Lead contamination in water poses serious risks to ecosystems and human health, highlighting the need for low-cost and efficient treatment technologies. In this study, natural attapulgite clay was thermally treated at various temperatures to improve its capacity for removing lead ions from aqueous solutions. The adsorbent prepared at 400°C exhibited the best performance, with a maximum adsorption capacity of 32.63 mg g–1. Characterization results indicated that while heating caused partial changes in the crystal structure, the nanorod morphology and key structural features of attapulgite were largely preserved. The enhanced adsorption ability was attributed to an increase in surface reactivity and greater accessibility of active functional groups. These findings demonstrate a simple and effective modification route that broadens the potential use of attapulgite for heavy-metal wastewater treatment.

We present a Late Pleistocene paleoecological record from King Island in western Bass Strait, Tasmania, and compare this to existing records from the eastern Bass Strait islands to improve our understanding of the region’s paleoecology and paleoclimatology. Vegetation change across the region followed similar trajectories during the late glacial–Middle Holocene, characterized by homogeneous warming and wetting trends. Spatial divergence occurred during the Middle Holocene when sea level rose, and different drivers began influencing western and eastern Bass Strait islands. In eastern Bass Strait, Middle Holocene sea-level rise caused replacement of woodland by coastal heathland, while in the west, a drier period accompanied by fires transformed forests to forest–scrub. The comparative analysis suggests that Westerly driven climatic anti-phasing was pronounced at higher latitudes of Tasmania during the late glacial–Early Holocene. A combination of weak Leeuwin Current, positive Indian Ocean Dipole (IOD), and El Niño–Southern Oscillation (ENSO) intensification contributed to Middle Holocene aridity across Bass Strait. Strong Westerlies and negative IOD phases led to greater regionalization of rainfall across western Bass Strait during the Late Holocene, while ENSO intensification drove rainfall declines in eastern Bass Strait. These findings provide new insights into the complexity of Late Pleistocene environmental dynamics across southeast Australia.

Near-surface ice layers in the lower accumulation zone of Arctic glaciers and ice sheets may significantly affect deep meltwater percolation and runoff availability. This study presents a framework to assess three methods for characterizing near-surface ice layer permeability and its influence on runoff and mass balance on the Devon Ice Cap using field data. In the most effective method, ice layer permeability depends on temperature and thickness: they remain permeable above a threshold temperature (Tth = −0.15°C) and become impermeable once exceed a critical thickness (Himp = 1 m). Our modelling replicates ice layers that are typically thinner in the upper accumulation zone and thicker in the lower accumulation zone. Additionally, we simulate an observed increase in the number of ice layers in the upper accumulation zone after 2007. The evolution of thicker (>1 m) ice layers (or ice slab) in the lower accumulation zone reduces meltwater retention through refreezing, making surface mass balance (SMB) and runoff sensitive to climate changes. Simulated mean SMB ranged from −0.09 to 0.26 m w.e. a−1 from 1999 to 2022. Our model can be applied to simulate the long-term evolution of ice slab and project its impact on ice sheet runoff.

Egg masses of Aplysia depilans consist of long and intertwined strings containing numerous capsules with eggs. Light microscopy stains and transmission electron microscopy revealed four layers in the gelatinous sheath that encircled and aggregated the chain of egg capsules. The outermost layer has a fluffy structure. The second, third, and fourth layers consisted of reticulated matrices with different densities. The second and third layers were divided into 5‒6 strata each. The fourth and innermost layer of the gelatinous sheath has a higher density and no visible stratification. This layer glues the tightly packed capsules to one another and to the outer layers of the gelatinous sheath. The thin wall of the capsules is formed by a homogeneous and highly electron-dense material. Inside the capsules, the eggs or embryos were bathed in an electron-lucent aqueous medium. Bacteria and diatoms were the most abundant microorganisms on the surface of egg strings. Bacteria penetrate the gelatinous sheath and appear to be involved in the degradation of the upper strata, but were never found inside the egg capsules. Metagenomic analysis revealed a large taxonomic diversity of bacteria associated with egg masses of A. depilans. Although 15 phyla could be recognized, the families Flavobacteriaceae (Bacteroidota), Lentisphaeraceae (Lentisphaerota), and Rhodobacteraceae (Pseudomonadota) represented 67.9% ± 11.6% of the relative abundance in the microbiome of the egg string samples. The presence of genera capable of decomposing polysaccharides, such as Tenacibaculum and Cellulophaga, supports the idea that bacteria are responsible for the degradation of the gelatinous layers of the egg strings.

Dry permafrost underlain by ice-cemented permafrost has been reported in several locations in Antarctica. Initially thought to be relic ice, it is now understood that this subsurface ice is in equilibrium with the surface conditions, although it is not in equilibrium with the atmosphere. We use year-round data from University Valley in the Dry Valleys and Elephant Head in the Ellsworth Mountains to investigate the seasonal variations in water vapour flux that control the depth to the ice table under dry permafrost. Our analysis shows that the mean annual water vapour density of the soil surface exceeds the atmospheric value by a factor of up to ~2 due to summer snow. The attenuation and phase shift of the annual temperature cycle with depth result in colder temperatures at the ice table than at the surface of the soil in summer. We conclude that this temperature gradient, combined with the summer snow, provides the flux of water to the ice table necessary to maintain the ice. In University Valley, reducing the snow days by 40% moves the stability depth of the ice table from 42 to 66 cm. Increasing the snow days by 60% shifts the ice table to 17 cm. These variations can explain the observed gradient in the depth to the ice table in University Valley.

To date, published studies have proven that the reactions at the iron/bentonite interface are complex and only partly understood. In the present study, mixtures of bentonite powder and iron powder were prepared, which allowed for varying individual parameters. The results confirmed some controversial previously reported conclusions and revealed new findings. More specifically, Na-exchanged samples showed a reduced extent of corrosion compared to Ca/Mg-exchanged ones, and the addition of reactive silica increased the extent of corrosion, which has not been reported to date. The negative temperature effect (less corrosion at higher temperatures), which was reported previously, could only be confirmed for Ca/Mg-bentonites. One Na-bentonite showed the opposite effect, but this sample also contained reactive silica in contrast to the others. The present study proves for the first time that the type of exchangeable cation can affect the type of corrosion product, which could be an explanation for why the 7 Å corrosion product was not reported in all corrosion tests (sometimes only magnetite was reported). In addition, experiments that ran for 36 months showed that the corrosion progress of six different bentonites was different. Three bentonite/iron mixtures did not show progress in corrosion after 12 months, whereas the other three showed ongoing corrosion. Using the former three bentonite/iron mixtures would significantly increase high-level radioactive waste canister lifetime, but future work should be devoted to the identification of the reason for this differing long-term performance, differing thermal behaviour and differing corrosion products resulting from different types of exchangeable cation.

Tropical Andean glaciers provide an important flux of freshwater to communities living both in high-altitude Cordillera and population centres downstream in countries such as Peru and Bolivia. Glacier recession threatens the sustainability of these water resources, and accurate modelling of future glacier behaviour is required to manage water stress in the region. These models must capture all processes contributing significantly to overall glacier mass budgets. Here we examine supraglacial pond and ice cliff development on three clean-ice glaciers in the Cordillera Vilcanota, Peru and their overall contribution to glacier mass balance. Whilst such features are common and well-studied on debris-covered glaciers, their development on debris-free glaciers has not been examined in detail. We use high-resolution contemporary and historical satellite imagery and repeat drone surveys to examine surface structure and geometry change over three glaciers during 1977–2024. We show how cliff and pond formation is driven by aspect-dependent surface melt of crevasse walls. These features act as ice loss hotspots, which enhance glacier net mass loss by ∼10% despite accounting for <5% glacier surface area. Incorporation of such amplified ice loss processes should be a priority for glacier model advances to achieve more accurate projections of future tropical glacier recession.

Reproductive synchrony is common in populations that inhabit seasonal environments where reproductive timing is important to offspring survival. Weddell seals (Leptonychotes weddellii) reproduce in strongly seasonal Antarctic environments and are known to exhibit reproductive synchrony that varies by latitude, whereby more southerly populations give birth later. The Erebus Bay population of Weddell seals is the southernmost mammal population in the world, and birth-date synchrony has been demonstrated in this population. Various life history correlates including sex, maternal age and reproductive status have been identified as predictors of birth timing, but all prior work has been done on pups born to locally born mothers. Immigrant females originating from unknown sites in more northerly locations also produce pups in Erebus Bay and may have different birth timing due to the earlier average birth dates in their natal colonies. Using 22 years of capture-mark-recapture data for Weddell seals in Erebus Bay, we aimed to assess whether the timing of birth dates for pups born to immigrant mothers differs from that of pups born to locally born mothers. To our knowledge, this is the first time that such a comparison has been studied in a wild population. Birth dates were examined using Bayesian linear regression. We analysed birth dates from 7539 pups (4932 from locally born mothers, 2607 from immigrant mothers) born to 2210 mothers (1254 locally born, 956 immigrant) and found that there were no biologically impactful differences in the birth dates of pups born to locally born or immigrant mothers. Additionally, birth-date patterns for immigrant mothers were similar to those for locally born mothers with respect to various traits. Our results demonstrate that immigrant Weddell seal mothers can synchronize birth timing with locally born mothers. More research is required to understand the underlying mechanisms that allow for immigrant seals to achieve birth-date synchrony.