Sea Cliffs Research Articles

Cliff Notching Due To Swash Abrasion: Insights From Physical Experiments

AbstractNotch development at the base of sea cliffs is an important control on cliff recession rates, but a detailed mechanistic understanding of notch formation by swash abrasion is lacking. We conducted physical experiments, using homogeneous erodible rock simulants, to study notch‐forming mechanisms under periodic sediment‐laden bore impacts. Our findings reveal shifts in the temporal dynamics of notch development. Initially, swash uprush and vortex formation contribute to a positive feedback loop that creates a shallow and wide notch. Subsequently, upward erosion ceases, and notch backwear and downwear are dominated by the vortex. Eventually, sediment deposition armors the notch floor; this negative feedback loop reduces erosion. The sediment size determines the amount of erosion, with a range of grain sizes generating maximum erosion. This indicates a dependence on the momentum of the sediment particles entrained within the bore. This research reveals fundamental notch formation mechanisms driven by swash abrasion.

Anthropogenic disturbance has altered the habitat of two Azorean endemic coastal plants

BackgroundAnthropogenic threats are causing alteration of coastal areas worldwide. Most of the coastal biodiversity is endangered, taking a particular toll on island ecosystems, like the Azores. To better understand the biotic and abiotic factors constraining the distribution and conservation status of two endemic plants, Azorina vidalii (Campanulaceae) and Lotus azoricus (Fabaceae), we performed a global survey of coastal plant communities in the archipelago, also covering environmental descriptors, natural and anthropogenic threats. Moreover, we revised their IUCN conservation status and estimated the population fractions within protected areas.ResultsNon-indigenous plants were commonly found in plots with or without the target endemics, contributing to the absence of well-defined coastal plant communities. Nonetheless, indigenous taxa commonly occurred at the plots with L. azoricus. With a larger area of occurrence, A. vidalii ecological niche differed from that of L. azoricus, the latter being restricted to dry and rocky sea cliffs, mostly in Santa Maria Island. Besides the presence of invasive plants, signs of habitat destruction, trampling and grazing, and of natural threats, such as coastal erosion, were commonly observed.ConclusionsOccurrence data indicated an endangered status for both species, although this would change to critically endangered for L. azoricus when using smaller-sized occurrence cells. Both species are threatened since their habitat is restricted to a very narrow vegetation belt, strongly limited by sea influence and human pressure, and with the frequent presence of invasive plants. While focusing on two endemic plants, our study allowed a broader view of the impact of anthropogenic disturbance on Azorean coastal plant communities.

An updated reconstruction of Campi Flegrei caldera (southern Italy) ground deformation history and its interaction with the human sphere since Roman time

Since the 19th century, many scientists have tried to reconstruct the ground motions that occurred in the Campi Flegrei caldera, one of the most dangerous volcanos in the Mediterranean area. This study aims to assess the joint effects of vertical ground movements and anthropic forcing along the coasts of this volcanic area. A huge dataset of hundreds of archeo-stratigraphic boreholes was coupled with direct and indirect surveys of the main underwater archaeological sites scattered along the whole coastal sector and with the reinterpretation of bibliographic sources. Clear evidence of a differential volcano-tectonic behaviour (highlighted for the first time in this study) led us to divide the study area into three coastal stretches with homogeneous vertical ground movements. In each sector, a new relative sea-level (RSL) curve was reconstructed, by interpreting our stratigraphic and archaeological data in terms of SL markers covering a wider timespan compared to the previous studies, from the first Roman urbanization to the present day. The comparison between RSL curves and GIA models allowed estimating vertical ground movements (See Supplementary material 2) that occurred along the coast with decimetres accuracy. For each of the 5 recognized phase of uplift or subsidence, we also studied the subsequent effects in terms of coastal geomorphological change, and advantages or negative impacts on ancient human activities. We measured an overall subsiding trend that brought the RSL from −12 ± 1 m (4th century BC) to 7 ± 0.2 m during three different episodes between 5th and 15th centuries (1450–450 y BP), which was interrupted by short-lived falls (less of 100 years) of RSL. During the phases of RSL fall and/or volcano-tectonic stability, detected for the first time in the eastern and western part of the caldera (1st-2nd century AD and 3rd-4th century AD), a basinward shift of the coastline created newly emerged land even at the base of the local sea cliffs, where shore platforms emerged, favouring intense phases of urbanization on them along the Baia – Miseno sector and at the footslope of Rione Terra. This trend also favoured the closure of the Lucrino lagoon with an extended spit bar during the 2nd century BC, allowing the establishment of a large oyster farming system belonging to Sergio Orata. On the contrary, the subsiding phases resulted in the flooding of coastal areas and anthropic structures such as villas, nymphaea and ports inducing the construction of coastal protection structures. In the extreme case of Portus Julius, subsidence led to the abandonment of the military port and its move to nearby Miseno.

Sea Cliff along Tasmanian Coast

Sea Cliff along Tasmanian Coast

Spatial Distribution Status of Landform in 1st Grade Area of Ecology and Nature Map

In this study, spatial distribution analysis was conducted on the landforms that appear within the 1st grade area using the ecology and nature map of 2023. As a result, a total of 97 landforms including tidal flat and incised meander were identified as unit landforms, and a total of 1,490 sites were distributed. The spatial distribution by administrative region was highest in Gangwon-do with 273 sites (12.8%), and by unit landform, cliff (173 sites), stream cliff (129 sites), and sea cliff (100 sites) were the most distributed. These landforms are cliffs found in mountainous, riverine, and coastal areas, respectively, and are characterized by their high geomorphological conservation value due to their large scale and geometric shape compared to other terrains. In terms of spatial distribution by landform type, stream landforms (501 sites, 33.6%) accounted for the largest proportion, and there were 24 units landforms. The results obtained can be utilized for future designation of expanded ecosystem protection areas or ecosystem monitoring surveys, along with continued landform conservation.

Biological Flora of Britain and Ireland: Silene uniflora‡

Abstract This account presents information on all aspects of the biology of Silene uniflora Roth (S. maritima With., S. vulgaris Garcke subsp. maritima (With.) Á. & D. Löve), Sea Campion, that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of Britain and Ireland: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history and conservation. Silene uniflora is a mat‐like perennial herb that in Britain and Ireland is primarily distributed in coastal habitats, notably on sea cliffs and shingle banks but also at the drift line and rarely on sand; it also has populations on mountains and heavy metal mine waste tips. All of these substrates tend to be oligotrophic, loose‐textured and freely draining, and often with adverse ion concentrations. It is found in suitable habitats around much of the Atlantic and Baltic coasts of Europe. Its breeding system is gynodioecious and gynomonoecious (some individuals bearing female flowers only, some bearing hermaphrodite flowers only and others with both types of flower). The proportions of the three types of individual vary considerably between populations, but hermaphrodite flowers tend to predominate. The showy, white, nectar‐producing flowers are produced continuously over the entire summer and are pollinated mainly by long‐tongued Hymenoptera and night‐flying moths but autogamous selfing is also frequent. Silene uniflora and its close relative S. vulgaris were the subject of a classic, decadal study involving genetical and transplant experiments that was seminal in the development of ‘experimental taxonomy’. More recently, attention has focused on the rapid evolution of Zn‐tolerant populations of S. uniflora growing on mine spoil and contaminated river gravels. It has also become a model organism for the study of sexually transmitted, castrating fungal diseases in plants (notably of the genus Microbotryum).

Eocene (50–55 Ma) greenhouse climate recorded in nonmarine rocks of San Diego, CA, USA

Nonmarine rocks in sea cliffs of southern California store a detailed record of weathering under tropical conditions millions of years ago, where today the climate is much drier and cooler. This work examines early Eocene (~ 50–55 million-year-old) deeply weathered paleosols (ancient, buried soils) exposed in marine terraces of northern San Diego County, California, and uses their geochemistry and mineralogy to reconstruct climate and weathering intensity during early Eocene greenhouse climates. These Eocene warm spikes have been modeled as prequels for ongoing anthropogenic global warming driven by a spike in atmospheric CO2. Paleocene-Eocene thermal maximum (PETM, ~ 55 Ma) kaolinitic paleosols developed in volcaniclastic conglomerates are evidence of intense weathering (CIA > 98) under warm and wet conditions (mean annual temperature [MAT] of ~ 17 °C ± 4.4 °C and mean annual precipitation [MAP] of ~ 1500 ± 299 mm). Geologically younger Early Eocene climatic optimum (EECO, 50 Ma) high shrink-swell (Vertisol) paleosols developed in coarse sandstones are also intensely weathered (CIA > 80) with MAT estimates of ~ 20 °C ± 4.4 °C but have lower estimated MAP (~ 1100 ± 299 mm), suggesting a less humid climate for the EECO greenhouse spike than for the earlier PETM greenhouse spike.

Coastal retreat and sea-cliff dynamic on the North Atlantic coast (Gerra Beach, Cantabrian Coast, Spain)

Gerra is small beach located at the foot of a cliff on the Western coast of Cantabria (North of Iberian Peninsula). It has a sandy distal part and a proximal part at the foot of the cliff made up of boulders, supported by rockfalls and landslides from the cliff. Claystones, limestones and marls of the Triassic and Cretaceous ages form the cliff. To study geomorphological processes, a geomorphological map was drawn up; analysis of the beach deposits as texture, granulometry and Atterberg limits; analysis of photogrammetric flights between 1957 and 2017; drone flights between 2017 and 2020; and geomatic monitoring of the cliff and the beach by means of a terrestrial laser scanner (TLS) between 2012 and 2019. The processes involved in the coastal dynamic and retreat of the cliff and beach have been established, as well as the rates of erosion and retreat, which coincide with other beaches on the Cantabrian Coast. The current dynamics are characterized by the moderate regression of the coastline and greater regression and dynamism at the cliff-top, which implies the gradual degradation of the cliff due to loss of verticality. Among the factors involved in the cliff degradation, the main changes in the present and future evolution of the sea cliff can only be ascribed to sea level rise.

Anomalous facies of the Kinnesswood Formation in the Cumbraes Basin: a late Famennian playa complex in SW Scotland

Among the important geological attributes of the small Cumbraes Basin in the southwestern off-shore Midland Valley of Scotland, the 4 km-long, fragmented but well-exposed section through the Devonian–Carboniferous boundary sequence in southern Great Cumbrae island ranks highly. In a continuous short stretch of the south and west coasts, large portions of this sequence are superbly preserved in tide-washed strandline surfaces and in old post-glacial sea cliff. This enhanced exposure leaves no doubt that the outcrops belong to two, immediately successive, members of the Kinnesswood Formation – the lower the Doughend Sandstone, the upper the Foul Port Mudstone – and that they provide some of the best available exposures on which to base description and interpretation. The facies of the fluviatile Doughend Sandstone shares many characteristics with the underlying Kelly Burn Sandstone of the Upper Old Red Sandstone, whereas that of the Foul Port Mudstone is distinct and unusual, attributed to local tectonics, influenced by movements on older and more major fractures such as the Highland Boundary Fault, with sediment accumulation taking place in a playa-lake complex of considerable extent.

Geomorphological Evolution of Volcanic Cliffs in Coastal Areas: The Case of Maronti Bay (Ischia Island)

The morphoevolution of coastal areas is due to the interactions of multiple continental and marine processes that define a highly dynamic environment. These processes can occur as rapid catastrophic events (e.g., landslides, storms, and coastal land use) or as slower continuous processes (i.e., wave, tidal, and current actions), creating a multi-hazard scenario. Maronti Bay (Ischia Island, Southern Italy) can be classified as a pocket beach that represents an important tourist and environmental area for the island, although it has been historically affected by slope instability, sea cliff recession, and coastal erosion. In this study, the historical morphoevolution of the shoreline was analysed by means of a dataset of aerial photographs and cartographic information available in the literature over a 25-year period. Furthermore, the role of cliff recession and its impact on the beach was also explored, as in recent years, the stability condition of the area was worsened by the occurrence of a remarkable landslide in 2019. The latter was reactivated following a cloudburst on the 26th of November 2022 that affected the whole Island and was analysed with the Dem of Difference technique. It provided an estimate of the mobilised volumes and showed how the erosion and deposition areas were distributed and modified by wave action. The insights from this research can be valuable in developing mitigation strategies and protective measures to safeguard the surrounding environment and ensure the safety of residents and tourists in this multi-hazard environment.

Smartphone Structure-from-Motion Photogrammetry from a Boat for Coastal Cliff Face Monitoring Compared with Pléiades Tri-Stereoscopic Imagery and Unmanned Aerial System Imagery

Many issues arise from the recession of sea cliffs, including threats to coastal communities and infrastructure. The best proxy to study cliff instability processes is the cliff face evolution. Unfortunately, due to its verticality, this proxy is difficult to observe and measure. This study proposed and compared three remote sensing methods based on structure-from-motion (SfM) photogrammetry or stereorestitution: boat-based SfM photogrammetry with smartphones, unmanned aerial system (UAS) or unmanned aerial vehicle (UAV) photogrammetry with centimetric positioning and Pléiades tri-stereo imagery. An inter-comparison showed that the mean distance between the point clouds produced by the different methods was about 2 m. The satellite approach had the advantage of covering greater distances. The SfM photogrammetry approach from a boat allowed for a better reconstruction of the cliff foot (especially in the case of overhangs). However, over long distances, significant geometric distortions affected the method. The UAS with centimetric positioning offered a good compromise, but flight autonomy limited the extent of the monitored area. SfM photogrammetry from a boat can be used as an initial estimate for risk management services following a localized emergency. For long-term monitoring of the coastline and its evolution, satellite photogrammetry is recommended.

Sea Caves and Other Landforms of the Coastal Scenery on Gozo Island (Malta): Inventory and New Data on Their Formation

Sea caves are a type of cave formed primarily by the wave action of the sea. The coastal scenery of the Gozitan coast is very interesting in that sea caves and other coastal landforms, such as sea arches, develop at the sea level. We mapped seventy-nine semi-submerged sea caves opening at the sea level, five completely submerged sea caves, seven sea arches, one sea stack, and one shelter around the coast of Gozo, mainly in the Western and Eastern parts of the island, due to favorable lithological and topographical conditions. Additionally, we surveyed the topography of the emerged part of nine sea caves using the iPhone build-in LiDAR sensor, and eight sea caves in the submerged part using SCUBA equipment. This inventory represents the most detailed example of a database of coastal caves and related forms in the Mediterranean, mainly sourced from a swimming survey along the entire island. Thanks to the combination of outputs of the above-water emerged and submerged surveys, we defined three types of semi-submerged sea caves: (i) box caves, (ii) joint caves, and (iii) complex caves. Moreover, we added a cave-like landform above the sea level on calcarenites called shelter, or a little extended notch deeply carved into the cliff. The shape mainly depends on the structural and lithological setting of sea cliffs. In the Western sector of the island, we also discovered the only sea cave in Gozo, measuring 122 m in length and 10 m in width, with its floor developing above the mean sea level. This cave base is of interest due to rounded landforms related to marine erosion. In the innermost part of the cave, there is also a beach with rounded pebble at an elevation of about 7 m asl. Considering the tectonic stability of the island, it could be possibly related to the MIS 5.5 highstand.

Analysis on Causes of the “4·21” Indonesian Submarine “Nanggala” Crash Based on Satellite Images

In view of the “4·21” Indonesian submarine “Nanggala” crash event, an analysis of the marine environmental factors that may lead to the crash is carried out. The results show that the ocean internal wave is one possible cause of the disappearance of Indonesian submarines. The event is most likely that the submarine was subject to the so called “sea cliff” when encountering large-amplitude ocean internal waves, and at the same time, the officers and soldiers on board failed to take reasonable evasive measures in time, resulting in the submarine losing control and falling below the maximum safe diving depth, making the submarine crack under the pressure of the huge sea, resulting in a submarine accident. This conclusion is obtained based on the analysis of integrated ocean internal wave satellite images and numerical simulations.

The Response of Sandstone Sea Cliffs to Holocene Sea-Level Rise by Means of Remote Sensing and Direct Surveys: The Case Study of Punta Licosa Promontory (Southern Italy)

Punta Licosa promontory is located in the northern part of the Cilento coast, in the southern Tyrrhenian basin. This promontory is bordered by sea cliffs connected to a wide shore platform sloping slightly towards the sea. This area has been considered stable at least since Late Pleistocene, as testified by a series of evidence well known in the literature. The aim of this research is to reconstruct the main coastal changes that have occurred in this area since the middle Holocene by means of the literature data, aerial photo interpretation, satellite images, GPS measurements, direct underwater surveys, GIS elaborations of high-resolution DTMs, bathymetric data and high-resolution orthophotos taken by UAV. Particular attention was paid to the wide platform positioned between −7.2 ± 1.2 m MSL and the present MSL, this being the coastal landform interpreted as the main consequence of sea cliff retreat. The elevation of this landform was compared with the GIA models calculated for the southern Tyrrhenian area, allowing establishing that it was shaped during the last 7.6 ± 1.1 ky BP. Moreover, the interpretation of archaeological and geomorphological markers led to the reconstruction of the shoreline evolution of this coastal sector since 7.6 ky BP. This research evaluates the cliff retreat under the effect of Holocene RSL variation on Cilento promontories, located in the western Mediterranean and characterised by the presence of monophasic platforms, and the applied method can be considered more effective and less complex and expensive if compared to other effective approaches such as those based on the usage of cosmogenic nuclides.

A statistical approach for sea cliff hazard and setback lines mapping in the northeast of Peniche, Portugal

The considerable increase in the occupation of coastal areas requires strategies to conceive and apply hazard prevention and mitigation measures, especially in coastlines with sea cliffs where mass movements are more likely to occur. To predict the potential of sea cliff failures and identify the more unstable cliff sections, analytical, physical and/or statistical tools can enable the assessment of cliff failure susceptibility, which is a progress towards a better understanding of sea cliff failure hazard assessment and mapping.In this study, statistical approaches for the assessment of sea cliff failure susceptibility and definition of safety set-back lines located landwards of the cliff top crest were adopted, in the coast located to northeast of Peniche, between Baleal and the Óbidos lagoon, in the western coast of Portugal. For the susceptibility assessment, the logistic regression was used to correlate a set of predictive factors, obtained from thematic maps of geology (lithology, structure, faults), geomorphology (cliff height, slope angle, exposure, curvature, toe protection) and wave action, with an inventory of cliff failures that caused cliff top retreat, compiled from aerial photographs from 1947 to 2010. This method enabled the production of cliff failure susceptibility models using terrain units with different sizes, encompassing cliff crest length segments of 50 m, 20 m, and 10 m. The ordinal logistic regression was applied for the setback lines definition.The modeling results were analyzed using diagnostic measures and external validation, with each model being validated against the cliff instability inventory which indicated very good statistical performance and allowed the production of reliable susceptibility maps.The application of such statistical techniques enables estimation of the degree of susceptibility for cliff failures at regional scales of analysis, and assists the definition of cliff setback lines, which provide answers to planning and hazard prevention problems of coastal areas with sea cliffs.

Cascadia Earthquake-Triggered Rockslide Burial of Beeswax Galleon Wreck Timbers in a Sea Cliff Wave-Cut Platform Site, North Smuggler Cove, Oregon, USA

Shipwreck timbers (n=27) from the Spanish galleon Santo Cristo de Burgos, also known as the Beeswax Wreck (lost in 1693), are examined for origins of multiple, simultaneous rockslide burials that protected and preserved the timbers on an intertidal wave-cut platform in the small Smuggler Cove in the Northern Oregon coast. The rockslides (n=3–4) that buried the shipwreck timbers are compared to nearby historic rockslide analogs to better establish the mechanisms of boulder distributions on the wave-cut platform. Large boulders (n=20), generally ≥1.0 m intermediate diameter, in the North Smuggler Cove (NSC) timber burial site were measured for estimated mass (1–41 t) and alongshore distribution below small gullies that routed the boulders to the wave-cut platform from overlying short (~100 m distance) but steep hillslopes (40–60% gradient). The multiple independent rockslides in the NSC site, dated to ~300 years by the buried Beeswax Wreck timbers, showed catastrophic, simultaneous activation by a widespread trigger. Anomalous rainfall and/or storm wave attack are unlikely mechanisms for these rockslide activations due to 1) hillslope protections from extended-upslope surface water discharge and 2) sea cliff protection from direct storm wave impacts. The most likely widespread trigger for rockslide activation in the NSC site is seismic ground shaking from an earthquake in the Central Cascadia subduction zone. Modern storm wind velocities (>10 s-1 sustained velocity and 170–225° bearing) and storm surge generated rip currents (≥0.5 km offshore distance) indicate that Beeswax Wreck timbers could have been transported north (1–10 km) to Smuggler Cove, within several winter seasons after the breakup of the Santo Cristo de Burgos. The most likely seismic trigger that could have activated the multiple rockslides in the NSC site, shortly after the brief accumulation of shipwreck timbers on the narrow, intertidal wave-cut platform in Smuggler Cove, is the 1700 Cascadia great earthquake (Mw~9.0). Additional sea cliff rockslide sites (n=8) in the central Cascadia margin are suggested for further investigations of seismically activated slope failures by the 1700 Cascadia great earthquake.

Geological Controls on Marine Cavernous Landforms along Japanese Pacific-side Rocky Coasts

Marine cavernous landforms, including notches, caves, arches and tunnels, characterize the rocky coast landscape and are strongly influenced by the geology (e.g., rock strength and structure) of sea cliffs. Geological controls on the development and shape of marine cavernous landforms are evaluated based on field investigations along the Pacific coastlines of Honshu Island, Japan. Morphological parameters, width (w), depth (d), and height (h), of cavernous landforms were measured directly or through images taken with an unmanned aerial vehicle, together with geological factors, such as rock types, strength (Schmidt hammer rebound values: R), dips and strikes of bedding, major joints, and fault planes. In total, 76 caves are investigated in six coastal areas: Sanriku Coast, Joban Coast, Boso Peninsula, Miura Peninsula, Izu Peninsula, and Kii Peninsula. According to shape index, d/w, and presence of the open end, cavernous landforms are classified into notches (d/w < 1, closed end), caves (d/w ≥ 1, closed end), arches (d/w < 1, open end), and tunnels (d/w ≥ 1, open end). An analysis shows that the major geological controls differ between notches and the other three forms. Low rock strength (R < 40) and sub-horizontal bedding are, respectively, the primary and secondary controls on the formation of notches, whereas weak rock structures (joints, faults and bedding) with a dip steeper than 30° (vertical or steeply inclined structures) and a strike trending perpendicular to the cliff face are the major controls on the formation of caves, arches and tunnels. Rock strength also affects planar forms defined by the shape index, promoting a deepening of cavernous forms, particularly when the cliff has a medium rock strength (R = 30-50) that provides an optimal balance between erosion force and resisting force. In general, vertical or steep structures contribute to the deepening of holes, whereas horizontal or gentle structures favor widening.

Diaporthe species associated with the maritime grass Festuca rubra subsp. pruinosa.

Festuca rubra subsp. pruinosa is a perennial grass growing in sea cliffs where plants are highly exposed to salinity and marine winds, and often grow in rock fissures where soil is absent. Diaporthe species are one of the most abundant components of the root microbiome of this grass and several Diaporthe isolates have been found to produce beneficial effects in their host and other plant species of agronomic importance. In this study, 22 strains of Diaporthe isolated as endophytes from roots of Festuca rubra subsp. pruinosa were characterized by molecular, morphological, and biochemical analyses. Sequences of the nuclear ribosomal internal transcribed spacers (ITS), translation elongation factor 1-α (TEF1), beta-tubulin (TUB), histone-3 (HIS), and calmodulin (CAL) genes were analyzed to identify the isolates. A multi-locus phylogenetic analysis of the combined five gene regions led to the identification of two new species named Diaporthe atlantica and Diaporthe iberica. Diaporthe atlantica is the most abundant Diaporthe species in its host plant, and Diaporthe iberica was also isolated from Celtica gigantea, another grass species growing in semiarid inland habitats. An in vitro biochemical characterization showed that all cultures of D. atlantica produced indole-3-acetic acid and ammonium, and the strains of D. iberica produced indole 3-acetic acid, ammonium, siderophores, and cellulase. Diaporthe atlantica is closely related to D. sclerotioides, a pathogen of cucurbits, and caused a growth reduction when inoculated in cucumber, melon, and watermelon.

Testing the potential of drowned shore platforms as sea level proxies in a temperate, microtidal environment: Victoria, Australia

Shore platforms are erosional benches, often found at the base sea cliffs, which form through erosion concentrated within the intertidal zone. In locations without suitable depositional proxies, these erosional landforms have been used to reconstruct past sea levels. The precision and accuracy of shore platforms as sea level proxies is highly variable as their morphology, particularly their vertical position in the intertidal zone, is modulated by boundary conditions especially those related to the geology in which they are formed. In this study the semi-horizontal shore platforms on the microtidal temperate coast of Victoria, Australia are examined to test the utility of these systems as sea level indicators. These results are then applied to a suite of submerged shore platforms found offshore using high-resolution LiDAR topographic and multi-beam sonar bathymetric data. The elevation of both the contemporary and drowned platforms are measured at both the cliff-platform junction and the mid-point of each profile line. Both methods are compared to assess their utility to represent sea level at the time of their formation. It is found that those platforms formed within resistant sandstone and basalt are the best proxies for sea level forming in the upper intertidal zone, while those formed in softer Tertiary carbonates are less precise being predominately subtidal features. The morphology of the drowned platforms is broadly similar to those at current sea level elevations, and they are concentrated at a depth 49.7 to 57.2 m below modern sea level. It is inferred that these drowned platforms likely formed during marine isotope stage 5a or 5d.

Diaporthe atlantica enhances tomato drought tolerance by improving photosynthesis, nutrient uptake and enzymatic antioxidant response.

Functional symbiosis with fungal endophytes can help plants adapt to environmental stress. Diaporthe atlantica is one of the most abundant fungal taxa associated with roots of Festuca rubra subsp. pruinosa, a grass growing in sea cliffs. This study aimed to investigate the ability of a strain of this fungus to ameliorate the impact of drought stress on tomato plants. In a greenhouse experiment, tomato plants were inoculated with Diaporthe atlantica strain EB4 and exposed to two alternative water regimes: well-watered and drought stress. Several physiological and biochemical plant parameters were evaluated. Inoculation with Diaporthe promoted plant growth in both water treatments. A significant interactive effect of Diaporthe-inoculation and water-regime showed that symbiotic plants had higher photosynthetic capacity, water-use efficiency, nutrient uptake (N, P, K, Fe and Zn), and proline content under drought stress, but not under well-watered conditions. In addition, Diaporthe improved the enzymatic antioxidant response of plants under drought, through an induced mechanism, in which catalase activity was modulated and conferred protection against reactive oxygen species generation during stress. The results support that Diaporthe atlantica plays a positive role in the modulation of tomato plant responses to drought stress by combining various processes such as improving photosynthetic capacity, nutrient uptake, enzymatic antioxidant response and osmo-protectant accumulation. Thus, drought stress in tomato can be enhanced with symbiotic fungi.