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Abstract: The identification and examination of ‘complete’ potential density overturns in CTD profiles, within the framework of SESAME project, are employed to assess vertical eddy diffusivities, mostly in the top 100m of the water column, for a broad area covering the East Mediterranean, the Turkish Straits and the Black Sea. The implementation of this method shows that, mixing induced by mechanical turbulence is enhanced in frontal areas, in the proximity of straits and inside anticyclones; furthermore, that mechanical turbulence is insignificant, down to the scale of CTD resolution, within areas of double diffusive staircases, encountered in deep layers of the water column. Consequently, only laminar theories about double diffusion are applied for assessing diffusivities therein. Susceptibility to different types of double diffusion seems to be related to the interaction of different types of water masses. [Copyright &y& Elsevier]

Abstract: We present new sulfur and oxygen isotope data in sulfate ( and , respectively), from globally distributed marine and estuary pore fluids. We use this data with a model of the biochemical steps involved in bacterial sulfate reduction (BSR) to explore how the slope on a vs. plot relates to the net sulfate reduction rate (nSRR) across a diverse range of natural environments. Our data demonstrate a correlation between the nSRR and the slope of the relative evolution of oxygen and sulfur isotopes ( vs. ) in the residual sulfate pool, such that higher nSRR results in a lower slope (sulfur isotopes increase faster relative to oxygen isotopes). We combine these results with previously published literature data to show that this correlation scales over many orders of magnitude of nSRR. Our model of the mechanism of BSR indicates that the critical parameter for the relative evolution of oxygen and sulfur isotopes in sulfate during BSR in natural environments is the rate of intracellular sulfite oxidation. In environments where sulfate reduction is fast, such as estuaries and marginal marine environments, this sulfite reoxidation is minimal, and the increases more slowly relative to the . In contrast, in environments where sulfate reduction is very slow, such as deep sea sediments, our model suggests sulfite reoxidation is far more extensive, with as much as 99% of the sulfate being thus recycled; in these environments the increases much more rapidly relative to the . We speculate that the recycling of sulfite plays a physiological role during BSR, helping maintain microbial activity where the availability of the electron donor (e.g. available organic matter) is low. [Copyright &y& Elsevier]

To better understand the sphere of influence of seafloor hydrocarbon seepage in an oligotrophic marine environment, we evaluated the near-bottom biogeochemistry in near-seep and control locations of the ultra-oligotrophic Southeast Mediterranean Sea. We observed corrosive pH (pH Total at 25 °C as low as 6.83) in water overlying a seepage site. The aberrant pH values (6.8–7.4) were measured up to 50 m above the seafloor and were accompanied by anomalously variable nutrient distribution with elevated nitrate + nitrite to phosphate ratio (30:1–53:1). The dissolved inorganic carbon (DIC) from the seeps has likely reached the water column, as low pH was decoupled from changes in alkalinity. Amplicon sequencing and metagenomics suggest that the oxidation of methane to CO 2 in the deep water is catalyzed by aerobic methane-oxidizing bacteria, which were prominent below 800 m depth. Incubation experiments suggest that gas seepage affected the sediment-water nutrient exchange. Oxygen consumption rates in bioturbated sediments near the seeps were three times above the background, the influx of NO 3 − and NH 4 + , was substantial, and we detected an early diagenetic loss of PO 4 3 − . The low δ13C values of particulate organic matter (-29.0 and -25.0‰), and its high C:N ratio (11.78–16.76) indicate that the seeps affect the suspended particles in the overlying water, and thus may influence the trophic webs. We show that the seeps affect the functionality of the deep-sea environment, being an important source of carbon and altering nutrient regimes in oligotrophic regions. • Gas seeps potentially affect the functionality of the deep oligotrophic Southeastern Mediterranean Sea. • Corrosive pH as low as 6.83 and elevated N to P ratio of 30:1–53:1 in water overlying a seepage site. • Bioturbated sediments near the Palmahim Disturbance seeps catalyze rapid nutrient cycling. • High microbial activity and changes in microbial communities near the seabed. • Potential C and N export from Palmahim Disturbance seeps. [ABSTRACT FROM AUTHOR]

The Eastern Mediterranean Sea (EMS) is a poorly studied ultra-oligotrophic marine environment, dominated by small-size phyto- and bacterioplankton. Here, we describe the dynamics of a single annual cycle (2018–19) of phyto- and bacterioplankton (abundances, pigments and productivity) in relation to the physical and chemical conditions in the photic water column at an offshore EMS site (Station THEMO-2, ∼1,500 m depth, 50 km offshore). We show that phytoplankton biomass (as chlorophyll a), primary and bacterial productivity differed between the mixed winter (January–April) and the thermally stratified (May–December) periods. Prochlorococcus and Synechococcus numerically dominated the picophytoplankton populations, with each clade revealing different temporal and depth changes indicative to them, while pico-eukaryotes (primarily haptophytes) were less abundant, yet likely contributed significant biomass. Estimated primary productivity (∼32 gC m−2 y−1) was lower compared with other well-studied oligotrophic locations, including the north Atlantic and Pacific (BATS and HOT observatories), the western Mediterranean (DYFAMED observatory) and the Red Sea, and was on-par with the ultra-oligotrophic South Pacific Gyre. In contrast, integrated bacterial production (∼11 gC m−2 y−1) was similar to other oligotrophic locations. Phytoplankton seasonal dynamics were similar to those at BATS and the Red Sea, suggesting an observable effect of winter mixing in this ultra-oligotrophic location. These results highlight the ultra-oligotrophic conditions in the EMS and provide, for the first time in this region, a full-year baseline and context to ocean observatories in the region. • Bacterioplankton dynamics were assessed monthly in the Eastern Mediterranean Sea. • Small-sized picophytoplankton numerically dominated the phytoplankton community. • Seasonal phytoplankton dynamics are similar to BATS and Red Sea, but not to HOT. • Annual primary productivity is among the lowest in the world's oceans. • Bacterial to primary production ratio is higher than most oligotrophic seas. [ABSTRACT FROM AUTHOR]

Efficient implementation of an environmental biomarker requires multi-annual comparability over a wide geographical range. The present study improved the comparability of a quantitative competitive metallothionein (MT) enzyme-linked-immuno-sorbent-assay (ELISA) in the sentinel fish Lithognathus mormyrus by introducing to the assay recombinant MT and beta-actin standards. Commercial antibodies for cod MT and mammalian actin were implemented. In addition, a sensitive anti L. mormyrus MT antibody was produced, adequate only for solid phase immunochemical assays. Cadmium was applied to the fish through injection and feeding to serve as a testing platform of the ELISA. The results demonstrated high potential protective capacity of the liver against toxic levels of transition metals through increasing MT levels. MT transcript levels were evaluated also from fish sampled at polluted and relatively clean natural sites, indicating applicability of MT as biomarker of exposure to a multi-factorial pollution, in comparison to its low revealed sensitivity to controlled cadmium exposure. [Copyright &y& Elsevier]

The Eastern Mediterranean Sea (EMS), is ultra-oligotrophic with unusual anti-estuarine circulation. It is P depleted and the limited enrichment studies which have been carried out, suggest seasonal changes in nutrient limitation. In this study high sensitivity dissolved nutrients (and associated parameters) were determined monthly over an annual cycle at a pelagic location in the SE Levantine basin. Nitrate & Nitrite (N ox) concentrations were high (300–500 nM) during the winter mixing period and enabled a concurrent phytoplankton increase in which larger picoeukaryotes and eukaryotes were dominant. After the thermal stratification of the water column commenced, N ox decreased through early summer transition period to low values (generally 50 nM or less) in the late summer. DIP remained at low nM concentrations the entire year while DOP decreased from 40 nM in winter to 30 nM in summer.. Prochlorococcus , the smallest picocyanobacteria, that does not typically utilize nitrate, dominated during the summer when both N ox and DIP concentrations were lowest. Ammonium concentrations were low (10–100 nM) with no systematic changes with season or depth. As a result, the DIN:DIP ratios were high (20–825) in winter and low (2–66) in summer, showing that these ratios vary seasonally. The dynamics of nutrient availability combined with the temporal changes in total chlorophyll and the altered dominance of the predominant phytoplankton species (i.e. nitrate-metabolizing Synechococcus during winter versus the smaller Prochlorococcus abundant in summer), leads to our hypothesis that the seasonal change in DIN:DIP indicates a switch from P limitation in winter during the annual phytoplankton increase to N&P or even N limitation in summer. Export Production (172 mmol N m−2 y−1) determined from the calculated loss of N ox from the photic zone, was similar to previous estimates in the EMS. Our results in terms of seasonally changing nutrient dynamics and resulting productivity confirm that the EMS has many of the characteristics found in P starved ocean gyre systems. • First seasonal high sensitivity nutrients in the Pelagic Eastern Mediterranean. • Excess Nitrate during winter mixing decreasing to Nutrient depleted in late stratified season. • Phosphate depleted entire year with low DOP (40-30 nM) in photic zone. • The measured N:P ratio depends on seasonality and not just location. • Calculated Export Production and other biogeochemical properties confirm EMS behaves like a P depleted ocean gyre. [ABSTRACT FROM AUTHOR]

• Foraminifera incorporate Zn and Pb in their calcite shells proportionate to seawater. • No species-specific or temperature effect on metal incorporation is observed. • Heavy metal concentrations can be measured by laser-ablation of individual chambers. • Such single-chamber analyses could record short-term pollution events. The establishment of sustainable coastal industries requires better temporal and spatial monitoring of heavy metal (HM) pollutants, even at low concentrations and during pulse-release events, before their accumulation becomes hazardous for local ecosystems or for the use of seawater in desalination (for drinking water). Foraminifera, unicellular marine organism, build their shells by sequential addition of chambers made of calcite, which contains impurities reflecting the composition of the growth medium. Therefore, the chemical composition of each chamber reflects HM in the ambient water at the time of calcification. To test the applicability of single-chamber analyses of foraminifera shells as a tool for HM monitoring in seawater, we conducted culturing experiments to calibrate the relationship of zinc and lead in foraminiferal shells and the ambient seawater. Two species of the cosmopolitan genus Amphistegina were cultured under a range of concentrations of both metals and two temperatures. We show that concentrations of zinc and lead in shells increase linearly with metal concentration in seawater with no difference between species and no effect of temperature. Our experiments further show that the concentrations in seawater can be directly inferred from concentrations in the shells at least up to the levels representing chronic pollution for both metals (68 ug/L for Zn and 8 ug/L for Pb). Combined with their high abundances in all marine environments and good preservation of their shells in sediments, our results demonstrate that foraminifera represent a powerful natural recording system offering high spatial and temporal resolution, allowing the establishment of historical baselines and detection of confined or short-term events of HM release, which could escape traditional monitoring methods. [ABSTRACT FROM AUTHOR]

Considering the thermal limits of coastal macroalgae habitats in the South-Eastern Mediterranean, it is important to study the response of the associated meiofauna to better understand the expected feedback of ecosystems to future warming. In this study, we compared benthic foraminiferal assemblages from two common macroalgal habitats, Turf and Coralline algae, based on ecological monitoring of a thermally polluted station representing near future warming, and an undisturbed environment. None of the common local species is confined to a specific algal habitat. This implies that their existence is not threatened by the disappearance of the Coralline algae. However, most likely their community structure will be impacted with coastal warming. Species that are more affiliated with Coralline algae are highly thermally tolerant, thus their proliferation might be reduced with warming. Specifically, the negative response of Coralline algae to warming may limit the contribution of invasive species such as Pararotalia calcariformata. • Benthic foraminifera occupy different macroalgae habitats. • The effect of warming on most species is not related to changes in algal substrates. • Coralline algae disappearance will significantly change the community structure. • Thermally tolerant species favoring coralline algae will reduce their proliferation. [ABSTRACT FROM AUTHOR]

The Levantine Basin, the saltiest, hottest and the most ultra-oligotrophic basin in the Mediterranean Sea, continues to be affected by recent anthropogenic changes. That includes the long-term influence of the opening of the Suez Canal and the enhanced oligotrophy in this region due to the damming of the Nile River. This study explores the spatial distribution and diversity patterns of living benthic foraminifera in this impacted SE Levantine shelf, between 40 and 100 water depths at 59 sites, sampled in August 2011 off the Israeli coast. Multivariate statistical analyses resulted in the identification of four distinct benthic foraminiferal assemblages, reflecting their ecological preferences distributed within four coherent biotopes with different environmental settings. Two biotopes were identified along the 40 m depth interval: 1. the middle and the southern shelf in which Deuterammina rotaliformis accompanied by Eggerelloides scaber predominate, and their abundance is positively related to Chl-a concentrations and negatively related to total organic carbon (TOC) and fine-grained sediment contents, and 2. the northern middle sandier carbonate rich shelf in which Lessepsian taxa and others calcareous foraminifera such as Quinqueloculina schlumbergeri and Ammonia tepida dominate the assemblage. The other two biotopes that occur between 60 m and 100 m water depths consist of high concentrations of fine-grained sediments, relatively rich with TOC. Hanzawaia rhodiensis , Asterigerinata mamilla and Rosalina spp. reveal a positive relationship with the carbonate-rich sediments of the northern outer shelf biotope. Lagenammina sp, Reophax scorpiurus , Glomospira charoides, Valvulineria bradyana, and Bolivina striatula exhibit a more positive relationship with higher clayey-silty organic rich sediment of the central-southern outer-shelf biotope. A comparison between the living assemblages investigated in the current study and during a previous study in the late 90s, at the same sites, indicates a prominent foraminiferal response to the ongoing human activity in this region. That includes (I) the expansion of some Lessepsian species into ~40 m water depths habitats indicating the availability of suitable bottom water conditions for these species attributed to the increase in ultra-oligotrophy at this water depth. (II) the very recent introduction (either by shipping/aquaculture) of Deuterammina rotaliformis to the Israeli coast, sometime between the late 90s and 2011and its becoming the most dominant species in the southern middle shelf, a region most affected by the ongoing consequences of the damming of the Nile. • Living foraminiferal distribution in the SE Levantine shelf (40–100 water depth). • Multivariate analyses were used for exploring species – environment relations. • Benthic foraminiferal bioindicators responded to the ongoing recent human activity. • We identified four biotopes with distinct depth zonation, sediment type and Chl-a. [ABSTRACT FROM AUTHOR]

In this paper, we present C export data from the southeastern Levantine Basin, 50 km west of Haifa, at water depth of 1500 m. Particulate organic carbon (POC) fluxes were measured for 18 months by automated and single bottle sediment traps at the recently-deployed DeepLev observatory and compared with water column profiles of 234Th. Calculations, based on POC/234Th ratios, result in water column-integrated export of 18 mmolC m−2 d−1 at the end of summer (Dec 2017) and remineralization during spring (e.g. 14.4 mmolC m−2 d−1, Apr, 2018). Based on the sediment traps POC export in the basin was generally low (0.05–1 mmolC m−2 d−1 at the base of the photic zone during Dec 2017–May 2018). Fluxes were quite variable, and the export pattern was mainly controlled by coastal discharge or shelf-resuspension (winter peaks) rather than by marine primary production. This was demonstrated by: i) larger POC fluxes measured by deep water (1300 m) and twilight zone (280 m) traps compared to fluxes measured at the base of euphotic zone, ii) tight correlation of POC with total mass flux, iii) decrease of the POC percentage during winter peak events and iv) imbalance (large integrated deficit or excess) of water column 234Th. Both deficit and excess are evidence of lateral flux, where the first probably results from wave-induced shelf resuspension of organic-poor material, which underwent minimal remineralization and induced scavenging, while the latter derives from the conveyance of large amount of land-derived organic matter, which undergoes remineralization, therefore input of 234Th to the water column. [ABSTRACT FROM AUTHOR]

The eastern Levantine basin (ELB) is an ultra-oligotrophic, warm and saline marine system, significantly affected by climate change during the past several decades. The deployment of the first moored station at the ELB (DeepLev), at 1500 m water depth, ~50 km offshore Haifa, Israel, aimed at enhancing synchronized measurements of physical and biogeochemical dynamics. The station carries an array of sediment traps and sensors that measure physical, chemical, and biological attributes along the water column. Here we describe the station and present sediment-flux data from the first 1.5 years of operation (since November 2016). We show that, despite DeepLev's offshore location and the open-sea characteristics of the water column, lateral transport from the continental margin contributes the greatest fraction of particulate flux to the seafloor at this site. This mostly occurs via intermediate nepheloid layer plumes entering the study area between depths of 180 and 800 m. Bottom currents are weak (average ± SD = 3.5 ± 2 cm s−1) and are unlikely to cause significant resuspension. Based on sedimentation rates obtained from nearby sediment cores and sediment particle fluxes sampled in the traps, calculated accumulation rates of total particulate matter and of particulate organic carbon at the seafloor were 95–108 g m−2 y−1 and 0.5–0.6 g m−2 y−1, respectively. Offshore changes in sedimentation rates and in surface sediment elemental ratios indicate that sediment originating from the continental margins is transported at least 100 km offshore. [ABSTRACT FROM AUTHOR]

Understanding the spreading pathways and variability of the intermediate and deep water of the eastern Mediterranean Sea is important, as they influence the water exchange between the MS and the Atlantic Ocean, and thus the North Atlantic circulation and global climate. Using a data set spanning over 8 years (2012–2019; 23 cruises) we describe the recent evolution of the Southeastern Levantine basin deep water and examine the controlling processes of the observed variability. Over a period of 5–6 years (2012 to mid-2017) the salinity minimum zone (located at ~1000 dbar) experienced a monotonic salinity rise at a rate of ~0.002 units per year. We demonstrate that this rise can be largely attributed to vertical diffusional processes that gradually eroded this layer. From August 2017, the salinity value at the 1000 dbar level stabilized at 38.76. Close to the bottom of the abyssal plain, we identify the first signal of the arrival of recently formed East Mediterranean Deep Water of Adriatic origin, first reported in the Ionian basin, after the Eastern Mediterranean Transient, in 2001. Additionally, we observe the warming and salinification of isopycnals over the pressure range of 600–1200 dbar and track the deepening of the 38.8 iso-haline, by ~100 dbar over a period of 4 years. These are attributed to the general salinification trend at shallow and intermediate levels of the Southeastern Levantine basin, and possibly also to Cretan intermediate water formation and spreading. These observations highlight the dynamics of the eastern MS water masses, and call for more systematic monitoring of this basin. [ABSTRACT FROM AUTHOR]

Due to ongoing ocean warming, subtropical environments are becoming accessible to tropical species. Among these environments are the vermetid reefs of the Southeastern Mediterranean (SEM). In the last decades, these valuable coastal habitats witnessed the proliferation of numerous alien species of tropical origin. Among the meiofauna thriving on these reefs are benthic foraminifera, single cell marine organisms that make a significant contribution to global carbonate production. It has been widely recognized that benthic foraminifera, among other invasive species, thrive in the macroalgal cover, and it has been suggested that their populations are becoming a significant new source of sediment substrate. Here, we report on the first systematic assessment of the population size of the benthic foraminifera, allowing a comparison with data from the native tropical habitat of these species. Our study is based on a seasonal sampling of benthic foraminifera from confined sampling areas at four sites along the vermetid reef platforms of the Israeli SEM coast. Our survey reveals a patchy distribution of each species with peak population densities exceeding 100,000 specimens per m 2 , making the SEM a hotspot of benthic foraminifera, with population densities comparable to tropical coral reef environments. The assemblages of the SEM hotspot are dominated by cosmopolitan foraminiferal taxa and tropical invaders from the Indo-Pacific (e.g., Amphistegina lobifera, Pararotalia calcariformata, soritids, and Hauerina diversa). In contrast to foraminiferal hotspots in the tropics, which are completely dominated by larger symbiont-bearing taxa, the SEM hotspot stands out due to high abundances of non-symbiont-bearing species Textularia agglutinans and small miliolids. An intriguing observation is the significant heterogeneity in composition and density of foraminiferal assemblages between the vermetid reefs' southern and northern areas (Israel), indicating that the productivity of the dominant species are also modulated by local yet unknown environmental factors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Coastal phytoplankton communities are often exposed to multiple anthropogenic stressors simultaneously. Here, we experimentally examined how temperature increase (20-26 °C) and triazine-type herbicides pollution (500 ng terbutryn L -1 ), both recognized as emerging stressors, affect the abundance, physiology and selected saxitoxin gene expression in the toxic dinoflagellate Alexandrium minutum. The results show that A. minutum is more susceptible to terbutryn pollution with increasing temperatures, resulting in a significant decline in its abundance (∼80 %) and photosynthetic activity (∼40 %), while saxitoxin gene expression increased (1.5-2.5-fold). This suggests that in warming polluted coastal areas where A. minutum is often found, saxitoxin poisoning may occur even in the absence of a massive bloom. Our results recommend the development of science-based monitoring practices for algal dissolved toxins in coastal waters and estuaries, supporting environmental policies under warming and contaminated coastal regions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests that could affect the work reported in this manuscript., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Planktonic Foraminifera are unique paleo-environmental indicators through their excellent fossil record in ocean sediments. Their distribution and diversity are affected by different environmental factors including anthropogenically forced ocean and climate change. Until now, historical changes in their distribution have not been fully assessed at the global scale. Here we present the FORCIS (Foraminifera Response to Climatic Stress) database on foraminiferal species diversity and distribution in the global ocean from 1910 until 2018 including published and unpublished data. The FORCIS database includes data collected using plankton tows, continuous plankton recorder, sediment traps and plankton pump, and contains ~22,000, ~157,000, ~9,000, ~400 subsamples, respectively (one single plankton aliquot collected within a depth range, time interval, size fraction range, at a single location) from each category. Our database provides a perspective of the distribution patterns of planktonic Foraminifera in the global ocean on large spatial (regional to basin scale, and at the vertical scale), and temporal (seasonal to interdecadal) scales over the past century., (© 2023. The Author(s).)

The marine macroalgae Ulva sp. is considered an ecosystem engineer in rocky shores of temperate waters worldwide. Ulva sp. harbors a rich diversity of associated microbial epibionts, which are known to affect the algae's typical morphological development and 'health'. We examined the interaction between airborne microbes derived from atmospheric aerosols and Ulva ohnoi growth and physiological state. Specifically, we measured U. ohnoi growth rates and photosynthetic efficiency (Fv/Fm), alongside its microbial epibionts abundance, activity and diversity following dust (containing nutrients and airborne microorganisms) or UV-treated dust (only nutrients) amendments to filtered seawater. Parallel incubations with epibionts-free U. ohnoi (treated with antibiotics that removed the algae epibionts) were also tested to specifically examine if dust-borne microbes can replenish the epibiont community of U. ohnoi. We show that viable airborne microbes can restore U. ohnoi natural microbial epibionts communities, thereby keeping the seaweed alive and 'healthy'. These results suggest that microbes delivered through atmospheric aerosols can affect epiphyte biodiversity in marine flora, especially in areas subjected to high annual atmospheric dust deposition such as the Mediterranean Sea., (© The Author(s) 2021. Published by Oxford University Press on behalf of FEMS.)

Sandy sediment and its infauna were annually sampled along the shallow waters of the Israeli coast during the 2005-2016 period, as a part of the Israeli National Environmental Program framework, aiming to detect anthropogenic interference in that province by monitoring changes in the species composition, abundance, and diversity of the infaunal communities and in accompanied abiotic parameters: the levels of total organic carbon and a series of heavy metals and the site-specific grain size distribution. The > 250-μm fraction of the fauna was segregated from the sampled sediment and was identified to species or higher taxonomic level. Three spatial biotopes were determined based on their unique faunal composition, Haifa Bay, Haifa harbor, and the southern coast. Species homogeneity among samples of each biotope was evaluated. Temporal and spatial changes of the species composition, abundance, and diversity were calculated for each biotope, mostly revealing random annual fluctuations. Only two minor temporal trends were observed: two spatially identical and temporally different faunal communities in the southern coast biotope, distinguishing the 2005-2007 and 2008-2016 periods, and a slight increase in the number of species across time in the two Haifa Bay provinces. Total organic carbon was highly correlated to the faunal composition with the highest organic carbon levels in the Haifa harbor biotope. The biotopes' mutually occurring abundant species were sufficient to determine biotope borders and the contribution of intermittently sampled rare species, including the zoogeographically Indo-Pacific originated ones was feeble, important only to identify species migration and faunistics. Practically, three sampling sites along the Israeli shallow soft substrate, corresponding to the defined spatial biotopes, are sufficient to monitor the effect of environmental changes. Seasonal sampling twice a year is recommended as well as more accurate species identification using molecular taxonomy.

Criteria for eutrophication related parameters to achieve and preserve good environmental status (GES) of the oligotrophic Israeli Mediterranean coast were proposed for nutrients, chlorophyll-a (Chl-a) and suspended particulate matter (SPM) concentrations. The criteria were derived from current conditions, the best choice for the area that has undergone large and irreversible ecological changes compared to the pristine background. A five-year data set (2010-2014, ca. 800 data points) was analyzed using statistical methods and best professional judgement. The coastal waters were divided into four provinces, data gaps were identified, and seasonal reference and threshold values for each province determined as the median and 1.5 times the median, respectively. Application of the derived criteria to data up to 2016 showed the coastal waters to be mainly in GES, with a few exceptions. Simplification of the proposed criteria for environmental management was addressed as well., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

In order to establish environmentally sustainable industries there is a need for high-resolution temporal and spatial monitoring of heavy metal pollutants even at low concentrations before they become hazardous for local ecosystems. Here we present single chamber records of Cu, Zn and Pb in shells of two benthic foraminifera species with different shell types from two shallow coastal stations in Israel: An area adjacent to an electrical power plant and desalination factory (Hadera) and an industrially free nature reserve (Nachsholim). Records of both foraminifera species show elevated metal concentrations in Hadera clearly identifying the footprint of the local industrial facilities. Moreover, short-term events of elevated Cu and Pb concentrations were detected by single chamber analyses. This study demonstrates the potential of using heavy metals anomalies in foraminiferal single chambers as a tool for detecting the industrial footprint of coastal facilities as well as short term events of elevated heavy metals., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The coastal waters of the southeastern Mediterranean-Sea (SEMS) are routinely enriched with naturally-occurring and anthropogenic land-based nutrient loads. These external inputs may affect autotrophic and heterotrophic microbial biomass and activity. Here, we conducted 13 microcosm bioassays with different additions of inorganic NO 3 -(N), PO 4 -(P) and Si(OH) 4 -(Si) in different seasons along the Mediterranean coast of Israel. Our results indicate that cyanobacteria are mainly N-limited, whereas N or Si (or both) limit pico-eukaryotes. Furthermore, the degree to which N affects phytoplankton depends on the ambient seawater's inorganic N and N:P characteristics. Heterotrophic bacteria displayed no response in all treatments, except when all nutrients were added simultaneously, suggesting a possible co-limitation by nutrients. These results contrast the N+P co-limitation of phytoplankton and the P-limitation of bacteria in the open waters of the SEMS. These observations enable the application for a better science-based environmental monitoring and policy implementation along the SEMS coast of Israel., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Persistent thermohaline pollution at a site along the northern coast of Israel, due to power and desalination plants, is used as a natural laboratory to evaluate the effects of rising temperature and salinity levels on benthic foraminifera living in shallow hard-bottom habitats. Biomonitoring of the disturbed area and a control station shows that elevated temperature is a more significant stressor compared to salinity, thus causing a decrease in abundance and richness. Critical temperature thresholds were observed at 30 and 35°C, the latter representing the most thermally tolerant species in the studied area Pararotalia calcariformata, which is the only symbiont-bearing species observed within the core of the heated area. Common species of the shallow hard-bottom habitats including several Lessepsian invaders are almost absent in the most exposed site indicating that excess warming will likely impede the survival of these species that currently benefit from the ongoing warming of the Eastern Mediterranean., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

We have assessed the redistribution of a secondary source of sedimentary anthropogenic mercury in the Haifa bay (HB) area (SE Levantine basin), which is the northern sink for Nile-driven sand. A long-term (30years) ~80% decrease of the total sedimentary mercury concentrations (THg) was recorded in the inner bay, while an up to 3-fold increase was recorded in the top sediments of the outer bay. Sedimentary THg depth profiles and their temporal variability were used to model the main re-distribution processes, mainly resuspension associated with winter storm-derived transport. This mechanism transforms a secondary, sandy and well-aerated sink into a tertiary, more silty and hypoxic source at adjacent peripheral areas, affecting mercury bioavailability. We revisited the concept of environmental relaxation, i.e. the rate of return of a polluted environment to an acceptable state, showing that sedimentary transport processes may affect the associated ecological risks, mainly at shallow-water coastal sites., (Copyright © 2016 Elsevier Ltd. All rights reserved.)