Earth and Environmental Sciences

Drone-based shark surveillance has been implemented as a non-lethal mitigation method to minimise the risk of human–shark interactions along beaches of New South Wales (NSW), Australia. However, real-time misidentification remains problematic, often triggering unnecessary countermeasures due to marine animals that pose little to no risk to humans. We investigated shark misidentification in drone surveys by comparing real-time identification with post-flight verification across 900 flights. Post-flight analyses revealed false-positive detection rates of 53%, 79%, and 100% for bull (Carcharhinus leucas), white (Carcharodon carcharias), and tiger (Galeocerdo cuvier) sharks, respectively, which collectively are the ‘target’ sharks of mitigation measures in NSW. Of the 269 flights in which sharks were identified in real time as target sharks, 62% were confirmed post-flight as other sharks (i.e., whaler species, grey nurse, leopard, or wobbegong), sharks that could not be identified (unknown sharks), or non-shark species (i.e., guitarfish). Conversely, 25% of flights with target sharks identified post-flight were recorded in real time as ‘other’ or ‘unknown’ sharks. Overall, real-time classification overestimated the presence of target sharks, with an apparent prevalence approximately twice the true prevalence. Countermeasure activations based on real-time classification of target sharks were accurate in only 36% of instances. Non-shark species (i.e., guitarfish or gamefish) also triggered 39 countermeasures, including 28 water evacuations. Integrating artificial intelligence or other advances (e.g., higher-resolution video on larger screens) may enhance the effectiveness of drone-based surveillance by assisting pilots with real-time shark detection and identification.

Introduction Marine macroalgae are increasingly recognized as promising sources of bioactive compounds for sustainable plant disease management. This study evaluated the anti-phytopathogenic potential of organic extracts from three intertidal macroalgal species, Ulva fasciata , Gracilaria khanjanapajiae , and Sargassum wightii , collected from Thalpe Reef, Sri Lanka. Methods Chloroform, ethyl acetate, and methanol extracts were screened against phytopathogenic fungi Aspergillus niger , Colletotrichum lindemuthianum , Colletotrichum fructicola , Sclerotinia sclerotiorum , and Fusarium oxysporum using the poisoned plate method, and against phytopathogenic bacteria Xanthomonas cucurbitae , Pectobacterium carotovorum , Pseudomonas syringae , Dickeya chrysanthemi , and Ralstonia sp. using the well diffusion assay. Bioassay-guided fractionation was performed on selected active extracts, and the resulting fractions were analyzed by gas chromatography–mass spectrometry. Results Antimicrobial activity varied significantly among macroalgal species, extraction solvents, concentrations, and target pathogens (ANOVA, p < 0.05). The ethyl acetate extract of G. khanjanapajiae exhibited the highest antifungal activity with 71.52 ± 1.60% inhibition against C. lindemuthianum . In contrast, the chloroform extract of U. fasciata showed the strongest antibacterial activity, producing a 24.2 ± 0.3 mm inhibition zone against D. chrysanthemi . Bioassay-guided fractionation further enhanced antimicrobial efficacy, with selected fractions demonstrating higher inhibition than crude extracts. GC–MS analysis of the most active fractions revealed diverse metabolites, including lipophilic phenolics, fatty acids, fatty amides, terpenes and terpenoid derivatives, long-chain alcohols, aldehydes, ketones, and long-chain hydrocarbons such as alkanes, alkenes, and α-olefins, many of which are known for antimicrobial properties. Discussion The findings necessitate further investigation of Sri Lankan marine macroalgae species and solvent-dependent variation of their antimicrobial potential, as candidates for environmentally compatible plant disease control strategies.

Abstract The essay describes the development of hydrogeology education in German universities over the past 25 years, based on the author’s own experience and an informal poll among German-speaking hydrogeology lecturers. Hydrogeology is an integral part of geoscience degree programmes in Germany, where it is increasingly recognized as an indispensable player in interdisciplinary efforts to solve societal, environmental and health-related problems. This is reflected by faculty positions in Germany shifting towards a focus on (bio) geochemistry and away from groundwater quantity-focused research.

In unmanned farms, machinery transfer between fields and access to field entrances are essential prerequisites for autonomous field operations, and both require support from an accurately structured farm-road network. However, existing road data are typically maintained as vector layers and lack the topological relationships and geometric attributes needed for transfer-route and field-entrance planning. This study proposes a method for constructing farm-road topological maps from road and field vector data. The method converts road polygons into a node–edge graph containing centerline geometry, estimates road-segment widths to support the safe passage of agricultural machinery, and establishes bidirectional road–field associations based on field-access nodes. Experiments in three farm areas show that the proposed method achieves a mean symmetric centerline error of 0.094 m; width-estimation mean absolute error (MAE) and root mean square error (RMSE) of 0.032 m and 0.060 m, respectively; and a 100% success rate in 50 random path-planning tasks. The farm-road topological map constructed by this method provides spatial infrastructure for agricultural-machinery path planning and operation scheduling in unmanned farms.

Abstract Exhumed metamorphic rocks yield critical insights into the mechanical, chemical, and thermal structure of the plate interface that can be used to infer exhumation pathways and their evolution throughout a subduction zone's lifetime. Metamorphosed oceanic rocks often record exhumation and underplating over relatively punctuated time periods, which appear to be linked to specific stages of subduction. Although plate velocities also vary from one stage of subduction to the next, the influence of this time dependence on exhumation and underplating remains unclear. We therefore use 2‐D time‐dependent subduction models to investigate how evolving plate velocities affect the timing and distribution of exhumation and underplating. By extracting plate velocities from a freely evolving subduction model and imposing them on kinematically driven models, we isolate the effects of realistic velocity variations on interface processes without the complexity of a dynamically evolving slab. We also explore the role of interface strength by varying its rheology and composition. In our models, exhumation consistently initiates during a punctuated detachment event following decreases in subduction velocity. Shallow exhumation (<50 km) occurs through corner flow within the accretionary prism, while deeper underplating (<140 km) involves crustal slicing and detachment along the whole interface. Weak interfaces favor continuous and voluminous exhumation, whereas strong interfaces restrict it to brief, punctuated episodes. Underplating is discontinuous throughout but increases in volume as convergence slows. These findings demonstrate that time‐dependent plate velocity variations exert significant control on interface processes and naturally generate punctuated exhumation and underplating consistent with the rock record.

The evolutionary assembly of the flight-adapted bird body plan encompasses some of the most profound morphological changes in terrestrial vertebrate history. Beyond feathered wings, the short pygostyle-bearing tail has been pivotal to the clade’s ecological success. However, transition from the long bony tail to the short pygostyle-bearing tail remains a mystery, hindered by the scarcity of early branching avialans with transitional morphologies. Here, we report on a new avialan, Zhengheornis buyu , gen. et sp. nov., from the Upper Jurassic of southeastern China, suggesting that the vertebral reduction and shortening preceded pygostyle fusion in early avialan evolution, providing critical evidence for the stepwise evolution of the bird tail. Z. buyu is smaller than all known non-pygostylian paravians, expanding the species and body size diversity of stemward taxa.

Abstract In 2023, the Mars 2020 Perseverance rover explored the youngest preserved deposits on the Western fan of Jezero crater, Mars: a field of meter‐scale boulders dispersed above the previously explored sandstone and siltstone units. Reflectance spectra of the boulders delineated two classes, one olivine‐bearing and one pyroxene‐bearing. A representative boulder from each class was analyzed; here, we present proximity data from the olivine‐rich target, Falcon Lake, revealing a magnesian dunite (Fo 74 ). Such magnesian dunite is distinct from other igneous materials observed in Jezero and consistent with crystallization from a mantle‐derived partial melt. Micron and mm‐scale secondary minerals, identified on the abraded patch of Falcon Lake, include Mg‐serpentine, Fe‐Mg carbonate, and Mg,Fe sulfate. This alteration sequence records sequential precipitation from a single evolving fluid, and the coexistence of disequilibrium sulfate and siderite represents a microscale analog to planet‐wide associations and detections of carbonates and sulfates.

Abstract Some large igneous provinces (LIPs) are associated with precursory carbonatite eruptions. Models for precursory carbonatites invoking partial melting of a carbonate metasomatized lithosphere appear implausible, given the long time needed for heat conduction from the plume head. Instead, we consider that the plume, not the lithosphere, is the source of carbon. We explore a range of carbon concentrations in the plume source (196 C 440 ppm) and various melting depths of carbonate‐bearing peridotite, depending on the mantle redox state. Our numerical simulations provide a fluid dynamically consistent evolution of the plume‐lithosphere system and enable us to calculate the ascent velocity of carbonate melts. Moreover, we advect millions of passive tracers to follow the 3‐D trajectories of melts. The term “precursory‐C” indicates plume carbon that has reached sub‐lithospheric depths (140 km) before the onset of anhydrous silicate melting. For models with carbonatite melt produced at great depths (200 km), we find that the precursory‐C flux can be up to 6 × mol(C)/yr during a time period of ∼2 Myr preceding the onset of anhydrous silicate melting. The considerable mass of precursory‐C, up to 2 × kg(C), can explain carbonatite complexes predating main phase volcanism in the Paraná province and the Deccan Traps. For some LIPs, environmental and biotic perturbations, indicated by negative carbon isotope excursions and mass extinctions, predate the main phase LIPs eruptions. For the Central Atlantic Magmatic Province (CAMP) we suggest that precursory‐C could represent a non‐negligible carbon source for the earliest volcanism, likely synchronous with the end‐Triassic extinction.