Petra Ten Hoopen

The Arctic is undergoing rapid change. Near-surface air temperatures are rising at around four times the global average, ocean temperatures are increasing, sea ice is thinning, retreating rapidly, and growing younger on average, while pan-arctic river run-off and glacial melt are both increasing. The increased fluxes of nutrient-loaded freshwater into the Arctic significantly impact marine systems both locally and globally. Arctic nutrient supplies underpin marine productivity not only within the Arctic Ocean, but also in temperate and tropical regions via oceanic exports. This makes the tracing of freshwater sources from land, the cryosphere and the atmosphere into and throughout the ocean a critical priority for understanding the global consequences of Arctic climate change. When combined with salinity measurements, stable oxygen isotope ratios (δ18O) in seawater are a powerful tracer for distinguishing freshwater contributions from meteoric sources (precipitation, rivers, glaciers) and sea-ice. While major previous efforts have compiled extensive δ18O observations in other regions, no up-to-date, centralised, accessible, and curated pan-Arctic compilation exists, despite the rapid growth in observational coverage over the recent decades. Here, we present a unified pan-Arctic seawater δ18O database comprising observations collected north of 60 °N, compiled from public repositories, peer-reviewed literature, and datasets contributed directly by colleagues across the scientific community. To unify these records, we harmonised metadata, applied standardised quality-control procedures, and integrated records into a single Artificial Intelligence (AI) compatible dataset adhering to FAIR (Findable, Accessible, Interoperable, and Reusable) data principles. We further added available barium (Ba) concentration data as another freshwater tracer, capable in some conditions of further de-convolving Arctic river run-off into separate sources. The resulting database comprises 45,714 unique δ18O measurements, paired with salinity measurements for non-freshwater samples, and 5531 unique Ba measurements spanning 1967–2025 (Thorpe-Morgan et al., 2026). This dataset provides a useful resource for quantifying sources of freshwater in the Arctic Ocean, in a format which facilitates data-driven and machine-learning approaches to spatio-temporally-sparse environmental datasets.

Antarctic krill (Euphausia superba, hereafter "krill") are an important component of Southern Ocean food webs, are efficient in sequestering carbon and support a major fishery. Knowledge of their early life cycle is key to understanding krill population dynamics and essential for fisheries management in a warming climate. Many data have been collected over the years on the distribution of krill larvae, but the data remain fragmented and hard to re-use. Here we have put these disparate data sources together into a large database of 10,762 net-sampling records with numerical abundance data on the various larval stages. This new KRILLBASE-larvae database complements two existing and circumpolar KRILLBASE open-access databases, namely KRILLBASE-abundance (numerical abundance of postlarval krill and salps) and KRILLBASE-length frequency (length, sex and maturity stage of postlarval krill). By completing the set to include larvae, we provide datasets that can underpin a more holistic appreciation of krill dynamics; for example to model the krill life cycle, population dynamics, response to climate change and to help manage the krill fishery. KRILLBASE-larvae is circumpolar, albeit with most data concentrated in the SW Atlantic sector which appears to be the major spawning ground and where the fishery operates. The data span 1926–2024 with >50 seasons of coverage spanning two epochs: 1926–1937 and 1976–2024. The database is based on net haul data on densities (numbers per m-2) of eggs, nauplii, metanauplii, calypotope- and furcilia stages, alongside key sampling information such as sampling depths, net type, net mesh size, water depth, temperature etc. This data paper provides a description of KRILLBASE-larvae, mapping data coverage in terms of space, time and sampling depth, providing pointers and caveats to its use. The KRILLBASE-larvae database is available here for reviewers: http://ramadda.data.bas.ac.uk/repository/entry/show?entryid=946546c8-b24f-422f-96e1-3bd872506c5f with user id reviewer_02221 and password VchJWSANpH1T5Wpj with instructions https://www.bas.ac.uk/data/polar-data-centre/reviewer-access/ [Pending publication and any subsequent amendment on review, the final dataset will be freely available with a doi and single click to download]. We request that this data doi and the data paper are cited when the data are used.

The Southern Ocean is central to global ocean mixing and climate regulation via its disproportionate uptake of human-induced heat and carbon dioxide, yet the underlying processes are still poorly understood. Coordinated and sustained effort in observation and modelling of Southern Ocean processes in the past, present and future is therefore critical for understanding and mitigating the changes underway. Free and equitable access to Southern Ocean data is a fundamental prerequisite to meeting this objective. Here, we present a tool for discovery of, and access to, existing Southern Ocean data—SOOSmap, Version 2 (soosmap.aq). SOOSmap is a gateway to physical, biogeochemical and biological open-access data, free for anyone to use, from ocean science experts to classroom students. SOOSmap was developed in a collaboration of the Southern Ocean Observing System and the European Marine Observations and Data Network Physics project, with the aim to provide an easy to use one-stop-shop for Southern Ocean data held in repositories around the world. In this article, we illustrate the different methods of data access within SOOSmap, describe SOOSmap in the context of other polar data resources and initiatives, demonstrate how SOOSmap can be put into practice by a variety of stakeholders, and instruct users on how they can get involved in the SOOS community and contribute new data to SOOSmap, which is fundamental for this tool to continue to be useful for informing policy and decision-making about changes occurring in the Southern Ocean.

A key challenge in understanding carbon cycling in the Southern Ocean is disentangling long-term responses from significant spatial and temporal variability in physical and biogeochemical parameters. As such, there is a critical need for regional long-term observations for the model validation and testing needed for a better mechanistic understanding of primary production drivers. We present a new macronutrient data product for the South Atlantic sector of the Southern Ocean, including depth profiles and underway surface measurements of nitrate, nitrite, ammonium, phosphate, silicic acid, temperature and salinity, collected from 1980 to 2009 and covering most months of the year (https://doi.org/10/h3qr). Using this data product, we explore the differences in shallow and deep-water nutrients around the island of South Georgia that are observed between years. We discuss both the biological and physical driving mechanisms behind this variability, which are interconnected with climate feedbacks. The new data product provides an unprecedented view of biogeochemical cycling in biologically productive regions of the Southern Ocean across a critical period in recent climate history, and illustrates the importance of building these scientifically valuable and FAIR (findability, accessibility, interoperability, and reusability) observational datasets.

We present a database from substantial collections of macronutrient data made on 20 oceanographic cruises, primarily from around the island of South Georgia and the Scotia Sea. This sector of the Southern Ocean was studied comprehensively during the Discovery Investigations between ∼1920 and 1950 and resulted in the hugely influential Discovery Reports. Following this pioneering research period, there was a lull of several decades prior to the British Antarctic Survey (BAS) initiation of an offshore biological programme to study the ecology of the South Atlantic sector of the Southern Ocean. These studies began in the late 1970s and have continued until the present day. Between 1980 and 2009, the programme included macronutrient measurements as part of an integrated ecosystem analysis. In addition to South Georgia and the Scotia Sea, measurements were also made in the Bellingshausen Sea and the waters to the west of the Antarctic Peninsula. Data were collected during all months of the year with the exceptions of May and June and compiled into a database. Vertical profile samples were taken from water bottles, while data along transects were collected by monitoring the ship's non-toxic seawater supply. Nutrients measured were silicate (Si(OH)₄–Si), phosphate (PO₄–P), nitrate (NO₃–N), ammonium (NH₄–N), and nitrite (NO₂–N). Our database includes nutrient data along with contemporaneous temperature and salinity data where available. Further background and supporting information is included for context. The profile and underway sample data have been deposited at the UK Polar Data Centre and are publicly available in NetCDF and CSV formats from https://doi.org/10.5285/4014370F-8EB2-492B-A5F3-6DC68BF12C1E (Whitehouse et al., 2022).

We present a database from substantial collections of macronutrient data made on 20 oceanographic cruises, primarily from around the island of South Georgia and the Scotia Sea. This sector of the Southern Ocean was studied comprehensively during the Discovery Investigations between ~1920 and 1950 and resulted in the hugely influential Discovery Reports. Following this pioneering research period, there was a lull of several decades prior to the British Antarctic Survey’s (BAS) initiation of an offshore biological programme to study the ecology of the South Atlantic sector of the Southern Ocean. These studies began in the late 1970s and have continued until the present day. Between 1980–2009, the programme included macronutrient measurements as part of an integrated ecosystem analysis. In addition to South Georgia and the Scotia Sea, measurements were also made in the Bellingshausen Sea and the waters to the west of the Antarctic Peninsula. Data were collected during all months of the year with the exceptions of May and June and compiled into a database. Vertical profile samples were taken from water bottles while data along transects were collected through monitoring the ship’s non-toxic seawater supply. Nutrients measured were silicate, Si(OH)₄-Si; phosphate, PO₄-P; nitrate, NO₃-N; ammonium NH₄-N; and nitrite, NO₂-N. Our database includes nutrient data along with contemporaneous temperature and salinity data where available. Further background and supporting information are included for context.

Cytokinins comprise a group of phytohormones with an organ-specific mode of action. Although the mechanisms controlling the complex networks of cytokinin metabolism are partially known, the role of individual cytokinin types in the maintenance of cytokinin homeostasis remains unclear. Utilizing the overproduction of single-chain Fv antibodies selected for their ability to bind trans-zeatin riboside and targeted to the endoplasmic reticulum, we post-synthetically modulated cytokinin ribosides, the proposed transport forms of cytokinins. We observed asymmetric activity of cytokinin biosynthetic genes and cytokinin distribution in wild-type tobacco seedlings with higher cytokinin abundance in the root than in the shoot. Antibody-mediated modulation of cytokinin ribosides further enhanced the relative cytokinin abundance in the roots and induced cytokinin-related phenotypes in an organ-specific manner. The activity of cytokinin oxidase/dehydrogenase in the roots was strongly up-regulated in response to antibody-mediated formation of the cytokinin pool in the endoplasmic reticulum. However, we only detected a slight decrease in the root cytokinin levels. In contrast, a significant decrease of cytokinins occurred in the shoot. We suggest the roots as the main site of cytokinin biosynthesis in tobacco seedlings. Conversely, cytokinin levels in the shoot seem to depend largely on long-range transport of cytokinin ribosides from the root and their subsequent metabolic activation.

EBI metagenomics (http://www.ebi.ac.uk/metagenomics) provides a free to use platform for the analysis and archiving of sequence data derived from the microbial populations found in a particular environment. Over the past two years, EBI metagenomics has increased the number of datasets analysed 10-fold. In addition to increased throughput, the underlying analysis pipeline has been overhauled to include both new or updated tools and reference databases. Of particular note is a new workflow for taxonomic assignments that has been extended to include assignments based on both the large and small subunit RNA marker genes and to encompass all cellular micro-organisms. We also describe the addition of metagenomic assembly as a new analysis service. Our pilot studies have produced over 2400 assemblies from datasets in the public domain. From these assemblies, we have produced a searchable, non-redundant protein database of over 50 million sequences. To provide improved access to the data stored within the resource, we have developed a programmatic interface that provides access to the analysis results and associated sample metadata. Finally, we have integrated the results of a series of statistical analyses that provide estimations of diversity and sample comparisons.