Fe3O4 nanoparticles coated with humic acid: synthesis, characterization and effect on cnidarian resilience

• Grant number: 23/00371-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2023
• End date: May 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Breno Pannia Esposito
• Grantee: Rachel Zaia
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Coral bleaching is a phenomenon that occurs when coral reefs lose their vibrant colors and become pale or white. This phenomenon is caused by the loss of symbiotic coral algae, known as zooxanthellae, which provide nutrients to corals and give them their characteristic colors. The process can be triggered by environmental stressors such as rising temperatures and ocean acidification. When coral reefs experience prolonged or severe bleaching events, it can lead to coral death and the degradation of the entire ecosystem. Knowing that corals are organisms evolutionarily related to anemones, and that the symbiotic relationship with zooxanthellae is also observed in such organisms, we chose to develop studies on them. Therefore, in order to help increase the resilience of cnidarians, it is proposed to enrich their environments with essential metals for their vitality, such as iron. Iron is an element entrusted with fundamental roles in marine processes, the most important being the modulation of ocean productivity through the control of photosynthesis. Despite this, its bioavailability in the marine environment is extremely low, since it is dependent on physicochemical characteristics. A possible way to correct this problem is the chelation or synthesis of nanoparticles as a strategy for iron solubilization. In this sense, the synthesis of nanoparticles coated with humic substances is proposed as a viable solution, since humic substances can be considered as ecological correctors of iron deficiency and free from the disadvantages of synthetic iron chelates. Through mechanisms such as the formation of more soluble complexes, the acquisition of this nutrient is modulated, promoting the growth of the species. In this project, therefore, Fe3O4 nanoparticles coated with humic acid will be produced and characterized as a strategy to increase the resilience of these organisms through greater mineral supplementation.