Coastal Morphology Research Articles

Holocene fringing reef along southern Andaman and Swaraj Dweep shoreline

The Andaman and Nicobar Islands are rimmed by discontinuous fringing reef that is in general wider on western margin vs the eastern margin. This study characterizes the facies updip from the modern fringing reefs to the present shoreline of south Andaman and Swaraj Dweep, and describes in detail the coral terraces/carpets within and above the inter-tidal zone representing the Holocene Fringing reef. Field studies, satellite, and drone datasets have been utilized to map different facies, that include: coralgal boundstone, biodetrital-grainstone, beachrock, and coralgal rudstone. Multiple exposed microatolls as well as coral terraces (coral carpets) of Acropora and Porites (dated 8.7-8.4 ka BP) have been identified within the intertidal zone (Radhanagar Beach, Swaraj Dweep) indicating that Holocene fringing reef have down-stepped offshore to the current location of modern fringing reefs owing to either tectonics or eustasy. The eustatic sea-level fluctuations are relatively well established for the Holocene and we compute the tectonic uplift rates utilizing the stream-power-incision and linear-inversion model. A tectonic uplift rate of ~ 0.05 mm/yr (for Swaraj Dweep) during the past 100 ka is estimated, while taking into account a wide range of erodibility indexes and response time intervals. It is identified that the computed uplift rate is an amalgamation of the coseismic deformation along with the interseismic and aseismic surface deformation. Thus, not all exposed coral terraces/microatolls are exposed due to coseismic deformation (for example uplift in parts of Andaman due to earthquake in 2004). The average long-term uplift rates are a magnitude lower than the eustatic sea-level fall rates during Holocene, thus, we suggest that most of the Holocene fringing reefs are exposed due to eustatic sea-level fall and down-stepped to the current location of the modern fringing reefs. This would entail that the eustatic sea-level change rates would play a significant role in determining future of the modern fringing reef (catch-up vs keep up vs give up), and the coastal morphology of south Andaman and Swaraj Dweep, with implications for coastal inundation and stability in the scenario of climate change.

Inundation and evacuation of shoreline populations during landslide-triggered tsunamis: an integrated numerical and statistical hazard assessment

Abstract. The volcanic island of Stromboli (southern Tyrrhenian Sea, Italy) is renowned for its persistent, periodic, low-intensity explosive activity, whose spectacular manifestations attract tens of thousands of tourists every year. However, sporadic more intense major explosive and effusive eruptions and paroxysms pose serious threats to the island. In addition to direct hazards, granular slides of volcanic debris and pyroclastic avalanches, which can rapidly reach the sea and potentially generate tsunamis, are often associated with such unpredictable eruptive activity. Due to the very fast propagation of the tsunami around the island and the consequent short tsunami warning time (ranging from less than a minute to only a few minutes), mitigation efforts and evacuation from the Strombolian coast must be carefully planned. In this paper, we describe a new GIS-assisted procedure that allows us to combine the outputs of an ensemble of 156 pre-computed landslide-generated tsunami hazard scenarios (with variable landslide volume, position, and density), statistical exposure data (i.e. the number of inhabitants and tourists), and digital geographic information to obtain a quantitative (scenario-based) risk analysis. By means of the analysis of the road network and coastal morphology, we develop a model with routes and times to reach a safe area from every pixel in the inundated area and an appraisal of the time needed to escape versus the wave arrival time. This allows us to evaluate and quantify the effectiveness of potential risk mitigation by means of evacuation. The creation of an impact score linking the predicted inundation extent and the tsunami warning signals is intended, in the long term, to be used to predict the intensity of future tsunamis and to adapt evacuation plans accordingly. The model, here applied to Stromboli, is general and can be applied to other volcanic islands. Evacuating an island hosting several thousand tourists every summer with very little warning time underlines the absolute necessity for such mitigation efforts, aimed at informing hazard planners and managers and all other stakeholders.

Pengembangan Potensi Wisata dan Kesesuaian Lahan Wisata terhadap Resiko Tsunami di Kawasan Teluk Pacitan

The southern coastal region of Pacitan Regency, particularly in six districts, namely Ngadirejo, Sudimoro, Kebonagung, Donorojo, Pringkuku, and Pacitan District, is classified as a high-risk tsunami red zone. Based on the research findings, the Pacitan Bay area consists of two villages, namely Sidoarjo Village and Ploso Village in Pacitan Distict. Sidoarjo Village covers an area of 8.36 km², while Ploso Village covers 3.66 km², making the total area 12.02 km² or 1202 hectares. The analysis of land suitability for tourism in relation to tsunami risk aims to assess the level of compatibility of a tourist area located in a tsunami-prone region. The environmental vulnerability parameters include elevation, land slope, coastal morphology, land use, distance from the coastline, and distance from rivers. Additionally, bathymetric data and tsunami run-up based on historical tsunami events in the southern coastal areas of Java Island are utilized to assess the extent and depth of tsunami inundation. In the analysis of tourism suitability based on tsunami disaster mitigation, the suitable tourism area is located in the eastern part of Sidoarjo Village and the entire Ploso Village. These areas fall into the high tsunami risk zone, but their tourism potential is also high due to the coastal location of tourist attractions

Dynamic Coastal Mapping Using Sentinel-1 and Sentinel-2 Data Through Digital Earth Africa

Abstract. Coastal erosion poses a continuous threat to ecosystems, infrastructure, and property. To address these challenges and mitigate the effects of coastal changes, effective and current monitoring is essential. It is particularly important to monitor coastlines and coastal changes in Africa, where a significant portion of the population resides in coastal regions. While optical satellite imagery has been used for large-scale annual coastlines and change monitoring for Africa, its availability and quality are largely limited by the presence of cloud and cloud shadow. In comparison, using radar satellite observations such as Sentinel-1 data can provide consistent coastal mapping and change detection regardless of cloud presence. This paper outlines a fully automated supervised machine learning workflow using Sentinel-1 data and training samples extracted from Sentinel-2 data. It also explores the performance of the workflow for different coastal morphology types across the African coast. The workflow has proved to perform better and produced results that were visually more consistent with Sentinel-2 data compared to thresholding methods. While challenges exist to distinguish between land and water over smooth sandy beaches and rough near-shore water surfaces, our workflow provides an alternative method for coastal change mapping where optical satellites provide insufficient observations free from clouds. Python code of the proposed methodology has been made publicly available.

Investigating the evolution of sand bars and natural channel formation in the Mandovi estuary along the central west coast of India

Coastal formations, such as sandbars, play a vital role in shaping the environment and maintaining local and regional coastal morphology. This study deals with two noteworthy sandbars, namely Aguada and Reis Magos which are in the Mandovi estuary of the Goa region in the central west coast of India. They have attracted great attention because of their dynamics and their role in shaping the adjoining coast. This study employs a comprehensive approach, incorporating in-situ observations and remote sensing methods, to investigate the mechanisms underlying the emergence and dissipation of these sandbars and their linkage with adjoining navigational channels and coastline. During the intense wave conditions of the southwest monsoon (June to September), these sandbars undergo a temporary phase of dispersion. This phenomenon results in the accumulation of sand from both the sandbars and the neighbouring Miramar beach within the navigational channel. As a consequence, it obstructs maritime traffic and forms a unified shallow bar, obstructing maritime navigation in the area. However, following the attenuation of monsoon waves in October to November, the sandbar and beach initiate a gradual replenishment process, aimed at compensating for the sediment loss incurred during the monsoon season. This recurring trend has demonstrated persistent characteristics over an extended period. The presence of the sandbar may pose navigational challenges for large barges, cruise ships, and fishing boats but on the other hand, it serves as an effective barrier against incoming high-energy waves into the inner parts of the Mandovi estuary. Results revealed notable variations in the extent of the sandbar over the study period. The maximum recorded extent of the sandbar was 82.48 ha and 32.59 ha on May 04, 2021, while the minimum extent was measured at 36.68 ha and 7.14 ha on February 14, 2019, for Reis Magos and Aguada bar respectively. The sandbar promotes a calm environment along the shoreline and reduces erosion susceptibility by dissipating the wave energy before reaching the riverbanks. The absence of this protective sandbar would have significantly impacted the parts of the Goa region. Notably, the maximum erosion of 107 m was observed at the right bank of the estuary, while the maximum accretion of 141 m was recorded in the Caranzalem from 1975 to 2023. This study contributes valuable insights into the formation, dissipation, and environmental implications of sandbars within the estuary in Goa. The integration of in-situ observations and remote sensing data affords a comprehensive understanding of sandbar dynamics, highlighting the essential role that they play in coastal protection, navigation and the preservation of the local environment.

A Bayesian network approach to assess the ecosystem integrity of mangroves in Tampamachoco, Veracruz, Mexico

Given the alarming rates of mangrove forest loss, resource managers must count on information regarding the condition of the mangrove forests. We propose a Bayesian network (BN) to assess mangrove forests' ecosystem integrity (EI) to support a mangrove monitoring system in Mexico. This approach allowed us to infer the system's condition based on variables on forest structure and function. We defined the BN structure based on informal interviews with specialists on vegetation and coastal geomorphology. We applied the expectation-maximization learning algorithm to train the model. Data from plots in two mangrove areas of an Avicennia germinans forest, defined based on their undisturbed and disturbed conditions, were used as training datasets. We applied sensitivity analysis to determine the degree of influence of each model variable. We evaluated the prediction capacity of the BN with a k-fold cross-validation (the process is repeated five times, starting from the database in 2 parts). The variables selected for the model were the Holdridge complexity index (HCI, Holdridge et al., 1971), Leaf area index (LAI), litter production (g/month/m2), leaf C, N and P concentration (%), and leaf N:P ratio. The most critical variable to infer mangrove condition was leaf N:P (Variance reduction = 11%), followed by forest structure variables HCI and LAI (Variance reduction > 5%). The cross-validation to test the model resulted in a minimum square error of 0.3, which indicates a reasonable capacity to predict the condition of mangrove integrity. The BN constructed can diagnose the integrity of a monospecific mangrove forest with acceptable precision, considering the environmental factors that define the forest structure and functioning locally. We then asked the experts to review and modify the model to apply to multispecies mangrove ecosystems and environmental contexts.

Characterizing Juvenile Common Snook and Tarpon Habitat to Guide Conservation and Restoration of Coastal Wetlands

To conserve or restore juvenile fish habitat, resource managers, restoration practitioners, and engineers need fine-scale information to understand what conditions they need to preserve or what specifications are needed to create new habitat. The objective of this study was to develop statistical models using a dataset of 18 coastal ponds in Southwest Florida, USA, to predict the abundance of juvenile common snook Centropomus undecimalis (hereafter snook) and presence of juvenile tarpon Megalops atlanticus, both of which are flagship species used for conservation and restoration of subtropical and tropical wetlands. Model predictors included water conditions and characteristics of vegetation, sediment, and geographic position. Modeling results indicated that juvenile snook used coastal ponds that were directly connected to tidal creeks. In contrast, juvenile tarpon were more likely to be present in coastal ponds that were separated from tidal creeks by dense mangrove forest (e.g., elevation > 0.48 m above Mean Low Water) characterized by highly organic sediment and low dissolved oxygen, to which tarpon are well adapted. Overlap between snook abundance and tarpon presence was greatest where connections between ponds and the nearest tidal creek were at a relatively low elevation (e.g., -0.12 m relative to Mean Low Water). Although these findings are most applicable to management and conservation of populations in areas along the Gulf coast of Florida (i.e., in areas of similar tidal range and coastal geomorphology), incorporating more detailed habitat surveys to better capture landscape context, geomorphology, and connectivity into fish sampling designs should be broadly applicable to estuarine fish ecology.

ANÁLISE DO COMPORTAMENTO EROSIVO E CARACTERIZAÇÃO SEDIMENTOLÓGICA DA BARRA ARENOSA NA FOZ DO RIO ITABAPOANA, PRESIDENTE KENNEDY-ES

The state of Espírito Santo, despite being the smallest in the Southeast region, presents a significant diversity in the variations between the effects of retrogradation and coastal progradation. This dynamic is influenced by a complex interplay of variable factors, such as coastal geomorphology, hydrodynamics, and geology, which directly affect coastal cities and their development. The objectives of this study are to understand the phenomenon of coastal erosion and to analyze the morphological behavior of the sandy bar at the mouth of the Itabapoana River and at Praia das Neves, generating relevant information for the preservation of the coastal environment and minimizing material losses in urban areas adjacent to the sea. This work used tools such as the Ground Penetrating Radar (GPR) for the interpretation of radarfacies, as well as remote sensing and satellite image geoprocessing methodologies, combined with sedimentological characterization studies applied to Environmental Geology. The integration of GPR data revealed a complex sedimentary dynamic, with reflectors that indicate the progradation of beach deposits, as well as eolian, fluvial and marine influences, observing the presence of filled paleochannels and fluvial deposits. The analysis of satellite images allowed us to identify variations in the morphology of the beach and the location of the sandy bar at the mouth of the Itabapoana River, which shows migration patterns in a north-south direction. The compilation of the results suggests that coastal erosion in the region is cyclical, alternating between moments of progradation and retrogradation throughout the analyzed period, reflecting a complex coastal environment that involves climatic factors and marine and fluvial dynamics. The sediments analyzed were well selected, ranging from fine to medium fraction, with heavy fine sediments from the Araçuaí-Ribeira Orogen, showing low textural maturity.

Coastal Vulnerability Index (CVI) Assessment: Evaluating Risks Associated with Human-Made Activities along the Limassol Coastline, Cyprus

Coastal risk assessment is crucial for coastal management and decision making, especially in areas already experiencing the negative impacts of climate change. This study aims to investigate the coastal vulnerability due to climate change and human activities in an area west of the Limassol district’s coastline, in Cyprus, on which there have been limited studies. Furthermore, an analysis is conducted utilising the Coastal Vulnerability Index (CVI) by exploiting eight key parameters: land cover, coastal slope, shoreline erosion rates, tidal range, significant wave height, coastal elevation, sea-level rise, and coastal geomorphology. These parameters were assessed utilising remote sensing (RS) data and Geographical Information Systems (GISs) along a 36.1 km stretch of coastline. The results exhibited varying risk levels of coastal vulnerability, mainly highlighting a coastal area where the Kouris River estuary is highly vulnerable. The study underscores the need for targeted coastal management strategies to address the risks associated with coastal erosion. Additionally, the CVI developed in this study can be exploited as a tool for decision makers, empowering them to prioritise areas for intervention and bolster the resilience of coastal areas in the face of environmental changes.

Kilometer‐Scale Assessment of the Adriatic Dense Water Multi‐Decadal Dynamics

AbstractThe North Adriatic Dense Water (NAddW)—the densest Mediterranean water generated by extreme cooling during wintertime hurricane‐strength winds—drives the thermohaline circulation, ventilates the deep layers, and changes the biogeochemical properties of the Adriatic Sea. However, modeling the dynamical properties of such dense water at the climate scale has been a challenge for decades due to the complex coastal geomorphology of the Adriatic basin not properly reproduced by existing climate models. To overcome these deficiencies, a 31‐year‐long simulation (1987–2017) of the Adriatic Sea and Coast (AdriSC) kilometer‐scale atmosphere‐ocean model is used to analyze the main NAddW dynamical phases (i.e., generation, spreading and accumulation). The study highlights four key results. First, during winter, the NAddW densities are higher in the shallow northern Adriatic shelf than in the deeper Kvarner Bay—where 25%–35% of the overall NAddW are found to be generated—due to a median bottom temperature difference of 2°C between the two generation sites. Second, the NAddW mass transported across most of the Adriatic peaks between February and May, except along the western side of the Otranto Strait. Third, for the accumulation sites, the bottom layer of the Kvarner Bay is found to be renewed annually while the renewal occurs every 1–3 years in the Jabuka Pit and every 5–10 years in the deep Southern Adriatic Pit. Fourth, the NAddW cascading and accumulation is more pronounced during basin‐wide high‐salinity conditions driven by circulation changes in the northern Ionian Sea.

Predicting beach profiles with machine learning from offshore wave reflection spectra

Tracking and forecasting changes in coastal morphology is vital for development, risk reduction, and overall coastal management. One challenge of current coastal research and engineering is to find a method able to accurately assess the bathymetry profile along the coast and key parameters such as slope and sandbars. Traditional bathymetry measurements are obtained through echo-sounding, which is time-consuming, hazardous and costly. Using a variety of simulated cases, we test the potential of machine learning and in particular Neural Networks to reconstruct the coastal bathymetry profile from offshore sensed waves, based on shore-based wave reflection. Features such as foreshore slope, curvature, sandbars amplitude and positions can be captured.

Comparative Study of the Coastal Geomorphology of Kajirbhati Sand-Spit Using Google Earth Pro Images (2005, 2011, 2023) and Landsat Satellite Data (2009, 2016, 2023): An Approach Towards the Impact of the Casuarina Plantation

Coastal geomorphology undergoes constant transformation due to a combination of coastal and fluvial processes and human intervention. Remote sensing and GIS tools are invaluable in identifying and studying these changes. Due to the dynamic interaction between land and sea, the coastline requires careful monitoring to detect hotspots and understand the spatial and temporal impacts of climate change on the coastal environment. Remote sensing data offers a comprehensive means of studying coastal landform changes. In a recent study, the focus was to analyze the impact of the Casuarina plantation on the coastal geomorphology of Kajirbhati spit. This involved studying various depositional features such as sand bars, sand spits, dunes, and beaches. The study utilized Google Earth Pro images from 2005, 2011, and 2023 to digitize 13 classes each year, enabling the identification of changing geomorphic classes. These include agriculture, swash zones, dunes on sand spits, berm lines, Casuarina and coconut plantations, estuary, mangroves, mudflats, open land, sea, settlement, and vegetation. The results revealed dramatic changes in land use and land cover classes from 2005 to 2023. In the years from 2011 to 2023, the area of sandspit covered by Casuarina plants expanded rapidly. To analyze the changes, Landsat 5, 8, and 9 data were used to check the intensity of NDVI (Normalized Difference Vegetation Index) in 2009, 2016, and 2023. NDVI is a critical factor in this research. The mean NDVI values for 2009, 2016, and 2023 were -0.002, 0.02, and 0.04 respectively. The changes in higher NDVI values from 2009 to 2023 were -0.10, 0.27, and 0.28, while the lower values were -0.10, -0.10, and -0.07 for the same years. The correlation calculation between the mean NDVI values and the years indicates a strong positive correlation with an R-value of 0.99. Casuarina plants play a crucial role in protecting the coast from strong winds and dynamic sea waves. They help protect mudflats, mangroves, settlements, and estuary land use and cover classes along the coast of Kajirbhati.

Climate controls on longshore sediment transport and coastal morphology adjacent to engineered inlets

Coastal jetties are commonly used throughout the world to stabilize channels and improve navigation through inlets. These engineered structures form artificial boundaries to littoral cells by reducing wave-driven longshore sediment transport across inlet entrances. Consequently, beaches adjacent to engineered inlets are subject to large gradients in longshore transport rates and are highly sensitive to changes in wave climate. Here, we quantify annual beach and nearshore sediment volume changes over a 9-yr time period along 80 km of wave-dominated coastlines in the U.S. Pacific Northwest. Beach and nearshore monitoring during the study period (2014–2023) reveal spatially coherent, multi-annual patterns of erosion and deposition on opposing sides of two engineered inlets, indicating a regional reversal of longshore-transport direction. A numerical wave model coupled with a longshore transport predictor was calibrated and validated to explore the causes for the observed spatial and temporal patterns of erosion and deposition adjacent to the inlets. The model results indicate that subtle but important changes in wave direction on seasonal to multi-annual time scales were responsible for the reversal in the net longshore sediment transport direction and opposing patterns of morphology change. Changes in longshore transport direction coincided with a reversal in the Pacific Decadal Oscillation (PDO) climate index, suggesting large-scale, multi-decadal climate variability may influence patterns of waves and sediment dynamics at other sites throughout the Pacific basin.

Shoreline and land use–land cover changes along the 2004-tsunami-affected South Andaman coast: understanding changing hazard susceptibility

Abstract. The 2004 tsunami affected the South Andaman coast, causing it to experience dynamic changes in the coastal geomorphology and making the region vulnerable. We focus on pre-and post-tsunami shoreline and land use–land cover changes from 2004, 2005, and 2022 to analyze the dynamic change in hazard. We used General Bathymetric Chart of the Ocean (GEBCO) data to calculate run-up [m], arrival times [min], and inundation [m] at a few locations using three tsunamigenic earthquake source parameters, namely the 2004 Sumatra, 1941 North Andaman, and 1881 Car Nicobar earthquakes. The Digital Shoreline Analysis System is used for the shoreline change estimates. Landsat data are used to calculate shoreline and land use–land cover (LULC) change in five classes, namely built-up areas, forests, inundation areas, croplands, and water bodies during the above period. We examine the correlation between the LULC changes and the dynamic change in shoreline due to population flux, infrastructural growth, and gross state domestic product growth. The Indian industry estimates the Andaman and Nicobar Islands losses exceeded INR 10 billion during 2004, which would today see a 5-fold increase in economic loss due to a doubling of built-up area, a 3-fold increase in tourist inflow, and population density growth. The unsustainable decline in the forest cover, mangroves, and cropland would affect sustainability during a disaster despite coastal safety measures.

The Application of Remote Sensing and Geoprocessing in Coastal Geomorphological Characterization: a case study in Paranaguá and Superagüi Strandplains, Southern Brazil

The Application of Remote Sensing and Geoprocessing in Coastal Geomorphological Characterization: a case study in Paranaguá and Superagüi Strandplains, Southern Brazil

Bronze Age to Roman period salt production in the coastal areas of peninsular Italy: Palaeoenvironments, production methods and archaeological evidence

The landscape characteristics and salt production methods along the coasts of peninsular Italy from the Bronze Age to the Roman period are examined, with a focus on the significance of marine salt for Italy's ancient food economy, given the limited availability of rock salt. Two main methods of marine salt production are highlighted. Briquetage involves using clay or pottery containers to evaporate seawater, which requires specific environmental conditions such as clay availability and significant human labour and technological skill. Conversely, salterns consist of creating shallow ponds or pools for seawater evaporation, demanding flat coastal areas, a stable climate, and controlled seawater flow. While this method is less labour-intensive, it requires substantial initial infrastructure.The potential for salt production in Italy's coastal palaeoenvironments using either method has been evaluated. Key factors include coastal geomorphology, climate stability, and access to raw materials. This environmental data supports an analysis of archaeological remains from salt production sites active from the Bronze Age to the Roman period. The assessment focuses on the material evidence such as clay containers from briquetage and structural remains of salterns, aiming to understand the spatial and temporal distribution of these sites.The discussion also explores the geopolitical implications of salt production, examining how the distribution and development of these sites were affected by broader geopolitical shifts in Italy, including the impact of (proto)urbanization on the expansion and adaptation of salt production practices.

Modeling cross-shore profile evolution in response to climate change: A case study for the Southwestern Black Sea Coast

Changes in wave climate and sea level as a result of global climate change cause significant effects on coastal morphology. Especially increasing wave heights, more frequent storms, and sea level rise (SLR) significantly alter the morphology of cross-shore profiles and diminish the security of coastal areas. In this study, profile surveys were carried out in two distinct regions along the Western Coast of the Black Sea, and the profile evolutions were analyzed using the XBeach numerical model. The XBeach model was executed using both its default parameters and the parameters derived from on-site measurements. This study was also conducted under the influence of hydrodynamic conditions (wave parameters) that vary according to the RCP4.5 and RCP8.5 climate scenarios, along with the effects of sea level rise (SLR), to analyze the potential impacts of climate change on profile evolution. The results indicated a linear relationship between the upper beach erosion and sea-level rise (SLR). The increased water level in front of the upper beach leads to greater erosion volume. The model results for the scenarios demonstrated moderate sensitivity to variations in offshore wave height, peak wave period, and storm duration, but were predominantly sensitive to accelerated sea level rise (SLR).

A newly formed lagoon under eutrophication on the coast of Kumlubent-Gelibolu, Çanakkale Strait (Dardanelles), Sea of Marmara

Lagoons are semi-enclosed and dynamic water bodies that are highly vulnerable to coastal dynamics and environmental stressors associated with anthropogenic activities and climate change. We investigated a pristine lagoon, hereafter referred to as Kumlubent Lagoon, located on the coast of Gelibolu in the Çanakkale Strait in the Sea of Marmara. The evolution of coastal morphology and Kumlubent Lagoon’s formation was investigated by using satellite images collected between 2006 and 2020. In addition, water samples were collected from the lagoon and the shore on April 15 and 16, 2022 for nutrient (NO3, NO2, NH4, PO4, and Si), chlorophyll-a (chl-a) and total organic carbon (TOC) analyses in order to determine the trophic status of the lagoon. Our results showed that the nearshore deposition of coastal sediments gradually formed a sand barrier that isolated the lagoon from the sea in the year 2013. The nutrient analyses showed a clear indication of eutrophication of the lagoon. Accordingly, 29.784 µm/L of NH4, 1.168 µm/L of PO4, 34.15 (±1.54) µg/L of chl-a and 40.50 mg/L of TOC were measured in the water samples from the Kumlubent Lagoon. Our study suggests that the deposition of longshore drifted sediments in a southwesterly direction along the Çanakkale Strait plays a dramatic role in the development of coastal morphology in the Gelibolu-Kumlubent region. The rapid eutrophication of the Kumlubent Lagoon may be related to the high nutrient input from agricultural activities in the region.

Iterative Mathematical Models Based on Curves and Applications to Coastal Profiles

The objective of this study is iterative systems based on general types of curves, not only on circumference arcs. We begin by presenting some implementations and generalizations of constructions based on arcs of circumference. Then we consider constructions based on general curves and give a “universal property” relating to the primary construction that exploits arcs of circumference. With the prospect of applying these theoretical models also to coastal geomorphology in the future, and inspired by one of the best-known models on the subject, the logarithmic spiral one for the so-called headland-bay beaches (HBBs), we study geometrically some cases in which the constructions are based on arcs of the golden spiral. Simultaneously we concretely illustrate and explain the universal property above. Finally we dedicate a section to discuss the possibility of how to numerically evaluate and compare the (infinite) lengths originating from our theoretical geometric constructions. Some explicit examples, calculations and comparisons will be provided by the use of infinity computing which is one of the various possible assets that contemporary non-standard mathematics makes available.

Assessment of erosion-accretion patterns, land dynamics, and climate change impacts on the islands of the south-central coastal zone of Bangladesh using remote sensing techniques

This study investigates morphological changes, erosion-accretion patterns, and climate change impacts on Bangladesh’s dynamic coastal regions focusing on the Meghna Estuary and islands like Sandwip, Urir Char, and Swarna Dweep. Using remote sensing and GIS techniques, the research analyzes short-term (5-year) and long-term (30-year) changes from 1991 to 2021. Satellite imagery reveals significant erosion and accretion rates. Sandwip experienced high erosion (up to 29.48 km2 every 5 years) until 2006 but recent stability. Urir Char faced substantial erosion (up to 22.73 km2 every 5 years) until 2001 in the southeast and accretion in the north. Swarna Dweep showed minimal erosion but significant accretion. The islands exhibited migration tendencies: Swarna Dweep southeast, Sandwip northeast, and Urir Char northwest. Cyclones, including the 1991 event, Sidr, and Aila, significantly reshaped coastal morphology. Climate change impacts include increasing rainfall trends (up to 0.8572 mm/year on Sandwip), rising temperatures (up to 0.005 °C/year on Urir Char), and accelerated sea-level rise (up to 11.93 mm/year on Sandwip). The study emphasizes the importance of monitoring, coastal management, and adaptation strategies for Bangladesh’s dynamic coastline in the face of ongoing environmental changes.