Thousands of oil spills have been recorded over the years, releasing large volumes of oil into marine ecosystems and causing lasting damage to biodiversity, fisheries, tourism and coastal economies. While major incidents attract attention, smaller fuel leakages and uncontrolled discharges, including diesel and similar pollutants, can be just as harmful when they go unnoticed.
At the same time, although facing fragile growth, rising costs and uncertainty, maritime transport remains central to global trade, making reliable monitoring and early detection more important than ever. As shipping activity continues to shape global commerce, improving the speed and accuracy of marine pollution detection is becoming an increasingly urgent priority.
It also reinforces the importance of frameworks such as the MARPOL Convention, which set the global standard for preventing pollution from ships.
Figure 1.Left: raw satellite image of the Odessa region, Ukraine. Middle: Coastal Intelligence operational interface output. Right: detected oil spill extent (red) on top of the river plume (green) — output for the client.
Why Fuel Spills Still Go Undetected
One of the biggest challenges is to detect not crude oil, but more volatile oil derivatives and fuel spill and leakage detection.
Moreover, not every suspicious patch on the sea surface equals pollution. Remote sensing operators must distinguish real discharges from naturally occurring phenomena that can look very similar in satellite imagery. These include biogenic slicks, low-wind areas, rainfall zones, internal waves and the leeward sides of islands.
That is exactly where advanced analytics becomes essential. SeaCras developed Coastal Intelligence, a tool that detects fuel spills with the combination of synthetic aperture radar and optical sensors, and different spatial resolutions of sensors. Coastal Intelligence utilises a series of additional atmospheric and marine data (often called auxiliary data) on a data fusion principle. This is a new methodology of deep learning that increases precision and detection rate of pollution incidents by reducing false positives in complex coastal environments.
Figure 2.Satellite-derived view of the incident in Hvar coastal region, showing the detected thin diesel leakage pollution intensity over the affected area, with warmer colors indicating higher surface concentrations of oil derivatives and the red outline marking the highlighted area of high pollution intensity area.
How Coastal Intelligence Improves Marine Pollution Monitoring
Coastal Intelligencecombines proprietary satellite imagery processing modules with an innovative data analysis approach to deliver more accurate results. The system achieves the best known commercial spill detection success rate, including for patches measuring only a few hundred square metres. By using different satellite technologies and different sources, SeaCras delivers operational services more frequently.
Our platform uses high- and very-high-resolution optical satellite data, enabling more precise monitoring even in smaller areas such as ports and marinas.
But its value goes beyond identifying oil-derived pollution. Coastal Intelligence also helps users distinguish between manmade pollution events, uncontrolled sewage discharges near port areas, and natural phenomena such as algal blooms. By combining satellite-derived water quality parameters, satellite images, and sea current vector field maps, the project’s partners have strengthened both their detection and identification capabilities.
This makes Coastal Intelligence especially relevant as a complementary solution to the European Maritime Safety Agency’s CleanSeaNet service, which supports participating states with satellite-based oil spill and vessel detection across Europe.
Figure 3.Satellite-derived view of the diesel spill in Baniyas coastal region, Syria. Left: very high spatial resolution analysis of the oil pollution showing the thin areas and small patches of pollution migration. Right: regional view of the catastrophe, showing the higher pollution levels depicted by warmer colors.
A Scalable Solution for Ports and Maritime Authorities
SeaCras has translated this scientific excellence and technical capability into a commercially available operational service. Today, Coastal Intelligence serves port operators and maritime authorities across the globe, which is an immense achievement, considering it was developed initially only for the Adriatic and Ionian regions.
Its added value lies in wide-area coverage, frequent and affordable monitoring as well as alert-based response support.
In practice, that means giving ports, authorities and coastal stakeholders a stronger chance to detect pollution early, respond faster and better protect the seas they depend on.
Other Marine Pollution Hazards and Unexpected Natural Events
Oil and fuel pollution are just a tip of the iceberg of a much broader range of marine and maritime threats. Floating marine litter, plastic pollution are some of the world’s largest problems, while climate change and warming of our oceans increase the occurrences of harmful and abnormal algal blooms.
Check out how Coastal Intelligence tackles those cases as well!
Figure 1. Example outputs of SeaCras’ vessel monitoring analytics in the Badija area. Left: Vessel detection and classification, showing anchored vessels, vessels moored to coastal infrastructure, and vessels in migration, with an inset of vessel-level attributes. Right: Detection of vessels moored along coastal infrastructure, with mooring length, total detected vessels, and estimated capacity occupancy.
Availability of anchoring or boat mooring spots, especially on remote islands
Environmental protection (MARPOL)
Navigation and Collision Avoidance (COLREGs)
While navigation and collision avoidance rules are something that skippers and boat owners generally abide by, the availability of anchoring or boat mooring spots, lack of established marine analytics, and environmental protection in general are sadly neglected.
1) Availability of Anchoring or Boat Mooring Spots, Especially on Remote Islands
Benthic Protection: Rules often prohibit anchoring in areas with sensitive seagrass (like Posidonia oceanica in the Mediterranean). Dropping a heavy anchor and chain can “scour” the seabed, destroying carbon-sequestering habitats.
Designated Mooring Zones: To prevent ecological damage, many coastal countries now require vessels to use “eco-friendly” permanent mooring buoys instead of dropping their own anchors.
The skipper is legally responsible for ensuring the anchor holds. If your anchor “drags” and you hit another boat, you are generally liable for the damages because you failed to maintain a proper anchor watch or failed to use sufficient scope (the ratio of chain length to water depth).
The WWF study on the Mediterranean published data suggesting that 179,000 vessels may have anchored on seagrass in 2024, 45% of them larger than 24 meters. The study which was based only on Automatic Identification System (AIS) data suggested a huge impact on protected environmental areas covered with seagrass Posidonia oceanica.
Figure 2. Maritime operation detection covered by satellite detection in an area located between Kornati National Park and the island of Žirje, in close proximity to a protected area hosting several sensitive species.
Measuring Environmental Impact
On the other hand, company SeaCras as a contractor to environmental agencies in 2023 identified over 150,000 vessels performing illegal anchoring over Posidonia oceanica meadows only on a small part of the Adriatic sea coastline. In 2025, the number increased by approximately 12%. Locations in Šibenik-Knin county, Split Dalmatia County, and Natura 2000 sites in Dubrovnik-Neretva County were subject to the study. Vessel fleet detected showed that the majority of vessel sizes were under 16m, which makes them invisible to AIS.
Figure 3. Vessel detection and size segmentation covered by satellite detection in an area located between Kornati National Park and the island of Žirje, in close proximity to a protected area hosting several sensitive species.
The scaling factor suggests that there are over 400 000 annual illegal vessel activities of anchoring over protected areas or using pristine nature instead of dedicated and specialised infrastructure only in Croatia’s coastline. The danger to benthic species and habitats is real and mechanical destruction by anchors is alarming. SeaCras’ calculation on the Mediterranean surpasses 1 million illegal anchoring of vessels of all sizes, annually. That’s right, 1 million.
Moreover, this means that governmental agencies are completely blind to more than 90% of maritime traffic, with nautical tourism forming a significant part of it.
This raises additional questions, such as: to what extent marine pollution occurs, based on MARPOL pollution definitions.
2) Environmental Protection (MARPOL)
International Convention for the Prevention of Pollution from Ships(MARPOL) is an international treaty adopted by the International Maritime Organisation to prevent and minimise pollution of the marine environment from ships due to operational or accidental causes.
Figure 4. MARPOL treaty with its six annexes. Source: International Maritime Organisation.
Oil Pollution (Annex I): Discharge of oil or oily mixtures into the sea is strictly prohibited. Even small bilge leaks can lead to heavy fines.
Garbage (Annex V): It is illegal to discharge any plastics into the sea. Food waste can only be discharged under specific conditions (usually more than 12 nautical miles from land).
Sewage (Annex IV): In many territorial waters (and specifically in “No Discharge Zones”), holding tanks must be used and emptied only at designated pump-out stations or beyond the 12-mile limit. Blackwater tanks are big problems for pollution hazards with intestinal enterococci and E. Coli diseases when released in smaller and shallower bays in vicinity of swimmers.
Another, less pronounced negative effect is invasive species expansion.
Figure 5. Direction of sea vessels and maritime safety covered by satellite detection in an area located between Kornati NP and the island of Žirje, in close proximity to a protected area hosting several sensitive species.
Under the international Rules of the Road, an anchored vessel has specific obligations because it is considered “restricted in its ability to maneuver” compared to a vessel under way:
Obstruction of Fairways: It is strictly prohibited to anchor in narrow channels or fairways where you might obstruct the passage of other vessels.
Day Shapes and Lights: You must display a black ball (day shape) or a single all-around white light at night to signal to other mariners that you are not moving.
Aground vs. Anchored: There are distinct rules for a boat that is intentionally anchored versus one that has run aground; the latter requires additional signaling (two red lights at night).
But can nautical tourism actually be sustainable? And how can data help us achieve that?
So What Can We Do to Continue Enjoying Nautical Tourism, but Minimise Our Adverse Effects?
Maritime operations — including nautical tourism, leisure activities, passenger vessels, and fishing boats — generate significant greenhouse gas emissions. Advanced marine analytics allow precise measurement of these emissions by region, specific locations, and across seasonal, annual, and multi-year periods.
These tools also enable accurate evaluation of newly regulated pollutants, such as underwater noise, which impacts fish and marine mammals such as dolphins and whales in different ways. Changes in animal behaviour caused by noise can threaten fragile marine ecosystems.
These effects are particularly evident in narrow channels and bays along the Adriatic coastline, as well as in the pristine crystalline seas of Greece, Indonesia, Thailand, and other sensitive marine environments.
Predictive analytics can forecast areas of dense maritime traffic, helping reduce the risk of collisions and ensuring safer journeys. This also improves nautical tourism passenger satisfaction, reduces costs for early responders and coast guards, and contributes to more effective management of maritime destinations.
Now is the time to turn insight into action — embrace marine analytics to safeguard our oceans, elevate maritime safety, and shape a smarter, cleaner future at sea.
Island trash in Bosnian Drina accumulates once again. Almost each winter, the Drina River develops a dramatic, floating accumulation of plastic and mixed municipal waste that gets trapped near hydropower infrastructure, most notably by barriers in the Višegrad area in eastern Bosnia and Herzegovina.
The Drina River is located in the Balkan region of Southeast Europe. It flows along much of the border between Bosnia and Herzegovina and Serbia before continuing northward to join the Danube River, into which it ultimately flows.
This is not a one-off incident. The phenomenon has been recurring for years, with documented major accumulations in 2020, 2023, 2024, and again during subsequent winter high-flow seasons.
Why does this keep happening?
The core drivers are consistent across reporting and field accounts:
Upstream mismanaged waste: illegal dumps and poorly regulated landfills sit close to riverbanks and tributaries across the wider Drina basin in the Balkan region (including parts of Bosnia and Herzegovina, Serbia, and Montenegro).
Seasonal hydrology: During heavy rain/snowmelt, waste is mobilized into the river network. So winter storms, swollen rivers, and melt events make “collection pulses” more likely.
Hydropower “capture effect”: The reservoir backwater zone creates a hydraulic bottleneck, allowing buoyant materials to accumulate and form dense surface mats.
But not all waste originates on the Drina itself. One particularly important contributor is the Lim River, a major tributary that transports significant debris loads into the Drina system.The basin is hydrologically connected, so upstream failures propagate downstream.
The result: a moving pollution stream becomes a stationary floating landfill.
What satellite imagery reveals and why do we NEED it?
Using multi- and hyperspectral satellite data, floating waste becomes detectable due to:
High reflectance in multiple bands
Surface texture anomalies compared to open water
Persistent spatial clustering at hydraulic convergence zones
Calculation of volume of plastic
Calculation of changes over time
Time-series analysis can show rapid growth following high-discharge events, quasi-stationary persistence once trapped at a barrier, and gradual reduction after mechanical removal or flushing.
This shows how using satellite imagery can help predict, plan, and react in order to prevent this accumulation.
This allows objective monitoring of:
Surface extent (area estimation)
Volume and the mass estimate of garbage island
Duration of accumulation
Growth rates following storm events
Cleanup effectiveness over time
But why does the accumulation present an issue?
The consequences extend far beyond visual pollution. Large-scale debris accumulation affects aquatic ecosystems by altering surface light penetration and oxygen exchange, potentially disrupting habitats and food webs.
It raises concerns about drinking water safety downstream, particularly where untreated or partially treated waste enters the river system. The economic implications are equally significant, impacting tourism, regional reputation, and even hydropower operations when debris interferes with infrastructure.
There are also broader public health considerations linked to contaminated water and unmanaged waste. More importantly, this recurring crisis underscores the need for basin-level governance rather than reactive, site-specific cleanup efforts.
Can we change the future for the better?
Satellite monitoring and other types of remote sensing technology do not and never will replace local action, but it provides transparent and repeatable evidence that shifts the discussion from anecdotal reporting to measurable impact assessment. As rivers often run from several countries, monitoring of the cross-border influences, both upstream and downstream, becomes crucial for preparedness and informing neighboring countries. If debris accumulation can be seen from orbit, it can be quantified—and if it can be quantified, it can be managed.
Furthermore, the collected results need to be the input for development of Transnational Joint Strategies and protocols that have immediate impact at reducing plastic pollution and safeguarding aquatic ecosystems through collaborative, cross-border action.
But these systems are needed for seas and oceans as well. One of projects is PREVENT project which has ambitious but obtainable goals which align with EU and global trends:
Joint Marine Litter Prevention and Management Strategy (JMLPMS)
Climate Resilient Adriatic-Ionian Action Plan (CRAIAP)
To further stress the importance of this subject, the EU Mission: Restore Ocean and Waters and Global Plastic Action Partnerships are making a huge effort in the area as well.
The sustainable development goals (SDGs) are the world’s most widely recognized framework for turning big sustainability ambitions into concrete, measurable action. Adopted as part of the UN’s 2030 Agenda, the SDGs connect environmental protection, resilient communities, and long-term economic stability — because progress in one area increasingly depends on progress in the others.
The UN Ocean Decade provides a convening framework for scientists and stakeholders from diverse sectors to develop the scientific knowledge and the partnerships needed to accelerate and harness advances in ocean science to achieve a better understanding of the ocean system, and deliver science-based solutions to achieve the 2030 Agenda. The UN General Assembly mandated UNESCO’s Intergovernmental Oceanographic Commission (IOC) to coordinate the preparations and implementation of the Decade.
At SeaCras, we, and as a result, our dear clients, align our work with SDG 6, SDG 11, SDG 13, and SDG 14 by using satellite-driven insights and data analysis to detect marine pollution, support early warning, and strengthen decision-making for cleaner water and healthier seas — especially across the Adriatic Sea and other vulnerable coastal regions.
How SeaCras maps to SDG 6, 11, 13, and 14
SDG 6 — Clean Water and Sanitation
We are aligned with the SDG 6 by using satellite AI to detect pollutants and monitor ecosystem health, and that also means our clients, thanks to using our technology and data, are aligned with the SDGs as well. SeaCras, regarding this Goal also provides authorities with scalable, high-resolution water quality data, enabling proactive protection of marine and freshwater resources globally.
SeaCras supports SDG 11 by enhancing coastal urban resilience. We provide satellite-based risk monitoring for “Target 11.5” to protect coastal settlements from pollution and climate-driven ecological disasters. A recent example is the devastating cyclone that caused severe damage in Sumatra, Indonesia. By partnering with us, stakeholders also strengthen their SDG 11 commitments by gaining credible, data-backed reporting and decision support that helps prioritise interventions, demonstrate impact to regulators and communities, and unlock sustainability-led opportunities.
SDG 11 focuses on making human settlements inclusive, safe, resilient, and sustainable. For coastal cities, marine pollution isn’t only an environmental issue — it affects public health, tourism, fisheries, and local infrastructure. SeaCras aligns with SDG 11 by translating complex marine conditions into actionable intelligence that helps municipalities such as Zavratnica and Jablanac area, ports such as Zadar Cruise Port, the Adriatic in its entirety, and regional actors make smarter, faster decisions — especially when risks escalate.
SDG 13 — Climate Action
SeaCras drives SDG 13 by monitoring ocean health indicators like algal blooms and water quality. Our satellite data provides vital climate intelligence to help coastal regions adapt to and mitigate the impacts of a warming planet. For our partners, this means earlier warnings, clearer climate-risk baselines, and stronger reporting — turning ocean insights into faster, better-funded resilience actions.
UN’s SDG 13 calls for urgent action on climate change and its impacts, including building resilience to climate-related hazards. SeaCras’ early-warning-oriented monitoring helps strengthen preparedness and response capacity where climate-driven extremes can worsen runoff and pollution events — supporting a more proactive, data-led approach to coastal risk management.
GOAL 14: Life Below Water
SDG 14 is specifically about conserving and sustainably using oceans, seas, and marine resources — with marine pollution named as a key threat. Our customers immediately get compliance here by detecting pollution signals, improving visibility over affected areas, and helping accelerate targeted action to protect marine ecosystems and the economies that depend on them. For partners, this delivers rapid, evidence-based insights they can act on, and report on with confidence.
SeaCras supports SDG 11, 13 and 14 by monitoring marine ecosystems, reducing pollution, aiding sustainable resource management, and providing data to research institutions for informed conservation and policy decisions.
Global Language for Sustainability
The sustainable development goals provide a shared global language for sustainability — making it easier to set priorities, measure progress, and collaborate across sectors. SeaCras’ focus on SDG 6, 11, 13, and 14 reflects a practical, outcomes-driven approach: protect water quality, strengthen coastal community resilience, improve climate readiness, and safeguard marine ecosystems through better visibility and faster, evidence-based response.
In short, when you can detect problems earlier and act with clarity, sustainability stops being aspirational — and becomes operational.
Scientific Reports, Springer Nature, one of the leading scientific journals in the world, ranks as the third most-cited journal in the world (surpassing almost all niche journals). In 2024 alone, it recorded over 834,000 citations. Scientific Reportsreceives widespread attention in policy documents and the media, making it the perfect match for dissemination of results to oceanography specialists, data science and AI community as well as policy- and decision makers.
The research, conducted by the the Center for Marine Research Rovinj of the Ruđer Bošković Institute (IRB), utilised high-frequency sensors at oceanographic buoys, flow cytometry, complemented by SeaCras’ Coastal Intelligence digital system of satellite remote sensing of detection and classification, and the Algebra Bernays University for data science protocols and models validation, to characterise physical, chemical, and biological conditions during mucilage events in the Northern Adriatic in 2024.
The study revealed that this phenomenon is a complex biological response driven by specific environmental stressors and dominated by specialised phytoplankton traits, as well as large-scale drifting fronts classification and fine-scale water constituents concentration variations on scales even at 50 m in length.
Figure 1. Satellite image of the Northern Adriatic showing mucilage aggregates in September 2024. The satellite image is based on Copernicus Sentinel-2 Level-1 data acquired in 2024 and provided by the European Space Agency (ESA). Medium resolution Sentinel-2 processed images visualised with in-house Coastal Intelligence software (SeaCras, Croatia) showing concentration of chlorophyll-a shows areas with high phytoplankton.
Who Took Part in the Study
Center for Marine Research, Ruđer Bošković Institute (Rovinj, Croatia)
SeaCras Ltd. (Zagreb, Croatia)
Algebra Bernays University
These partners, in a form of an innovative public-private endeavor, addressed the challenge of demystifying the enormous mucilage event that happened in summer of 2024 off the west coast of Istria — a shock for the local community and the numerous tourists and visitors of the destination. The scientists joined forces and resources, knowledge and technology to understand WHAT happened, WHY and WHERE it can have the most impact. Sadly, it’s mostly negative.
How the Research Was Conducted
The Center for Marine Research at the Ruđer Bošković Institute utilised a series of in-situ oceanographic, and meteorological measurements from their ODAS I and II buoys, alongside high-frequency flow cytometric observations. These data were systematically collected and processed depending on the method, from an hourly frequency to daily, with monthly averages, throughout 2024.
SeaCras complemented this single-point data using its Coastal Intelligence system, a digital platform for the detection and classification of sea surface and water column properties via satellite remote sensing. Several optical satellite payloads were deployed to characterise the physical, chemical, and biological conditions during the 2024 Northern Adriatic algal bloom events.
In addition to calculating mean concentrations over a larger area using ESA’s Sentinel-2 constellation data, Coastal Intelligence system processing was centered on the CIM ODAS I & II buoys. A grid of virtual sampling stations (or satellite-derived microlocation data points) was established to calculate the concentrations of water column constituents and sea surface properties on a finer spatial scale.
The fine-spatial processing by enabling virtual stations was conducted by using Planet Labs optical data. This approach enabled SeaCras and the Center for Marine Research to mitigate the effects of potential false-positive results and to better characterise the spatial heterogeneity of drifting mucilage aggregates.
Figure 2. View of the “mare sporco” phenomenon on the western coast of Istria in June 2024 (photo by Mihael Stojanović)
What We Previously Knew
The Northern Adriatic Sea is a shallow and the northernmost part of the Mediterranean. It is under the direct influence of one of the largest freshwater inputs into the Mediterranean — the river Po.
Meteorological and hydrological characteristics result in relatively long retention times of water masses in the Northern Adriatic.
The combination of the aforementioned renders the area one of the most productive areas in the Mediterranean with strong west to east gradient. The area is well known for high nutrient concentrations and phosphate limitation throughout the year.
This phenomenon called mare sporco (Italian for dirty sea) first attracted scientific attention in 1872 in the Gulf of Trieste.
So what are potential causes for this naturally occurring phenomenon to become abnormal? Are man-made influences to blame for triggering it or is it a climate-boosted occurrence?
What We Discovered About Algal Bloom
1. Environmental Drivers and Scale
Climate Triggers: The formation of the algal bloom was directly linked to rising sea temperatures and significant salinity drops caused by freshwater discharge from the Po River.
Massive Proportions: Coastal Intelligencesystem by SeaCras revealed that at its peak (June 2024), “macro-scale” mucilage fronts extended over 20 kilometers. While medium-spatial resolution imagery allowed for the evaluation of large-scale mucilage aggregates and the prediction of their migration, it could NOT estimate, within established confidence limits, the observed single-point, hourly variations of water constituents, provided by immersed real-time monitoring sensors on ODAS buoys.
High-spatial and temporal variation analysis using high-resolution optical payloads revealed extreme spatial heterogeneity on a small scale across the sea surface, with distinct patches detectable at scales smaller than 20 meters. Notably, these algal bloom patches have an optical footprint significantly distinct from the hydrocarbon slicks known to appear in the Northern Adriatic due to anthropogenic fossil fuel activities.
Ourvirtual estimation protocol, based on data comparisons with single-point, in-situ measurements of water constituents from sensors on ODAS buoys has, for the first time, demystified the alternating variations in optical properties recorded at these stations. The 20-meter variation in the concentrations of water constituents (e.g., chlorophyll-a (Chl-a) or total organic carbon (TOC)) worked in favour of the Center for Marine Research’s hypothesis: within the aggregates themselves, there is a complex distribution of ‘living’ and ‘dead’ phytoplankton within the carbohydrate (hydrocarbon) matrix.
Figure 3. The CIM ODAS II buoy with water constituents sensors
2. Phytoplankton Dynamics and “Unique Traits”
Taxonomic Shifts: The study identified a progression of specific microphytoplankton taxa — Cerataulina pelagica, Cylindrotheca closterium, Thalassionema spp., and Gonyaulax fragilis — which dominated different phases of the event.
Morphological Changes: Unlike healthy autumn blooms characterised by high diversity and chain-forming colonies, mucilage-associated blooms were defined by low diversity and a shift toward single, thicker, and more complex cells.
Biomass Increases: Microphytoplankton biomass and abundance surged as mucilage advanced toward the eastern Adriatic coast, suggesting a self-reinforcing biological cycle.
3. Physiological and Chemical Anomalies
Oxygen Depletion: A remarkable drop in surface water oxygen was recorded at the onset of the event. This raises critical questions about the role of microbial respiration and the potential for localised hypoxia.
Organic Release: The accumulation of mucilage, essentially a polymer of exuded sugars, was likely fueled by both the active secretion of organic matter from blooming species and the degradation of dead cells.
The Role of Cyanobacteria: While microphytoplankton (diatoms and dinoflagellates) were the primary drivers of the aggregate phases, cyanobacteria remained a constant but non-varying background presence, indicating they were not the catalyst for the event.
Figure 4.Mucilage aggregates in the Adriatic during the 2024 extreme algal bloom
Digital Twin as Key Technology Advancement in Detecting Algal Bloom
The integration of different types of sensors, in situ sampling, and satellite imaging revealed subtle phenomena at the study locations, as well as specific patterns across the entire Northern Adriatic. By combining these data sources within a Digital Twin of the sea, researchers were able to simulate conditions in near real time, test different scenarios, and better understand complex marine dynamics. This approach significantly improves the ability to predict changes, support decision-making, and respond more effectively to environmental risks.
Figure 5. High spatial resolution PlanetScope optical imagery over coastline of the city of Poreč. The data were processed and visualised using the in-house Coastal Intelligence software developed by SeaCras, Croatia. Image on the left shows migrating mucilage aggregates.
Who else can benefit from these findings?
Our insights highlight the key role of microphytoplankton and single cells in mucilage dynamics and the influence of environmental factors like temperature, wind and freshwater inputs on phytoplankton structure and biomass in coastal ecosystems.
Advancing the knowledge and capacities of the scientific community and sharing expertise with industry partners.
Tourism industry — early warning and short term forecasting of the such radical event for dissemination and public engagement
Fishermen in activity planning and choosing of appropriate tools. For example nets are almost impossible to use when an algal bloom event is in its intense phase.
Governing bodies and environmental agencies in estimating impact on environment and the influence on the fish stock for that and upcoming years.
The Next ‘Big Thing’ for The Partners
The partnership between the Center for Marine Research in Rovinj, part of the Ruđer Bošković Institute (IRB), and SeaCras is continuing in several directions where the capacities of both sides can be increased in greater synergy;. e.g. through the development of various early-warning systems based on the concept of a digital twin of the sea, seabed mapping, and public health applications for detecting different pollutants that harm coastal areas and the sea as a whole, such as microplastics, fecal contamination, and more.
In this way, Croatia is demonstrating strong internal capacities in this area. Moreover, it is pushing boundaries and setting standards of good practice for public–private partnerships.
About the Team
SeaCras is a Croatian company specialised in monitoring the sea through digital technologies, using satellites and artificial intelligence. SeaCras’ Coastal Intelligence software covers detection and analysis of a range of marine biochemical indicators, marine emissions, such as MARPOL pollutants, as well as underwater noise and GSG.
The company has been internationally recognised as one of the top five maritime technologies in the world by the World Economic Forum in 2024, and in 2025 was ranked among the top 10 most prominent European space startups by VC investors, according to Sifted.
Also in 2025, SeaCras was included in the Batch 6 of the Cassini Business Accelerator for the European Union’s space sector. Cassini Business Accelerator is an elite program by the European Space Agency and EUSPA, under governance by the Directorate-General for Defence and Space (DG DEFIS) of the European Commission.
Figure 6.From sea to screen: Ruder Bošković Institute researchers in the field work (left) and the SeaCras team analysing satellite data from the ‘virtual station’ (right).
The Center for Marine Research in Rovinj, part of the Ruđer Bošković Institute (IRB), leads a team of scientists that participates at a global level in the most important projects, such as the Euro-Argo, part of a global mission, and consistently brings excellence to the research and development of operational oceanography in the Adriatic.
The achievement regarding the abnormal algal bloom is the result of a strong joint effort by colleagues across all participating institutions, who combined their expertise, data, and methodologies to design, implement, and deliver this study at the highest scientific and professional standards. Through close collaboration and continuous knowledge exchange, the team ensured that the research reflects both scientific excellence and real-world applicability.
Source/References
Vlašiček, I., Pfannkuchen, D.M., Tanković, M.S., Špadina, M., Kopal R. Pfannkuchen, M. et al. High-frequency observations during Adriatic mucilage event reveal unique phytoplankton traits and diversity response. Sci Rep, Springer Nature (2025). https://doi.org/10.1038/s41598-025-31369-4
In late November 2025, a cataclysmic hydrometeorological disaster struck the Indonesian island of Sumatra. Torrential rainfall, associated with Tropical Cyclone Senyar, occurring during the peak of the monsoon season, triggered catastrophic flash floods and landslides across the provinces of Aceh, North Sumatra, and West Sumatra. As water levels rose rapidly, entire communities were hit by sudden flooding and collapsing terrain, marking one of the most destructive weather events Indonesia has experienced in years.
At least 977 people have lost their lives, with hundreds still unaccounted for, according to initial compiled reports from publicly available disaster tracking sources, such as National Disaster Management Authority (BNPB), as of December 10th.
More than 1.2 million residents were evacuated, and millions of people have been directly impacted by widespread flooding and landslides.
Although the immediate threat and rains have passed, thousands are injured, and entire villages face the devastation of infrastructure, homes, crops, and livelihoods. Countless residents have been left without homes or family support, and many are injured, sick, and running out of food and water.
A Message from SeaCras
On behalf of SeaCras, we extend our deepest condolences to all those affected by this tragedy — to the families mourning their loved ones and to entire communities now facing the daunting task of rebuilding.
We recognize the scale of suffering and disruption that these floods and landslides have caused. To support recovery efforts, we are offering our before-and-after satellite imagery geospatial analysis that includes both landcover changes and sediment dispersion in the nearby sea. We are giving this to any organization, authority, or humanitarian partner engaged in response work. Our data is available to help:
Map the most damaged areas
Prioritize relief routes and resource allocation
Assess infrastructure loss and plan reconstruction
Document environmental changes for future resilience planning
If you are coordinating relief, planning reconstruction, or directing aid — please reach out, and we will work with you to put this data to use where it’s needed most.
Now let’s look at what unfolded, and how it is visible through the satellite images:
Figure 1. captures the Aceh region before the flood (left image), an unprocessed RGB satellite view from 28 May 2025, showing a coastline and marine environment in a relatively stable state. As it can be seen, land vegetation is moderately dense, with river fluvial discharges being a moderate influence to the surrounding Andaman sea.
The contrast becomes striking in the post-event imagery. Figure 1, right image, taken on 29 November 2025 — just a few days after the disaster — shows the same region after the flood, where visible changes along the coastline point to the scale of the disturbance. Landslides have completely demolished the landscape, changed the coastal line, and caused enormous sediment dispersion into the marine environment.
But how does this flood-induced landslide impact the Andaman sea?
The answer can be found in SeaCras calculation of water quality parameters of the Andaman sea. SeaCras used its Coastal Intelligence software package to calculate values of dispersed sediments in the sea surrounding the island before and after the flood. The results are presented in Figure 2.
In Figure 2, on the left, we can see the calculated concentration of dispersed sediments in the surrounding sea, reflecting normal conditions driven by routine fluvial discharges typical of the dry season in Southeast Asia.
In the right image, we can see abnormally high concentrations of dispersed sediments throughout the water column of the adjacent sea. These elevated values are a direct consequence of the abrupt flooding, vividly demonstrating how extreme events can rapidly transform both land and marine systems.
In Figure 3, we compared values of dispersed sediments for three (3) distinct locations before and after the floods. The results show striking sediment dispersion over a thousand of square kilometers of the surrounding sea, with values skyrocketing to 50 times higher than normal, even as far as 10 km from the coastline. This points to a large-scale change of biodiversity and habitat not only on land, but in the sea as well.
What Happened… and Why?
Days of extremely heavy rainfall, far stronger than what is typical even during the monsoon, soaked the ground and caused rivers to overflow across Sumatra. At the same time, a rare cyclone formed unusually close to the equator, adding even more rain and overwhelming both natural waterways and man-made drainage systems.
As water rushed downhill, it tore through towns, swept away entire villages, and buried communities under mud. Roads collapsed or disappeared underwater, leaving many areas completely cut off. Survivors in isolated regions went days without clean water, food, or medical help as the risk of disease and hunger quickly increased.
Underlying Factors
Experts note that, while the immediate cause was extreme weather, the severity of the disaster was amplified by ecological vulnerability — including deforestation, soil degradation, and loss of natural water retention in upstream areas that normally moderate flood impacts.
Was This Connected to Climate Change?
Climate scientists warn that climate change is making extreme rainfall events far more intense and frequent, and Tropical Cyclone Senyar is a clear example of this trend. Senyar formed in the Strait of Malacca, a region so close to the equator that cyclones almost never develop there, making the storm highly unusual.
Warmer oceans and a warmer atmosphere — both driven by human-caused climate change — allowed the storm to hold far more moisture, leading to record-breaking rainfall and severe flooding across Indonesia, Malaysia, and Thailand.
Early attribution studies suggest that these elevated temperatures likely intensified Senyar’s rainfall and destructive power. Even if climate change doesn’t always increase the number of storms, warmer oceans and air hold more moisture meaning storms produce heavier rain and more flooding than they used to — a pattern seen in Senyar and the associated monsoon extremes.
What is to be expected?
Recovery will be a long and complex process. The Indonesian government estimates that over $3 billion USD will be needed for reconstruction and relief across the hardest-hit regions.
Critical needs include:
Clean water, food, and medical support for displaced families
Restoring access to isolated communities
Rebuilding homes, bridges, schools, and critical infrastructure
Ongoing disease prevention and health care services
How Climate Change Hits Vulnerable Communities First
Climate change does not affect all people in the same way. Low-income and marginalized communities are hit the hardest, because they often have fewer resources, weaker infrastructure, and a larger dependence on natural resources like local land and water for daily survival. Many also live in high-risk areas, simply because safer land is unaffordable or unavailable.
So when disasters strike, they lack the means to prepare, recover or adapt. This deepens existing inequalities, pushing people even more into poverty as livelihoods, homes, water supplies, and food systems are destroyed.
International research shows that low-income populations are disproportionately exposed to climate hazards and less able to cope with loss or rebuild, whereas wealthier countries and communities can invest in more resilient infrastructure, early warning systems, and recovery.
But children bear the heaviest toll, as their bodies are still developing, making them more vulnerable to illness, malnutrition, and injury when disasters strike. Floods and storms often cut off clean water, healthcare, and schooling. Since they depend on adults for safety and support, any disruption leaves them exposed to greater risk, and the impacts can follow them throughout their lives.
This catastrophe is not only a story of devastating weather, but a warning of what a warming world can bring. Recovery must be matched with action — to protect people, strengthen ecosystems, and prevent future extremes from becoming even more deadly.
