The Southern Ocean remains one of the most data-deficient ocean basins despite its crucial role in global climate regulation. This study uses racing sailboats from the Barcelona World Race (2010/2011 and 2014/2015) and the Vendée Globe Race (2020/2021) as vessels of opportunity to collect sea-surface temperature and salinity measurements, offering a unique dataset for assessing oceanographic variability in this remote region. We conducted an inter-annual analysis of surface temperature and salinity anomalies relative to ARMOR-3D reanalysis and World Ocean Atlas 2023 climatological datasets, identifying regional patterns of change and variability. The results reveal a warming trend and general freshening of the Southern Ocean surface over the last decade, with the highest anomalies observed in the Indian and Atlantic sectors, whereas the Pacific sector showed the lowest anomalies in absolute terms. Notably, El Niño-Southern Oscillation (La Niña) and Southern Annular Mode phases played a significant role in modulating these temperature and salinity anomalies. This study underscores the scientific value of non-research vessels in monitoring climate-driven changes in Antarctic and sub-Antarctic waters, highlighting their potential to complement traditional observation networks in data-sparse regions.

Terrestrial vascular plants affect Earth’s long-term geological processes, contributing to carbon cycling, chemical weathering and soil formation. Plants transport elements from the soil to their above-ground structures, accumulating a range of macroelements including Na, K, Mg, Ca, Si, S, P and Cl. Wildfire combustion concentrates these macroelements into inorganic ash. This ash is dominated by oxides, carbonates, halides, sulfates and phosphates of Na, K, Mg and Ca. This work describes K₂Ca₂(CO₃)₃, which occurs abundantly in the ash of the desert spoon (Dasylirion wheeleri), a plant native to the Sonoran Desert. Electron microprobe analysis, powder X-ray diffraction Rietveld refinement and Raman spectroscopy confirm that this phase matches synthetic rhombohedral (R3) K₂Ca₂(CO₃)₃. This phase forms during the smouldering combustion of D. wheeleri trunks, producing friable, decimetre-sized, porous, ash lumps that pseudomorphically preserve the plant’s fibrous structure. This ash occurs as glassy, sintered, porous aggregates, dominated by K₂Ca₂(CO₃)₃, with sylvite, calcite, fairchildite, arcanite and minor hydroxyapatite and periclase. Several double K–Ca carbonates form under surficial pressures and temperatures below ~800°C, including K₂Ca₂(CO₃)₃, and bütschliite (K₂Ca(CO₃)₂) and its dimorph, fairchildite. The occurrence of rhombohedral K₂Ca₂(CO₃)₃ and fairchildite are consistent with smouldering between 518 and 780°C. Upon exposure to water, K₂Ca₂(CO₃)₃ rapidly decomposes, leaving calcite. The occurrence of K₂Ca₂(CO₃)₃ as a major phase in the plant ash expands our understanding of Earth’s mineral diversity, provides new insights into the widespread geological process of wildfire ash formation and highlights the role that these fires play in forming mineral phases that are rare in other geological settings. Though K₂Ca₂(CO₃)₃ was first identified in Dasylirion wheeleri, this phase probably forms in other fire-adapted plant species. The occurrence of K₂Ca₂(CO₃)₃ in plant ash is an example of an inorganic phase that bridges the gap between biomineralisation and geological mineral formation.

Organismal metabolic rate is linked to environmental temperature and oxygen consumption, and as such, may be a useful predictor of extinction risk. This is especially true during major climate-driven extinctions, given the tightly linked stressors of warming and hypoxia. However, metabolic attributes can be quantified in different ways, highlighting differing aspects of organisms’ ecology. Here, we estimate resting whole-body and mass-specific metabolic rates in post-Carboniferous bivalve taxa using body size, seawater paleotemperature, and a taxon-specific adjustment factor to assess how metabolic rate correlates with survival both during and outside intervals of rapid climate warming, or “hyperthermals.” Accounting for the effects of geographic range size, we find a pattern of preferential extinction of bivalves with lower total calorific needs, consistent with increasing body size and the postulated ramping up of ecosystem energetics over the Meso-Cenozoic. Contrary to expectations, extinction selectivity based on total calorific needs, which emphasizes body size, does not differ between hyperthermals and other time intervals. However, a higher metabolic rate per gram of tissue—which is more strongly determined by environmental temperature than by body size—consistently increases the probability of extinction during hyperthermals relative to baseline conditions, particularly within the paleotropics. This serves to highlight the potential significance of environmental temperature on metabolic performance, particularly in organisms that are already living close to their thermal limits. In tandem with previously documented patterns of extinction selectivity based on relative activity levels, including motility and feeding style, these results enhance our understanding of the role of metabolic rate through time and during climate-driven extinctions. When standardized by mass, metabolic rate may represent a useful metric through which to predict the effects of anthropogenic climate change on modern marine faunas.

The spatial competition in the White Sea’s Halichondria panicea sponge was studied through a field experiment assessing growth in isogeneic and allogeneic sponge fragments of equal or different sizes. After 3 months and 1 year in seawater, growth was evaluated using ImageJ software on photographs. Intraspecific competition among allogeneic H. panicea individuals led to a decrease in relative growth, with the size of interacting individuals influencing competitive strategy. Optimal growth occurred when competitors were larger, minimal when sizes were equal, suggesting an alternative competitive strategy in the latter case. Competition between isogeneic individuals of H. panicea was weak or even absent; fusion of isogeneic fragments increased the growth intensity and substrate coverage by the sponge. Analysing the growth directions of sponges, we have found a phenomenon that may be interpreted as an attempt to ‘avoid’ physical contact with a competitor. In the neighbourhood with an allogeneic individual of larger or smaller size, the growth towards the competitor was lower than in other directions, regardless of whether the neighbouring individuals reached contact with each other or not. This may indicate that growth was redirected due to some distant communication mechanisms. The growth of allogeneic and isogeneic explants before contact occurred in a similar manner. Apparently, H. panicea cannot recognize the genetic nature of a competitor at a certain distance.

The aim of this study was to evaluate the antifungal spectrum of activity, synergy, and mode of action of carboxy-terminally amidated antimicrobial peptides (AMPs) derived from tachyplesin-I (T-I) from the horseshoe crab Tachypleus tridentatus and a lysine-rich analogue of magainin-2 (MSI-94) from the clawed frog Xenopus laevis. In vitro antimicrobial tests against 17 fungal strains demonstrated that the modified AMPs exhibited broad antifungal activity, particularly against filamentous fungi and yeasts relevant to aquaculture and agriculture. Additive antimicrobial activity was observed with the combination of T-I and MSI-94 against Candida albicans and Rhodotorula mucilaginosa, indicating an enhancement of their antiyeast properties. Furthermore, we found that both peptides target the fungal cell surface, increasing membrane permeability and leading to cell death. Overall, our findings highlight the biotechnological potential of aquatic AMPs in developing novel antifungal therapeutics applicable across various fields.

Swelling soils, particularly those rich in smectite, present significant challenges to civil engineering due to their shrinking–swelling behaviour. Lime stabilization is a commonly used practice to address this, but the reactivity of smectite minerals in an alkaline limestone environment differs widely. This study investigates the reactivity of two Moroccan smectite-rich clays – montmorillonite-dominated bentonite and stevensite/saponite-rich bentonite – when treated with aerial lime. Through mineralogical, microstructural and mechanical analyses, this study highlights the distinct behaviour of montmorillonite, which reacts with lime to form calcium silicate hydrate gels, compared to the inert response of stevensite/saponite. Despite its low pozzolanic activity, stevensite-bentonite demonstrates greater mechanical strength, reaching 2.5 MPa in the S3 mixture (90% stevensite-bentonite and 10% lime). This strength is attributed to the formation of calcite through the de-dolomitization of dolomite. The findings reveal different stabilization mechanisms between dioctahedral and trioctahedral smectites, offering new insights for soil stabilization strategies involving these smectite types.