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Unravelling the Seagrass Microbiome
Full text linkSeagrass meadows are marine angiosperms critically important for carbon sequestration and fauna nursery grounds. The global decline of seagrass habitats is associated with coastal nutrient pollution.The seagrass microbiome influences plant health under changing environmental conditions. The response of microbial interactions to nutrient overload are poorly understood. This study used a novel high throughput workflow to map interactions within the seagrass microbiome and evaluate the effect of nutrients on these interactions. Twelve bacterial strains isolated from seagrass seeds were used, creating pairwise co-cultures using robot-assisted colony printing. These bacterial co-cultures were grown and monitored on control and nutrient-enriched media (nitrate, phosphate, iron and copper)using automated imaging and image analysis. Use of these novel technologies both in bacterial pinning and growth monitoring, allowed detection of pronounced differences in growth with mono-cultures of Lysobacter luteus S6 reaching a colony size of 12 mm2 whereas Psychromonas arctica S11 showed minimal growth reaching 4 mm2. Across nutrient addition treatments the microbial growth and co-culture interactions showed dramatic shifts with multiple strains being inhibited while other strains developed mutualisms to combat the nutrient stress. For example, Pseudoalteromonas spiralis S5 when paired with Rhodococcus cerasti S3 in high phosphate concentrations showed 827.9 ±14.3 mm larger growth whereas Rhodococcus cerasti S3 showed the highest growth curves with Pseudoalteromonas spiralis S5 than it did with any other condition. Additionally, four fungal species were isolated and identified in this research by extraction from seagrass meadows. These including endophytes (Pyrenochaetopsis leptospora, Pseudeurotium zonatum) potentially contributing to blade health and epiphytes (Penicillium commune, Cladosporium halotolerans) linked to root-associated defence. This research demonstrates high throughput technologies can successfully be used for large scale microbial interactions cross-examinations to understand partnerships and ideal growth conditions. These could be utilised towards probiotic-based approaches to improve seagrass health, germination and resilience to anthropogenic stress
A hybrid strategy of OTPA and machine learning for efficient root-cause analysis of NVH in multi-source systems
Full text linkThe growing awareness of health benefits, along with the competitive emphasis on vehicle comfort, has led automakers to place greater attention on reducing Noise, Vibration, and Harshness (NVH). One of the most beneficial techniques for NVH engineers to identify, rank, and eliminate dominant noise and vibration sources and paths is Transfer Path Analysis (TPA). Unlike traditional TPA, Operational Transfer Path Analysis (OTPA) requires neither the preliminary acquisition of the transfer matrix between excitation and response points nor the measurement of forces transferred through the active and passive side connection points. Although the OTPA method offers significant advantages over classical TPA methods, it still faces challenges such as data loss caused by the pseudo-inversion of the indicator matrix. In this paper, we estimate the transmissibility matrix using a machine learning-based regression algorithm (random forest). We demonstrated that machine learning is an effective alternative to the truncated Singular Value Decomposition (SVD) method for estimating the transmissibility matrix, as it is a swift solution that preserves essential information in the indicator matrix. The efficiency of the method has been verified by a 2.28 % improvement in the Sound Pressure Level (SPL) of the driver’s ear noise of a sedan-type vehicle through the modification of the most critical path found by this approach
Temperature-dependent spatial and seasonal distribution patterns of the invasive zebra mussel in an artificial lake assessed using environmental DNA
No full textEnvironmental DNA (eDNA) combined with quantitative PCR analysis is a fast and accurate alternative to more costly and laborious physical methods to detect the highly invasive zebra mussel (Dreissena polymorpha). We have developed, in collaboration with the managing authorities of an artificial reservoir, a cost-effective eDNA qPCR-High resolution melt (HRM) assay for zebra mussel which we used for a pilot monitoring of spatial-temporal fluctuations in density across the reservoir. Zebra mussel eDNA densities varied significantly across sampling locations and months, being lower in the winter (when zebra mussel growth is slower) and the highest in April (about a month ahead of the reproductive peak). Temperature was a significant predictor of eDNA concentration. We hypothesise that extreme temperatures might have triggered early reproduction, highlighting the need to plan regular monitoring exercises considering environmental variation, particularly in years with extreme variations. Establishing fast, accurate and affordable methods for regular zebra mussel monitoring is particularly relevant in relation to climate change and may allow prediction of reproductive peaks or distribution shifts. The collaboration with the managing authorities is essential for the regular monitoring of aquatic invasive species such as the zebra mussel
The value of satellite tracking across multiple year cohorts to identify key areas for conservation
No full textWhile satellite tracking is widely used to identify areas of conservation importance, whether there is a need to continue tag deployments across many years is unclear. We show that destinations of migrating animals from the same breeding population can differ significantly across years, and hence we highlight the value of multi-year tracking studies. Between 2012 and 2024, we used Fastloc-GPS Argos and Iridium tags to track 58 green turtles (Chelonia mydas) from their nesting sites in the Chagos Archipelago. If tracking had taken place in a single year, the number of countries used as foraging destinations could have been hugely underestimated (n = 1 country in 2024 versus n = 7 countries across years). Overall, 47% of tracked individuals foraged in the Seychelles, which likely hosts hundreds of thousands of foraging turtles across age classes. Further, the importance of foraging in areas beyond national jurisdiction (ABNJs) was only revealed by tracking over multiple years. Across years, 9% of tracked individuals foraged on the Saya de Malha Bank, a remote ABNJ, equating to likely >1000 adult females and >10 000 green turtles using this foraging area. This cumulative insight from multi-year tracking likely applies broadly to capital breeders where there is environmental variability across the foraging range
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