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Ocean knowledge is crucial for shaping policies that enable sustainable development, adaptation, and well-being at all levels, as everyone—either directly or indirectly—depends on the ocean, which today faces escalating threats from climate change, pollution, and biodiversity loss, pushing us beyond critical planetary boundaries. Ocean indicators are crucial for translating ocean science and data into practical metrics, guidance, and tools informing on the state and health of the ocean that can be directly applied by policymakers, practitioners, and the public. Despite their critical importance, ocean indicators trail behind those for continental areas, limiting effective monitoring and policy integration. Developing reliable, comparable, and regularly updated ocean indicators, backed by a unified international framework, is essential for delivering coherent, actionable insights that can guide global goals and protect the ocean's future. This paper establishes a scientific foundation for ocean indicators through international and multidisciplinary collaboration, presenting defined criteria and a set of pilot indicators for the ocean’s physical, biogeochemical, biodiversity, and ecosystem aspects. The proposed framework offers a solid foundation for generating indicators that not only track the ocean state but also provide outputs for application in informing policy and decision-making.
Sharks and rays are sentinels of the state of the ocean. Since the mid-twentieth century, overall abundance has declined by nearly 65
Volcanic ballistic projectiles (VBPs) are a dangerous near-vent hazard. Physics-based models are often used to estimate potential impact locations to help reduce risk to nearby people and environment. Drag is an essential model component, but many VBPs, especially molten VBPs (bombs), are irregular in shape and their drag behaviour has not previously been quantified. We measure 3D-printed models of in-flight Strombolian bomb shapes in a wind tunnel to quantify drag effects in terms of drag coefficient (C-D) and Reynolds number (Re). Tests were performed on static models across increasingly oblique angles to the air flow, and on dynamically rotating models across increasing spin frequencies. The model size and air speeds tested here correspond with Re values 9.3 x 10(4) to 1.2 x 10(6), encompassing the laminar-turbulent flow transition into the supercritical Re regime (which occurs at similar to 2.5 x 10(5) for spheres). We find rounded and bilobate shapes have distinctly different drag behaviour. The C-D of bilobate shapes varies significantly with changes in orientation (0.29-0.41 head-on, 0.64-0.88 broadside). The C-D of rounded shapes varies little with changes in orientation (0.2-0.4 head-on, 0.33-0.44 broadside), lower than the range for bilobate shapes at both head-on and broadside. The average C-D of a rotating model approaches its broadside static C-D. We compare results to in-flight observations where spin is commonly observed and conclude that the broadside C-D is most applicable for use in scenario modelling. For Strombolian VBPs at supercritical Reynolds number, we therefore recommend a C-D range of 0.33-0.88 and propose a new methodology for physics-based models which accounts for relationships between size, shape, Reynolds number, and C-D.
Late Cretaceous-Cenozoic diffuse intraplate volcanism is widespread across the continent of Zealandia, but only in the Chatham Islands have intraplate volcanoes erupted repeatedly for over 80 million years. Here we use new whole-rock major and trace element, and Sr-Nd-Pb-Hf isotope geochemical data from the Chatham Islands to characterize changes in the geochemical fingerprint of the melting sources over time to provide a better understanding of Zealandian intraplate volcanism. The first and most voluminous magmatic stage (similar to 85-75 Ma; Southern Volcanics) at the Chatham Islands has an isotopic signature nearly identical to the St. Helena HIMU-type end member. The following Red Bluff Tuff volcanic stage (similar to 65-50 Ma) has a distinct isotopic composition, influenced by an enriched mantle one-type, probably derived from the neighboring Hikurangi Plateau. The following magmatic stages, the Northern Volcanics (similar to 40-30 Ma) and Rangitihi Volcanics (< 10 Ma) extend from this compositional array to compositions with higher Pb-206/Pb-204 and Pb-208/Pb-204 ratios at given Pb-207/Pb-204 ratio. This 'Cenozoic array' reflects radiogenic in-growth with high U/Pb and Th/U ratios derived from a metasomatized lithospheric mantle source. The recorded temporal geochemical evolution confirms a widespread Late Cretaceous HIMU melting event in Zealandia, which metasomatized the lithospheric mantle forming the Cenozoic HIMU-like melting source. This also reflects a change from asthenospheric to lithospheric melting sources. The nearly continuous volcanism during the Cenozoic in the Chathams and wider eastern Chatham Rise could have been triggered by asthenospheric upwelling causing melting of the base of the metasomatized lithosphere. Considering the fast-northward motion of Zealandia during the Cenozoic (similar to 2500 km), the upwelling is most plausibly explained by the change in lithospheric thickness caused by the partly subducted Hikurangi Plateau that lies directly north of the Chatham Islands.
Recent technical advances have significantly enhanced the value of museum specimens for molecular research, with metagenomic and metabarcoding approaches expanding further the utility of museum collections. However, given the finite number of specimens, there is a critical need to move past destructive DNA extraction approaches and to explore non-destructive techniques. In this proof-of-concept study, we evaluated the feasibility of extracting historical eDNA from the ethanol preservative used to store museum specimens. We compared a variety of extraction methods (centrifugation, evaporation, filtration, and precipitation) using ten replicate samples per treatment for statistical analyses. To assess potential differences in preservative-derived eDNA recovery across different filter-feeding taxonomic groups, we included a bryozoan, a demosponge, and a glass sponge. Comparative analyses with tissue biopsies revealed that 10 mL ethanol filtration performed equal to or, in some instances, outperformed tissue biopsies for all three specimens when examining the historical eDNA of Antarctic fish using a 16S rRNA metabarcoding approach, both for the number of species detected (α-diversity) and community characterisation (β-diversity). This initial study demonstrates the potential of ethanol preservative as a valuable, non-destructive source of historical eDNA from museum-stored filter-feeding specimens. These findings highlight the viability of non-destructive sampling for molecular research on museum collections, preserving specimen integrity while enabling biodiversity assessments. Further refinement of non-destructive eDNA extraction could expand its applicability across taxa, collection types, and preservation methods, ensuring the long-term sustainability of museum-based genomic, metagenomic, and metabarcoding research.
