World Water Day with MARE and ARNET: preservation is essential

Antarctica and the future of fresh water 
Afonso Ferreira and Sofia Nunes, researchers at MARE, are dedicated to studying the marine ecosystems of Antarctica, a region that holds around 70% of the planet's freshwater reserves. For them, glaciers are much more than ice: they are the key to the balance of the climate and the water cycle, but “the melting of glaciers is not only decreasing this percentage, but also contributing to the rise in the average sea level and the disruption of the global water cycle”, they say.

These researchers are studying one of the most important biological components for water quality, phytoplankton, small microscopic organisms that are the basis of the Antarctic marine ecosystem. According to Afonso and Sofia, “phytoplankton are essential for water quality because they remove carbon dioxide and produce oxygen, guaranteeing a vital balance for life in the ocean”.

They are involved in projects that study the impacts of climate change in Antarctica, such as PHYTO-SHIFT, which aims to investigate changes in phytoplankton communities and their consequences for the Antarctic ecosystem, and IMPACTANT, which studies the impacts throughout the Antarctic trophic web, from phytoplankton to birds and whales.

For Afonso and Sofia “the main way we can protect the balance of the ecosystem and water quality in Antarctica is by mitigating and reducing our carbon emissions and day-to-day impacts” and they stress that any changes that occur in the balance of the Antarctic ecosystem will end up affecting the entire planet, including Portugal.

The invisible threat of contaminants
Bernardo Duarte, a researcher at MARE's BIOTOX Lab, warns of an invisible threat affecting aquatic ecosystems, from estuaries and coastal areas near large urban and industrial centers to remote locations like Antarctica: contamination by pollutants.

According to the researcher, “there is a wide variety of contaminants that are found in practically all the ecosystems we have been analyzing,” highlighting heavy metals, biocides, organochlorine compounds, pharmaceutical compounds, and PFAS, also known as eternal contaminants resistant to degradation. Bernardo points out that “these pollutants, although often present in low concentrations, can have impacts on aquatic life far beyond those predicted”.

Bernardo Duarte's team not only directly measures the presence of these contaminants in the water, but also in the sediments and organisms that inhabit the ecosystems it studies: “in terms of ecological impacts, it is important to assess ecosystems as a whole, including changes in the dynamics of species and populations, the behavior of individuals and their physiology,” he says.

The Biotox Lab is involved in several projects such as ONE-BLUE, which assesses the water quality of European seas, and uRESTART, which aims to mitigate the effects of pollution by restoring salt marsh ecosystems to improve water quality. “Salt marshes are recognized as nature's kidneys, retaining various contaminants in their sediments and removing them from estuaries,” he says.

Bernardo believes that “monitoring and regulation, combined with public information and awareness, are the best tools we have to achieve better water quality”.

Monitoring to protect 
João Paulo Medeiros, a researcher at MARE, is dedicated to the study of transitional bodies of water, such as estuaries and coastlines, and believes that the water quality of the systems he has analyzed is good. According to the researcher, “the quality of a body of water results from the overall assessment of a set of physical-chemical, hydromorphological and biological elements”.

In his work, he uses various sampling techniques, such as dredges to collect sediments where certain organisms susceptible to pollution live, or trawling to catch fish of conservation and economic importance. He also uses a multiparameter probe to assess environmental variables and thus immediately understand the quality of the body of water he is working on.

João Paulo is involved in the monitoring program for the effluent disposed of by the Data Center in Sines, in order to understand its potential impacts on aquatic communities and water quality. He also collaborates in the monitoring program for the 3rd cycle of assessment of national water bodies under the Water Framework Directive, which takes place every 6 years and aims to preserve the good ecological status of these bodies.
In his opinion, the existence of continuous monitoring programs and greater supervision of economic/industrial activities would be the most effective measures to guarantee better water quality.

Restoring and protecting riverine ecosystems
Giorgio Pace, a researcher at the CBMA, studies water quality in river and riparian ecosystems, with a special focus on the northern region of Portugal. For him, the situation is worrying: “Only 37% of surface water bodies in Europe have reached ‘good’ or ‘high’ ecological status, according to the criteria of the European Union's Water Framework Directive, and only 29% have reached a chemical status considered ‘good’ in recent years. In Portugal, we are following this trend, but there are still places that deserve urgent attention, especially in remote areas like Trás-os-Montes.”

His work combines traditional monitoring methods, in line with European Union guidelines, and innovative approaches, such as the use of hyperspectral satellite images: “These images are different from normal ones. Each element of the landscape - such as water, vegetation or soil - has a kind of 'fingerprint' that satellites can detect with great precision. In this way, the researcher can quickly identify different types of environmental problems. 

He is currently part of the RIPARIANET project, funded by the Biodiversa+ European Partnership, where he is investigating the impact of emerging pollutants, such as pesticides and microplastics, on the transfer systems between land and river. The aim is to identify areas of high biodiversity that need enhanced protection, in line with the European Biodiversity Strategy 2030.

To improve water quality, he argues that it is essential to restore and protect riverside ecosystems. “We need to increase the coverage of riverbanks with trees (...), reduce the use of pesticides and strengthen control over emerging pollutants, which are now beginning to prove a major environmental challenge.”

Innovating Water Management

Manuela Moreira da Silva, from CIMA, has been dedicated to urban ecohydrology, particularly in the Algarve region. According to the researcher, “urban aquatic ecosystems, which are predominantly lakes, suffer contamination from pollutants, leading to eutrophication processes with various risks to public health.” Eutrophication, which consists of the excessive enrichment of water with nutrients such as nitrogen and phosphorus, has been identified by the COPERNICUS Marine Service as the main cause of water quality degradation over the past five decades.

To mitigate these impacts, the researcher has combined the optimisation of cities' hydraulic conditions with the use of phytoremediation macrophytes, that is, aquatic plants capable of removing pollutants from the water.

Manuela Moreira da Silva has collaborated with Loulé’s City Council on the Jardim das Comunidades project, in Almancil. The project aims to “improve the environmental performance of this garden by: promoting the ecological health of its lake; optimising water consumption for irrigation and avoiding the use of treated water intended for human consumption by replacing it with previously stored rainwater; characterising the existing vegetation and intervening to increase its potential for carbon sequestration”. It stands as an example of a local action for climate change adaptation, aiming to enhance resilience to water scarcity, mitigate the effects of extreme precipitation events, and reduce the impact of heatwaves.

She advocates that efficient water management is of utmost importance, highlighting the need for “alternative water sources, saving water at home and in businesses, especially in the tourism sector, and training on new solutions for local government officials.”

A future with water for all
World Water Day 2025 calls for the “Preservation of Glaciers”.

Glaciers are essential for life, as the melting of their water is not only a source of drinking water, but also releases water that is used in agriculture, industry and the production of clean energy, contributing to healthy ecosystems.

At MARE and our associated laboratory ARNET, we remain committed to research and innovation, but the responsibility lies with everyone. Reducing water consumption, supporting environmental policies and adopting sustainable practices in everyday life are essential steps to protect this vital resource. 

Photos by (in order of appearance) Afonso Ferreira and Sofia Nunes, Bernardo Duarte, João Paulo Medeiros, Giorgio Pace (and Niaz Ahmed-Unsplash).