Monitoring of sargassum in the sea and coasts of Quintana Roo

The objective is to detect and measure the size of sargassum stains, as well as to help prevent their arrival on the Quintana Roo reefs and beaches. The images captured are freely available and come from the Sentinel-2 satellite of the European Space Agency.

Monitoring of sargassum in the sea and coasts of Quintana Roo
Continuous monitoring of the advance of sargassum in the sea and coasts of Quintana Roo. Credit: UNAM

Associated with climate change, ocean acidification, and the number of nutrients that are dumped as pollutants into the seas, the arrival of sargassum to Mexican coasts is a serious environmental, economic, and tourism problem for which solutions are urgently needed, which is why specialists from the Institutes of Geography (IGg), Atmospheric Sciences and Climate Change (ICAyCC) and Marine Sciences and Limnology (ICMyL) of this university work in a multidisciplinary manner to address the complexity of the phenomenon.

At the National Laboratory of Earth Observation (LANOT), located at the IGg, they developed a portal where they follow up on its appearance and progress in the Caribbean Sea and the coasts of Quintana Roo. The first objective is to monitor the spots to avoid their arrival on the reefs and beaches. The study area covers the coast of Quintana Roo and 230 kilometers offshore on average, extending towards Belize, Guatemala, and part of Honduras.

The images generated by the portal are of free access, coming from the Sentinel-2 satellite of the European Space Agency, which are produced with a resolution of 10 to 60 meters, with almost six thousand pixels and an image coverage of 109 x 109 kilometers, which offers an excellent spatial sharpness. The university portal (, available to the public free of charge, uses 18 Sentinel-2 images, obtained every five days, which cover an area of approximately 150,000 square kilometers.

Dynamic modeling of the sargasso is also carried out, in which an ocean current model (called HYCOM) is used to cover the intervals without images, to monitor and predict its arrival to the coasts. Additionally, the number of sargassum rafts landed on the beach is quantified. So far, this analysis tool has a collection of 4,700 images of the study area generated from 2015 to 2022, which facilitates scientific analysis with time series and historical evolution of the phenomenon.

A detection algorithm allows scientists to know the presence or absence of sargassum, data that can be compared with a real and visible image. The portal informs about the size of the stain and offers figures of its dimensions, in addition to locating it in the ocean and on the beach. It is possible to consult the phenomenon in previous years, for comparative or historical works of the accumulated month, in addition to measuring the distances to the coast.

It is a problem associated with climate change and pollution. Sargassum is a fantastic bioremediator that absorbs food, fertilizers, and nutrients. It absorbs everything it picks up, which rots and releases leachates of elements such as arsenic and cadmium, which are very harmful. When it reaches the beach, a good part of the battle is lost, so now they must focus their efforts on capturing it in the sea.

Sargassum is the natural response to ocean acidification, and it is essential to explore from the sciences its potential uses in the construction of bricks, in obtaining various chemicals for industry, and even for the generation of gas to produce electricity.