume of the lagoon basin estimated at 0.22 km3), located on the SW coast of Albania and connected with the Ionian Sea (Eastern Mediterranean) through the natural Vivari Channel. It is surrounded by dense forested hills and rocky coast, and complemented by saltwater and freshwater marshlands. The southern part of the lake is situated within the boundaries of the Butrint National Park and is a wetland site designated to be of international importance under the Ramsar Convention. In addition, the lake is considered as a significant bird and plant area, because it supports remarkable numbers of bird and plant species. Sediment quality has been broadly recognizing as an important and sensitive indicator or geo-marker of environmental pollution in water bodies, since sediments can act as a 'sink' for various pollutants, which have been discharged into the environment. Hence, the quality assessment of the sediments in the Lake Butrint and its neighbouring coastal area in the Ionian Sea was determined, based on the contents of heavy metals (HMs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethanes (DDTs). The elemental and organic chemical analyses showed that the contents (mg kg-1 dw) of priority HMs in the lagoon are 11.0±2.6 for As, 0.125±0.081 for Cd, 340.0±78.0 for Cr, 38.8±11.8 for Cu, 0.117±0.066 for Hg, 220.7±67.0 for Ni, 18.4±3.1 for Pb and 104.0±30.3 for Zn, while the contents of organic substances (μg kg-1 dw) are 132.5 ± 51.9 for the total PAHs (sum of 32 compounds), 0.45 ± 0.20 for the total PCB (sum of 13 congeners) and 1.23 ± 1.29 for the total DDTs (p,p-DDT and its metabolites p,p-DDE and p,p-DDD). The application of reliable chemometric indicators (e.g. Enrichment Factor, Geoaccumulation index, Combined Contamination Index, Modified Contamination Degree, Ecological Risk Index and Toxicity Response Index) together with the use of widely-used Sediment Quality Guidelines (e.g. ERL/ERM and TEL/PEL thresholds) indicate an unpolluted to a slightly polluted environment. This has rather been resulted by the abandonment, for several decades, of the agricultural operations based on the communal agriculture model applied in the nearby plains of Vurgu and Vrina. Thus, the achievement of the desired good environmental status is of huge benefit for the Lake Butrint, since this superb site has been also designated as a Cultural Monument since 1948 and as an outstanding Word Heritage Property in 1992 and 1999.

Keywords: chemometric assessment of pollution; Sediment Quality Guidelines, environmental status, Ramsar site

 

2. Late Glacial marine transgression and ecosystem response in the landlocked Elefsis Bay (northern Saronic Gulf, Greece)

Katerina Kouli 1,*, Maria V. Triantaphyllou 1, Olga Koukousioura 2, Margarita D. Dimiza 1, Constantine S. Parinos 3, Ioannis P. Panagiotopoulos 1,3, Alexandra Gogou 3, Styliani Kyrikou 1, Nikolaos Mavrommatis 2, George Syrides 2, Theodora Tsourou 1 , Elisavet Skampa 1, Christos Anagnostou3 and Aristomenis P. Karageorgis 3

1    National and Kapodistrian University of Athens, Department of Geology and Geoenvironment, Panepistimioupolis, 15784 Zografou, Greece;

2    Aristotle University of Thessaloniki, School of Geology, 54124 Thessaloniki, Greece;

3       Hellenic Centre for Marine Research, Institute of Oceanography, 46.7 km Athens-Sounio Ave., 19013 Anavyssos, Attica, Greece;

Abstract: Coastal landscapes are sensitive to changes due to the interplay between surface and submarine geological processes, climate variability and relative sea level fluctuations. The sedimentary archives of such marginal areas record in detail the complex evolution of the paleoenvironment and the diachronic biota response. The Elefsis Bay is nowadays a landlocked shallow marine basin with restricted communication to the open Saronic Gulf. A combined multi-proxy investigation of a high-resolution sediment core from the deepest part of the basin offers a unique opportunity to record the paleoenvironmental and aquatic ecosystem response to climate and glacioeustatic sea level changes since the Late Glacial. The retrieved deposits, subjected to exhaustive palynological (pollen, non-pollen palynomorphs, dinoflagellates,), micropaleontological (benthic foraminifera, calcareous nannoplankton, ostracods) and mollusc analyses, indicate isolation of the bay from the Saronic Gulf and the occurrence of a shallow freshwater paleolake since at least 13,500 BP, while after 11,000 BP the transition towards lagoon conditions is evidenced. The marine trangression in the Elefsis Bay is dated at 8000 BP marking the establishment of the modern marine realm. Finally, estimations of the Sea-Surface Temperatures (SSTs), based on organic biomarkers (i.e. alkenones), point to their distinct decrease after 250 BP.

Keywords: paleoenvironment, sea level rise, pollen spectra, dinoflagellate cysts, benthic foraminifera, calcareous nannoplankton, ostracods, molluscs, alkenone-based SSTs

 

3. Paleoenvironmental evolution and sea level change in theSaronic Gulf (Aegean Sea, Greece): evidence from the Piraeus coastal plain and Elefsis Gulf sedimentary records

Maria V. Triantaphyllou 1*, Theodora Tsourou 1, Katerina Kouli 1, Olga Koukousioura 2, Margarita D. Dimiza 1, Elina V. Aidona 2; George E. Syrides 2, Varvara Antoniou 1, Ioannis P. Panagiotopoulos 1,3, Dimitris Vandarakis 1, Aggelos Pallikarakis 5, Sophie Cheillari 2, Jean-Philippe Goiran 6, Eric Fouache 7 and Kosmas P. Pavlopoulos 4,7

1    National and Kapodistrian University of Athens, School of Science, Faculty of Geology and Geoenvironment, University Campus, 15784 Zografou, Greece

2    Aristotle University of Thessaloniki, School of Geology, 54124 Thessaloniki, Greece;

3    Hellenic Centre for Marine Research, Institute of Oceanography, 46.7 km Athens-Sounio Ave., 19013 Anavyssos, Greece;

4    Harokopio University, Geography Department, Eleftheriou Venizelou 70, 17671 Athens, Greece;

5    Agricultural University of Athens, Department of Earth and Atmospheric Sciences, Mineralogy-Geology Laboratory, Iera Odos 75, 118-55 Athens, Greece;

6    Centre National de la Recherche Scientifique (CNRS), UMR 5133-Archéorient, MOM, 7 rue Raulin, 69007 Lyon, France;

7    Université Paris Sorbonne Abu Dhabi, Département de géographie et d'aménagement, Al Reem Island, Abu Dhabi, U.A.E;

Abstract: Thorough analyses of benthic foraminifera, ostracods, molluscs, pollen and non-pollen palynomorphs as well as magnetic susceptibility measurements in the Piraeus coastal plain deposits shed light on the palaeoenvironmental evolution of the area during the Holocene. The main factors that feature the evolution of the Piraeus coastal landscape have been described as the relative sea level rise in the Holocene due to glacio-hydro-isostatic changes, the tectonic stability of the area and the progradation of deltaic fans. Benthic foraminiferal assemblages at the lower part of the sequence revealed the dominance of Ammonia tepida coupled with an increased presence of Haynesina germanica and molluscan species such as Cerastoderma glaucum, Abra spp. and Hydrobiidae, suggesting a typical inner lagoonal environment after 8700 BP. Accordingly, ostracod content was characterized by typical lagoonal assemblages, which were dominated by the occurrence of Cyprideis torosa, accompanied by Loxoconcha elliptica, Cyprinotus salinus and several freshwater species, pointing to significant freshwater input. For the same time period, palynomorphs indicate soil erosion and increased riverine runoff. The high values of magnetic susceptibility confirm a closed lagoon system A gradually improved communication with the sea is recorded till 7800 BP, in the Early Neolithic. In the pollen spectra, the profound short-lived abundance peak of Abies and Artemisia may be related to a climatic deterioration event; the increase of Cerealia-type towards the upper part of this unit signals the first farming communities in the area. Between 6800 and 5400 yr cal. BP, microfaunal assemblages and mollusc fauna suggest a shallow marine palaeoenvironment. In accordance, magnetic susceptibility values are low, indicating the presence of marine deposits. Apparently, during this time interval Piraeus was an island in the centre of a wide shallow marine bay. Since ~4800 BP, a closed oligohaline lagoon is evidenced by the presence of C. torosa and oligohaline to freshwater ostracod species.That lagoon was used for grazing, as indicated by the coprophilous fungal remains of Sordaria and parasites. The human presence has been inevitably detected since the Early Bronze Age by the increase of cultivars like Cerealia-type and Olea. After 2800 BP, a marshy oligohaline depositional environment had already been established. Magnetic susceptibility shows maximum values, thus, implying both fresh water input and anthropogenic impacts. Cultivation and pastoral activities appear intensified during the Antiquity. A comparison with a well-dated marine record, recovered from the nearby shallow Elefsis Gulf, contributes to accurate estimations for the sea level rise rate in the inner Saronic Gulf during the Holocene.

Keywords: Holocene; sea level rise; benthic foraminifera; ostracods; molluscs; pollen spectra; magnetic susceptibility

 

4. Cross-comparison of the BathySent coastal bathymetry to the ratio model technique and sonar measurements

Paraskevi Drakopoulou 1,5*, Vasilios Kapsimalis 1, Marcello de Michele 2, Daniel Raucoules 2, Isidoros Livanos 1, Ioannis Morfis 1, Ioannis P. Panagiotopoulos 1,6, Michael Foumelis 2, Espen Volden 3 and Przemysław Mujta 4

1    Hellenic Centre for Marine Research, Institute of Oceanography, 46.7 km Athens-Sounio Ave., 19013 Anavyssos, Attica, Greece;

2    BRGM - French Geological Survey, 3 avenue Claude-Guillemin - BP 36009, 45060 Orléans Cedex 2, France;

3       European Space Agency (ESA), The European Space Research Institute (ESRIN), Largo Galileo Galilei 1, 00034 Frascati, Roma, Italy

4       CloudFerro sp. z o.o., ul. Nowogrodzka 31, 00-511 Warszawa, Poland

5       Harokopio University, Geography Department, Eleftheriou Venizelou 70, 17671 Athens, Greece;

6       National and Kapodistrian University of Athens, School of Science, Faculty of Geology and Geoenvironment, Department of Historical Geology and Paleontology, University Campus, 15784 Zografou, Greece;

Abstract: The proposed novel approach “BathySent” for coastal bathymetric mapping, using the Copernicus Sentinel-2 mission, as well as the assessment and specification of the uncertainties of the derived depth results are the objectives of this research effort. For this reason, Sentinel-2 bathymetry retrieval results for three different pilot sites in Greece (i.e. Kos, Kasos and Crete islands) were compared with ground-truth data. These data comprised high-resolution swath bathymetry measurements, single-beam echosounder measurements at very shallow waters (1-10 m) and the EMODnet DTM 2018 release. The synthetic tests showed that the “BathySent” approach could restitute bathymetry in the range of 5-14 m depth, showing a standard deviation of 2 m with respect to the sonar-based bathymetry. In addition, a comparison with the “ratio model” multispectral technique was performed. The absolute differences between conventional Earth Observation - based bathymetry retrieval approaches (i.e. linear ratio model) and the suggested innovative solution, using the Sentinel-2 data, were mainly lower than 2 m. According to the outcome evaluation, both models were considered to provide results that are more reliable within the depth zone of 5-25 m. The “ratio model” technique exhibits a saturation at ~25 m depth and demands ground calibration. Though, the “BathySent” method provides bathymetric data at a lower spatial resolution compared to the “ratio model” technique, however, it does not require in situ calibration and can also perform reliably deeper than 25 m.

Keywords: shallow-water bathymetry; waves, space-borne optical data; Sentinel-2 data; echosounder data, South Aegean Sea

 

5. Assessment of the coastal vulnerability to the ongoing sea level rise for the exquisite Rhodes Island (SE Aegean Sea, Greece)

Dimitris Vandarakis 1,*, Ioannis P. Panagiotopoulos 1,2, Vassiliki Loukaidi 1, Aikaterini Kikaki 1, Fragkiska Karmela Gad 1, Paraskevi Drakopoulou 1, Stelios Petrakis 2, Ioannis Morfis 1, Georgios-Angelos Hatiris 3,4, Theodore D. Kanellopoulos 1 and Vasilios Kapsimalis 1

1    Hellenic Centre for Marine Research, Institute of Oceanography, 46.7 km Athens-Sounio Ave., 19013 Anavyssos, Greece;

2    National and Kapodistrian University of Athens, School of Science, Faculty of Geology and Geoenvironment, University Campus, 15784 Zografou, Greece;

3    Hydrobiological Station of Rhodes, Cos Street, 85131 Rhodes, Greece;

4    Harokopio University, Geography Department, Eleftheriou Venizelou 70, 17671 Athens, Greece;

Abstract: The foreseeable acceleration of global sea level rise (SLR) could potentially pose a major threat to the natural charm and functional integrity of the world-renowned tourist coastal attractions of Rhodes Island, as a result of the anticipated increasing frequency of flooding and erosion events. Hence, this study aims to determine the most vulnerable segments (in terms of physical impact) of the Rhodes littoral zone through the widely-accepted coastal vulnerability index (CVI), applying a combination of the broadly-used approaches of Gornitz (1991), Gornitz et al. (1994) and Thieler and Hammar-Klose (2000). The relative frequency distribution of the current CVI along the Rhodes coastline suggested a rather worrying High to Very High vulnerability of ~40%. Further, a projection of the CVI to the end of the 21st century (based on the Intergovernmental Panel on Climate Change predictions) indicated an enhancement of the total vulnerability by ~8%. Thus, a considerable number of popular coastal destinations in the island shall remain under unignorable threat and, therefore, coastal managers and decision makers need to hatch an integrated plan to minimize human losses, private property damage and tourism infrastructure deterioration from flooding and erosion episodes, whose intensity will most likely be enhanced in the future.

Keywords: accelerated sea level rise; coastal vulnerability index; coastal tourism; coastal vulnerability mitigation strategy

 

6. Application of Image Super-Resolution via Sparse Representation algorithm to multibeam backscatter data

Ioannis Morfis 1,*, Christos Mavrokefalidis 2, Kostas Berberidis 2, Dimitris Sakellariou 1, George Papatheodorou 3, Grigoris Rousakis 1, Ioannis P. Panagiotopoulos 1,4

1    Hellenic Centre for Marine Research, Institute of Oceanography, 46.7 km Athens-Sounio Ave., 19013 Anavyssos, Greece;

2    University of Patras, Department of Computer Engineering and Informatics, University Campus, 26504 Patra, Greece;

3    University of Patras, Department of Geology, Marine Geology and Geodynamics, University Campus, 26504 Patra, Greece;

4    National and Kapodistrian University of Athens, School of Science, Faculty of Geology and Geoenvironment, University Campus, 15784 Zografou, Greece;

Abstract: Seabed mapping plays a key role in the understanding of the marine hydrodynamic flows that form a variety of micro- and macro-geomorphological/sedimentological features, while it is crucially important for a wide range of underwater activities, including offshore oil and gas exploration, pipeline and cable surveying, dredging operations, coastal works, exploration of cultural heritage, fishing, environmental monitoring and mineral resource exploration. For all the aforementioned activities, the demand for high-resolution data has been substantially increasing. Hence, this study aims to apply for the first time Compressed Sensing techniques, through the Super Resolution via Sparse Representation algorithm (Yang, 2010), to low-resolution images derived from multibeam backscatter data, attempting to reconstruct a high-resolution version of the input data. The application of the Super Resolution algorithm indicates an improvement of 25% for the input data according to image quality indices such as Peak Signal to Noise Ratio, Mean Absolute Error and Structural Similarity. Furthermore, the Super Resolution algorithm achieves a 10% image improvement compared with other established image enhancement techniques. Therefore, the use of the proposed method could offer the promise of overcoming some of the inherent hardware design and physical limitations, leading to a more reliable data intepretation carried out by marine and environmental scientists.

Keywords: seafloor mapping; image enhancement techniques; compressive sensing, sparse representation algorithms

 

7. Assessment of the chemical and ecological status of a Mediterranean semi-enclosed embayment with low oxygen conditions: Amvrakikos Gulf, Greece

Alexandra Pavlidou 1*, Ioannis Hatzianestis 1, Harilaos Kontoyiannis 1, Manolis Tsapakis 1, Eleni Rousselaki 1, Constantine Parinos 1, Georgia Assimakopoulou 1, Paraskevi Drakopoulou 1, Nikolaos Katsiaras 1, Sofia Reizopoulou 1, Vasilis Gerakaris 1, Ioannis Issaris 1, Polytimi-loli Lardi 1, Konstantinos Tsiamis 1, Alexandra Gogou 1, Panayotis Panayotidis 1 and Nomiki Simboura 1

1   Hellenic Centre for Marine Research, Institute of Oceanography, 46.7 km Athens-Sounio Ave., 19013 Anavyssos, Greece; [email protected] (A.P.); [email protected] (I.H.); [email protected] (H.K.); [email protected] (M.T.); [email protected] (E.R.); [email protected] (C.P.); [email protected] (G.A.); [email protected] (P.D.); [email protected] (N.K.); [email protected] (S.R.); [email protected] (V.G.); [email protected] (I.I.); [email protected] (P.L.); [email protected] (K.T.); [email protected] (A.G.); [email protected] (P.P.)

*   Correspondence: [email protected]; Tel. no: +30 2291076365

Abstract: Amvrakikos Gulf is a shallow, landlocked bay in the Ionian Sea, hosting a great number of ecologically important lagoon systems included in the Natura 2000 network and protected by the Ramsar convention. In the present study, the pollution and ecological status was assessed in relation to the anthropogenic pressures. The southern part of the gulf is classified in a poor ecological status due to the decomposition of high organic load, leading to the development of hypoxic/anoxic, nutrient-rich zones. The reduced exchange with the open sea waters due to the coastline and bottom topography, the strong stratification caused by the freshwater inputs from two rivers, and eutrophication are the main drivers that lead to the formation of hypoxic/anoxic zones in the bottom waters of the gulf, resulting in sporadic events of fish mortalities. Hypoxic conditions have also been recorded in the northern part of the gulf, near the coast, showing a decreasing trend in the dissolved oxygen concentrations from west to east. Concerning the coastal lagoons in the area, hypoxic/anoxic events have not been detected, and most of the transitional water bodies are classified as being in a moderate ecological status. When anoxic conditions prevail in the gulf, the processes of nitrate-reduction and denitrification cause a decrease in the nitrate concentrations with a parallel increase in the ammonium content reaching, for instance, up to ~90 ppb. Finally, a molecular marker approach and several diagnostic criteria and indices were used for the investigation of the role of the estuaries as a transit zone for the transport of pollutants to the central and southern parts of the gulf.

Authors' Note: This work is dedicated to the Memory of the late Nomiki Simboura

Keywords: Amvrakikos Gulf; stratification; ecological status; Louros River; Arachthos River; low oxygen

 

8. Palaeogeographical Evolution of Akrotiri Salt Lake, Lemesos, Cyprus

Miltiadis Polidorou 1, Evelpidou Niki 1, Hara Drinia 1, Theodora Tsourou 1, Ferreol Salomon 2, Lucy Blue 3

Abstract: Akrotiri Salt Lake is located 5 km west of the city of Lemesos, in the southern-most part of the island of Cyprus. The evolution of the Akrotiri Salt Lake presents a great scientific interest during the Holocene, where the eustatic and isostatic movements, combined with local active tectonics and climate changes have developed a unique geomorphological environment. The Salt Lake today closed lagoon, which is depicted in Venetian maps as being connected to the sea, can provide evidence of the geological settings and landscape evolution of the area. In this study, we investigate the development of Akrotiri Salt Lake through a series of cores which penetrated the Holocene sediment sequence. Sedimentological, micropaleontological analyses and geochronological studies performed on deposited sediments, identifying the complexity of the evolution of the Salt Lake and the progressive change of the area from maritime space to an open bay and finally to a closed Salt Lake.  

Keywords: Palaeogeography; Salt Lake; Landscape evolution; Holocene stratigraphy; Coastal Geomorphology; Micropaleontology.

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