Marine and inland fisheries are the fastest developing sector in the world and there is an increasing need for appropriate governance through remote sensing and information and communication technologies (ICTs) for its sustainable development in Indo-Pacific region for food security. Lack of information and communication facilities , remote sensing maps in fishing communities inhibits the social, political and economic empowerment of the majority of the population. ICTs played a significant role in all aquaculture community specially women in marine science across the world since the dawn of civilization to increase the productivity of food from remote sensing data. ICTs play a crucial role for the development of the marine and inland aquaculture in our Indo-Pacific region for food security.
This presentation deal with the role of remote sensing data in marine science practicing information and communication technologies in governance of fishery sector for greater food security. The presentation aims at discussing the forms of remote sensing data and ICTs which are being used across the globe in fisheries sector for identifynig marine plastic pollution for resource assessment, capture or culture to processing and commercialization. This presentation will be based on specialist applications of remote sensing data, ICTs in fishery sector for sustainable exploitation of the marine and inland fishery resources for food security considering the transboundary issues in Asia- Pacific region. This presentation intends to focus the role of data analysis from remote sensing in marine science specially planners, managers, researchers and community workers functioning on interdisciplinary issue involved in conclave of fisheries management, coastal risk and vulnerability, social-ecological vulnerability and resilience in coastal region, Human Pressures on Coastal Environments, land water-seawater interactions, economic issues and challenges related to Indo-Pacific aquatic resources for achieving the SDG 14 on Food Security.

How to cite: Chaudhari, K., Cerreta, M., and De Toro, P.: Application of Remote Sensing and Information and Communication Technologies for Governing and Sustaining Fishery Sector in Indo-Pacific and Beyond: Lessons Learned For Transfer of Science to Society., One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-40, https://doi.org/10.5194/oos2025-40, 2025.

The international BioGeoChemical-Argo program recommends the measurement of 6 essential ocean variables (EOVs), one of which being the inorganic carbon. Estimates of pH variation in the open ocean using traditional sampling methods show a decrease of 0.002 units per year [1]. Understanding and predicting pH variations using precise, certified in situ detection over oceans around the world over the long term is currently essential. In the frame of the PIANO (Plan d’Investissement Argo Nouvelles Observations, Ifremer) project we designed and developed a new submersible pH_T colorimetric sensor deployable on profiling floats sensible enough to be suitable for the acidification monitoring. This development is aimed on the use of the referenced colorimetric method ([2]–[4]), applied to microfluidic channels with in situ calibration using on-board standards. The first phase of the project was to determine the miniaturized actuators able of working under 350 bars and 4°C. Then, a 3D printed manifold was fabricated using stereolithography. It was optimized to integrate a micromixing area, an optical detection and a temperature sensor (pt100). Once the final architecture of the manifold was fixed, the system's repeatability and accuracy were then tested. Electronic and mechanic design were established considering minimum energy consumption and space. In parallel, tests were set up with the metrology laboratory to study the ageing of on-board pH_T standards over time (2-years test). An overall protocol was devised, focusing on the procedure for rinsing the bags to minimize bacterial contamination and purchasing stable standards. The first results of this future submersible pH_T sensor against robust benchtop spectroscopic measurements of referenced waters will be discussed.

Figure 1: 3D printing of the optical cell

Figure 2: 3D printing mixing unit (based on tesla design)

[1]         F. J. Millero, “The marine inorganic carbon cycle.,” Chem. Rev., vol. 107, no. Table 1, pp. 308–341, 2007.

[2]         X. Liu, M. C. Patsavas, and R. H. Byrne, “Purification and characterization of meta-cresol purple for spectrophotometric seawater ph measurements,” Environ. Sci. Technol., vol. 45, no. 11, pp. 4862–4868, 2011.

[3]         J. D. Müller et al., “Metrology for pH measurements in brackish waters-part 1: Extending electrochemical pHT measurements of TRIS buffers to salinities 5-20,” Front. Mar. Sci., vol. 5, no. JUL, pp. 1–12, 2018.

[4]         J. D. Müller and G. Rehder, “Metrology of pH measurements in brackish waters-part 2: Experimental characterization of purified meta-cresol purple for spectrophotometric pHT measurements,” Front. Mar. Sci., vol. 5, no. JUL, pp. 1–9, 2018.

How to cite: Davy, R., courson, R., Salvetat, F., André, X., Guillemot, A., Le Gall, C., Chalopin, M., Bescond, T., Coail, J.-Y., Cotty, C., Leymarie, E., and Laes, A.: Development of a new submersible colorimetric sensor for in situ detection of pHT on profiling floats, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-117, https://doi.org/10.5194/oos2025-117, 2025.

To address the specific demands of ocean science, unmanned aerial vehicles (UAVs) and their associated equipment can be tailored to create a sophisticated technological system designed to support marine research. A diverse array of UAVs, each with unique payload capacities and operational ranges, along with a variety of specialized onboard equipment, have been engineered. These UAVs are capable of autonomously conducting high-precision operations within the intricate marine environment, enabling tasks such as time-series sampling and environmental monitoring. This capability significantly expedites the collection of primary data. The integration of this technical system represents a crucial component in fulfilling the most pressing needs of marine science, thereby greatly enhancing the field of marine scientific research.

How to cite: Zhang, C., Wang, H., and Xu, Y.:  Research and Development of UAV Array Technologies for Ocean Sciences, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-276, https://doi.org/10.5194/oos2025-276, 2025.

Over recent decades, the Mediterranean basin has faced enhanced wildfire risks due to longer dry seasons and higher temperatures associated with global changes. Wildfire-generated aerosols could travel long distances and ultimately end in the ocean, where they may subsequently impact the marine microbial communities that are the key drivers of global geochemical cycles. However, the current knowledge about the influence of wildfire ash on the abundance and composition of marine microbes remains limited. We conducted experiments where surface seawater from the Northwestern Mediterranean Sea was incubated (up to 10 days) in (300L) minicosms amended with different concentrations of ashes, which were previously collected during a real wildfire in the Mediterranean region. Ash additions had a direct effect by increasing microbial abundance and diversity, likely due to the release of both inorganic and organic substrates that alleviated nutrient limitations. At a later stage, ash additions also indirectly affected microbial biomass and diversity via the stimulation and ulterior decline of phytoplankton communities. These mechanisms induced changes in prokaryotic community composition, reflecting a succession of different taxa adapted to different nutrient qualities and quantities. Ashes had a negative effect on Cyanobiaceae, but promoted the growth of Flavobacteriaceae, Rhodobacteraceae, and SAR11 clade I among other taxa. Our findings suggest that wildfire ash can alter Mediterranean prokaryotic communities over time during oligotrophic periods, with broad implications for the Mediterranean Sea biogeochemical cycles.

How to cite: Nault, N., Gazeau, F., Catala, P., Marie, B., Llort, J., Guieu, C., Bressac, M., Pulido-Villena, E., Santín, C., Galand, P. E., and Ortega-Retuerta, E.: From flames to oceans: biomass burning aerosols shape microbial communities in the Mediterranean Sea, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-442, https://doi.org/10.5194/oos2025-442, 2025.

Being the largest high-nutrient-low-chlorophyll (HNLC) region, surface waters in the Southern Ocean (SO) hold a large potential for biological activity, with implications for carbon dioxide drawdown. However, the trace element iron (Fe) is a major constraint for microbially-mediated processes. During the past 40 years, the ice cap on Kerguelen Island (SO) has decreased in surface by 20% and its disappearance is predicted by the end of the century. This glacial erosion could be a significant new source of Fe, but whether Fe contained in matter of glacial origin (MGO) is bioavailable to microorganisms is not well understood. The main objective of the project MARGO (Matter of glacial origin and its fate in the ocean) is to quantify the input of Fe to the waters surrounding Kerguelen Island and to investigate its consequences on ecosystem functioning. We present here results from onboard incubation experiments carried out during a cruise in February 2024 to investigate the bioavailability of matter of glacial origin for marine bacteria and phytoplankton in Fe-limited HNLC waters. Our observations reveal that Fe in the form of glacial colloids (20-200 nm) stimulates phytoplankton and bacterial growth and leads to modifications in the composition of these microbial communities. Fe-related gene annotation analyses showed a higher abundance of siderophore synthesis and transport genes in communities growing in the presence of glacial colloids as compared to unamended controls. These observations suggest that siderophores, produced by bacteria, could be one mechanism rendering Fe of glacial origin bioavailable, and could potentially lead to strong interactions between bacteria and phytoplankton. Our results provide novel insights on the influence of glacial Fe on marine microbes and the consequences on the carbon cycle. They further highlight the importance of processes occurring along the glacier-to-ocean continuum for biogeochemical processes in the SO.

How to cite: Thoppil, R., Obernosterer, I., Catala, P., Crispi, O., Guéneuguès, A., Marie, B., and Blain, S.: Effect of matter of glacial origin on Southern Ocean ecosystems: A Kerguelen Island case study, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-517, https://doi.org/10.5194/oos2025-517, 2025.

The ongoing biodiversity crisis may result in much of the ocean's biodiversity being lost or deeply modified without even being known. Biological observations need to improve radically to serve our understanding of marine ecosystems and biodiversity under multiple climate and anthropogenic-related impacts. In the European ANERIS project (operAtional seNsing lifE technologies for maRIne ecosystemS), we address these observational challenges by developing the next generation technologies for sensing marine-life.

The project proposes the concept of Operational Marine Biology, understood (in analogy with the Operational Oceanography) as a systematic and long-term routine measurements of the ocean and coastal life, and their rapid interpretation and dissemination. ANERIS will improve and integrate different acquisition technologies based on genomics, imaging and participatory systems to cover the wide range of body sizes of the different organisms that lives in the ocean. The achievement of the Operational Marine Biology network is a key goal for the next decade and will enable a base line of biological information related to Essential Biodiversity Variables (EBVs) and Essential Ocean Variables (EOVs). It will also deliver critical data for descriptors for Marine Policies, in particular the Marine Strategy Framework Directive (MSFD).

Overall, the project proposes to benefit all the actors involved in the quintuple helix framework of innovation, promoting innovation and knowledge sharing among them: (1) the academy with new life-sensing technologies to use in research; (2) the industry with new technologies and methods to exploit; (3) the governments, with improved observational systems and data products to be used in  environmental management directives; (4) the civil society, empowered through the proposed participative technologies and large collaborative networks and (5) the involved Marine Research Infrastructures in ANERIS, integrating new generation of sensing instruments and methods, and their staff being trained on those new technologies.

We acknowledge the whole ANERIS consortium for the various contributions to validate the concept of the Operational Marine Biology.

How to cite: Piera, J., Companys, B., Salvador, X., and Luna, A.: ANERIS: Marine Life Sensing Technologies for an Operational Marine Biology Network, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-634, https://doi.org/10.5194/oos2025-634, 2025.

How to cite: Matallana Surget, S., Wattiez, R., Jeffrey, W., Messer, L., Lee, C., and Johnson, F.: Guiding ocean policy with microbial insights: Tackling pollution through innovative science, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-736, https://doi.org/10.5194/oos2025-736, 2025.

Since 2000, the international Argo program has measured in situ Essential Oceanographic Variables (EOVs) across the global oceans using a fleet of robotic profiling floats. The global Argo array has revolutionized oceanography by providing more than 3 million of high quality profiles in near real-time (within 24 hrs) and in delayed-mode to the scientific and operational communities. Argo data is freely available from two Global Data Access Centres. In 2019, the OneArgo program has endorsed new missions including biogeochemical variables (BGC Mission), the deep oceans below 2000m (Deep Argo Mission) and to the polar regions (Polar Argo Mission).

Observations of the polar oceans are critical to understanding earth’s climate, heat, freshwater and carbon budgets and future sea level rise. Argo floats have been deployed in the polar oceans since 2001. Two-way Iridium communications and ice-detection algorithms introduced in the mid 2000’s improved float longevity and return of data collected beneath ice. Survival rates for polar floats are now equivalent to those of core floats. Polar Argo floats are a proven platform for high-quality, cost-effective, broad-scale observations of the seasonally ice-covered oceans, even sampling beneath ice shelves. Despite significant progress, our polar regions are the most under-sampled regions in the global ocean. Remaining challenges include sustained funding pathways for a scaled-up Polar Argo array, filling observational gaps and further improving under-ice positioning capability.

The Polar Argo Mission Team has been established to encourage international coordination in the development of the polar Argo array, share knowledge of scientific and technological advances, develop best-practices, improve setting and post-processing techniques for under-ice profiles, and strengthen interactions with the other Argo Mission Teams, international programs, expert groups, and the operational oceanography community. Here, we will review the status of the Polar Argo array, report on recent advances in science and technology and highlight remaining challenges and knowledge gaps.

How to cite: Kolodziejczyk, N. and Van Wijk, E. and the Polar Argo Mission Team: OneArgo Polar Mission : Status, highlights and challenges, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-758, https://doi.org/10.5194/oos2025-758, 2025.

The Ocean Race, known as one of the world’s most challenging round-the-world sailing competitions, has evolved into a significant platform for ocean science, advocacy, and innovation. Through its Science Program, The Race leverages its global presence to drive environmental awareness and promote ocean conservation, collaborating with scientists, sailing teams, industry, and international organizations. The 2023 edition of The Race equipped all competing boats with advanced scientific instruments to enable extensive data collection, especially across under-sampled regions like the Southern Ocean. Throughout the 32,000-mile course, teams gathered over four million data points, capturing key ocean parameters such as temperature, salinity, dissolved oxygen, and CO₂ levels. The program also utilized the deployment of surface drifters, marine plastic samplers, eDNA collection devices, trace element samplers, and a phytoplankton imaging device, positioning these racing boats as “vessels of opportunity” to collect data in otherwise unreachable areas, thereby filling critical gaps in ocean monitoring. Following the 2023 event, The Ocean Race continued its Science Program by re-deploying its instruments on additional sailing vessels, facilitating data collection across multiple transatlantic races. Data has also been gathered from private expeditions in the Southern Ocean and the Arctic’s Northwest Passage. The Race plans to sustain this initiative through upcoming events, including The Ocean Race Europe in 2025, a transatlantic race from Barcelona to New York in 2026, and its next global edition in 2027.

Collaborating with leading research institutes and programs (including GEOMAR, NOAA, NOC, Ifremer, VLIZ, MPI, CNRS, ICM-CSIC, MeteoFrance, Citizens Of The Sea, OceanOPS, GOOS, EU MINKE, E-SurfMar, GOOD, and SOOP), The Race and its industrial partners co-developed compact, reliable instruments to meet the demanding conditions of racing. By installing redundant devices across the fleet, The Race enhanced data reliability and enabled direct comparisons between boats. The innovative design, which includes water inlets on the keel, allowed teams to collect data autonomously without impacting performance—demonstrating the synergy between sport and science.

 In parallel with its Science Program, The Ocean Race has launched a global learning initiative to educate young audiences about ocean health and sustainability. The educational materials cover essential topics like climate change, plastic pollution, and marine biodiversity, inspiring youth to understand and protect the ocean. This program, aligned with the UN Decade of Ocean Science, aims to foster inclusive, science-based learning and engage future generations in ocean stewardship.

Beyond science and education, The Ocean Race advocates for improved ocean governance through its support of the Universal Declaration of Ocean Rights. This ambitious policy initiative seeks to recognize the ocean’s intrinsic right to thrive and to establish a global framework for its protection. Together, the Race’s science, education, and policy efforts highlight how sport can inspire environmental responsibility across diverse sectors, demonstrating the essential role all industries can play in conserving our natural world.

This presentation will outline The Ocean Race’s contributions to the objectives of the UN Ocean Decade, showcasing the Race’s science program and educational initiatives as models of impactful collaboration, resilient data collection, and actionable ocean stewardship.

How to cite: Raimund, S., Tanhua, T., Garçon, V., Landschützer, P., Kramp, M., Reynaud, T., Pabortsava, K., Fulfer, V., Walsh, J. P., Desprez de Gésincourt, O., Pochon, X., Dolk, S., Bratkič, A., and Hunt, L.: Navigating New Frontiers: Transformative Ocean Science, Data Collection and Action through The Ocean Race, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-781, https://doi.org/10.5194/oos2025-781, 2025.

A long-term research program is built around the Polar POD vessel, a new, crew-operated, state-of-the-art and zero-emission oceanographic and atmospheric platform. The platform is designed to enable on-site studies all year-round in the Southern Ocean. It is a 100-m tall drifting structure inspired by the US-Navy FLIP R/V with adaptation to Southern Ocean conditions. The design is adjusted to make the POD largely insensitive to waves and able to withstand the harsh conditions of the Southern Ocean down to 55°S. Its vertical stability will minimise air and water turbulence and perturbations of the water-air interface. A scientific deck is situated 25m above the average sea level and will be equipped with the best atmospheric and oceanographic instruments and facilities, power will be continuously provided with wind generators and batteries. These outstanding capacities allow scientists to perform myriad science measurements with excellent conditions in the last very poorly known area of the Earth surface.

It is anticipated that the Polar POD will circumnavigate the Southern Ocean for an expected 2-year voyage.

The concept of this innovative outstanding scientific platform and the overall expedition were proposed by Dr Jean-Louis Etienne, a French explorer who has devoted his life to exploration of some of the Earth most harsh environments (Arctic and Antarctic in particular). He has brought together a large group of private sponsors to support the expedition, in addition to what the French Government brought to build the platform and to support the science team that has been formed around the expedition. This includes the Institut français de recherche pour l'exploitation de la mer (IFREMER), the French National Centre for Scientific Research (CNRS) and its National Institute for Sciences of the Universe (INSU), the French National Agency for Research (ANR) and the French Space Agency (CNES).

A comprehensive science program has been designed by a group of about 50 investigators, taking advantage of the Polar POD capability. It includes 4 main research themes. 1- Energy and gas exchange at the air-sea interface and dynamics of the Southern Ocean (air-sea exchange of energy and gases, with emphasis on CO2 and the Southern Ocean role on climate,  impact of ocean acidification, wave dynamics and weather, eddies and turbulence), 2 – Calibration/validation of satellite observations (ocean colour, waves, wind speed, temperature), 3 – Biodiversity and structure of marine ecosystems (acoustic inventory of marine fauna (marine mammals, krill etc.), ocean floor noise, and aerial observation of marine life like whales and seabirds, 4 – Anthropogenic impacts (aerosol amounts and sources, anthropogenic pollution in all its aspects, including heavy metals, persistent organic pollutants, micro-plastics, acoustic for ocean sound with human origin). 

How to cite: Antoine, D., Leblanc, K., Losno, R., Cotté, C., Sutherland, P., and Garçon, V.: The Polar POD expedition: a multi-year research voyage around the Southern Ocean, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-859, https://doi.org/10.5194/oos2025-859, 2025.

Phytoplankton is a central component of marine ecosystems. It contributes to biogeochemical cycles by absorbing carbon through photosynthesis at the ocean surface and transporting it deeper through sinking and subduction—processes central to the so-called biological carbon pump. Plankton also represents the first link in marine food webs, supporting a wide range of marine life, from other plankters to the most productive fisheries on earth.

In many places of the ocean, climate change is expected to result in warmer and more oligotrophic surface waters. This should influence the composition of phytoplankton communities, displacing the dominance towards smaller-sized organisms. This community change would, in turn, affect the services that phytoplankton provides to humans, such as carbon sequestration and the support of fisheries. This is why large-scale monitoring of the abundance and composition of phytoplankton communities is essential for assessing ocean health.

Ocean color sensors on satellites can provide such large-scale monitoring. Current products comprise daily, 4 km-resolution maps of chlorophyll-a concentration (the most widely used estimator of phytoplankton biomass) and its distribution across three phytoplankton size classes (pico-, nano- and micro-phytoplankton). The algorithms to produce these maps rely on the relationships between in situ measurements and reflectances at a few wavelengths, over a few pixels, matching the time and location of the in situ measurement. While incredibly useful, they still yield 30% error for total chlorophyll-a concentration and 40% for community composition. 

Notably, they cannot capture mesoscale oceanic structures, such as fronts and eddies, while they significantly influence phytoplankton production and distribution. The signature of these structures can be observed through infrared and radio wave satellite data and spans tens to hundreds of kilometers. 

In this work, we use deep learning models to (1) naturally combine reflectances with other satellite-derived variables that describe ocean physics (sea surface temperature, sea level anomalies, etc.), (2) use arrays of data covering dozens of kilometers around the in situ observations, that can be summarized through convolutional layers, instead of a single point as input. These two approaches should enable us to capture the effect of mesoscale oceanic structures on the abundance and composition of phytoplankton. The models developed already result in  more accurate and nuanced products that can offer valuable information for policymakers and stakeholders, particularly in fisheries management, where understanding plankton distribution is key to assessing fish stock health and ecosystem resilience in a changing climate.

How to cite: Labourdette, E., Irisson, J. O., Sauzede, R., and Abbas Turki, L.: How can convolutional neural networks help account for the impact of mesoscale ocean structures on phytoplankton distributions ?, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1073, https://doi.org/10.5194/oos2025-1073, 2025.

Whale distribution is a key indicator of ocean health and ecosystem stability, highlighting the need for informed conservation efforts. Yet, current monitoring methods such as visual surveys or autonomous passive acoustic monitoring, lack the spatial and temporal resolution necessary for detailed and continuous surveys at scale.

Distributed Acoustic Sensing (DAS) is a game-changing innovative technology that transforms optical fibers into a dense network of sensors for geophysical and acoustic measurements. By emitting laser pulses propagating along the fiber, DAS detects signals reflected back from various points along the cable, providing high-resolution spatial data, over tens of kms. At the cost of massive amounts of data that require fast, optimized  algorithms, this technology can operate on any optical fiber, including the hundreds of telecom cables already crisscrossing the world’s oceans.

In this presentation, we will illustrate how DAS implemented on seafloor cables along the French Mediterranean coast enables whale detection and localization. This innovative project aims to track the presence, migration patterns, and locations of whales, contributing valuable insights into their behavior and movement patterns. Moreover, with the ability to collect and process data in real-time opens up the possibility of sharing the cetacean locations with relevant stakeholders, including nearby vessels.This information can enable vessel operators to adjust their speed, thereby reducing the risk of collisions and protecting marine mammals from the impacts of human activities.

How to cite: Andres, L., Sladen, A., Dumont, N., Bouffaut, L., Salivas, M., Salvador, S., Lebrun, J., and Galve, A.: The Future of Whale Conservation: Harnessing Distributed Acoustic Sensing for Real-Time Monitoring, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1160, https://doi.org/10.5194/oos2025-1160, 2025.

Observations from space are essential for more accurate description of the processes that dominate polar regions, but existing or planned space-borne sensors do not provide all the necessary geophysical parameters at the required spatial coverage and resolution, revisit time, and accuracy. Processes that need particular attention are: the freshening of the Arctic Ocean (impacted by effects such as melting sea ice, increased continental runoff, and ocean circulation changes); variations in sea surface salinity in the Southern Ocean associated with the changes of Antarctic sea ice extent and thickness and their implications for oceanic circulation and for the ocean’s capability to absorb atmospheric heat and carbon; the progressive reduction in sea ice extent and thickness and its effects on Earth’s climate including environmental, economic and societal impacts; the acceleration of ice sheet mass loss and its effect on sea level rise; the collapse of Antarctic ice shelves, which affect the ocean stratification and bottom water formation.

The CryoRad satellite mission, a European Space Agency Earth Explorer 12 candidate mission, aims to address all these limitations by developing an innovative sensor able to investigate physical properties of the cryosphere and its cold oceans, and to better understand their interconnections.

CryoRad consists of a wideband, low-frequency microwave radiometer that explores a new spectral range from 0.4 to 2 GHz with continuous frequency sampling. This new technology will enable breakthroughs in key climate variable measurements such as :

• the sea surface salinity (SSS) : it will eliminate the high uncertainties in cold waters of current L-band spaceborne radiometers;
• the sea ice thickness by improving current estimations in the range 0.5-1 m

It will also provide measurements of the sea ice salinity, that has never previously been obtained from space, to improve estimates of sea ice freshwater fluxes, and of the ice sheet and shelf temperature profile of Antarctica and Greenland from the top to the bottom, never previously measured from space with sufficient accuracy and available only from sparse borehole sites.

The CryoRad swath will be 120 km, with a spatial resolution on the ground that varies from 47 km at 0.4 GHz to 14 km at 2 GHz. The average revisit time will be around 3 days at latitudes higher than 55° and about 10 days at the equator. CryoRad will open a new era in microwave radiometry and will provide a better understanding of polar processes in a warming climate from the ice sheet interior to the open ocean.

How to cite: Macelloni, G., Boutin, J., Kaleshcke, L., Bertino, L., Brogioni, M., Leduc-Leballeur, M., and Drusch, M.: CryoRad : An innovative Radiometric Mission for the study of the polar oceans and of the cryosphere, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1181, https://doi.org/10.5194/oos2025-1181, 2025.

The French-U.S. SWOT (Surface Water Ocean Topography) satellite with contributions from Canada and the UK, launched in December 2022, has been delivering surface water height data of exceptional quality from all over the globe for more than 18 months now.

Led by the French space agency CNES (Centre National d’Études Spatiales) and NASA (National Aeronautics and Space Administration), the SWOT mission is able to measure and survey water on over 90% of Earth’s surface, providing a high-resolution map of our planet’s water resources for the first time ever. The satellite’s measurements of surface water and ocean heights will help to further in-depth studies of water resource management and revolutionize our understanding of the global water cycle and how it is being affected by climate change.

The satellite’s wide-swath interferometric radar sensor provides a detailed picture of sea surface height at a resolution of two kilometres and of surface water bodies wider than 100 metres with a revisit frequency of 21 days. SWOT data draw on a heritage of 30 years of continuous progress in the field of satellite altimetry and are the culmination of several decades of French-U.S. space cooperation. SWOT is able to detect eddies ten times smaller than anything seen by previous satellite altimetry missions.

This new vision of the oceans and coastal regions should help us to delve deeper into the role of small eddies in shaping climate, as well as their relationship with major ocean currents and zones rich in biodiversity. It brings a new dimension to ocean research, enabling closer interactions between physical oceanography and biological productivity and paving the way for better management of the marine environment (e.g. through the identification and creation of Marine Protected Areas).

How to cite: Faugère, Y. and Vinogradova Shiffer, N.: The “Surface Water Ocean Topography” satellite, a major step forward in understanding the oceans, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1216, https://doi.org/10.5194/oos2025-1216, 2025.

New Caledonia, an archipelago in the Coral Sea in the southwestern tropical Pacific, is internationally recognized for its marine biodiversity including its coral reef systems and lagoons (UNESCO World Heritage Site). Yet, only 10 % of the Coral Sea Marine Park is currently under full protection by restricting human and economic activities. Further conservation efforts have failed inter alia linked to political conflicts of interest and scientific knowledge gaps of the local ecosystem. Continuous efforts for marine reserves in ecologically important and vulnerable places such as New Caledonia are highly needed, which may eventually help maintain ocean resilience in the face of climate change. To close the current knowledge gaps, a clear understanding of the governing physical mechanisms at work and their implications for biogeochemical processes are crucial for transdisciplinary ocean governance and management.

Fine-scale ocean physics around New Caledonia are to a large part dominated by internal tides. Internal tides are freely propagating waves at tidal frequency in the ocean interior. They are ubiquitous in the global ocean and are argued to play an essential role in our understanding of open-ocean mixing and the global oceanic energy budget. They are generated by the interaction of tidal currents with the seafloor topography and feature oscillations of surfaces of constant density as large as 100 m. Therefore, internal tides impact local hydrodynamical and biogeochemical properties and have important implications for marine ecosystems and biodiversity through nutrient inputs while thriving biological productivity - potentially up to high trophic levels and marine fauna.

Internal tides around New Caledonia have very recently been studied and quantified using state-of-the-art numerical modeling giving insight into temporal and spatial variability of their generation, propagation, and dissipation. They are closely linked to the major bathymetric features such as continental slopes, shelf breaks, ridges, and seamounts, which represent potential hot spots of marine biodiversity. Yet, in-situ and remote sensing observations are missing to assess the relevance of our findings based on numerical simulations. Promising insight into internal tides is given by the Surface Water Ocean Topography (SWOT) satellite altimetry mission. Launched in December 2022, SWOT represents a breakthrough in sea surface height (SSH) observations along two swaths of 60-km width at unprecedented spatial scales of up to 10x higher resolution than conventional altimetry. The internal-tide generation hot spot around New Caledonia is located just beneath those two swaths during SWOT’s fast-sampling phase, during which SWOT orbited in a 1-day cycle for a duration of 3 months representing a unique study site to infer high-frequency internal-tide variability from SSH. Available in-situ mooring observations at fixed locations beneath the swaths allow for a dynamical interpretation of SWOT SSH while capturing the temporal evolution of the internal tide’s vertical structure.

Several efforts have been initiated in this area of exceptional biodiversity to characterize internal tides (SWOTALIS, SWOTOBS-NC, ScInObs, etc.). We are encouraged that observing and understanding the local impact of internal tides on the ecosystem will play an essential role in marine conservation efforts around New Caledonia.

How to cite: Bendinger, A., Mangolte, I., Vic, C., and Cravatte, S.: Linking fine-scale ocean physics and marine conservation efforts: The importance of internal tides around New Caledonia, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1221, https://doi.org/10.5194/oos2025-1221, 2025.

Trans-oceanic submarine telecommunication cables have been used since the end of the 19th century to send information rapidly across the ocean. Today their cumulative length has reached 1.5 million km, transporting 99% of all digital data (finance, media, internet, communication) to users across the planet. Thanks to recent technological developments, these submarine cables can now be used simultaneously as scientific observatories, without interfering with telecommunication operations. Their global distribution offers great potential for monitoring the deep ocean environment, which is otherwise difficult and costly to instrument. Owing to the data transfer capacity and power supply provided by the cable, this new type of undersea observatory is able to provide continuous and spatially dense data in near-real time for many years to come. Scientific sensors can be installed all along the cable route, particularly at sites that are difficult to access because of their remoteness or depth.

Two types of instrumentation strategy are applied today: the grouping of scientific sensors (temperature, pressure, seismology, requiring electric power) within observation nodes (called ‘SMART’ nodes for ‘Science Monitoring And Reliable Telecommunications’) and/or the use of the optical fiber itself as a scientific sensor along its entire length (‘Distributed Fiber Optic Sensing’).

We present the example of the Tam-Tam SMART cable, a submarine observatory project which will be deployed in the SW Pacific between Vanuatu and New Caledonia. This cable will cross the New Hebrides subduction zone, one of the most rapid and active plate boundaries in the world and therefore a major source of natural hazards, posing a seismic and tsunami risk to nearby populations. The Tam-Tam project's SMART nodes will be placed on both sides of the subduction front, close to the zones where earthquakes and tsunamis originate. In addition, two optical fibers will be dedicated to science, allowing us to use the 450 km cable as a series of tens of thousands of sensors. The instrumented cable will continuously monitor the activity of the subduction zone, with data being transferred in real time to earthquake and tsunami regional centers in order  to improve early warning systems. In addition to providing a better understanding of how tectonic plate boundaries work, the system has numerous environmental monitoring applications (temperature, ship traffic, storms/ocean wave intensity, marine mammal calls).

How to cite: Sladen, A. and the Tam-Tam SMART cable scientific team: A Dual-Purpose Submarine Cable for Communication and Science: Monitoring Plate Boundaries and Ocean Health with the Tam-Tam SMART System, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1304, https://doi.org/10.5194/oos2025-1304, 2025.

Phytoplankton, microscopic algae floating in water, is the foundation of the marine food chain and plays a crucial role in Earth's carbon system by fixing CO2 and producing oxygen. Phytoplankton productivity is especially high in coastal areas, typically supplied with abundant nutrients near estuaries. However, phytoplankton blooms can have detrimental effects, as some can be toxic and potentially create hypoxic zones. Harmful algal blooms, often called "red tides," can persist from hours to months and are challenging to predict due to their dependence on food chain relationships and environmental conditions. Monitoring these blooms is important for local management, as they affect coastal recreational activities, fishing, aquaculture, and overall human and ecosystem health. 

To address these challenges, various projects were recently supported in Europe, one of them is the LandSeaLot project, aiming to integrate and enhance existing observation efforts in the land-sea interface area [1]. This initiative combines in-situ observations, satellite data, numerical modeling, and citizen science to better understand this complex transitional zone and to create a unified observation strategy for European coastal areas [1, 2]. On the smaller scale, there is a local French Phenomer project, launched in 2013 by Ifremer and partners, that engages citizens in reporting colored seawater events caused by phytoplankton blooms [3]. This citizen science initiative helps scientists detect and study bloom events that might otherwise go unnoticed, particularly in areas not covered by regular monitoring programs [3]. At the same time, in the frame of this project, the scientific community is planning to propose the analysis of harmful coastal bloom situations based on satellite data.

Being part of the mentioned initiatives, we propose to discuss the latest technological advancements that have revolutionized our ability to study phytoplankton populations. In particular, recently we have developed an algorithm to detect various optical types of phytoplankton blooms using high-resolution Sentinel-2 satellite data provided by ESA. This innovation builds upon improvements in optical imagery algorithms, enabling the identification of specific bloom types based on the unique spectral signatures of different plankton species, attributed to their distinct pigment compositions, and is a part of CNES project TOSCA. We also review the advantages and limits of state-of-art atmospheric corrections and cloud and land masks algorithms, as well as retrieval of temperature and optical properties and ocean surface dynamical conditions from high resolution satellite data.

The combination of large-scale projects like LandSeaLot, citizen science initiatives such as Phenomer, and advanced satellite-based detection methods provides a comprehensive approach to monitoring and understanding phytoplankton dynamics. These efforts are crucial for predicting harmful algal blooms and assessing the impacts of climate change on marine environments. This approach to studying the land-sea interface will contribute to more effective coastal management strategies and support the sustainable use of marine resources in the face of increasing environmental pressures.

Citations:

[1] https://landsealot.eu

[2] https://dyneco.ifremer.fr/en/Who-are-we/Hydro-sedimentary-dynamics-DHYSED/DHYSED/Recherche/Projects/LANDSEALOT

[3]  https://www.phenomer.org/

How to cite: Tarasenko, A. and Gernez, P.: Phytoplankton blooms in coastal areas from space and in situ data, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1402, https://doi.org/10.5194/oos2025-1402, 2025.

How to cite: Hinz, H., Illa-López, L., Mendoza, C., Gil, M. M., and de Juan, S.: Advances in Benthic Ecosystem Function Research: Integrating Current Practices and Future Technologies for Enhanced Assessments, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1416, https://doi.org/10.5194/oos2025-1416, 2025.

Until recently, scientists had no idea how loggerhead sea turtles (Caretta caretta) migrate from their nesting beaches in Japan to nursery grounds in Baja California, Mexico. The Thermal Corridor Hypothesis (TCH, Briscoe et al. 2021) combined 16 years of satellite-tracked movement data to propose an intermittent thermal corridor that allows juvenile loggerheads to transition from the Central North Pacific (CNP) to the west coast of North America. The TCH proposes that this migratory corridor opens during anomalously warm conditions and closes during cool conditions, causing turtles to stay in the CNP. Here we report on the deployment of two experimental cohorts, one in 2023, during warm El Niño conditions, and one on 2024, during the onset of cooler La Niña conditions. In 2023, all loggerheads experienced warmer than average SST, due to a marine heatwave and an El Niño. The entire cohort moved north until September 2023, and then they moved south, with 7 of 23 turtles moving towards North America — 3 of which entered coastal waters of Southern California and Baja Mexico. These responses confirmed the TCH that under warm conditions, loggerheads can pass through the thermal corridor. In 2024, the experimental cohort was deployed with a projected onset of La Niña into the fall. Initially, nearly 2/3rds of the turtles headed east. It is possible that strong Ekman transport and/or warm SST anomalies, in response to especially strong westerlies, may have driven these eastward movements, leading to the loggerheads entering the California Current further north than is typical. Late fall movements tended to shift southward again, but the cold California current may prevent reaching the coastline. Distributional shifts due to changing ocean conditions will allow us to dynamically manage and protect this species. If a corridor were to open more frequently or in a changing ocean location, it could alter abundances and risks for these endangered turtles.

How to cite: Crowder, L., Briscoe, D., Balazs, G., Polovina, J., Seminoff, J., Abreu-Grobois, A., Kurita, M., Lee Hing, C., Mori, M., Parker, D., Rice, M., Saito, T., Santos, B., Turner Tomaszewicz, C., and Yamaguchi, N.: Exploration of a dynamic thermal corridor: Experimental oceanography and migration of North Pacific loggerhead sea turtles. , One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1578, https://doi.org/10.5194/oos2025-1578, 2025.

The Ocean Dynamics and Surface Exchange with the Atmosphere (ODYSEA) is a concept for a future satellite now under evaluation by NASA as part of its Earth System Explorer program. ODYSEA is one of the four concepts pre-selected in 2024 with a final selection in 2025 of two missions to be launched in 2030 and 2032. ODYSEA is proposed by our international science team led by Sarah Gille, with a strong technical support from JPL and CNES. If selected, ODYSEA would provide the first-ever global measure of total surface currents velocities. ODYSEA includes simultaneous ocean vector winds with improved resolution for coupled air-sea science and applications closer than ever to the coast. ODYSEA is designed to target speciific science objectives on the understanding of coupled dynamics of ocean currents and winds, the exchange of kinetic energy between the ocean and atmosphere, and the response of currents to winds. Besides the science of the coupled ocean and atmosphere dynamics, ODYSEA data is expected to contribute to a wide range of applications, either directly (indentification of surface transport pathways from plankton to pollution) or indirectly via the assimilation of surface winds and currents into operational forecasting system or numerical twins of different components of the Earth System. 

How to cite: Gille, S. and Ardhuin, F. and the The ODYSEA Science Team: ODYSEA: a future satellite for measuring surface winds and currents and their interactions, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-962, https://doi.org/10.5194/oos2025-962, 2025.

Evidence of climate-change effects on the Southern Ocean (SO) is accumulating. Making up about 10 % of the Ocean surface area, the SO plays a disproportionately important role in the global climate system. It accounts for 75% of uptake of heat excess, 25% of the Ocean’s primary production, and 43% of anthropogenic CO2 uptake. The SO owes two-thirds of its carbon-sequestration capacities to its physical and one-third to its biological pump export of organic carbon. In that context and as part of an international project, over the last twenty years animal-borne satellite data relayed loggers collecting both environmental data and behavioral represent the most significant contribution in documenting changes in the physical properties of the SO in complement to other observational approaches (oceanographic vessels, Argo floats, satellite observations…).

Historically physical parameters: temperature, salinity, light level, wind/sea-state were measured in a first stage, before being completed by the collection of biogeochemical parameters: chlorophyll-a and dissolved oxygen allowing the monitoring of an increasing number of oceanographic parameters critically important to address numerous oceanographic questions. These data are critical in assessing how quickly the SO changing and their ecological consequences on southern elephant seals. Currently, efforts focus on the developments of a new generation of animal-borne sensors dedicated to the assessment of the biological component of the SO, in particular of the poorly known but essential mid-trophic levels, by measuring bioluminescence, echo-sounding and photographing small marine organisms to characterize them. In this talk, we present how this approach contributes to the understanding of how changes in oceanographic conditions could influence the orientation of the SO food webs cascading from phytoplankton to upper marine predators with major expected consequences on the ecological services provided by the SO to humanity.

How to cite: Guinet, C. and the Christophe Guinet: The contribution of animal-borne biologgers in observing the Southern Ocean physical and biological changes while studying their ecology., One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1032, https://doi.org/10.5194/oos2025-1032, 2025.