Widespread marine heatwaves (MHWs) affected Australia over the 2024/25 summer and autumn. They impacted marine species, ecosystems, and coastal communities, with emerging economic consequences. Across northern Australia, severe coral bleaching occurred for the first time along both the western and eastern coasts, and a mass fish kill occurred in Western Australia. In South Australia, prolonged MHW conditions and impacts from an extensive harmful algal bloom of the dinoflagellate Karenia included extensive fish kills, human health effects, losses for ocean-dependent industries, and currently unquantified effects on the broader marine ecosystem. In Tasmania, a range of impacts were linked to warm water, including blooms of salps, Noctiluca, and jellyfish. In New South Wales, a fish mortality event linked to thermal shock generated considerable community concern and media coverage. Trial seasonal forecasts available several months ahead of MHW emergence, combined with national marine climate briefings, helped prepare industry, researchers, and governments for possible impacts. This resulted in increased awareness and development of regional and industry MHW response plans with proactive strategies at both short and long timescales.

Single beam sonars can provide valuable acoustic information on the structure of benthic habitats and the contents of the water column. Nominally, acoustic sensors that provide water column data in scientific applications can cost tens or hundreds of thousands of dollars. In contrast, consumer grade fish finders that are mass produced are very inexpensive, costing only tens or hundreds of dollars. Unlocking a fish finder for scientific use could increase access to low-cost sensing methods for coastal communities that are historically underserved. The principal challenge with using a fish finder for benthic habitat classification is that the sonars are generally not interoperable and are often limited to visualization on a display or chart plotter made by the sonar manufacturer. This vendor lock prevents the sonar data, and in particular water column data, from being stored and processed to create mapping products. In this project, “SonarPhony” was developed to provide interoperability software to enable the real-time visualization and logging of water column data from a low-cost fish finder. A machine learning approach was used to demonstrate that the logged data could be used to estimate bottom type and identify the presence of seagrasses. This solution thus provides a low-cost means for both benthic habitat classification and bathymetric mapping.

The overlapping missions of the NASA Surface Water and Ocean Topography (SWOT) satellite and NASA Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite provide the opportunity to observe oceanic biophysical interactions from space at unprecedented spatiotemporal scales. We use provisional datasets from these two cutting-edge missions to investigate subseasonal to seasonal variability in the microbial community compositions of subtropical mesoscale eddies. The results highlight the capacity of mesoscale eddies to act as transient ecological niches that restructure the surface marine microbial community. For the first time, the combination of SWOT and PACE enables space-based observations of plankton community composition alongside the physical processes that structure it.

In this article we provide pipelines for acquiring and processing Sea-Bird Scientific Spectral Absorption and Attenuation Sensor (ac-s) data through a high-level Python package. The raw streamed and converted instrument output is complex and requires several post-processing steps rooted in optical theory and empirical methods to create base products for algorithms that approximate biogeochemical properties and appeal to a broader oceanographic community. Because datasets from the ac-s are becoming more available in public archives and in real time from large oceanographic infrastructure programs, it is important to establish uncomplicated software packages and interfaces that support the implementation of best practices and the distribution of findable, accessible, interoperable, and reusable (FAIR) data. acspype provides means to perform both instrument-intrinsic and human-in-the-loop corrections with flexibility and clear provenance following well-established manufacturer and research community guidelines. Core functions are provided that allow for the acquisition of real-time data and for post-processing archived datasets. As best practices continue to evolve, acspype would benefit from the addition of time-lag correction functions, methods for assessing instrument drift, and improved uncertainty estimation procedures.

Micronekton consist of crustaceans, cephalopods, gelatinous organisms, and fishes that are 2–20 cm in size (Figure 1). These organisms have unique functional traits that impact their vertical migration patterns and ecosystem processes (Aparecido et al., 2023). Our understanding of their potential carbon transport and sequestration from the epipelagic (upper 200 m) to mesopelagic zones (200–1,000 m) or deeper (e.g., Boyd et al., 2019; Le Moigne, 2019; Cavan et al., 2019) is limited by the tools traditionally used to assess their biomass, diversity, and varied migration patterns (e.g., Annasawmy et al., 2019, 2024; Barbin et al., 2024; Eduardo et al., 2024). These knowledge gaps are notable considering that micronekton are ubiquitous throughout the world ocean.

The NOAA/Atlantic Oceanographic and Meteorological Laboratory (AOML) AX97 High Density eXpendable Bathy­Thermo­graph (XBT) transect constitutes the longest sustained monitoring system of the Brazil Current (BC), having so far provided two decades of observational data. The BC plays an important role in oceanic variability and related processes, as it significantly influences regional and global climate dynamics. The BC is also the main pathway by which subtropical waters are carried to high latitudes. The AX97 data integration into assimilation schemes enhances the accuracy of short-term ocean predictions and long-term reanalyses, benefiting global forecasting centers by improving ocean models at regional, basin, and global scales. Moreover, the AX97 data contribute to global datasets used to quantify ocean heat content, and they are pivotal in assessing high-resolution ocean forecast systems and Earth system models, including those employed by the Intergovernmental Panel on Climate Change. This bimonthly sampling effort, a collaboration between Brazilian universities, the Brazilian Navy, and NOAA/AOML, successfully completed 100 cruises between August 2004 and August 2024, deploying 4,704 XBTs along the transect from Rio de Janeiro to Trindade Island near 22°S. Here, we analyze the BC’s structure and variability over the period 2004–2023, examining its behavior under extreme warm and cold oceanic conditions, including positive and negative anomalies in sea surface height and temperature.

The goal of this activity is to help students become acquainted with key procedures in oceanographic data acquisition, processing, validation, and management. These skills are learned through using sensor-based underway fluorescence and discrete chlorophyll a (Chl-a) measurements. By encompassing a wide range of skills necessary for oceanographic research—from at-sea operations, to precise lab work, to data management—this activity showcases the diverse learning opportunities that oceanography offers for educating science and engineering students. This activity highlights the critical, yet often overlooked, steps required to process and validate high-resolution data from autonomous sensors, such as those mounted on ocean observing platforms (e.g., research vessels, moorings, gliders), before utilizing them to investigate relevant oceanographic processes. It offers students the opportunity to develop proficiency in the various steps of managing open-access data from diverse sources, while also introducing them to the principles of findable, accessible, interoperable, and reusable (FAIR) data practices in scientific research (Wilkinson et al., 2016). Additionally, it familiarizes them with the requirements of the Open-Source Science Initiative (OSSI) for open, transparent, accessible, inclusive, and reproducible science. Emerging mandates that make funding availability contingent on open data managing and sharing procedures make the skills delivered in this activity essential for researchers and technicians (Kaiser and Brainard, 2023).

Addressing global challenges such as climate change requires large-scale collective actions, but such actions are hindered by the complexity and scale of the problem and the uncertainty in the long-term benefit of short-term actions (Jagers et al., 2019). In addition to climate change, socio-ecological systems face the cumulative pressures associated with resource needs, technology development, industrial expansion, and area conflicts. In marine systems, this has been called “the blue acceleration” (Jouffray et al., 2020) and is referred to as “socio-ecological pressures” in this paper. These socio-ecological pressures reduce our ability to reach the UN Sustainable Development Goals and meet the challenges of the UN Ocean Decade, and require integrating knowledge within a shared conceptual framework. For example, achieving sustainable growth must integrate ecological, socioeconomic, and governance perspectives on a larger scale by considering ecological impacts, ecosystem carrying capacities, economic trade-offs, social acceptability, and policy realities. This requires capacity development whereby actors unite to bridge disciplinary boundaries to meet challenges of complex systems.