Uraren azidotasunari buruzko ikerketa Bizkaiko hiru estuarioetan: Urdaibai, Plentzia eta Nerbioi-Ibaizabal

Abstract

Oceans cover around a 70% of the planet surface and play a key role in the Earth's major processes. In the last 200 years, CO₂ emissions have increased due to human activities. Atmospheric CO₂ concentration has increased from the pre-industrial level of 280 ppm to around 415 ppm nowadays, and according to some studies, it may reach values of 936 ppm by 2100, if emissions continue unabated. The increase of CO₂ concentration has two main effects: the rise of the global temperature, known as the intensification of the greenhouse effect; and ocean acidification. Oceans absorb CO₂ excess, lowering its concentration in the atmosphere but decreasing the pH of the water. Besides seawater, the necessity of researching other interesting water systems, such as estuaries, has been signaled. The effects of CO₂ increase have not been widely studied in these systems, which are considered very important since they are the habitat for a lot of species of animals and plants. There are four measurable parameters to study the CO₂ system: total alkalinity, dissolved inorganic carbon, pH and fugacity. Due to their thermodynamic relationship, it is only necessary to empirically measure two of them to calculate the other two. In this work, the total alkalinity and the dissolved inorganic carbon were measured. These four parameters were studied in three estuaries of Biscay: Urdaibai, Plentzia and Nerbioi-Ibaizabal. Samples were collected for 3 years, in each season, in order to see similarities and differences between the estuaries and to study possible trends with time.