Phytoplankton communities in the Southern Ocean are shifting as the region experiences rapid environmental change. Using 15 years of Southern Ocean Continuous Plankton Recorder (SO‑CPR) data (2007–2021), this study assesses trends in phytoplankton composition, with emphasis on the ecologically important diatom genus Chaetoceros. Overall diatom and dinoflagellate abundances increased significantly across the sampling domain, while the diatom:dinoflagellate ratio showed only a slight, but significant, increase, indicating broadly stable functional group structure despite higher total biomass. In contrast, Chaetoceros abundance declined per year, suggesting that this genus may be responding differently to recent environmental conditions than other diatom taxa. Twelve Chaetoceros taxa were recorded, with C. dichaeta, C. atlanticus, and C. criophilus dominating observations, and species richness peaking at higher latitudes. Spatial patterns show that Chaetoceros species were broadly distributed across the Indian sector, with elevated abundances near major Southern Ocean fronts. The divergence between increasing total phytoplankton abundance and declining Chaetoceros counts highlights potential shifts in community structure with implications for carbon export and the foraging ecology of key grazers such as Antarctic krill. These results demonstrate the value of long‑term CPR observations for detecting ecosystem change in a rapidly warming Southern Ocean.

Antarctic terrestrial systems are changing as a result of climate change, pollution, local human impacts, and biological invasions. Documenting transformation of these systems has been piecemeal, but in some cases of long enough duration or wide enough extent to provide clear evidence of impacts from each of these drivers and/or their interaction. The evidence has revealed substantial impacts, the significance of land-sea interactions, and the reciprocal insights unveiled by jointly investigating earth and life through time. It has also revealed the growing influence of evidence on Antarctic policy and, in turn, the effectiveness of that policy. In this talk, these successes, and ongoing requirements to build on them, are illustrated with multiple examples. At a time when physical systems are approaching thresholds, change appears to be accelerating, science investment is declining, and Antarctic policymaking efforts criticized for their tardiness, these findings provide the justification needed for ongoing science support, policymaking efforts, and closer alignment between them.

The large-scale exploitation of whale populations in the whaling era led to the near extirpation of large whales across the globe. Whether present-day conditions are adequate to support full recovery of pre-whaling population sizes is uncertain, and the effects climate change and other anthropogenic stressors raise further concerns.
Southern right whales (Eubalaena australis, SRW) were heavily targeted by whaling, leaving only few hundred individuals left across the Southern hemisphere in the 1900s. In Australia the population size has grown since the 1970s, but their population growth is slow due to the species’ multi-year reproduction cycle. Using 50 years of systematic aerial survey data, we assessed the recovery trajectory of this population. Whilst the present population size resides far below pre-whaling levels (8-26% of pre-whaling abundance estimates), annual calf production has started declining since 2016, likely linked to a lengthening of female’s reproduction cycle. Annual coastal abundances of unaccompanied individuals have plummeted, showing a 74% decline since 2011. Our results signal the end of an era of this population's recovery, highlighting that an initial period of steady recovery does not guarantee successful re-establishment of previous abundance levels. We discuss various potential underlying drivers of these marked population-level trends, and identified the knowledge gaps that hamper our understanding of the factors that may be affecting the further recovery of SRWs.

Conservation of Antarctic terrestrial ecosystems requires effective techniques for monitoring vegetation change. Assessments of historical vegetation change are hampered by patchy vegetation distribution and data scarcity, making traditional time series approaches, such as with Landsat, unfeasible. This research incorporates archival high-resolution aerial and oblique ground photography captured from the 1970s – late 1980s to investigate human impacts to vegetation on Bailey Peninsula, East Antarctica, in the vicinity of Casey station and in the nearby Antarctic Specially Protected Area (ASPA) 135. The extent of moss and lichen communities will be mapped using photogrammetry and deep learning image classification in the period before and soon after construction of the current Casey station, and impacts of this construction and associated station activity investigated. Key remote sensing challenges investigated will include multi-modal data harmonisation between aerial and ground-based imagery, and RGB image segmentation for Antarctic vegetation mapping. Furthermore, we will investigate the capacity for quantitative ecological inference from resultant maps to assess human impacts on the Bailey Peninsula. To support this assessment, historical documentation of station management practices will be consulted to identify key local anthropogenic drivers. Resultant observations can be utilised to inform station and ASPA management in light of vegetation responses to past conditions.

Outlets of the East Antarctic Ice Sheet are sensitive to warming of the Southern Ocean and have the potential to significantly raise global sea-level if melted. Rennick, Lillie, and Matesuvich glaciers are large marine-terminating glaciers that drain most of Northern Victoria Land (NVL) on the Pacific Coast. These glaciers may act as precursory indicators of ocean-driven change to adjacent and highly-vulnerable outlets of the Wilkes Subglacial Basin. However, glaciological, climatological, and oceanographic observations are spatially- and temporally-sparse leading to highly uncertain mass balance estimates of the region. Here, we aim to create precise digital elevation models of NVL using >4500 historical aerial images from 1947 and 1961 using photogrammetry. An ~80-year thinning record to the present day can be obtained by differencing historical elevations from satellite-based elevation data. The relationship between ocean conditions and surface thinning will be explored using a high-resolution ocean circulation model under modern and historical conditions. It is hypothesised that recent warm ocean water intrusions are driving basal melt and ice drawdown, and that outlets further ’downstream’ (e.g., Cook, Ninnis, Mertz glaciers) will be forced by similar regional ocean warming.