Seabirds play an important role as top consumers in the food web and can be used as biomonitors for exposure to pollutants. Erythrocyte nuclear abnormalities (ENAs) represent one of the most important ways to detect genomic damage associated with environmental degradation and pollution. This study investigates the number of ENAs in three populations of two species of Leucocarbo shags. Blood samples from the Antarctic shag (Leucocarbo bransfieldensis) breeding on the Antarctic Peninsula and the South Shetland Islands and the South Georgia shag (Leucocarbo georgianus) breeding on the South Orkney Islands were analysed. The results revealed evidence of genomic damage in all individuals, with a mean number of ENAs of 26.54 and 43.51/10 000 red blood cells for Antarctic and South Georgia shags, respectively. Thus, the shags from the Orkney Islands showed a higher number of erythrocyte abnormalities, whereas no significant differences were observed among shag populations across the Antarctic Peninsula and South Shetland Islands. These results suggest that, in the northern part of the region, shags might be more exposed to pollutants. They also provide the first reference values for cytogenetic damage in this species and establish a critical baseline for future biomonitoring efforts.

Since 1994, the Andalusian Institute of Geophysics of the University of Granada group has been monitoring the seismic activity of Deception Island volcano (South Shetland Islands, Antarctica) during summer surveys. In this review, we analyse long-period and volcanic-tectonic events, including tremor episodes, recorded from 2011–2012 to 2021–2022 surveys with a local network and a seismic array. The seismo-volcanic activity on Deception Island occurs very locally, mainly as a result of tectonic destabilization induced by volcanic activity along with regional stresses, as a consequence of rifting and subduction processes spanning the South Shetland Islands, Bransfield Strait and Antarctica Peninsula. During this period, two changes to the volcanic alert level due to different volcanic parameters can be highlighted. The first of them was caused by the 2014–2015 seismic swarm as a consequence of a great regional perturbation located to the north-east of Deception Island, which spread around to the entire volcano. The second one, in the 2019–2020 survey, was established as a result of a significant increase in deformation parameters as a prelude of the August 2020 massive earthquake swarm that occurred in the Bransfield Strait, near the Orca submarine volcano. Furthermore, in the previous 2018–2019 survey, a peak of seismic activity was also recorded.

Antarctica, which has always been of great interest to researchers worldwide, is currently attracting considerable attention owing to climate change and other topics. In this context, bibliometric analysis allows the identification of hot topics, scientific productivity, cooperation, research gaps and strategic areas of potential interest. We conducted a bibliometric study to evaluate the global production of Antarctic research between 1980 and 2023 and analysed Spanish National Antarctic Programme (NAP) production as a case study. Scientific publications were reviewed and classified based on their main themes, key word co-occurrence and international collaborations. We found that scientific production worldwide and in the Spanish NAP has progressively increased since 1980. Globally, the main areas of research are the geosciences, oceanography and atmospheric sciences. However, the Spanish NAP, which reported 2287 publications, has focused more on the geosciences and ecology. Spanish Antarctic researchers have mainly collaborated with researchers from the USA, the UK, Germany and Italy. Our research highlights the importance of strengthening research plans to diversify and facilitate international collaboration, promoting a more interdisciplinary approach to address the current and future challenges identified by the scientific community. In this context, specific opportunities for developing a Spanish NAP strategic plan are discussed.

Marine microorganisms play a crucial role in biogeochemical cycles, especially in the surface microlayer (SML), which differs from adjacent subsurface waters (SSW). In this study, we sampled the SML and SSW at 20 sites along the western Antarctic Peninsula during the summers of 2015 and 2019, examining microbial, viral and environmental differences. We focused on phototrophic protists, specifically Phaeocystis-like species, known for their high dimethylsulphoniopropionate (DMSP) contents, which can be released through viral lysis. DMSP is a precursor to dimethylsulphide (DMS), a gas influencing Earth’s climate. We hypothesized a significant relationship between Phaeocystis-like abundance and DMSP concentration, with strong interactions with their specific viruses (V4) in the SML. Most biotic variables showed higher mean values in the SML, although these differences often were not statistically significant. DMSP concentrations correlated with Phaeocystis-like species abundance in both layers (R2 = 0.482, P ≤ 0.01; R2 = 0.532, P ≤ 0.01, respectively), whereas V4 abundance significantly correlated with Phaeocystis-like species only in the SML (R2 = 0.572, P ≤ 0.01). These results suggest stronger interactions between viruses and DMSP-rich hosts in the SML, potentially increasing DMS emissions to the atmosphere and impacting climate regulation.

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.

The Bransfield Strait stands out as one of the most accessible places to study Antarctic submarine volcanism, hosting seven active principal submarine volcanic edifices (Edifices A, B and C, Three Sisters, Orca, Hook Ridge, G Ridge) and ~100 smaller seamounts. Only two of them have names (Eastern and Western Seamounts), and ~80 are grouped into two named areas: Spanish Rise and Gibbs Rise. During recent decades, numerous studies have assigned different names to the same volcanic edifices, leading to confusion. Only one of them, Orca, is formally registered in the Scientific Committee of Antarctic Research Composite Gazetteer of Antarctica, which is the catalogue collecting all of the official location names in Antarctica. A unified toponymy is essential, particularly to effectively manage regional logistic operations in case of eruption. Therefore, this study compiles the distinct names assigned to these edifices as a toponymy reference for future research. We recommend using the names most commonly cited in previous studies and, when new names are necessary, submitting them to the Scientific Committee of Antarctic Research Composite Gazetteer of Antarctica to avoid further confusion.

The use of seismic airguns has an environmental impact that is especially intense in relation to marine mammals. As a result, new techniques are being explored to replace or complement this tool. In this study, we test our ability to obtain seismic information about the shallow seafloor structure using fin whale songs as an alternative seismic source. We analyse data collected by ocean-bottom seismometers deployed around Orca volcano in the Bransfield Strait, Antarctica, in 2019. We detected fin whale calls and designed an algorithm to calculate their locations and origin times. We used a relative approach to reduce location uncertainty based on the similarity of waveforms between consecutive calls. We were able to calculate the trajectory of a fin whale that crossed over Orca volcano. Strikingly, the whale path coincided partially with a multi-channel seismic profile carried out with airgun shots. This coincidence allowed us to investigate the performance of the whale calls as seismic sources, comparing them to the almost co-located airgun profile. We constructed receiver gathers using both whale calls and airgun shots. The main features of the whale call sections are consistent with the results obtained using the airgun source. We conclude that although this method has some drawbacks, such as the unpredictable behaviour of whales and the smaller power and lower resolution capabilities of the whale calls compared to the airgun surveys, it is still a feasible alternative as a complement for active-source seismic studies in the marine environment.

Leopard seals (Hydrurga leptonyx) lead solitary lives, mainly associated with sea ice, and they are parasitized by the sucking louse Antarctophthirus ogmorhini, one of the few known marine insects and probably the only group adapted to survive in deep-ocean environments. A challenge for seal lice is that their eggs do not survive underwater, requiring them to complete their life cycle during the host’s reproductive or moulting season. We investigated the infestation parameters of A. ogmorhini in leopard seals on the Danco Coast, Antarctic Peninsula, estimating prevalence and mean abundance, comparing by sex, age class and interannual variability and determining the relationship between these parameters and the body condition of the seals. Over four field seasons (2014, 2015, 2019 and 2020), we collected data from 50 seals: 12 females and 38 males, including 47 adults and 3 juveniles. The overall prevalence (14%) was the lowest recorded for an Antarctic seal, with higher rates in juveniles (33.3%) than adults (12.8%) and in males (15.8%) compared with females (8.3%). Generalized linear models analysis, considering body condition and interannual variability, did not reveal a strong correlation between body condition and lice infestation. Although no strong correlation was found, there is some indication that seals in poorer condition may be more heavily infested.

We evaluated the physiological condition of the Pygoscelis penguins at Isla 25 de Mayo/King George Island (Antarctica Peninsula). Samples were collected from adults and chicks of Adélie (Pygoscelis adeliae, n = 20 each), gentoo (Pygoscelis papua, n = 20 chicks and n = 24 adults) and chinstrap penguins (Pygoscelis antarcticus, n = 18 each). We analysed haematological and biochemical parameters as indicators of health, immune response and nutrition. Gentoo penguin chicks exhibited higher haematocrits, indicating development linked to erythropoiesis and reticulocyte release from bone marrow or signalling dehydration related to fasting periods in chicks. Adélie penguins had increased total leukocyte counts, basophils and eosinophils, whereas gentoo penguins showed elevated heterophils and decreased lymphocytes, resulting in a higher heterophil/lymphocyte ratio stress index, possibly due to the impact of human activities. Chinstrap penguins from a remote area exhibited the lowest heterophil/lymphocyte ratio values. Adélie penguins showed more erythrocytic nuclear abnormalities, indicating sensitivity to environmental deterioration due to human impacts. The biochemical results were less consistent; Adélie penguins had higher cholesterol, whereas gentoo penguins had elevated triglycerides. Gentoo penguins showed dietary adaptability based on prey availability in this area. Our findings highlight the vulnerability of Adélie penguins and contribute to a 20 year physiological monitoring dataset for Antarctic penguins, which will aid future comparative studies.