Photo Credit: Cliff Watts
Scientific Frontline: Extended "At a Glance" Summary: Climate Change and Riverine Aquatic Fungi
The Core Concept: Aquatic fungi are critical microorganisms that decompose organic matter and degrade contaminants in freshwater ecosystems, but their biodiversity and biological functions are currently threatened by the impacts of global climate change.
Key Distinction/Mechanism: While river management has traditionally focused on reducing chemical pollutants like nitrates and phosphates from agricultural runoff, research indicates aquatic fungi are actually far more vulnerable to elevated temperatures, prolonged droughts, and the loss of shade-providing riparian vegetation.
Major Frameworks/Components:
- Nutrient and Energy Cycling: Aquatic fungi are fundamental to processing organic matter, degrading contaminants, and sustaining energy flows in river ecosystems.
- Climate Vulnerability: The loss of riparian forests directly increases sunlight exposure and temperature on riverbeds, which harms microbial populations.
- Sediment Refuge: Riverbed sediments offer a temporary buffer by providing stable moisture and temperature during unfavorable, dry periods, though this capacity is limited.
- Adaptive River Management: Effective conservation requires shifting focus from strictly chemical regulation to mitigating climate impacts through physical habitat restoration.
Branch of Science: Ecology, Mycology, Environmental Science, and Evolutionary Biology.
Future Application: Implementing targeted ecological management strategies, such as restoring riparian woodlands to increase shade and strictly regulating excessive water extraction during the summer, to protect freshwater biodiversity.
Why It Matters: Preserving aquatic fungi is essential to maintaining the self-purification capacity, nutrient cycling, and overall resilience of riverine ecosystems against the escalating impacts of global warming.
Aquatic fungi are microorganisms that play a key role in the ecological balance of rivers. They help decompose organic matter, degrade contaminants, and are part of the nutrient and energy cycles in freshwater ecosystems. Despite their ecological importance, a study published in the journal Freshwater Biology warns that the biodiversity and biological functions of these microorganisms in these natural environments are at risk due to rising temperatures, prolonged dry periods, and the loss of riparian vegetation caused by climate change.
The University of Barcelona and the Global Change Research Institute at Rey Juan Carlos University (IICG-URJC) led the study. It reviews how aquatic fungi and their functions respond to human activity, aiming to better understand the functioning of riverine ecosystems and improve their management.
"The loss of riparian forest has negative effects on fungi, as it increases sunlight exposure and temperature on the riverbed," says Aida Viza, a researcher at the Department of Evolutionary Biology, Ecology, and Environmental Sciences within the University of Barcelona's Faculty of Biology and at the Institute of Environmental Sciences at the RPTU University of Kaiserslautern-Landau (Germany).
"However, contrary to our expectations, the increase in chemical compounds such as nitrate and phosphate, associated with agricultural or urban impacts, had almost no influence on the biodiversity or functions of aquatic fungi. This may be because Iberian rivers have a large supply of nutrients, and fungi do not require large amounts to carry out their functions," the researcher notes.
Global warming and increasing droughts can affect the biodiversity and functioning of microorganisms in freshwater ecosystems.
The study describes how microbial activity in sediments is highly resistant to human impacts; the sediments provide more stable moisture and temperature conditions that allow rivers to sustain life and function during unfavorable periods. "These results show promising data for rivers. However, we must bear in mind that, with climate change, these unfavorable conditions will become increasingly prolonged and that the refuge capacity offered by sediment is limited," adds Viza.
The work, framed within the context of the Iberian River Observatory (IberRios), involved nineteen researchers from various universities and research institutes in Spain, Portugal, Germany, and Switzerland. In total, researchers collected information from sixty-two rivers located in seven Iberian regions with a diverse range of soils and climates.
"Our approach allows us to use the rivers of the Iberian Peninsula as a natural experiment to assess how climate change and human impacts can affect the biodiversity of these ecosystems and the benefits they provide to society," says Cayetano Gutiérrez, a researcher at the IICG-URJC.
Improvements in the Management and Monitoring of Rivers
The study's conclusions have important applications for the management and monitoring of rivers in the context of the climate crisis. Although river management has often focused on reducing nitrate and phosphate concentrations, these measures alone are insufficient to preserve the biodiversity and functions provided by aquatic fungi.
"The new study suggests that urgent action is needed and that measures must be adopted to mitigate the impacts of the climate crisis on rivers. One such action could be, for example, increasing shade by restoring riparian woodland or preventing excessive water extraction, especially during the summer," concludes Gutiérrez.
Published in journal: Freshwater Biology
Authors: Aida Viza, Encarnación Fenoy, Meritxell Abril, Mario Álvarez-Cabria, Rebeca Arias-Real, Christian Arnanz, José Barquín, Andreas Bruder, Red Calore, Íñigo Donázar, Isabel Fernandes, Antonio J. García-Meseguer, Anna Lupon, Itxaso Martinez-Sanz, Margarita Menéndez, Isabel Muñoz, Cláudia Pascoal, Marina Tomás-Martín, and Cayetano Gutiérrez-Cánovas
Source/Credit: University of Barcelona
Edited by: Scientific Frontline
Reference Number: eco062226_01