NITROMICS: microbial nitrogen processing in wildfire-affected Mediterranean catchments through multi-omics

Wildfires act as positive feedbacks to global change by altering biogeochemical cycles, particularly through their effects on nitrogen availability, a key driver of ecosystem productivity. Fires remove or transform nitrogen through volatilization, the formation of pyrogenic organic matter, and ash production, while post-fire runoff transports nutrients to freshwater ecosystems, potentially increasing the risk of eutrophication and other ecological disturbances. A major challenge is understanding how these changes propagate through the terrestrial–freshwater continuum and influence the microbiome and functioning of headwater streams.

NITROMICS investigates how wildfires reshape the microbial processes that regulate the nitrogen cycle in Mediterranean forest catchments. By combining stable isotope techniques with cutting-edge multi-omics approaches, including metagenomics, metatranscriptomics, and genome-resolved metaproteomics, we aim to identify not only which microorganisms are present, but also which are metabolically active and how they regulate nutrient cycling across post-fire landscapes.

NITROBIOREM: microbial mats from early Earth to environmental biotechnology

Hypersaline lakes are among the most extreme and vulnerable ecosystems on Earth. Their microbial mats, descendants of some of the earliest ecosystems that transformed the primitive planet, regulate key biogeochemical processes and contribute to the natural attenuation of pollutants. However, increasing agricultural pressures are exposing these environments to high nutrient loads and herbicides such as atrazine and glyphosate, with largely unknown consequences for microbial diversity, nitrogen cycling, and ecosystem functioning.

NITROBIOREM investigates how herbicide contamination affects the microbial communities and metabolic pathways that regulate the nitrogen cycle in hypersaline microbial mats. By combining stable isotope techniques, microscale characterization, and advanced environmental genomics approaches (e.g., metagenomics, single-cell genomics), we aim to identify the microorganisms that sustain these unique ecosystems and evaluate their potential for the biodegradation of agricultural pollutants and the discovery of novel biotechnological resources.

Microbial gene pool driving nitrogen cycling in hypersaline lakes

Hypersaline lakes harbor highly specialized microbial communities that thrive under extreme osmotic stress while sustaining essential biogeochemical processes. Despite their ecological importance, the diversity and functional potential of these microorganisms remain poorly understood, particularly regarding the pathways controlling nitrogen transformations.

Our research explores the microbial gene pool associated with nitrogen cycling in hypersaline lakes, with special emphasis on the diversity, distribution, and evolutionary history of functional genes involved in nitrogen fixation, nitrification, denitrification, and anaerobic ammonium oxidation. By combining metagenomics and microbial ecology, we investigate how environmental conditions shape the functional potential of these unique ecosystems and how microbial communities adapt to extreme salinity.

Linking microbial genomics and greenhouse gas saturation in high Arctic freshwaters

Climate change is causing temperatures in the Arctic to rise faster than in any other region of the world. This rapid warming leads, among other effects, to the massive loss of ice masses, development of thermokarst features when permafrost thaws, intensification of the hydrological cycle, and increasing loads of nutrients and organic carbon to surface waters. Freshwaters are highly sensitive to these changes, which affect microbial community composition and diversity. Therefore, these ecosystems are good sentinels to study processes in primary ecological succession related to ecosystem processes such as productivity and greenhouse gas emissions.

We aim to contribute to a deeper understanding of the linkages between biogeochemistry, microbiology and hydrology in high Arctic freshwaters. To do so, we conducted several fieldwork campaigns in Arctic and sub-Arctic localities (Svalbard, Finnmark, Finse, Northwest Territories) to unravel microbial diversity and metabolism in such unique ecosystems.

NITROKARST: Nitrogen cycling in thawing permafrost landscapes

Permafrost regions store vast amounts of organic matter that become increasingly available for microbial degradation as temperatures rise. The formation of thermokarst ponds and lakes following permafrost degradation creates dynamic environments where microbial activity can strongly influence nutrient cycling and greenhouse gas production.

Through the EU-funded NITROKARST project, we investigated how permafrost degradation reshapes the nitrogen cycle in thermokarst aquatic ecosystems of the Northwest Territories (Canada). By integrating microbial ecology, genomics, and biogeochemistry, we explored the pathways controlling nitrogen transformation and their implications for ecosystem functioning under a warming climate.

ARCTIC-BIODIVER: filling gaps in Arctic freshwater biodiversity knowledge

Arctic freshwater ecosystems are under increasing threat from stressors such as climate change, land-use changes, introduced species, increased UV-radiation and exploitation of natural resources. Climate change is predicted to cause direct and indirect effects to these ecosystems and the biodiversity they support, including the fish used by people inhabiting the Arctic.

Within the ARCTIC-BIODIVER project, we aim to facilitate development of biodiversity scenarios at national and circumpolar scales. These include freshwaters from remote locations within Norway, Sweden, Greenland, Canada and Alaska. Within each region, selection of data focused on maximizing spatial and temporal coverage to ensure that the data covered the variability in Arctic lakes and rivers. A primary focus is to develop strong links between climate change predictions, biodiversity scenarios, and the consequences for ecosystem services in Arctic freshwaters. I personally also contribute to circumpolar harmonization of microbial sampling methods and large-scale analysis of microbial biodiversity change.