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Native biodiversity loss and invasions by nonindigenous species (NIS) have massively altered ecosystems worldwide, but trajectories of taxonomic and functional reorganization remain poorly understood due to the scarcity of long‐term data. Where ecological time series are available, their temporal coverage is often shorter than the history of anthropogenic changes, posing the risk of drawing misleading conclusions on systems' current states and future development. Focusing on the Eastern Mediterranean Sea, a region affected by massive biological invasions and the largest climate change‐driven collapse of native marine biodiversity ever documented, we followed the taxonomic and functional evolution of an emerging "novel ecosystem", using a unique dataset on shelled mollusks sampled in 2005–2022 on the Israeli shelf. To quantify the alteration of observed assemblages relative to historical times, we also analyzed decades‐ to centuries‐old ecological baselines reconstructed from radiometrically dated death assemblages, time‐averaged accumulations of shells on the seafloor that constitute natural archives of past community states. Against expectations, we found no major loss of native biodiversity in the past two decades, suggesting that its collapse had occurred even earlier than 2005. Instead, assemblage taxonomic and functional richness increased, reflecting the diversification of NIS whose trait structure was, and has remained, different from the native one. The comparison with the death assemblage, however, revealed that modern assemblages are taxonomically and functionally much impoverished compared to historical communities. This implies that NIS did not compensate for the functional loss of native taxa, and that even the most complete observational dataset available for the region represents a shifted baseline that does not reflect the actual magnitude of anthropogenic changes. While highlighting the great value of observational time series, our results call for the integration of multiple information sources on past ecosystem states to better understand patterns of biodiversity loss in the Anthropocene. [ABSTRACT FROM AUTHOR]

The present study sought to quantitatively characterize the live and dead benthic foraminifera communities of the deep southeastern Levantine basin of the Mediterranean Sea (33.4º–31.7 ºN, 31.3º–34.9 ºE; 100–1900 m water depth) and their relationships to environmental conditions. Box corer samples were collected at 50 sites between June and July 2013. The foraminiferal macrofauna (> 250 µm) were enumerated and identified (76% to the species level). Six live foraminiferal assemblages were identified, inhabiting six biotopes, the shelf margin (SM), two upper continental slopes (UCS1 and UCS2), the lower continental slope (LCS), the eastern bathyal plain (EBP) and the western bathyal plain (WBP). The dead communities were divided into four biotopes, generally compatible with the live ones, excluding the UCS2 and the EBP. The foraminiferal density in the various live biotopes was relatively stable across the studied area, excluding the UCS2 and EBP, unlike the density of the dead shells, which increased with depth. The number of taxa per biotope was estimated by rarefaction curves and compared to the observed numbers, with a decreasing number of live taxa with water depth. The alpha-diversity, which was evaluated in relation to the number of sampled individuals, reached an asymptote in all biotopes, with very low values in the WBP. The within-biotope heterogeneity was evaluated by the average Chao-Sørensen similarity index and by a beta-diversity index (exp(gamma diversity) - exp(alpha diversity)), revealing variable heterogeneities in both assemblages. Water depth, sediment grain size mode, CaCO 3 (wt%), and clay fraction (wt%) were jointly but feebly correlated with live faunal composition. [ABSTRACT FROM AUTHOR]

The present study sought to quantify the infauna and environmental characteristics of the deep SE Levantine Basin, Mediterranean Sea (33.4-31.7 N, 31.3-34.9E; 100-1900 m water depth). Box corer samples were collected at 50 sites in June-July 2013. The infauna (>250 μm) were enumerated and identified to the lowest possible taxonomic level (~37 % to the species level). Three faunal assemblages were identified, inhabiting three biotopes, the shelf margin (SM), the continental slope (CS) and the bathyal plain (BP). The within-biotope heterogeneity was evaluated by the average Chao-Sørensen similarity index and the beta diversity (exp(gamma diversity)-exp(alpha diversity)), revealing values of 0.64-0.7 and 1.73-2.77, respectively, upon applying the pooled bathyal plain samples. The corresponding non-pooled samples revealed higher heterogeneity, with values of 0.26 and 6.27, respectively, likely due to insufficient sampling. The infaunal density in the various biotopes (geometric mean 59-2220 ind m) exhibited a logarithmic decline with water depth. The estimated number of taxa per biotope was calculated by rarefaction analysis in relation to the sampled area and the number of sampled individuals, resulting in 203 (sampled area)−206 (number of individuals) (SM), 170-163 (CS) and 144-130 (BP) taxa. The rarified alpha diversity in relation to the sampled area revealed decreasing values toward the deeper biotopes. However, similar rarified alpha diversities were found in all the biotopes in relation to the number of sampled individuals. Water depth, sediment grain size mode, CaCO%, and clay% were jointly correlated with faunal composition; water depth provided the single strongest correlate. [ABSTRACT FROM AUTHOR]

The <3% dissimilar Amplicon Sequence Variant (ASV) clusters of the 18S‐V4 barcode were used as species‐proxies for the evaluation of ASV composition and ASV diversity indices characterizing the hitherto poorly investigated meiofaunal communities of the south‐eastern part of the Levantine basin. Accompanied by abundance measurements, the relationships of these characteristics with sedimentary and bottom terrain parameters were interpreted. The construction of community composition profiles, namely ASVs' list and their estimated abundances, was done using our previously established procedure (Harbuzov et al., 2022, Marine Genomics 65, 100980), combining metabarcoding with sample reads normalization by the abundance of hard‐bodied meiofaunal taxa. The study province included the 54–1418 m depth range, across vertical sub‐bottom horizons ranging 0–17 cm. Oxygen, hydrogen sulfide and methane concentrations in the pore water, as well as sediment grain size spectra and sedimentary protein and carbohydrate levels, were measured, followed by an evaluation of their involvement in the shaping of the meiofaunal communities' characteristics. Community composition was generally site‐and‐horizon dependent and its abundance decreased with increasing bottom depth and across sub‐bottom horizons, typical to benthic habitats which are nourished by organic carbon from the euphotic zone. The relatively sharply inclined continental slope bottom located in the northern part of the Israeli coast was an exception. Its meiofaunal community characteristics were speculated to be affected by intensive sediment mixing and lateral transport of food from the shelf, in addition to the effect of the euphotic zone‐originated food sources. [ABSTRACT FROM AUTHOR]

A new species, Elanella haifensis, is described from off the coast of Israel, collected in depths ranging from 9.8–22.4 m. It is easily distinguishable from congeners by the spinulate bulbous setae III and IV of the female caudal ramus, and the shape of the male antennule. A new diagnosis is presented for the genus Elanella. This is the first record of the genus in Mediterranean waters. [ABSTRACT FROM AUTHOR]

New data on 52 non-indigenous mollusks in the Eastern Mediterranean Sea is reported. Fossarus sp. (aff. aptus sensu Blatterer 2019), Coriophora lessepsiana Albano, Bakker & Sabelli, sp. nov., Cerithiopsis sp. aff. pulvis, Joculator problematicus Albano & Steger, sp. nov., Cerithiopsis sp., Elachisina sp., Iravadia aff. elongata, Vitrinella aff. Vitrinella sp. 1 (sensu Blatterer 2019), Melanella orientalis, Parvioris aff. dilecta, Odostomia cf. dalli, Oscilla virginiae, Parthenina cossmanni, Parthenina typica, Pyrgulina craticulata, Turbonilla funiculata, Cylichna collyra, Musculus coenobitus, Musculus aff. viridulus, Chavania erythraea, Scintilla cf. violescens, Iacra seychellarum and Corbula erythraeensis are new records for the Mediterranean. An unidentified gastropod, Skeneidae indet., Triphora sp., Hypermastus sp., Sticteulima sp., Vitreolina cf. philippi, Odostomia (s.l.) sp. 1, Henrya (?) sp., and Semelidae sp. are further potential new non-indigenous species although their status should be confirmed upon final taxonomic assessment. Additionally, the status of Dikoleps micalii, Hemiliostraca clandestina comb. nov. and H. athenamariae comb. nov. is changed to non-indigenous, range extensions for nine species and the occurrence of living individuals for species previously recorded from empty shells only are reported. Opimaphora blattereri Albano, Bakker & Sabelli, sp. nov. is described from the Red Sea for comparison with the morphologically similar C. lessepsiana Albano, Bakker & Sabelli, sp. nov. The taxonomic part is followed by a discussion on how intensive fieldwork and cooperation among institutions and individuals enabled such a massive report, and how the poor taxonomic knowledge of the Indo-Pacific fauna hampers non-indigenous species detection and identification. Finally, the hypothesis that the simultaneous analysis of quantitative benthic death assemblages can support the assignment of non-indigenous status to taxonomically undetermined species is discussed. [ABSTRACT FROM AUTHOR]

Cephalaspidean gastropods are common marine mollusks with a unique digestive apparatus containing 3 hardened plates of millimeter size inside the muscular esophageal crop (gizzard). The gizzard plates are reported to either grind or crush shelled prey. The current study aims at better understanding the manner in which the gizzard plates of the cephalaspid Philine quadripartita function in the overall digestion process by relating their structural and mechanical properties. Philine quadripartita possesses 3 gizzard plates which have one of the common configurations of cephalaspidean gizzard plates: two paired plates that are mirror images of each other and one smaller unpaired plate. We used micro-CT to characterize the gizzard musculature, the food which is present at different stages of the digestion process and the working surface of the gizzard plates. We show that the gizzard plates are used to crush the shelled prey, and that the functional mode of the small unpaired plate is different from the larger plates. All 3 plates are composed of a mixture of amorphous calcium carbonate and amorphous calcium phosphate embedded in a chitinous matrix. The proportions of these two mineral phases vary systematically within the plate. The plates have a complex layered structure, whose elastic moduli and hardness also vary in a continuous systematic manner. We observed that the stiffest layer is below the working surface, unlike most teeth where the stiffest layer is at the surface. Rigorous analysis of the elasticity indices of the gizzard plates as compared with sea urchin teeth and synthetic calcite provided insights into the connection between the biological function and the mechanical properties of biological composites. Specifically, we show that materials used for grinding require harder surfaces to avoid excessive wear compared to materials for crushing, whereas both of these functions require high toughness. [ABSTRACT FROM AUTHOR]

• A foraminiferal succession is studied along an anthropogenic C org gradient. • Two biotic indices, TSI-Med and Foram-AMBI, are tested along the C org gradient. • For two major species, a corrected ecological assignment is proposed. • Both foraminiferal indices describe the organic pollution gradient very well. • It is important to distinguish between stress-tolerant and opportunistic species. Coastal environments are affected by multiple pressures resulting from anthropogenic activities, among which organic enrichment (C org) is particularly important. Foraminiferal communities react to organic enrichment by changes in community structure (density, diversity, species composition) and behaviour (metabolism, feeding strategy, reproduction, mortality, etc.). A number of biotic indices based on foraminiferal faunas have been developed to measure the impact of anthropogenic organic enrichment on the ecological quality of marine soft bottom environments. However, the multiple origins of organic matter and its diffuse dispersion make it difficult to clearly identify enrichment gradients and the community changes along them. In this context, marine disposals of activated sewage sludge, which represent localised point sources of organic matter, offer the possibility to study faunal successions along a well-developed stress gradient. The main objectives of this study are to test 1) the ecological assignments of Mediterranean foraminifera species as recently proposed by Jorissen et al. (2018) , and 2) two biotic indices, based on groups of indicator species, developed in the Mediterranean Sea, TSI-Med and Foram-AMBI, along such an organic matter gradient, resulting from a sewage outlet off the Israeli coast, south of Tel-Aviv. Along the studied organic enrichment gradient, Caronia silvestrii dominated the foraminiferal faunas in the most severely impacted zone. Further away from the sewage outlet, faunas were characterised by the dominance of Ammonia tepida. Finally, in the least affected area, farthest away from the sewage outlet , Leptohalysis scottii was the dominant taxon. Our observations strongly contrast with earlier assignments of C. silvestrii and L. scottii to ecological groups III (3rd order opportunists) and V (1st order opportunists), respectively (Jorissen et al., 2018). This discrepancy strongly suggests that additional studies are urgently needed to better characterise the ecological strategies of major ecological index species. When, as we propose here, L. scottii is not included in the group of stress-tolerant taxa for TSI-Med, and C. silvestrii and L. scottii are reassigned respectively to ecological groups V and III for Foram-AMBI, both tested indices clearly show the decreasing impact of organic enrichment with greater distance from the sewage outlet. These species reassignments underline the need to distinguish between stress-tolerant and opportunistic taxa, which do not give the same information about environmental quality. [ABSTRACT FROM AUTHOR]