Santiago de Compostela, 22 April 2020. The Spanish National Research Council (CSIC), through the Institute of Marine Research (Galicia), the Pyrenean Institute of Ecology (Aragon) and the Jaume Almera Institute of Earth Sciences (Catalonia), has carried out research showing that changes in land use and land cover over the last thirty years have altered the nitrogen cycle more than any climate change or human activity in the previous 500 years.
The research was carried out within the framework of the Chilean “CONICY” and “FONDECYT” projects and in collaboration with the International Laboratory for Global Change (LINCGlobal PUC-CSIC). In addition to the three CSIC institutes, the Pontifical Catholic University of Chile (PUC) and the Federal University of Rio de Janeiro (UFRJ) also participated.
The results have recently been published in Scientific Reports. The article notes that the replacement of natural land cover affects not only erosion processes and loss of soil fertility, but also productivity, organic matter accumulation and the trophic state of lakes, through changes in sediment and nutrient inputs from terrestrial ecosystems into aquatic ecosystems.
The article focuses on how human activities have profoundly altered the global nutrient cycle through changes in land use and land cover since the Industrial Revolution, and especially during the Great Acceleration (1950 CE). It also highlights the usefulness of lake records as a long-term baseline for better addressing the challenges posed by current global change.
The research was conducted in Laguna Matanzas, a coastal lake in central Chile that is currently dry because of reduced rainfall and water use for agroforestry activities. The study used an approach integrating multiple indicators: sedimentological, geochemical and isotopic analyses of cores from Laguna Matanzas, historical records, climate data and satellite images, in order to assess the role of land-use and land-cover changes and climate changes in the nitrogen cycle in Chile over the last five centuries.
“The study shows that recent changes are the most significant in the last 500 years and that neither climatic changes nor previous human activities had produced a similar impact on nutrient inputs and nitrogen availability,” the authors highlight.
CSIC participation in Galicia
CSIC in Galicia participated in this research through the Marine Biogeochemistry group (BGQM) at the Institute of Marine Research. This group studies the biogeochemical cycles of minor elements (nitrogen, phosphorus and silicon) and trace elements (bioactive elements, platinum-group elements and rare earths), their exchanges at the land-ocean interface and anthropogenic influences.
“In this article, our work focused on paleoproductivity interpreted through the sedimentary record, especially the content of biogenic silicon in Laguna Matanzas, and on discussing the data. This is an enriching collaboration for BGQM with scientists from other specialities and helps us better understand the impact of the Anthropocene on the Galician rías, a line of work BGQM began five years ago,” highlights CSIC research professor Ricardo Prego Reboredo.