The possible role of geothermal areas, such as volcanoes, in fostering biodiversity in Antarctica has received considerable recent attention. Under a geothermal refugia hypothesis, diverse life could be supported near or at geothermal sites, and we should see decreasing diversity and/or patterns of nestedness moving away from ‘hotspots’. Although there is evidence that geothermal areas have played a role in the persistence of some terrestrial species through glacial periods in Antarctica, the spatial scales at which such refugia operate is not clear. We sampled sediment from a range of locations across volcanic Deception Island in the Maritime Antarctic and used eDNA metabarcoding approaches (targeting a region of the 28S marker) to assess patterns of diversity in relation to thermal gradients. We found that although colder sites harboured significantly greater taxonomic richness than warmer sites, phylogenetic diversity was lower at colder sites (i.e. taxa at colder sites tend to be more evolutionary close to each other). We infer that increased selective processes in low-temperature environments have reduced phylogenetic diversity, supporting a hypothesis of geothermal locations acting as refugia for diverse taxa, even on fine spatial scales, in cold-climate regions such as Antarctica.

The hot spring water discharging from a flank of an active volcano is precipitating unique monomineralic manganese deposits over volcanic terrain. The major and trace element chemistry, XRD mineralogy, DTA, and SEM observations indicate that the deposits consist of 10 Å phyllomanganate (buserite) accommodating inter-layer Ca and Mg with negligible amounts of detrital minerals. Other metallic elements can be accommodated by buserite, but concentrations are negligible ranging less than 10 ppm to 500 ppm. Abundance and pattern of REE (less than 100 ppm in total) are similar to those from hydrothermal manganese deposits. The buserite is enriched in Ca and Mg but depleted in Na in comparison with those in the spring water. The distribution coefficients for Ca, Mg and Na between the buserite and the host water were calculated assuming an ion-exchange equilibrium in the Yuno-Taki Fails, which proved applicable to other manganese deposits from surficial environments on land and oceans.

Loss of local biodiversity resulting from abrupt environmental change is a significant environmental problem throughout the world. Extinctions of plants are particularly important yet are often overlooked. Drawing from a case in Hawai‘i, a global hotspot for plant and other extinctions, we demonstrate an effort to better understand and determine priorities for the management of an endangered plant (‘Ihi makole or Portulaca sclerocarpa) in the face of rapid and extreme environmental change. Volcanic heat emissions and biological invasions have anecdotally been suggested as possible threats to the species. We integrated P. sclerocarpa outplanting with efforts to collect geological and ecological data to gauge the role of elevated soil temperatures and invasive grasses in driving P. sclerocarpa mortality and population decline. We measured soil temperature, soil depth, surrounding cover and P. sclerocarpa survivorship over three decades. The abundance of wild P. sclerocarpa decreased by 99.7% from the 1990s to 2021. Only 51% of outplantings persisted through 3–4 years. Binomial regression and structural equation modelling revealed that, among the variables we analysed, high soil temperatures were most strongly associated with population decline. Finding the niche where soil temperatures are low enough to allow P. sclerocarpa survival but high enough to limit other agents of P. sclerocarpa mortality may be necessary to increase population growth of this species.

Volcanoes cause a wide range of hazardous phenomena. Close to volcanic vents, hazards can be highly dangerous and destructive and include pyroclastic flows and surges, ballistic projectiles, lava flows, lahars, thick ashfalls, and gas and aerosol emissions. Direct health impacts include trauma, burns, and exacerbation of respiratory diseases. Far-reaching volcanic hazards include volcanic ashfalls, gas and aerosol dispersion, and lahars. Within Oceania, the island arc countries of Papua New Guinea (PNG), the Solomon Islands, Vanuatu, Tonga, and New Zealand are the most at-risk from volcanic activity. Since 1500ad, approximately 10,000 lives have been lost due to volcanic activity across Oceania, with 39 lives lost since 2000. While volcano monitoring and surveillance save lives, residual risks remain from small, sudden, unheralded eruptions, such as the December 9, 2019 eruption of Whakaari/White Island volcano, New Zealand which has a death toll of 21 at the time of writing. Widespread volcanic ashfalls can affect the habitability of downwind communities by contaminating water supplies, damaging crops and buildings, and degrading indoor and outdoor air quality, as well as disrupting transport and communication networks and access to health services. While the fatality rate due to volcanic eruptions may be low, far greater numbers of people may be affected by volcanic activity with approximately 100,000 people in PNG and Vanuatu displaced since 2000. It is challenging to manage health impacts for displaced people, particularly in low-income countries where events such as eruptions occur against a background of low, variable vaccination rates, high prevalence of infectious diseases, poor sanitation infrastructure, and poor nutritional status. As a case study, the 2017-2018 eruption of Ambae volcano, Vanuatu caused no casualties but triggered two separate mandatory off-island evacuations of the entire population of approximately 11,700 people. On the neighboring island of Santo, a health disaster response was coordinated by local government and provided acute care when evacuees arrived. Involving primary care clinicians in this setting enhanced local capacity for health care provision and allowed for an improved understanding of the impact of displacement on evacuee communities.

High-resolution diatom stratigraphies from mid-Holocene sediments taken from fringe and central locations in Moss Lake, a small lake in the foothills of the Cascade Range, Washington, have been analyzed to investigate the impacts (and duration) of tephra deposition on the aquatic ecosystem. Up to 50 mm of tephra was deposited from the climactic eruption of Mount Mazama 7958–7795 cal yr BP, with coincident changes in the aquatic ecosystem. The diatom response from both cores indicates a change in habitat type following blanket tephra deposition, with a decline in tychoplanktonic Fragilaria brevistriata and Staurosira venter and epiphytic diatom taxa indicating a reduction in aquatic macrophyte abundance. Additionally, the central core shows an increase in tychoplanktonic Aulacoseira taxa, interpreted as a response to increased silica availability following tephra deposition. Partial redundancy analysis, however, provides only limited evidence of direct effects from the tephra deposition, and only from the central core, but significant effects from underlying environmental changes associated with climatic and lake development processes. The analyses highlight the importance of duplicate analyses (fringe and central cores) and vigorous statistical analyses for the robust evaluation of aquatic ecosystem change.

Rhönite occurs in lower crustal pyroxenite xenoliths erupted in phonolite from the Mount Sidley composite volcano, Marie Byrd Land, Antarctica, as a localized breakdown product, with plagioclase, clinopyroxene, ± olivine ± Ti-magnetite + melt, of kaersutite, and as microphenocrysts (with olivine, plagioclase, clinopyroxene) in pockets of basanitic melt. Rhö nite after kaersutite has a more NaSi-rich/ CaAl-poor composition, lower Ti, and formed at higher oxidation (∼NNO) conditions than rhönite occurring as microphenocrysts in basanite. Comparison with experimentally determined rhönite stability in understaturated alkali basalt and as a reaction product after Ti-amphibole indicates that the Mount Sidley rhönite (and associated minerals) formed between 1090 and 1190°C at <0.5 kbar, presumably during temporary residence of the xenoliths in a shallow magma chamber below the volcanic edifice.

Seed longevity in situ is a prerequisite for understanding the life histories and community dynamics of species, although long-term longevity under thick tephra has not been documented because of a lack of opportunity and/or awareness. The seed bank for this study was estimated by both germination and flotation tests. Seeds of 17 species have survived with high density, having been buried under thick tephra for 30 years, since the 1977–1978 eruptions on Mount Usu, Hokkaido Island, northern Japan. The total seed density was >1000/m2. Rumex obtusifolius was the most common seed-bank species for 30 years, but decreased in density between 20 and 30 years. More seeds of Hypericum erectum occurred in deeper soil. The total seed density decreased gradually for 30 years, but H. erectum and Juncus effusus did not decline. Native seeds tended to be viable longer than exotic seeds. These results suggest that small, native seeds tend to survive longer with deep burial, while the more numerous weedy, exotic seeds located at the soil surface declined faster. The seed bank provides long-term monitoring of seed survival under natural conditions, and could be used to detect genetic changes.

Studies of the recovery of the fauna following the 1967–70 eruptions at Deception Island, South Shetland Islands, have made it one of the best-studied marine sites of the Southern Ocean for biodiversity. Using SCUBA we surveyed the mega- and macro-epifauna of its subtidal zones in the entrance (Neptune's Bellows), immediately inside the caldera (Whaler's Bay) and well within the caldera (Fumarole Bay). Richness declined from 10 phyla, 13 classes and 35 species at Neptune's Bellows to three phyla, four classes and five species in Whaler's Bay and just two phyla, classes and species at Fumarole Bay. Amongst the 35 species we found at Neptune's Bellows, 14 were previously unrecorded from Deception Island. Despite many ship visits and amongst the warmest sea temperatures in the Southern Ocean, the Non Indigenous Species (NIS) algae were not found in our survey. Deception Island has been recolonized considerably since the recent eruptions, but many taxa are still very poorly represented and the colonizers present are mainly those with planktotrophic larvae. Examination of the literature revealed that to date 163 named marine species have been found within the caldera as well as at least 50 more morphospecies, which are yet to be identified. Species accumulation has consistently increased across eight recent samples reported and the number of species reported there is likely to reach 300 when taxa such as the nematodes are identified to species level. This represents a first meaningful total species estimate for an Antarctic marine area and, as the site is comparatively impoverished, indicates how rich the surrounding Antarctic shelf must be.

Upper Amazonian tree communities are famous for their very high alpha-diversity. This paper describes an anomalous forest just 6 km south of the equator in lowland Ecuador that is structurally mature, surrounded by hyperdiverse forest, but strikingly poor in species. To investigate the anomaly, a 1-ha tree inventory and soil analysis were carried out and compared with 15 similar surveys of upland forest in the same region. The anomalous forest contains only 102 tree species ha−1, compared with a regional mean of 239±28 species ha−1. It is structurally indistinguishable from richer forests, and closest in composition to upland forest, but lacks the uplands' typically rich understorey tree community. Three hypotheses for its origin are examined: recovery from anthropogenic disturbance, unique soil conditions and recovery from a large-scale natural catastrophe. The third hypothesis is the best supported. Mineralogical, geological and remote-sensing evidence, and 14C-dating suggest that the forest grows on a vast debris plain left by a catastrophic flooding event roughly 500 y ago. The forest's low diversity today is most likely due to the failure of a full complement of the region's tree species – especially understorey taxa – to recolonize the outwash plain in the time since the disaster.

From at least the Early Jurassic to the Miocene, eastward subduction of oceanic crust took place beneath the Antarctic Peninsula. Magmatism associated with the subduction generated a N-S linear belt of volcanic rocks known as the Antarctic Peninsula Volcanic Group (APVG), and which erosion has now exposed at about the plutonic/volcanic interface. Large central volcanoes from the APVG are described here for the first time. The structures are situated in north-west Palmer Land within the main Mesozoic magmatic arc. One centre, Zonda Towers, is recognized by the presence of a 160 m thick silicic ignimbrite, containing accidental lava blocks up to 25 m in diameter. This megabreccia is interpreted as a caldera-fill deposit which formed by land sliding of steep caldera walls during ignimbrite eruption and deposition. A larger centre, Mount Edgell-Wright Spires, is dominated by coarse-grained debris flow deposits and silicic ignimbrites which, with minor lavas and fine-grained tuffs, form a volcanic succession some 1.5 km thick. Basic intermediate and silicic sills c. 50 m thick intrude the succession. A central gabbro-granite intrusion is interpreted to be a high-level magma chamber of the Mount Edgell volcano.

The prediction of future disasters drives the priorities, urgencies, and perceived adequacies of disaster management, public policy, and government funding. Disasters always arise from some fundamental dysequilibrium between hazards in the environment and the vulnerabilities of human communities. Understanding the major factors that will tend to produce hazards and vulnerabilities in the future plays a key role in disaster risk assessment.

The factors tending to produce hazards in the 21st Century include population growth, environmental degradation, infectious agents (including biological warfare agents), hazardous materials (industrial chemicals, chemical warfare agents, nuclear materials, and hazardous waste), economic imbalance (usually within countries), and cultural tribalism. The factors tending to generate vulnerabilities to hazardous events include population growth, aging populations, poverty, maldistribution of populations to disaster-prone areas, urbanization, marginalization of populations to informal settlements within urban areas, and structural vulnerability.

An increasing global interconnectedness also will bring hazards and vulnerabilities together in unique ways to produce familiar disasters in unfamiliar forms and unfamiliar disasters in forms not yet imagined. Despite concerns about novel disasters, many of the disasters common today also will be common tomorrow.

The risk of any given disaster is modifiable through its manageability. Effective disaster management has the potential to counter many of the factors tending to produce future hazards and vulnerabilities. Hazard mitigation and vulnerability reduction based on a clear understanding of the complex causal chains that comprise disasters will be critical in the complex world of the 21st Century.