Historically, factors such as wetland reclamation, pollution, and altered hydrology have been the primary drivers of coastal wetland loss. According to the WET Index, marine and coastal wetlands have declined by approximately 35% between 1970 and 2015. While climate change previously played a minor role compared to these direct human impacts, its influence is now growing significantly. More than a billion people live within 10 kilometers of the sea, and over one-third of the global population resides within 100 kilometers of the coast, highlighting humanity’s heavy reliance on these areas. Consequently, 40% of coastal areas are developed globally, making their wetlands particularly vulnerable. As sea-level rise and warming accelerate, the cumulative effects of climate change are expected to dominate the trajectory of wetland loss, outpacing traditional drivers of degradation.

Vegetation in coastal wetlands is highly varied, ranging from submerged macrophytes to shrub formations and forests, with compositions that differ significantly across geographic regions. These plants perform critical ecosystem services, including organic matter production, sediment trapping, and wave energy reduction. Monitoring data from over 390 sites suggest that climate change negatively affects all wetland plant communities. Increased salinity and flooding are major ongoing impacts of sea-level rise and warming on salt marshes. For instance, in a disconnected wetland in southern Spain, salinity increased from 4.5 g/L in 2003 to 7.5 g/L in 2008, potentially affecting approximately 20% of species. Experimental studies have also shown that warming can reduce Shannon diversity in salt marsh vegetation by 44–74%, favoring certain invasive or dominant species over others, thereby altering the structural integrity of the ecosystem.

The survival of wetland vegetation in the face of rising seas is strongly correlated with the availability of suspended matter for vertical accretion and the capacity of plant species to migrate inland. Plants with fibrous roots accrete sediment more efficiently than those with tap roots, and perennial plants are generally more effective than annuals in maintaining marsh elevation. However, rising sea levels can compromise the resilience of salt marshes if flooding exceeds thresholds that decrease plant productivity. In transitional waters, species richness is often low at higher salinities, and species are highly sensitive to salinity changes. Warmer conditions tend to favor C4 plant species over C3 species, but salinity stress and alternating flooded and dry conditions make predicting plant responses complex. Rare and endemic species tolerant of specific flooding and salinity regimes, such as Limonium and Salicornia, are particularly threatened by coastal erosion and changes in hydro-saline conditions.

Coastal wetland fauna, including birds and fish, are also experiencing significant impacts from climate change. For birds, nesting declines in species such as flamingos, terns, and sparrows have been directly linked to sea-level changes. Increased flooding risk has more than doubled for six saltmarsh species in the Wadden Sea, sufficient to cause population declines. Most coastal birds build nests near the ground, making them vulnerable to inundation during high tides or storms. For fish, rising water temperatures and altered salinity are disrupting metabolic rates and reproductive cycles. In the German Wadden Sea, the growth and abundance of the non-migratory eelpout declined when summer temperatures and dissolved oxygen levels exceeded critical thresholds. Sea-level rise can cause substantial shifts in coastal habitats, altering environmental factors that influence community structure and the population dynamics of certain fish species, potentially reducing safe zones for juvenile fish that rely on protected areas for food and shelter.

Future scenarios under accelerated climate change paint a concerning picture for coastal wetlands. The Intergovernmental Panel on Climate Change projects that global sea-level rise will average between 40–46 cm and 79–81 cm by 2100, and between 56–62 cm and 122–127 cm by 2150, depending on greenhouse gas emissions scenarios. Passive inundation models suggest that 20–90% of the current coastal wetland area will be lost under low and high sea-level rise scenarios, respectively. In the Mediterranean, widespread coastal marsh loss is projected to range from 8% to 92% of current extents by the end of the 21st century. While coastal wetlands could potentially migrate inland, human infrastructure often prevents this shift, a phenomenon known as coastal squeeze. As sea-level rise rates accelerate, sediment accumulation may be insufficient to maintain the hydrosedimentary balance, leading to the disappearance of certain wetlands and beaches if natural processes are not supported.

Warming temperatures in confined coastal systems such as marshes, lagoons, and bays can have more severe impacts than in the open sea due to shallow depths and small volumes. Modelling studies suggest that water temperature increases in these systems can be 15% greater than in the open sea. The general trend is for water temperature in lagoons to match air temperature trends with short time lags. Increased intensity and duration of marine heat waves might have more severe impacts on biodiversity than average seawater temperature changes. Expected impacts of warming include increased respiration relative to photosynthesis, reducing net primary production, and composition shifts towards species adapted to higher temperatures. Mortality of species susceptible to extreme temperatures and increased hypoxia, particularly fish and bivalves, is a significant concern. Changes in community composition can alter biogeochemical cycles and energy transfer, affecting water quality and the adaptability of species.

Management options to enhance the resilience of coastal wetlands are critical to avoiding biodiversity loss. Natural resilience mechanisms, such as the positive feedback between increased flooding and sedimentation, can allow coastal wetlands to maintain elevation relative to sea level, provided there is sufficient sediment available. However, high rates of sea-level rise or reduced sediment supply can lead to the collapse of these ecosystems. Management strategies must align with natural processes to avoid maladaptation. These include improving hydrological connectivity, increasing sediment inputs, boosting wetland plant productivity, and allowing space for natural coastal processes. In the Mediterranean, for example, implementing coastal management that supports passive inland migration of marshes or actively restores wetlands and river-to-coast connectivity may be necessary to mitigate losses. If upland migration is impossible, maintaining wetlands in place requires substantial increases in sediment supply and biogenic accretion, which can be achieved through the removal of dams and impoundments to release trapped sediment.

Integrated management, large-scale restoration, and comprehensive territorial planning are essential to minimize the loss of coastal wetlands due to climate change. Barriers to restoration are often financial and governance-related rather than technical. Policy recommendations should stress the need for the interconnectedness of land, water, and marine environments, including funding for research and monitoring, incentives for sustainable practices, and frameworks for community involvement in decision-making. Specific management actions include adding sediment to raise elevations, altering hydrology to improve drainage, and engineering shorelines to mimic natural systems. Living shorelines, which offer potential to create new habitats while protecting existing ones, are increasingly seen as an alternative to hardening the coast with physical structures. Restoration efforts can also focus on rehabilitating degraded habitats, such as replanting vegetation in marshes or seagrass beds, to maintain nursery areas and improve water quality.

In conclusion, the future of coastal wetland biodiversity will vary significantly based on the climate scenarios that unfold and the policies implemented. Addressing the challenges posed by climate change requires a comprehensive approach that integrates scientific knowledge, effective management, and robust policy frameworks. By taking proactive measures to enhance the resilience of coastal ecosystems, we can ensure the sustainability of their valuable biodiversity and ecosystem services. The urgency of this task cannot be overstated, as the combined impacts of climate change and other global drivers are already causing significant degradation and loss of these vital habitats. Continued research and adaptive management will be crucial in understanding and mitigating the complex interactions between climate change and coastal wetland ecosystems, ensuring they continue to support the diverse life forms and human communities that depend on them.

Subject of Research: Impact of climate change on coastal wetland biodiversity and resilience

Article Title: To what extent is coastal wetland biodiversity endangered by climate change? How can we boost the resilience of coastal ecosystems?

Article References: Ibáñez, C., Caiola, N., Elphick, C. S., & Grillas, P. (2026). To what extent is coastal wetland biodiversity endangered by climate change? How can we boost the resilience of coastal ecosystems?. Nature Conservation, 62, 63-94. https://doi.org/10.3897/natureconservation.62.154795

Image Credits: AI Generated

DOI: 10.3897/natureconservation.62.154795

Keywords: coastal wetlands, climate change, sea-level rise, biodiversity, salt marshes, ecosystem resilience, habitat loss, conservation, marine ecosystems, sediment dynamics, extent, coastal

The Po rests in 33 to 37 meters of water on a gently inclined shelf inside the Karaburun-Sazan Marine Protected Area, Albania’s first and largest. The team combined high-resolution multibeam echosounder and side-scan sonar surveys with Structure-from-Motion photogrammetry, sediment sampling, and biological censuses to capture the wreck’s interaction with its environment. Over 32 scientific dives conducted between June 2022 and September 2024, divers and a small remotely operated vehicle documented more than 2,000 high-resolution images per survey, building sub-centimetric 3D models of the upper decks and hull. Twelve sediment samples were collected with a Van Veen grab at stations flanking the wreck and at reference sites 200 meters away, while twelve visual census dives cataloged the fish and invertebrate communities.

The geophysical data revealed a striking asymmetry in the seabed around the hull. On the upstream, northwest-facing side, a scour hollow plunges 2.1 meters below the reference seabed level, carved out by currents that accelerate around the obstruction. Downstream, a depositional tail of accumulated sediment stretches roughly 45 meters from the stern. Side-scan sonar backscatter showed small sedimentary ripples with wavelengths of 0.6 to 1.2 meters aligned with the dominant current, but these bedforms vanish within a five-meter radius of the wreckage, evidence that the ship acts as a local hydrodynamic obstacle disrupting near-bed flow.

Sediment analysis sharpened the picture. The reference sites 200 meters away consist of medium sand with a median grain size of 350 micrometers, while samples taken immediately adjacent to the hull contain fine silt and clay fractions smaller than 63 micrometers. The researchers interpret this gradient as consistent with deposition under regional sediment-supply conditions influenced by the Vjosa River, one of Europe’s last undammed rivers, whose delta lies about 15 kilometers to the northwest. During flood events, the Vjosa discharges an average of roughly 195 cubic meters per second, increasing turbidity and sediment transport across the bay. The team is careful to note that direct attribution of the fine sediments to the river requires further validation through time-series monitoring or sediment-trap data, but the spatial pattern strongly suggests the wreck intercepts part of the suspended load and shelters it in its wake.

Biologically, the wreck has become what the researchers describe as a living structure. More than 80 percent of its hard surfaces are covered by a dense, multi-layered biogenic crust comprising 54 identified taxa across eleven phyla. Encrusting sponges such as Crambe crambe and Spirastrella cunctatrix dominate, alongside sea squirts like Botryllus schlosseri and calcified bryozoans including Myriapora truncata and Reteporella septentrionalis. Mediterranean mussels and European flat oysters cluster on vertical surfaces and upper hull sections, while photophilic algae and turf-forming species favor the horizontal decks exposed to light. This zonation reflects eight decades of ecological succession on an artificial substrate in a region where natural hard bottoms are scarce.

Statistical analysis confirmed that the wreck is not uniformly colonized. A one-way PERMANOVA on species abundance data, using a Bray-Curtis resemblance matrix and 9,999 permutations, showed that the bow, midship, stern, and adjacent seabed host significantly different assemblages. The bow section, which faces the prevailing northwest flow, exhibited the highest structural complexity and a Shannon-Wiener diversity index of 2.91, compared with 2.14 in the more sheltered midship and stern sections. Vertical, current-exposed surfaces support richer filter-feeding communities, a pattern consistent with established findings on artificial reefs throughout the Mediterranean. An exploratory Spearman rank correlation between sediment texture and biological cover yielded a coefficient of negative 0.83, suggesting that finer sediments in the wreck’s wake are associated with greater biological cover, hinting at a coupled eco-geomorphological feedback.

The visual censuses recorded 28 fish species from 14 families, including dusky grouper, Mediterranean moray, red scorpionfish, and greater amberjack. Juvenile Diplodus vulgaris, Serranus scriba, and Mullus surmuletus were observed using the structure, with the striped red mullet foraging preferentially in the fine-grained sediments of the depositional tail rather than on the surrounding medium sands. More remarkable were three exceptional records. Large gelatinous egg clusters, likely from the squid Illex coindetii, adhered to vertical surfaces at depths of 22 to 25 meters, evidence of spawning activity. The non-indigenous lionfish Pterois miles was confirmed through direct observation and citizen science photography, with up to seven individuals seen simultaneously, one of the northernmost occurrences yet reported in the Adriatic Sea. And on August 12, 2023, a camera captured a transient Mediterranean monk seal, Monachus monachus, resting within the sheltered cavities of the wreck’s upper structure, the first confirmed sighting in Vlora Bay since 1996.

To distill these heterogeneous observations into usable numbers, the team proposed two preliminary indices. The Geometric-Geomorphological Wreck Effect Index, or IGEOM, combines three dimensionless ratios: the length of the depositional tail relative to the wreck’s length, the scour depth relative to local water depth, and the contrast in median grain size between the far-field reference and the wake zone. Using the measured values, the index yields 0.52. The Ecological Hotspot Value Index, or IECO, integrates normalized benthic diversity, percentage cover, and the presence of key indicator species, producing a score of 0.83. Both indices use geometric means so that no single component can compensate for the absence of another. The researchers stress that these are site-specific descriptive tools, not calibrated thresholds, and that multi-site validation would be needed before they can support cross-wreck comparisons or formal ecological classifications.

The findings carry weight beyond a single wreck. Around 45 ships sank in and around Vlora Bay during the two World Wars and later years, 27 of them inside the bay, most at depths shallower than 50 meters. These structures, largely unstudied until now, represent a distributed network of hard substrates in a soft-bottom environment. The Po demonstrates that such wrecks can serve as long-term observatories of ecological and geomorphological change, fixed reference points against which the effects of river inputs, warming waters, and shifting currents can be measured. The presence of Pterois miles, a thermophilic invader expanding northward through the Adriatic, suggests that wrecks may function as stepping stones for non-indigenous species, while the monk seal sighting hints that artificial structures could provide occasional resting or foraging opportunities where natural habitats are fragmented.

The authors frame the work as a hypothesis-generating baseline rather than a definitive causal analysis. The survey window was short, lacking time-series current data or seasonal biological monitoring, and benthic coverage estimates remain sensitive to spatial variability. Future directions include extending surveys to other wrecks in the bay, deploying current meters and sediment traps, completing the 3D digital twin of the Po, and developing virtual reality models for public engagement and Marine Spatial Planning. By coupling the methodological workflow with high-resolution hydrodynamic modeling, the researchers aim to establish a standardized protocol for evaluating the wreck-effect across the Adriatic-Ionian region, transforming historical shipwrecks from isolated artifacts into integrated tools for conservation, monitoring, and the sustainable management of the Mediterranean’s submerged cultural heritage.

Subject of Research: Marine geomorphology and bio-colonization of the Hospital Ship Po wreck in Vlora Bay, Albania

Article Title: First assessments on marine geomorphology and bio-colonization through the study and survey of the wreck of the Hospital Ship “Po” along the Albanian coasts (Vlora Bay)

Article References: Modugno, S., Castro, R., Pustina, I., Kromidha, G., Dedej, Z., & Meçöllari, A. (2026). First assessments on marine geomorphology and bio-colonization through the study and survey of the wreck of the Hospital Ship “Po” along the Albanian coasts (Vlora Bay). Frontiers in Ocean Sustainability, 4, Article 1762680. https://doi.org/10.3389/focsu.2026.1762680

Image Credits: AI Generated

DOI: 10.3389/focsu.2026.1762680

Keywords: shipwreck, artificial reef, marine geomorphology, benthic colonization, Vlora Bay, Albania, Mediterranean monk seal, lionfish, Pterois miles, sediment dynamics, Marine Protected Area, photogrammetry

The team collected surface sediment samples from the inner shelf before and after the monsoon and analyzed their sand, silt, and clay fractions. Inverse Distance Weighting interpolation in ArcGIS, run with a power parameter of two and a twelve-point fixed-radius neighborhood, transformed these point measurements into continuous maps of seabed texture. The results are striking: sand concentrations reach 99 percent in high-energy offshore zones during the pre-monsoon period and 98 percent after the monsoon, while silt climbs to 69 percent pre-monsoon and 67 percent post-monsoon in sheltered nearshore and estuarine settings. Clay, the finest fraction, peaks at 11 percent before the monsoon and 8 percent after it. These patterns trace the boundary between energetic open waters that winnow away fines and calm, protected embayments where fine particles settle out.

Grain-size statistics, computed with the Folk and Ward logarithmic method using GRADISTAT v9.1, add texture to the picture. Mean grain sizes ranged from 1.533 to 3.767 phi before the monsoon and from 1.267 to 4.233 phi afterward, spanning medium to very fine sands. Most samples were poorly sorted, about 70 percent pre-monsoon and 76.6 percent post-monsoon, a signature of deposition under fluctuating currents and river influence. Skewness values, ranging from minus 0.620 to 0.614 phi pre-monsoon and minus 0.425 to 0.496 phi post-monsoon, were predominantly positive, indicating the accumulation of fine sediments under low-energy conditions. Localized negative skewness at a handful of nearshore and offshore stations betrayed pockets of active winnowing, where waves strip away fines and leave coarser grains behind.

Correlation analysis quantified the hydraulic sorting that governs the system. Sand and silt displayed a strong inverse relationship, with coefficients near minus 0.97 after reprocessing, and sand and clay correlated negatively at roughly minus 0.84 to minus 0.88. Silt and clay, by contrast, co-occurred strongly, with positive correlations of about 0.79 to 0.85, reflecting their shared fate in low-energy depositional environments such as estuarine mouths and tidal flats. Notably, the authors report that an initially tabulated perfect inverse correlation of minus 1.00 between sand and silt turned out to be an artifact of output rounding, and the corrected values did not change the study’s central interpretation. Most telling of all, inter-seasonal correlations were exceptionally high, with pre- and post-monsoon sand fractions matching at roughly 0.95 and silt fractions at 0.96, evidence that the monsoon redistributes sediment without dismantling the underlying spatial order.

To disentangle the sediment populations driving these patterns, the team applied End-Member Modelling Analysis using the EMMAgeo package in R. Three statistically robust end members emerged. The first, peaking near 1.0 phi, represents coarse to medium sand winnowed and transported by high-energy offshore wave action; its contribution fell from 43 percent pre-monsoon to 31 percent post-monsoon as hydrodynamic energy waned. The second, peaking near 2.5 phi, is fine sand redistributed by littoral drift and mid-shelf reworking, and it held nearly steady at 38 to 34 percent across seasons, marking it as a year-round player. The third end member, peaking near 5.0 phi, captures silt-clay mixtures deposited in quiet estuarine and nearshore waters, and its share nearly doubled, rising from 19 percent to 35 percent after the monsoon, consistent with monsoon-fed river discharge delivering suspended fines while wave reworking diminished.

Canonical Correlation Analysis sharpened the seasonal contrast. Pre-monsoon samples clustered tightly within narrow canonical score ranges, indicating a uniform sand-silt-clay distribution under steady wave energy and limited river input. Post-monsoon samples, however, spread widely across the score plot, a statistical fingerprint of the turbulence unleashed by monsoon waves, increased river discharge, and runoff that resuspend seabed sediments and sweep finer particles shoreward. Complementary Empirical Orthogonal Function analysis of the interpolated sand grids identified two dominant modes explaining about 65 percent of total variance: an offshore-onshore gradient accounting for roughly 45 percent, and a nearshore fine-sediment accumulation zone adjacent to the estuarine mouth contributing about 20 percent, with stronger expression after the monsoon.

Principal Component Analysis and Hierarchical Cluster Analysis then distilled the dataset into its essential geography. The first two principal components explained 48.0 and 26.6 percent of variance respectively, a cumulative 74.6 percent, and the analysis passed standard suitability checks with a Kaiser-Meyer-Olkin value of 0.81 and a significant Bartlett’s test of sphericity. High positive scores on the first component marked sand-dominated, high-energy shelf environments, while the second component separated sites by finer distinctions between clay and silt. Cluster analysis, using Ward’s linkage and Euclidean distance, grouped samples into three recurring settings: sand-rich high-energy zones exposed to wave action, transitional sand-silt environments shaped by littoral drift and estuarine mixing, and fine-rich, low-energy mud deposits near estuarine mouths. With a cophenetic correlation coefficient of 0.89 and 86.7 percent of samples retaining consistent cluster membership across seasons, these three depositional provinces proved to be the enduring architecture of the Nagapattinam inner shelf.

The study also sounds a note of caution about human fingerprints on the seabed. Stations near jetties, seawalls, and harbor structures consistently fell within transitional clusters, showing elevated silt and clay contents and poorer sorting, hallmarks of sediment trapped on the updrift side of structures and starved supply downdrift. Dredging near fishing harbors resuspends fine sediments that later settle in sheltered nearshore and estuarine zones, contributing to the fine-fraction anomalies visible in the interpolation maps. The region’s new jetty for transporting offshore oil and gas adds another engineered element to a coastline already juggling natural and anthropogenic pressures. Model performance metrics confirmed that predictions were most reliable for sand, with an R-squared of 0.91 pre-monsoon, while clay showed the largest relative errors, at 48.3 percent pre-monsoon and 55.8 percent post-monsoon, reflecting the challenge of tracking suspended fines.

The authors acknowledge that a two-season sampling design cannot capture disturbances from cyclones, storm surges, or extreme river discharge events, and they call for continued monitoring, sediment-transport modeling, and wave-climate analysis using wave-rose diagrams. Still, the takeaway is compelling for coastal managers and ecologists alike: the Nagapattinam inner shelf is not a chaotic system at the mercy of the monsoon but a structured one, in which seasonal pulses of energy and river discharge redistribute sediment within a stable, three-part granulometric framework. That stability, maintained by persistent wave regimes, littoral drift, and the steady delivery of Cauvery sediments, provides a baseline against which future erosion, habitat change, and infrastructure impacts can be measured, in a monsoon-dominated coastal segment that has, until now, lacked such a detailed assessment.

Subject of Research: Seasonal sediment dynamics and grain-size distribution on the Nagapattinam inner shelf of the Cauvery basin, southern India

Article Title: Seasonal variations of inner shelf sediment dynamics and granulometric characteristics along the Nagapattinam coast of the Cauvery basin, Southern India

Article References: Pitchaimani, V. S., Abishek, S. R., Joe, R. J. J., & Promilton, A. A. A. (2026). Seasonal variations of inner shelf sediment dynamics and granulometric characteristics along the Nagapattinam coast of the Cauvery basin, Southern India. Discover Oceans, 3(1), Article 4. https://doi.org/10.1007/s44289-025-00109-x

Image Credits: AI Generated

DOI: 10.1007/s44289-025-00109-x

Keywords: sediment dynamics, granulometric analysis, Nagapattinam coast, Cauvery basin, monsoon, inner shelf, grain size analysis, IDW interpolation, end-member modelling, PCA, coastal geomorphology, Bay of Bengal

The study, published in the journal Discover Oceans, involved measuring gamma radiation at thirty locations spread across an area of roughly two kilometres by six hundred metres, arranged on an imaginary grid with two hundred metres between adjacent points. The researchers used a portable sodium iodide detector sealed inside a PVC pipe to record total gamma counts directly on the beach, logging each position with a handheld GPS receiver. Back in the laboratory, sediment collected from the same thirty sites was dried, sieved and analysed with a high-resolution germanium detector to quantify specific radionuclides. The in-situ counts ranged from 1800 to 6498 counts per minute, and the interpolated map showed that radioactivity was noticeably higher toward the south-west of the beach than the north-east.

What makes the pattern scientifically interesting is that different radionuclides behave in opposite ways depending on the size of the sand grains they inhabit. In the finest fraction studied, grains between 53 and 100 micrometres, the mean activity concentrations of radium-226, radium-228 and potassium-40 were 151.2, 369.4 and 209.7 becquerels per kilogram respectively. In the dominant medium fraction, between 101 and 250 micrometres, the same isotopes averaged just 28.7, 60.6 and 272.6 becquerels per kilogram. In other words, radium concentrates in fine grains while potassium-40 favours coarse ones, a split that reflects two entirely different geochemical stories.

The radium story is one of surface chemistry. Radium-226 and radium-228 are daughter products of the uranium-238 and thorium-232 decay chains, and both isotopes are strongly adsorbed onto particle surfaces. Fine grains carry far more surface area per unit mass than coarse grains, so they adsorb more radium from seawater and pore fluids. Potassium-40 behaves differently: it is an integral constituent of silicate minerals derived from igneous rocks, and its compatibility with silica means it travels locked inside the mineral lattice rather than clinging to grain surfaces. Coarse sediments, being richer in such minerals and less easily washed back out by the tide, end up enriched in potassium-40. The tidal sorting mechanism is simple but effective: waves wash lighter fine grains away and leave heavier particles behind on the beach.

To characterise the sediments chemically, the team used energy-dispersive X-ray fluorescence on the medium grain fraction, which makes up more than seventy percent of the sediment by weight at most locations. The dark grey sand proved mineral-rich, with iron, aluminium, calcium, magnesium, titanium, potassium, vanadium, manganese, zirconium, chromium and lanthanum as the major elements. Mean iron concentration reached about 84,900 parts per million, with aluminium near 54,000 and calcium around 50,000 parts per million. This composition points to substantial heavy-mineral content, the kind of material that waves and currents concentrate into placers and that can markedly raise local radioactivity, as seen dramatically in the monazite-rich black sands of Kerala on India’s south-west coast.

Compared with other Indian and international beaches, Jampore sits in a middle ground. Kerala’s high-background radiation area shows thorium-232 activities that can reach thousands of becquerels per kilogram, far beyond anything measured at Daman. Tamil Nadu beach sands typically report radium-226 between 13 and 198 becquerels per kilogram, while the Odisha and Andhra coasts fall in the tens to low hundreds. Globally, beaches in Ghana, Turkey and Thailand report broadly similar values, with radium isotopes in the tens and potassium-40 in the low hundreds of becquerels per kilogram. Jampore’s fine fraction is moderately elevated relative to many of these sites, but remains well below the classical high-background zones, meaning the beach is radiologically ordinary while still being dynamically informative.

The most consequential finding concerns the ratio of the two radium isotopes. Across the fine fraction the radium-226 to radium-228 ratio ranged from 0.29 to 0.55, and in the medium fraction from 0.39 to 0.61. Crucially, zones with lower ratios coincided with higher total gamma counts. Building on earlier work in the Yangtze Estuary, where smaller radium ratios were linked to sediment accretion, the researchers interpret the low-ratio, high-count areas of Jampore beach as zones where sand is accumulating. The strong linear correlation between the two radium isotopes, with a coefficient of determination of 0.9878, suggests they share a common origin and are governed by the same adsorption and desorption processes, which makes their ratio a stable and interpretable indicator.

The in-situ measurements also proved to be a surprisingly faithful proxy for laboratory analysis. Correlation plots showed that the spatial pattern of total gamma counts closely mirrors the distributions of both radium-226 and radium-228, but not potassium-40. The reason lies in nuclear structure: the uranium and thorium series emit multiple high-intensity gamma lines, including strong peaks at 609.3 and 1764.5 kiloelectronvolts for the radium-226 chain and at 583.2 and 2614.5 kiloelectronvolts for the radium-228 chain, whereas potassium-40 emits only a single gamma ray at 1460.82 kiloelectronvolts with a modest ten percent emission probability. The integrated field signal is therefore dominated by the radium chains, which is precisely what makes a rapid field survey with a portable detector a viable stand-in for detailed laboratory spectrometry when the goal is mapping sediment regimes.

The broader motivation is methodological. Since 1954, investigations of coastal sediment dynamics have relied on artificial radiotracers produced in nuclear reactors, materials that are effective but burdened by public concern and strict regulatory clearance requirements from nuclear safety authorities. Natural radionuclides embedded in the sediment offer an alternative that requires nothing to be released. Researchers in Spain, the Canary Islands, South Africa and elsewhere have already proposed radium isotopes and lead-210 as tracers of erosion and accretion, and the Indian team frames its Jampore survey as a first step toward establishing a radiometric database and a methodology for using natural isotopes as tracers along Indian coasts. The data could also serve as benchmarks against which numerical sediment transport models can be validated, increasing confidence in their predictions.

For a beach flanked by the mouths of the Daman Ganga and Kolak rivers, where fluvial supply, wave sorting and monsoon-driven erosion continuously redistribute the sand, the ability to read accretion and erosion directly from the sediment’s own radioactivity is a genuinely practical tool. Harbour dredging, dumping-site selection and coastal protection all depend on knowing where sediment goes, and a technique that replaces costly and regulated artificial tracers with a portable detector and a GPS unit could change how coastal engineers gather that knowledge. The Jampore map is a modest survey of one four-and-a-half-kilometre beach, but it demonstrates a principle with wide reach: every shoreline already carries its own radioactive diary of movement, and learning to read it may be as simple as walking the sand with a detector in hand.

Subject of Research: Spatial distribution of natural radioactivity in beach sediments as a tracer of coastal sediment dynamics

Article Title: Investigation of distribution pattern of natural radioactivity in the sediments of Jampore beach, Daman, India

Article References: Biswal, J., Goswami, S., Yadav, V. B., Sartandel, S. J., Samantray, J. S., Pulhani, V., & Sharma, V. K. (2026). Investigation of distribution pattern of natural radioactivity in the sediments of Jampore beach, Daman, India. Discover Oceans, 3(1), Article 12. https://doi.org/10.1007/s44289-026-00124-6

Image Credits: AI Generated

DOI: 10.1007/s44289-026-00124-6

Keywords: natural radioactivity, Jampore beach, Daman, sediment dynamics, gamma spectrometry, radium-226, radium-228, potassium-40, heavy minerals, coastal erosion, accretion, EDXRF