Iraya Volcano, situated at the northern tip of Batan Island in the Batanes group, marks the northernmost extent of the Philippine archipelago. Aside from the presence of accessible tephra deposits, the numerous archaeological sites on the island provide key insight into tephrochronology and volcanic hazard assessment. This paper presents stratigraphy and 21 radiocarbon ages of Holocene tephra layers distributed on the island. The eruption ages of the Holocene tephra are approximately 12.4 cal ka BP for Rolling Hills at the bottom, 4.5–4.9 cal ka BP for San Antonio, 2.1–2.5 cal ka BP for Mahatao, 1.6 cal ka BP for Basco, and 1.2–1.6 cal ka BP for Boulder Beach, with most of the tephra concentrated in the latter half of the Holocene. Artifacts excavated from Reydante Cabizon Property Site, San Antonio, Basco can be thought to date to around 4 to 2 cal ka BP, which is consistent with tephrochronology.

The archaeology of glaciers and ice patches has developed as a distinct new field in response to climate change and the melting of mountain ice. Thousands of artefacts and biological materials, dating back up to 10 000 years are being released from melting ice patches and retreating glaciers, offering unique insight into past human activities in cold environments. This paper examines the historical development of glacial archaeology, the preservation or loss of archaeological material from snow and ice, and the methodological challenges in locating and recovering such finds. Key finds and sites from North America, the Alps and Norway are presented. The emerging history demonstrates that high mountain areas were used more intensively in the past than previously assumed, including during winter. The paper argues that closer collaboration between glacial archaeology, glaciology and palaeoclimate research would be highly beneficial, particularly through joint investigations of the ice at glacial archaeological sites.

This work aims to clarify the absolute chronology of the construction phases of the St. Peter and Paul Rotunda at Budeč, focusing on the erection of the rotunda and the tower. Fifteen mortar samples were taken from various structural parts, two of which also contained remnants of charcoal. The mortar samples were mechanically treated to extract a purified calcitic binder that was dated by radiocarbon analysis. The effectiveness of the sample pretreatment methodology was assessed by means of cathodoluminescence microscopy. Thin sections of mortars were characterized by polarized light microscopy. The petrographic characterization allowed for the samples to be grouped according to their binder, aggregate, and structure. This was compared with the evaluation of the calibrated dates, expected chronology known from legends, as well as with formal and stylistic analyses of the structure. The radiocarbon dating distinguished the different construction phases well, and the accuracy and reliability of the dating is discussed. The presence of silts and clays probably led to geogenic carbon contamination of the samples from the foundations, as the obtained dates are older than expected. These dating results were thus regarded as inconclusive. However, the samples from the vaulted dome of the rotunda did not show any anomalies, and the calibrated date period obtained was regarded as relevant and thus successfully dated. The dating based on the legends also fits the determined interval.

Emperor penguins are highly reliant on stable fast ice for successful breeding, and some studies project possible quasi-extinction for most colonies by 2100 due to future sea-ice loss. To better understand the future response of emperor penguins to ocean-climate warming and the possibility of major changes to their habitat, it is essential to better understand how colonies have responded to past changes in ice conditions. In this study, we identify the historical locations of the SANAE, Astrid and Mertz colonies in all available Landsat 4–9, Advanced Spaceborne Thermal Emission and Reflections satellite (ASTER) and Sentinel-2 imagery for the period 1984–2024. We record the location and surface type of the colonies’ breeding locations each year while also recording major calving events, early fast-ice breakouts, distance to the fast-ice edge, and colony location span within a season. The results show that colonies usually return to approximately the same sites annually, but we observe variations due to major calving events. Following such events at Mertz (2010) and SANAE (2011), colonies relocate to different sites, where they may be more vulnerable to early fast-ice breakout or must travel longer distances to the fast-ice edge. In subsequent years, the colonies eventually return to sites close to their original location. Additionally, we observe early fast-ice breakouts that may impact breeding success at Mertz and SANAE colonies, including as early as September at Mertz (2016). Such breakouts coincide with both broader sea-ice lows and variations in colony location. Furthermore, all three colonies move onto the adjacent ice shelf in some years (and at Astrid and Mertz, also icebergs), including when stable fast ice is available, suggesting that this behaviour may be more common than previously thought. Observation of these behaviours contributes to broader understanding of emperor penguins’ adaptability and will aid future efforts to model the response of the species to ice loss.

Four new species of Poecilosclerida (Porifera, Demospongiae) assigned to the genera Latrunculia and Iophon are described from South Africa and Namibia, located in the Namaqua ecoregion. The Porifera occurring along the continental shelf within this ecoregion are relatively well-known, with 76 species formally described in previous literature. Of these, 35 species belong to the Order Poecilosclerida. Additionally, Latrunculia (Aciculatrunculia) biformis is reported from the continental shelf on the west coast of South Africa, extending its range further northwards into the South Atlantic. DNA barcoding and molecular phylogenetic analyses were employed to ensure accurate taxonomic assignment and designation of new species.

Crystal cells in echinoderms have been described in the literature as a type of coelomocyte (immune cell) containing a crystalline structure. Their putative function has been widely ascribed to osmoregulation but this assertion was never robustly tested. In the present paper, a review of crystal cells and crystalline structures provides evidence supporting a different identity and function. First, the same microcrystals can be found either free or encapsulated by a cell membrane (with or without a structure resembling a nucleus). Specifically, they are typically non-encapsulated when found inside tissues of internal organs and encapsulated when free floating in the hydrovascular or perivisceral fluids. Although usually individually packaged, microcrystals were also observed encapsulated in groups of up to four, with or without other particles. Their morphological features, coupled with their chemical and optical properties, match that of microcrystals of uric acid, described in other phyla, including chordates. Two pathways of excretion of these crystallised by-products were evidenced: rejected with sea water out of the respiratory tree and expelled via transrectal coelomoducts among coelomocyte aggregates. Overall, the present synthesis strongly supports that ‘crystal cells’ historically described as a distinct type of coelomocyte in holothuroids are phagocytes that have engulfed uric acid microcrystals generated as waste by metabolic activities.

Melting alpine ice threatens (pre)historic archaeological sites. Current trends suggest loss of ice will continue. Here, we present recent fluctuations in yearly minimum extent from 2017 to 2024 for three central Norwegian ice patches: Storhornet, Elghøa and Lågtangan. We discuss how melting ice affects their archaeological potential and introduce the term ghost patch to describe archaeological ice patch sites no longer containing ice. Future archaeological fieldwork prioritization must account for ice patch to ghost patch transitions. We suggest updated archaeological approaches for a future with less and less ice.

The optically stimulated luminescence (OSL) sensitivity of quartz ranges across five orders of magnitude. Previous studies suggested that quartz OSL sensitivity is enhanced by solar exposure–burial irradiation cycles. Spatially resolved luminescence measurements and laboratory illumination–irradiation experiments were used to investigate the OSL sensitivity of quartz crystals from a granodiorite cobble and quartz grains from a fluvial sand. Quartz from the granodiorite cobble has low OSL sensitivity, showing an approximately linear sensitization path that resulted from laboratory illumination–irradiation cycles. The mean OSL sensitivity of quartz sand grains (100 grains) increased from ∼40 to 80 counts after 1260 illumination–irradiation cycles. Each grain has a specific sensitization trajectory due to illumination–irradiation cycles, suggesting that quartz crystal composition heterogeneities drive the OSL sensitization of their daughter sediment grains. Maximum OSL sensitivity of quartz sand grains is reached after illumination–irradiation cycles representing an accumulated dose of around 4000 Gy. This dose corresponds to sediment burial time of 2–4 Ma, which is unlikely to occur during a single sediment transport route. This study suggests that illumination–irradiation cycles are unable to produce quartz sand grains with OSL sensitivity up to five orders of magnitude higher than the sensitivity of parent crystals in igneous or metamorphic rocks.

Our analysis of 61 versions of the Great Basin (GB) Indigenous oral-history narrative, Theft of Pine Nuts, provides valuable new paleoecological insights into late Pleistocene (LP) and Holocene biogeography of pinyon pine (Pinus monophylla). Pinyon homelands indicated by Indigenous sources were located not only within the current pinyon distribution but also north of the known range, in northern California and Nevada, southern Oregon and Idaho, and western Wyoming. These extramarginal pinyon locations corroborate and expand a Western science hypothesis that proposed LP or Early Holocene refugial populations for pinyon in northern GB that subsequently became extirpated. The narratives also provide new evidence for pre-contact distributions of native mammals in the GB. From analysis of the “ice-barrier” accounts in the Indigenous narratives, we propose parts of this oral-history narrative may have been transmitted since LP times. Whereas most prior efforts have assessed Indigenous oral histories that describe catastrophic geologic events, we document that important ecological dynamics are also embedded in these stories. Our analysis joins other studies in recognizing that oral-history narratives can contain reliable eyewitness observations that are useful for reconstructing paleoenvironmental events and conditions.