Two-way bioinvasion: tracking the neritic non-native cyclopoid copepods Dioithona oculata and Oithona davisae (Oithonidae) in the Eastern Mediterranean Sea

Accelerated anthropogenic changes in the Eastern Mediterranean Sea (EMS) have facilitated the introduction, spread and establishment of invasive copepod species in this region. Here, we report the introduction of two non-native cyclopoid copepods Dioithona oculata and Oithona davisae for the first time in the Israeli coastal waters and describe their temporal variability. The species were identified by morphological characteristics, DNA barcoding and phylogenetic inference. Molecular identification and phylogenetic analysis supported the taxonomical identification, nevertheless, showed cryptic speciation within D. oculata, separating the Western Pacific and EMS clades. In the Israeli coastal waters, D. oculata presented a temporally restricted occurrence, appearing from September 2019 to December 2019 (30.0±0.7 – 21.0±1.1 °C) and October 2020 (28.0±0.7 °C). The highest abundances of D. oculata occurred in the autumn (October 2019 and 2020), when the water temperature reached 28.0 °C (7 and 10 ind. m-3, respectively). The lowest abundance occurred in December 2019 (0.35 ind. m-3), when the water temperature decreased to 21.0 °C, indicating that the thermal affinity of D. oculata for warm-temperate conditions, for reproduction and the maintenance of viable populations, has persisted in the introduced range. In contrast, O. davisae appeared almost all year around (17.0±0.5 – 28.0±0.7 °C). This species demonstrated peaks in abundance both in October 2019 and October 2020, when the water temperature reached 28.0 °C (406 and 92 ind. m-3), as well as when the temperature decreased to 17.0 °C (31 ind. m-3, February 2020), confirming its wide eurythermal tolerance. Based on our findings and previous observations, we suggest that D. oculata may have invaded the EMS through the Suez Canal and is now at the onset of its spread in the Mediterranean Sea, whereas O. davisae has been introduced via shipping, likely from the Northeast Atlantic, widely spreading and successfully establishing viable populations across the entire Mediterranean Sea, until the coastal Levantine Sea

Two-way bioinvasion: tracking the neritic non-native cyclopoid copepods Dioithona oculata and Oithona davisae (Oithonidae) in the Eastern Mediterranean Sea

Accelerated anthropogenic changes in the Eastern Mediterranean Sea (EMS) have facilitated the introduction, spread and establishment of invasive copepod species in this region. Here, we report the introduction of two non-native cyclopoid copepods Dioithona oculata and Oithona davisae for the first time in the Israeli coastal waters and describe their temporal variability. The species were identified by morphological characteristics, DNA barcoding and phylogenetic inference. Molecular identification and phylogenetic analysis supported the taxonomical identification, nevertheless, showed cryptic speciation within D. oculata, separating the Western Pacific and EMS clades. In the Israeli coastal waters, D. oculata presented a temporally restricted occurrence, appearing from September 2019 to December 2019 (30.0±0.7 – 21.0±1.1 °C) and October 2020 (28.0±0.7 °C). The highest abundances of D. oculata occurred in the autumn (October 2019 and 2020), when the water temperature reached 28.0 °C (7 and 10 ind. m-3, respectively). The lowest abundance occurred in December 2019 (0.35 ind. m-3), when the water temperature decreased to 21.0 °C, indicating that the thermal affinity of D. oculata for warm-temperate conditions, for reproduction and the maintenance of viable populations, has persisted in the introduced range. In contrast, O. davisae appeared almost all year around (17.0±0.5 – 28.0±0.7 °C). This species demonstrated peaks in abundance both in October 2019 and October 2020, when the water temperature reached 28.0 °C (406 and 92 ind. m-3), as well as when the temperature decreased to 17.0 °C (31 ind. m-3, February 2020), confirming its wide eurythermal tolerance. Based on our findings and previous observations, we suggest that D. oculata may have invaded the EMS through the Suez Canal and is now at the onset of its spread in the Mediterranean Sea, whereas O. davisae has been introduced via shipping, likely from the Northeast Atlantic, widely spreading and successfully establishing viable populations across the entire Mediterranean Sea, until the coastal Levantine Sea

Microbiota dynamics in lionfish (Pterois): insights into invasion and establishment in the Mediterranean Sea

Lionfishes (Pterois spp.), originally native to the Indo-Pacific and Red Sea, have become one of the most invasive marine species globally, including the recent establishment in the Mediterranean Sea. This study investigates the microbiota of lionfish to explore its potential role in their invasion success and establishment. Using high-throughput sequencing and microbiota analyses, we characterized the species-specific core microbiome and identified habitat-specific markers across different regions (Red Sea, Mediterranean Sea, Caribbean, and aquarium populations) and organs. Focusing on the Mediterranean invasion, we tracked lionfish distribution and population dynamics along the Israeli coastline from 2017 to 2023, monitoring size, seasonal trends, and depth preferences. Our findings reveal that lionfish initially established themselves in deeper waters before expanding to shallower habitats, with a gradual increase in population size and body length over time. From a microbial aspect, we compared the microbiota of lionfish organs and identified a similar pattern (Photobacterium), to Earlier Lessepsian migrants fish species. This study provides novel insights into the interactions between microbiota and host ecology, shedding light on the mechanisms that may support the successful invasion. This study contributes to the understanding of lionfish invasion dynamics in the Mediterranean. It highlights the microbiota as an integral component for studying the ecological and biological mechanisms underpinning invasive species’ success and establishment of lionfish

Environmental sensitivity of Neogoniolithon Brassica-Florida associated with vermetid reefs in the Mediterranean Sea

Vermetid reefs in the Mediterranean Sea are increasingly affected by both anthropogenic actions and global climate change, which are putting this coastal ecosystem at risk. The main species involved in building these reefs are two species of intertidal vermetid gastropods and the crustose calcareous alga, Neogoniolithon brassica-Florida, which cements the gastropod shells and thus solidifying the reef edges. In the present study, we examined the pattern of distribution in the field and the environmental sensitivity (thermal tolerance, resilience to low pH, high light intensity and desiccation) of N. brassica-Florida along the coasts of Sicily and Israel by means of chlorophyll fluorescence and total alkalinity measurements in situ and in the laboratory. Tidal regimes did not affect photosynthesis of N. brassica-Florida but light intensity in the intertidal did. Sensitivity to increased light intensity was amplified by elevated temperature and reduced pH. Winter temperature above 16 °C caused a decrease in the photosynthetic performance of photo-system II. Similarly, a decrease in pH resulted in decreased maximum photosynthetic yield and electron transport rate. Calcification was significantly lower at pH 7.9 as compared with ambient (8.1) pH. In fact, dissolution at pH 7.9 at night was higher than net calcification during the day, suggesting that N. brassica-Florida may not be able to contribute to reef accretion under the levels of seawater warming and ocean acidification projected by the end of this century

Two-way bioinvasion: tracking the neritic non-native cyclopoid copepods Dioithona oculata and Oithona davisae (Oithonidae) in the Eastern Mediterranean Sea

Accelerated anthropogenic changes in the Eastern Mediterranean Sea (EMS) have facilitated the introduction, spread and establishment of invasive copepod species in this region. Here, we report the introduction of two non-native cyclopoid copepods Dioithona oculata and Oithona davisae for the first time in the Israeli coastal waters and describe their temporal variability. The species were identified by morphological characteristics, DNA barcoding and phylogenetic inference. Molecular identification and phylogenetic analysis supported the taxonomical identification, nevertheless, showed cryptic speciation within D. oculata, separating the Western Pacific and EMS clades. In the Israeli coastal waters, D. oculata presented a temporally restricted occurrence, appearing from September 2019 to December 2019 (30.0±0.7 – 21.0±1.1 °C) and October 2020 (28.0±0.7 °C). The highest abundances of D. oculata occurred in the autumn (October 2019 and 2020), when the water temperature reached 28.0 °C (7 and 10 ind. m-3, respectively). The lowest abundance occurred in December 2019 (0.35 ind. m-3), when the water temperature decreased to 21.0 °C, indicating that the thermal affinity of D. oculata for warm-temperate conditions, for reproduction and the maintenance of viable populations, has persisted in the introduced range. In contrast, O. davisae appeared almost all year around (17.0±0.5 – 28.0±0.7 °C). This species demonstrated peaks in abundance both in October 2019 and October 2020, when the water temperature reached 28.0 °C (406 and 92 ind. m-3), as well as when the temperature decreased to 17.0 °C (31 ind. m-3, February 2020), confirming its wide eurythermal tolerance. Based on our findings and previous observations, we suggest that D. oculata may have invaded the EMS through the Suez Canal and is now at the onset of its spread in the Mediterranean Sea, whereas O. davisae has been introduced via shipping, likely from the Northeast Atlantic, widely spreading and successfully establishing viable populations across the entire Mediterranean Sea, until the coastal Levantine Sea.</jats:p

Exploring the Microbial Mosaic: Insights into Composition, Diversity, and Environmental Drivers in the Pearl River Estuary Sediments

River estuaries are dynamic and complex ecosystems influenced by various natural processes, including climatic fluctuations and anthropogenic activities. The Pearl River Estuary (PRE), one of the largest in China, receives significant land-based pollutants due to its proximity to densely populated areas and urban development. This study aimed to characterize the composition, diversity, and distribution patterns of sediment microbial communities (bacteria, archaea, and eukaryotes) and investigated the connection with environmental parameters within the PRE and adjacent shelf. Physicochemical conditions, such as oxygen levels, nitrogen compounds, and carbon content, were analyzed. The study found that the microbial community structure was mainly influenced by site location and core depth, which explained approximately 67% of the variation in each kingdom. Sites and core depths varied in sediment properties such as organic matter content and redox conditions, leading to distinct microbial groups associated with specific chemical properties of the sediment, notably C/N ratio and NH4+ concentration. Despite these differences, certain dominant taxonomic groups were consistently present across all sites: Gammaproteobacteria in bacteria; Bathyarchaeia, Nitrososphaeria, and Thermoplasmata in archaea; and SAR in Eukaryota. The community diversity index was the highest in the bacteria kingdom, while the lowest values were observed at site P03 across the three kingdoms and were significantly different from all other sites. Overall, this study highlights the effect of depth, core depth, and chemical properties on sediment microbiota composition. The sensitivity and dynamism of the microbiota, along with the possibility of identifying specific markers for changes in environmental conditions, is valuable for managing and preserving the health of estuaries and coastal ecosystems

Sediment Microbiota as a Proxy of Environmental Health: Discovering Inter- and Intrakingdom Dynamics along the Eastern Mediterranean Continental Shelf

Analysis of data, curated over 3 years of sediment sampling, improves our understanding of microbiota assembly in marine sediment. Furthermore, we demonstrate the importance of cross-kingdom integration of information in the study of microbial community ecology. Finally, the urgent need to propose an applicable approach for environmental health monitoring is addressed here by establishment of sediment microbiota as a robust and sensitive model.</jats:p

The Complexity of the Holobiont in the Red Sea Coral Euphyllia paradivisa under Heat Stress

The recognition of the microbiota complexity and their role in the evolution of their host is leading to the popularization of the holobiont concept. However, the coral holobiont (host and its microbiota) is still enigmatic and unclear. Here, we explore the complex relations between different holobiont members of a mesophotic coral Euphyllia paradivisa. We subjected two lines of the coral—with photosymbionts, and without photosymbionts (apo-symbiotic)—to increasing temperatures and to antibiotics. The different symbiotic states were characterized using transcriptomics, microbiology and physiology techniques. The bacterial community’s composition is dominated by bacteroidetes, alphaproteobacteria, and gammaproteobacteria, but is dependent upon the symbiont state, colony, temperature treatment, and antibiotic exposure. Overall, the most important parameter determining the response was whether the coral was a symbiont/apo-symbiotic, while the colony and bacterial composition were secondary factors. Enrichment Gene Ontology analysis of coral host’s differentially expressed genes demonstrated the cellular differences between symbiotic and apo-symbiotic samples. Our results demonstrate the significance of each component of the holobiont consortium and imply a coherent link between them, which dramatically impacts the molecular and cellular processes of the coral host, which possibly affect its fitness, particularly under environmental stress.</jats:p