Publications

Abstract Salinity is one of the most relevant parameters in oceanography used to study properties of the oceans as well as the effects of climate change. Salinity measurements are challenging, due to the harsh environment that leads to corrosion and biofouling. In the context of animal monitors, salinity sensors should also be minimally intrusive and have a long lifetime. Here, a conductivity cell for salinity sensing is presented based on a single‐step laser irradiation process on flexible polyimide substrate. The sensors are characterized by lightweight, flexibility, low power consumption and low fabrication costs. A two‐electrode cell is used to measure the impedance, and thereby the conductivity, of the water in the MHz frequency range. It offers an accuracy of ±0.5 psu, which is not affected by sensor deformation. Deployment of the sensors in the Red Sea revealed that the materials are corrosion resistant and can withstand the harsh environment. While biofouling is strongly affecting commonly employed low frequency conductivity measurements, in the MHz frequency range, it acts like a short‐circuited capacitance. Hence, biofouling independent salinity sensing can be achieved using a two‐electrode impedance measurement at a frequency of 1 MHz.

The capacity of Blue Carbon Ecosystems to act as carbon sinks is strongly influenced by the metabolism of soil-associated microbes, which ultimately determine how much carbon is accumulated or returned to the atmosphere. The rapid evolution of sequencing technologies has facilitated the generation of tremendous amounts of data on what taxa comprise belowground microbial assemblages, largely available as isolated datasets, offering an opportunity for synthesis research that informs progress on understanding Blue Carbon microbiomes. We identified questions that can be addressed with a synthesis approach, including the high variability across datasets, space, and time due to differing sampling techniques, ecosystem or vegetation specificity, and the relationship between microbiome community and edaphic properties, particularly soil carbon. To address these questions, we collated 34 16S rRNA amplicon sequencing datasets, including bulk soil or rhizosphere from seagrass, mangroves, and saltmarshes within publicly available repositories. We identified technical and theoretical challenges that precluded a synthesis of multiple studies with currently available data, and opportunities for addressing the knowledge gaps within Blue Carbon microbial ecology going forward. Here, we provide a standardisation toolbox that supports enacting tasks for the acquisition, management, and integration of Blue Carbon-associated sequencing data and metadata to potentially elucidate novel mechanisms behind Blue Carbon dynamics.

Additional file 1: Table S1. Metadata of the collected samples and metagenomes. Table S2. Sequence data of the obtained viral genomes and genome fragments. Table S3. Functional and taxonomic annotation of the CDS encoded in the viral genomes and genome fragments. Table S4. Relative abundances of viral viral genomes and genome fragments across 58 metagenomes calculated as RPKM. Table S5. Relative abundances of viral KEGG KOs across 58 metagenomes calculated based on RPKM of individual viral viral genomes and genome fragments. Table S6. Relative abundances of viral KEGG pathways across 58 metagenomes calculated based on RPKM of individualviral genomes and genome fragments. Table S7. Relative abundances of viral KEGG metabolism across 58 metagenomes calculated based on RPKM of individual viral genomes and genome fragments. Table S8. Relative abundances of viruses grouped according to family level taxonomic affiliation based on RPKM of individual viral genomes and genome fragments. Table S9. Relative abundances of viruses grouped according to predicted host phylum (or class for Proteobacteria) taxonomic affiliation based on RPKM of individual viral scaffolds. Table S10. Results of Mann-Whitney tests used to compare the relative abundances of: viruses grouped according to predicted host phylum (or class for Proteobacteria), family level taxonomic affiliation, viral KEGG pathways, and viral KEGG metabolisms. Table S11. Results of Pearson and Spearman correlation analyses used to quantify the degrees of association between environmental parameters and the relative abundances of: viruses grouped according to predicted host phylum (or class for Proteobacteria), family level taxonomic affiliation, viral KEGG pathways, and viral KEGG metabolisms.

Abstract The management of coastal blue carbon ecosystems can contribute to mitigate anthropogenic greenhouse gas emissions. However, limited information on soil organic carbon (OC) decay rates in tidal marsh, mangrove, and seagrass soils hinders their inclusion in climate strategies and carbon-crediting schemes. Here, we analyzed downcore OC trends in 3761 soil cores from blue carbon ecosystems worldwide. A decrease in OC content with soil depth was measured in 63% of the cores, whereas stable and increasing trends were observed in 22% and 15% of the cores, respectively. Based on 85 profiles where OC decay could be modelled, the OC decay rate in blue carbon ecosystems was 0.023 ± 0.002 yr−1 over the last 100 years and 0.007 ± 0.0007 yr−1 over the last 1000 years. This results in the stabilization of 9% and 0.1% of the soil OC inputs 100 and 1000 yr after burial, respectively, showcasing the long residence time of OC in the sinks associated to blue carbon ecosystems. This study provides baseline estimates of soil OC decay under natural conditions for short- and long-term periods, and to assess the carbon abatement and additionally provided by carbon offsetting projects in blue carbon ecosystems.

Abstract The tropical seagrass Halophila stipulacea invaded the Eastern Mediterranean Sea in the late nineteenth century and progressively spread throughout the basin ever since. Its spread is expected to continue north-westward as the Mediterranean Sea becomes warmer, potentially changing the seagrass biogeography of the basin. Given the power of genomics to assess invasion dynamics in non-model species, we report the first ddRAD-seq study of H. stipulacea and small-scale population genomic analysis addressing its century-old Mediterranean invasion. Based on 868 SNPs and 35 genotyped native (Red Sea) and exotic (from Cyprus, Greece, and Italy) samples, results suggest that genetic structure was high, especially between major geographic discontinuities, and that exotic populations maintain comparably lower genetic diversity than native populations, despite 130 years of invasion. The evidence of high heterozygosity excess, coupled with previously reported male-dominated and rare flowering records in the exotic range, suggests that clonal propagation likely played a pivotal role in the successful colonization and spread of H. stipulacea in the Mediterranean. This shift in reproductive strategy, particularly evident in the Italian populations located closest to the western boundary and representing more recent establishments, underscores the importance of this cost-effective mode of reproduction, especially during the initial stages of invasion, raising questions about the species future expansion trajectory. Our findings serve as a catalyst for future research into the species’ invasion dynamics, including deciphering the intricate roles of acclimatization and rapid adaptation, important for a comprehensive assessment of invasion risks and improving management strategies aimed at conserving seagrass ecosystems.