Sea-level Indicators Research Articles

Re-evaluating Marine Isotope Stage 5a paleo-sea-level trends from across the Florida Keys reef tract

Unraveling how Global Mean Sea Level (GMSL) fluctuated during past warm periods can improve our understanding of linkages between sea-level fluctuations, orbital forcing, and ice-sheet dynamics. Current estimates of GMSL for Marine Isotope Stages (MIS) 5a and 5c — two warm intervals following the relatively well-documented MIS 5e — contain meters of uncertainty and fewer data due to several challenges. These challenges include concealment of datable in-situ coral facies by MIS 1 deposits and inaccessibility due to submergence by modern sea level. We present a comprehensive dataset based on U–Th dating and stratigraphic correlation of 23 cores totaling over 170 m of recovered coral-reef deposits across the tectonically stable Florida Keys Reef Tract (FKRT). Following detailed facies descriptions, 34 in-situ, minimally altered aragonitic coral samples (≤2.7% calcite) below the Holocene-Pleistocene boundary were targeted for U–Th geochronology. Fourteen closed-system coral U–Th ages from MIS 5a include the commonly used sea-level indicator Acropora palmata, but also the massive coral taxa Pseudodiploria strigosa, Siderastrea siderea, Orbicella spp., and Porites astreoides. Dating yielded ages in the range of 88–81 ka (average 2σ uncertainty of less than 200 years). These ages suggest MIS 5a reef initiation at ∼88 ka BP, a peak near 83 ka with minimum elevations between −6.0 ± 0.5 and −5.6 ± 0.5 m MSL (2σ uncertainty and subsidence-corrected), and reef termination and sea-level fall by ∼81 ka BP. Notably, the range of peak MIS 5a relative sea-level estimates of −6.5 to −5.1 m MSL are more than 2 m shallower (higher) than previous estimates of −11 to −9 m. Our higher resolution regional sea-level reconstruction across four subregions of the Florida Keys reef tract aligns with changes in July insolation at 65° N: a trend that most other records, such as deep-sea sediments, do not have the accuracy and precision to resolve. Three massive coral samples from MIS 5c, consisting of Pseudodiploria clivosa, and Orbicella spp., yielded ages in the range of 104 to 99 ka (average 2σ uncertainty less than 200 years); however, because only one sample met the closed-system criteria, our ability to estimate MIS 5c sea level is relatively limited. More empirical estimates of sea-level from the MIS 5a and MIS 5c intervals based on numerical dating of reliable local sea-level constraints are critical for GMSL calculations and relating changes in sea-level amplitude and timing to global ice volume modeling and glacio-isostatic effects, all of which can improve predictions of future sea-level changes in coastal regions.

Last interglacial and MIS 9e relative sea-level highstands in the Central Mediterranean: a reappraisal from coastal cave deposits in the Cilento area, Southern Italy

A revaluation of the relative sea-level (RSL) indicators in the Baia di Infreschi (Cilento, Southern Italy) supported by new 30 U/Th dating on speleothems indicates that the upper level of Lithophaga burrows identified by Bini et al. (2020) at ∼9 m a.s.l. and correlated to the Last Interglacial (LIG) highstand should be referred to the highstand of the MIS 9e, whereas the local RSL for the highstand of the LIG is now reassessed at 5.3 ± 0.18 m a.s.l. The upper level of the Lithophaga marker can be followed for ∼12 km along the coast, suggesting a substantial absence of important relative tectonic movements. In the Baia di Infreschi an additional marine indicator, a notch sealed by a flowstone dated ∼110 ka, indicates several phases of RSL stationing below the maximum highstand of the LIG. The presence of flowstones as low as 2 m a.s.l. dated to the MIS 7 shows that the highstand of MIS 7 was probably below the present sea level. All these evidences allow us to reassess the stratigraphy of some archaeological caves in the area, indicating that the sedimentary successions preserved there are older than what was previously believed.

Late Holocene relative sea-level records from coral microatolls in Singapore

Late Holocene relative sea-level (RSL) data are important to understand the drivers of RSL change, but there is a lack of precise RSL records from the Sunda Shelf. Here, we produced a Late Holocene RSL reconstruction from coral microatolls in Singapore, demonstrating for the first time the utility of Diploastrea heliopora microatolls as sea-level indicators. We produced 12 sea-level index points and three marine limiting data with a precision of < ± 0.2 m (2σ) and < ± 26 years uncertainties (95% highest density region). The data show a RSL fall of 0.31 ± 0.18 m between 2.8 and 0.6 thousand years before present (kyr BP), at rates between − 0.1 ± 0.3 and − 0.2 ± 0.7 mm/year. Surface profiles of the fossil coral microatolls suggest fluctuations in the rate of RSL fall: (1) stable between 2.8 and 2.5 kyr BP; (2) rising at ~ 1.8 kyr BP; and (3) stable from 0.8 to 0.6 kyr BP. The microatoll record shows general agreement with published, high-quality RSL data within the Sunda Shelf. Comparison to a suite of glacial isostatic adjustment (GIA) models indicate preference for lower viscosities in the mantle. However, more high quality and precise Late Holocene RSL data are needed to further evaluate the drivers of RSL change in the region and better constrain GIA model parameters.

Dipping Tidal Notch (DTN): Exposed vs. Sheltered Morphometry

Tidal notches, long regarded as reliable indicators of mean sea level, have been extensively studied along carbonate coasts in the central Mediterranean Sea. Previous studies revealed a correlation between the genesis of tidal notches and tidal range, lithology, cliff foot depth, and wave energy. In the 2020 Geoswim campaigns at Lampedusa, the southernmost island of the Pelagie archipelago (Italy), and in Gozo Island (Malta), ‘anomalous’ tidal notches were identified. Unlike normal notches observed elsewhere, those in Lampedusa’s southern bays exhibited a particular behaviour—constantly deepening in the inner part of the bays, reaching a maximum depth of approximately 30 cm below sea level and narrowing inwards. Similar phenomena were previously observed near Marseille (France). As confirmed by the literature, all these areas are tectonically stable. Time-lapse images, alongside measurements of morphometric parameters, were collected during the survey. Our hypothesis indicates that a combination of marine factors influenced by local marine conditions driven by the local morphology of the small bays exposed to southern quadrants contribute to the formation of these unique landforms. The latter manifests higher lowering erosion rates slightly below the mean sea level in sheltered areas, challenging conventional notions about tidal notch formation.

Indicative meanings of geological sea-level indicators in the Solent region and Sussex coast (south coast of England) and implications for uplift rates

The Solent Region and Sussex coastal plain in southern England have preserved palaeo-sea-level indicators from multiple interglacial periods, with a particularly complete record of deposition throughout the last interglacial. However, as yet, none of the research on these indicators has fully addressed the relationship of the different types of deposits preserved to mean sea-level. In this paper we apply recent approaches to estimating past relative sea-levels based on applying modern analogues to understand the indicative meaning of these indicators. We also apply a synchronous correlation model previously developed on rapidly uplifting coastlines to assess uplift rates. The uplift rates required to match the elevations of sequences suggest a significant decrease in uplift rates between the Late Wolstonian Substage and Ipswichian Stage; that is, the c. 240 and c. 125 ka sea-level highstands, broadly equivalent to marine isotope stages (MIS) 7 and 5e. This coincides in time with the final opening of the Straits of Dover. Supplementary material: Fossil data from sites that have not previously been published are available at https://doi.org/10.6084/m9.figshare.c.7172532

Dominant gastrointestinal strongylatosis in sheep in the context of the altitudinal zonation in Dagestan

The purpose of the research is to study the epizootology of the dominant gastrointestinal strongylatosis in sheep in different natural zones of Dagestan.Materials and methods. In 2005–2021, 180 forestomachs of the thin and thick sections of the digestive tract and 600 fecal samples from sheep at the altitude (above 2000 m above sea level) were studied based on dissection results. The study was performed by season among young animals aged up to 1 year, from 1 to 2 years and 3 years and older. The study used methods of complete helminthological dissection per K. I. Skryabin, larvae cultivation in a thermostat at 27 оC, and flotation with a saturated ammonium nitrate solution by Kotelnikov-Khrenov and Berman-Orlov.Results and discussion. Helminth infections are recorded among sheep annually on lowland, moist, steppe pastures of the plains and foothills in various combinations of multiple infections with the prevalence of 11.2–18.7% and the infection intensity of 18.5–186.4 sp./animal. In the mountain zone at altitudes above 2000 m above sea level, the quantitative and qualitative indicators of helminthosis pathogens were sharply limited. On these lands, dicrocoeliosis, monieziosis, larval echinococcosis, chabertiosis, haemonchosis, and nematodirosis were recorded in sheep with the prevalence of 3.2–10.4% and the infection intensity of 2.4–6.3 sp./animal. Gastrointestinal Strongylata dominate in sheep on all types of pastures in the lowland, foothill, and mountain zones: Chabertia ovina, Bunostomum trigоnocephalum, Trichostrongylus axei, T. capricola, T. colubriformis, T. vitrinus, Haemonchus contortus, Nematodirus filicollis, N. helvetianus, N. oiratianus, and N. spathiger.

WALIS dashboard: An online tool to explore a global paleo sea-level database.

In this paper, we present WALIS Dashboard, an open-access interface to the World Atlas of Last Interglacial Shorelines (WALIS), which was developed and compiled thanks to funding from the European Research Council. WALIS is a database that includes thousands of samples (dated with different radiometric methods) and sea-level indicators formed during the Last Interglacial (~80 to 130 ka). The WALIS Dashboard was coded in R (shiny app), and allows querying a simplified version of WALIS by either geographic extent or by attributes. The user can then download the queried data and perform simple and reproducible data analysis. The WALIS Dashboard can be used both online and offline.

Holocene relative sea-level changes along the Caribbean and Pacific coasts of northwestern South America

Abstract Predicting coastal change depends upon our knowledge of postglacial relative sea-level variability, partly controlled by glacio-isostatic responses to ice-sheet melting. Here, we reconstruct the postglacial relative sea-level changes along the Caribbean and Pacific coasts of northwestern South America by numerically solving the sea-level equation with two scenarios of mantle viscosity: global standard average and high viscosity. Our results with the standard model (applicable to the Pacific coast) agree with earlier studies by indicating a mid-Northgrippian high stand of ~2 m. The high-viscosity simulation (relevant to the Caribbean coast) shows that the transition from far- to intermediate-field influence of the Laurentide Ice Sheet occurs between Manzanillo del Mar and the Gulf of Morrosquillo. South of this location, the Colombian Caribbean coast has exhibited a still stand with a nearly constant Holocene relative sea level. By analyzing our simulations considering sea-level indicators, we argue that tectonics is more prominent than previously assumed, especially along the Caribbean coast. This influence prevents a simplified view of regional relative sea-level changes on the northwestern South American coast.

Paleo sea-level indicators and proxies from Greenland in the GAPSLIP database and comparison with modelled sea level from the PaleoMIST ice-sheet reconstruction

One of the most common ways to assess ice-sheet reconstructions of the past is to evaluate how they impact changes in sea level through glacial isostatic adjustment. PaleoMIST 1.0, a preliminary reconstruction of topography and ice sheets during the past 80 000 years, was created without a rigorous comparison with past sea-level indicators and proxies in Greenland. The basal shear stress values for the Greenland ice sheet were deduced from the present day ice-sheet configuration, which were used for the entire 80 000 years without modification. The margin chronology was based on previous reconstructions and interpolation between them. As a result, it was not known if the Greenland component was representative of its ice-sheet history. In this study, I compile sea–level proxy data into the Global Archive of Paleo Sea Level Indicators and Proxies (GAPSLIP) database and use them to evaluate the PaleoMIST 1.0 reconstruction. The Last Glacial Maximum (c.20 000 years before present) contribution to sea level in PaleoMIST 1.0 is about 3.5 m, intermediate of other reconstructions of the Greenland ice sheet. The results of the data-model comparison show that PaleoMIST requires a larger pre-Holocene ice volume than it currently has to match the sea-level highstands observed around Greenland, especially in southern Greenland. Some of this mismatch is likely because of the crude 2500 year time step used in the margin reconstruction and the limited Last Glacial Maximum extent. Much of the mismatch can also be mitigated if different Earth model structures, particularly a thinner lithosphere, are assumed. Additional ice in Greenland would contribute to increasing the 3–5 m mismatch between the modelled far-field sea level at the Last Glacial Maximum and proxies in PaleoMIST 1.0.

Holocene Relative Sea-Level Changes Along the Southern Coast of Bodrum Peninsula, SW Anatolia

Bodrum Peninsula, which developed under the influence of the extensional tectonic regime in the west of the Anatolian plate, is one of the areas where indicators reflecting relative sea-level changes are seen above the present sea level. These indicators appear in different types throughout the peninsula. This study examined shorelines from sea level to +2.6 m at 6 locations on the southern coast of the Bodrum Peninsula. Suitable indicators for dating were found at two different locations in the study area, and two relative sea-level indicators using mollusk shells were dated by radiocarbon method. One of the indicators is a +1.3 m high beach deposit at Gerenkuyu and was dated to 2678.5±79.5 yr BP. The other indicator is a +1.2 m high beach deposit at Gerindere, which is thought to be compatible with the tidal notch and dated to 2241±88 yr BP. Based on the age data and the reliability of tidal notches as a shoreline indicator, the uplift rate of this indicator in Gerindere for the last 2241±88 years has been calculated to be 0.53 mm/yr.

Refining patterns of melt with forward stratigraphic models of stable Pleistocene coastlines

Abstract. The warmest peak of the Last Interglacial (ca. 128–116 ka) is considered a process analogue and is often studied to better understand the effects of a future warmer climate on the Earth's system. In particular, significant efforts have been made to better constrain ice sheet contributions to the peak Last Interglacial sea level through field observation of paleo relative sea level indicators. Along tropical coastal margins, these observations are predominantly based on fossil shallow coral reef sequences, which also provide the possibility of gathering reliable U-series chronological constraints. However, the preservation of many Pleistocene reef sequences is often limited to a series of discrete relative sea level positions within the interglacial, where corals suitable for dating were preserved. This, in turn, limits our ability to understand the continuous evolution of paleo relative sea level through an entire interglacial, also affecting the possibility of unraveling the existence and pattern of sub-stadial sea level oscillations. While the interpretation of lithostratigraphic and geomorphologic properties is often used to overcome this hurdle, geological interpretation may present issues related to subjectivity when dealing with missing facies or incomplete sequences. In this study, we try to step back from a conventional approach, generating a spectrum of synthetic Quaternary subtropical fringing reefs for a site in southwestern Madagascar (Indian Ocean). We use the Dionisos forward stratigraphic model (from Beicip-Franlab) to build a fossil reef at this location. In each model run, we use distinct Greenland and Antarctica ice sheet melt scenarios produced by a coupled ANICE–SELEN glacial isostatic adjustment model. The resulting synthetic reef sequences are then used test these melt scenarios against the stratigraphic record. We propose that this sort of stratigraphic modeling may provide further quantitative control when interpreting Last Interglacial reef sequences.

Reconstruction of Holocene relative sea-level from beach ridges of the central west coast of India using GPR and OSL dating

The Holocene sea-level and associated shoreline regression of beach ridges in the central west coast of India have been reconstructed based on internal sedimentary architecture and luminescence chronology. For this purpose, various techniques namely ground penetrating radar (GPR), optically-stimulated luminescence (OSL) dating, and interferometry synthetic aperture radar (InSAR) have been used. The berm and beach-dune boundary of paleo beach ridges have been mapped from the high-resolution sub-surface images and converted into sea-level indicators using modern analogs and OSL ages. GPR reflection data shows a number of seaward dipping radar facies with a few landward dipping facies in paleo beach ridges. In the case of the swale, radar signal has been highly attenuated due to the presence of water and mud causing the appearance of multiple horizontal and parallel positive and negative couplets in the sedimentary layer. The results of the research reveal that the oldest beach ridge was formed around 7.7 kyr BP and sea-level was +2 m above mean sea-level. The average progradation rate of these ridges is 0.14 m/yr. From the grain size analysis, it has been found that the larger share of grain size falls into the classes of fine and moderate sand. The present displacement map of the region, which has been generated from the Sentinel-1 datasets, demonstrates that the average upliftment is 2.5 mm/yr whereas subsidence is 1 mm/yr. The fall of the Holocene relative sea-level with respect to the study region is the consequence of both global and regional events.

Influence of reef isostasy, dynamic topography, and glacial isostatic adjustment on sea-level records in Northeastern Australia

Understanding sea level during the peak of the Last Interglacial (125,000 yrs ago) is important for assessing future ice-sheet dynamics in response to climate change. The coasts and continental shelves of northeastern Australia (Queensland) preserve an extensive Last Interglacial record in the facies of coastal strandplains onland and fossil reefs offshore. However, there is a discrepancy, amounting to tens of meters, in the elevation of sea-level indicators between offshore and onshore sites. Here, we assess the influence of geophysical processes that may have changed the elevation of these sea-level indicators. We modeled sea-level change due to dynamic topography, glacial isostatic adjustment, and isostatic adjustment due to coral reef loading. We find that these processes caused relative sea-level changes on the order of, respectively, 10 m, 5 m, and 0.3 m. Of these geophysical processes, the dynamic topography predictions most closely match the tilting observed between onshore and offshore sea-level markers.

Record of the last interglacial sea level highstand based on new coastal deposits in the Cantabrian margin (Northern Iberian Peninsula)

Quaternary sea level fluctuations have been responsible for significant remodelling of coastal landscapes, generating distinctive sea level indicators at different positions and altitudes that are still visible today. Raised coastal deposits are among the characteristic features of significant value in reconstructing the tectonic and sea-level history of the areas in which they are preserved. To date, few remnants of Quaternary coastal deposits have been described and directly dated along the coast of the Cantabrian margin (on the north of the Iberian Peninsula). In this work, two new deposits located in the towns of Castro-Urdiales and Mendexa were analysed and dated using U/Th geochronology and Optically Stimulated Luminescence. Considering the ages and altitudes of these deposits, it seems most likely that they correlate to the Marine Isotope Stage (MIS) 5e. Furthermore, the data acquired suggest that most of the Cantabrian margin underwent a similar tectonic evolution, with no significant tectonic uplift, since at least MIS 5e.

WALIS dashboard: An online tool to explore a global paleo sea-level database

This paper describes the WALIS dashboard, an open-access interface to the World Atlas of Last Interglacial Shorelines (WALIS), which was developed and compiled thanks to funding from the European Research Council. WALIS is a database that includes thousands of samples (dated with different radiometric methods) and sea-level indicators formed during the Last Interglacial (125 ka). The WALIS dashboard was coded in R (shiny app) and is connected with a simplified version of the WALIS database. The app allows querying data by geographic extent or by filtering metadata. It then allows the user to download the queried data and perform simple reproducible data analysis. The WALIS dashboard can be used both online and offline.

Three-dimensional glacial isostatic adjustment modeling reconciles conflicting geographic trends in North American marine isotope stage 5a relative sea level observations

Abstract Glacial isostatic adjustment (GIA) simulations using earth models that vary viscoelastic structure with depth alone cannot simultaneously fit geographic trends in the elevation of marine isotope stage (MIS) 5a relative sea level (RSL) indicators across continental North America and the Caribbean and yield conflicting estimates of global mean sea level (GMSL). We present simulations with a GIA model that incorporates three-dimensional (3-D) variation in North American viscoelastic earth structure constructed by combining high-resolution seismic tomographic imaging with a new method for mapping this imaging into lateral variations in lithospheric thickness and mantle viscosity. We pair this earth model with a global ice history based on updated constraints on ice volume and geometry. The GIA prediction provides the first simultaneous reconciliation of MIS 5a North American and Caribbean RSL highstands and strengthens arguments that MIS 5a peak GMSL reached values close to that of the Last Interglacial. This result highlights the necessity of incorporating realistic 3-D earth structure into GIA predictions with continent-scale RSL data sets.

Paleoecological indicators of the highstand sea level on the Amazonian supralittoral until the last two millennia

Holocene sea-level changes are ubiquitous worldwide. The relative sea levels (RSL) of the Northeast and Southeast littoral zones of Brazil were higher than the current level during the middle Holocene. It has been assumed that the RSL was stable since 7 ka BP in the North Brazilian littoral, particularly in the Amazonian coast. Based on a multiproxy approach (pollen content, δ13C, 14C-dating, and sedimentary and geomorphological features) applied to a sediment core obtained from the Amazonian supralittoral zone (>50 km away from the modern coastline), our study investigated the signatures of the RSL highstand in this region. The results show that the marine influence was more intense from 8410 to 1490 cal yr BP than that of the present. During this period, a mangrove community represented by Rhizophora and Avicennia established and thrived on the Itacuruçá tidal flat, probably due to post-glacial sea-level rise, which surpassed the present level during the middle Holocene. The mangrove population declined after 1490 cal yr BP, while freshwater vegetation developed, with the dominance of various associations of taxa. The sudden deposition of organic debris in the sedimentary record is consistent with the decrease in mangrove communities. This pronounced environmental change is possibly related to the reduction of the RSL, which reached the present-day position before the last millennium. Climate influence has not been recognized as significant in this process. Irrespective of the curve model showing the position or values from the RSL and related causes, this investigation addresses the indicators of this phenomenon. The results presented here suggest that understanding the variable trends of the Late Holocene RSL and their influence on paleoecological dynamics and paleogeographical evolution requires further advancement.

Holocene relative sea-level histories of far-field islands in the mid-Pacific

Holocene relative sea-level (RSL) data from far-field islands in the mid-Pacific have been used to validate the ice-melting histories of glacial isostatic adjustment (GIA) models. However, a lack of quality control in the reconstruction of RSL hinders the understanding of regional variability that can constrain ice-equivalent sea-level changes. Here, we present a standardised database of Holocene RSL data from five regions in the mid-Pacific (Cook Islands, Tuamotu Islands, Christmas (Kiritimati) Island, Gilbert Islands and Fiji). We categorised the data as high or low quality based on the susceptibility of samples to age and/or elevation errors. Of the 614 data points that were reviewed, 25% were rejected and 100 sea-level index points (SLIPs) were reinterpreted as limiting data. The new database consists of 141 SLIPs and 262 marine and 56 terrestrial limiting data points reconstructed from a variety of sea-level indicators (e.g., coral microatolls, mangrove peat, beachrock, and beach ridges), of which 71% provide high-quality constraints on RSL. The early to mid Holocene RSL evolution in the Cook Islands, Gilbert Islands and Fiji are poorly constrained due to a lack of high-quality SLIPs and limiting data during this period. The Tuamotu Islands provided the only record of early to mid Holocene evolution of RSL, indicating rapid RSL rise from between −22.9 m and −15.2 m at ∼9.0 ka to between −0.2 m and 0.5 m by ∼6.5 ka, at rates as high as 9.8 ± 5.1 mm/a, with a slowdown in the rate of RSL rise sometime between ∼8.2 ka and ∼6 ka. The Christmas (Kiritimati) Island record indicates stable RSL within ∼1.5 m of present-day levels over the past ∼6.6 ka. In the late Holocene, the Cook Islands record suggests a gradual fall in RSL over the past ∼2.9 ka at rates below 0.1 ± 4.3 mm/a. SLIPs at Fiji also indicate a slight fall in RSL at rates of less than 0.5 ± ∼4.4 mm/a at ∼4 ka, following which RSL fell from above 0.9 m at ∼3 ka to between −0.3 m and 0.6 m by ∼2.5– ∼2.1 ka. We highlight the importance of standardisation and quality control to critically evaluate the processes controlling RSL and validate GIA models. Indeed, the new standardised database has implications for the timing of the mid- Holocene highstand, which has been used to support the ICE-4G and ICE-7G_NA models. Due to the poor constraints of data in the mid-Pacific islands, particularly in the early Holocene, there remains no unique solution for a global ice-melting history.

A re-evaluation of Holocene relative sea-level change along the Fujian coast, southeastern China

The southeastern China coast is a region of special interest in the study of past and present relative sea-level change, given its distal location from giant ice sheets (far-field regions). During the past decades, a large number of biological, geological, and archaeological sea-level indicators have been retrieved from the Fujian coastal region which allows for recalibration and recalculation of sea-level index points (SLIPs). This study constructs a database of Holocene relative sea-level (RSL) observations for the Fujian coast, southeastern China. The database contains 59 quality-controlled SLIPs which show that RSL for the Fujian coast did not exceed present (0 m) during the Holocene, except potentially during 7.5–5.5 cal. kyr BP and 1.8–0.7 cal. kyr BP. Rates of RSL change were highest during the early Holocene and have decreased over time, due to the diminishing response of the Earth's mantle to glacial isostatic adjustment (GIA) and reduction of meltwater input. A series of sea-level oscillations were recorded in our SLIPs-based reconstructions which might correspond to global climate warming or cooling events. We assessed the spatial variability of RSL histories and compared these with the ICE-6G_C and ANU-ICE GIA model predictions. Substantial misfits between GIA predictions and regional RSL reconstructions were recognized: (1) the deceleration of the early-Holocene sea-level rise ended about one millennia earlier in the ICE-6G_C model than in the SLIPs-based reconstructions; (2) GIA model predictions show a mid-Holocene sea-level highstand of 1–3 m which is absent from our SLIPs-based reconstructions; and (3) all GIA model predicted a gradual RSL fall to 0 m since the middle Holocene, while our reconstruction displays significant RSL oscillations. It is presently unknown whether these misfits are caused by uncertainties in regional tectonic movement estimation or parameters used in the GIA models. Future applications of spatiotemporal statistical techniques are required to better quantify the gradient of the isostatic contribution and to provide improved context for the assessment of the ongoing acceleration of sea-level rise.

The Fish Tanks of the Mediterranean Sea

Roman fish tanks are found in various coastal regions of the Mediterranean, although the vast majority is found on the Tyrrhenian coast of Italy. In this work, a database was developed with information on 62 fish tanks along the Mediterranean coasts to document and compare their features and characteristics. The analysis of the developed database from the Mediterranean fish tanks has shown that, among the 62 fish tanks, ~56% were cut into the rock, indicating that this type of construction was the most popular at that time and probably had advantages over the others. Fish tanks as sea level indicators can provide accurate data on the sea level 2000 years ago. Well-preserved installations with prominent architectural features have a crucial role in determining the paleo sea level. The architectural elements that are mostly used in fish tanks for paleo sea level reconstructions are the crepido, cataractae and channels. Besides the scientific importance of the fish tanks as sea level markers, they also have great cultural and historical significance. Fish tanks can be promoted as heritage monuments and scholarly models to strengthen awareness about climate change, sea level rise and its consequences.