Saharan Dust Changes Microbial Diversity in High-Mountain Lake Sediments

Jenn Hoskins
28th July, 2024

Saharan Dust Changes Microbial Diversity in High-Mountain Lake Sediments

Image Source: Natural Science News, 2024

Key Findings

  • The study focused on nine high-mountain lakes in Sierra Nevada, Spain, affected by a severe Saharan dust event in 2022
  • The 2022 dust event significantly increased nutrient levels in lake sediments compared to 2021
  • These nutrient increases led to changes in the diversity and composition of microscopic organisms in the lake sediments
Mediterranean high-mountain lakes are increasingly affected by Saharan dust deposition events, but the ecological impacts of these severe atmospheric episodes remain largely unknown. A recent study by the Universidad de Granada[1] examined the effects of a strong Saharan dust intrusion to the Iberian Peninsula in 2022 on the physicochemical parameters and prokaryotic communities in sediments of nine high-mountain lakes of Sierra Nevada, Spain. The study compared the year 2022, which experienced a strong Saharan dust deposition, with 2021, a year with lower dust deposition. The researchers found that the strong dust deposition in 2022 resulted in a significant increase in sediment nutrient availability. This increase in nutrients was linked to changes in the composition of prokaryotic communities, which are microscopic organisms including bacteria and archaea that play crucial roles in nutrient cycling. One of the key findings was a decrease in alpha diversity, which measures the variety of species within a specific area, and changes in beta diversity, which measures the differences in species composition between areas. These changes were more pronounced in lakes located in the southern orientation compared to those in the north, likely due to the south being more directly affected by the atmospheric dust deposition. The study also observed significant changes in the relative abundance of specific genera involved in important nutrient cycling processes such as phosphate solubilization, nitrogen fixation, nitrification, and denitrification. These processes are essential for maintaining the nutrient balance in ecosystems. For instance, denitrification, which is the reduction of nitrate to molecular nitrogen (N2), plays a critical role in removing excess nitrogen from aquatic systems[2]. Previous studies have shown that atmospheric transport of dust and organic aggregates can facilitate the long-range transport of bacteria and viruses across the atmosphere[3]. The current study builds on this by showing that dust deposition can significantly alter the microbial communities in high-mountain lakes, affecting their biodiversity and nutrient cycling processes. Additionally, the study's findings align with earlier research on the responses of heterotrophic microbial food webs (HMFW) to abiotic stressors in high-mountain lakes. For example, a study conducted in an oligotrophic high-mountain lake found that HMFW underwent significant changes following phosphorus enrichment and ultraviolet radiation exposure[4]. Similarly, the current study found that Saharan dust deposition, which increases nutrient availability, can lead to significant changes in microbial communities. The researchers used various methods to analyze the effects of dust deposition, including measuring nutrient levels in sediments and assessing the composition and diversity of prokaryotic communities. They found that the increased nutrient availability from dust deposition led to changes in microbial functionality, with increases in processes like nitrogen fixation and denitrification. In conclusion, the study by the Universidad de Granada demonstrates that severe Saharan dust deposition events can have significant biogeochemical and biodiversity consequences in high-mountain lakes of Sierra Nevada. By increasing nutrient availability, these dust intrusions can alter the composition and functionality of prokaryotic communities in lake sediments. This research contributes to our understanding of how Mediterranean high-mountain lakes respond to atmospheric dust inputs and highlights the importance of considering these events in ecological studies and conservation efforts.

EnvironmentBiochemEcology

References

Main Study

1) Strong Saharan Dust Deposition Events Alter Microbial Diversity and Composition in Sediments of High-Mountain Lakes of Sierra Nevada (Spain)

Published 27th July, 2024

https://doi.org/10.1007/s00248-024-02416-w

Related Studies

2) Denitrification and Biodiversity of Denitrifiers in a High-Mountain Mediterranean Lake.

https://doi.org/10.3389/fmicb.2017.01911

3) Deposition rates of viruses and bacteria above the atmospheric boundary layer.

https://doi.org/10.1038/s41396-017-0042-4

4) Maximum in the middle: nonlinear response of microbial plankton to ultraviolet radiation and phosphorus.

https://doi.org/10.1371/journal.pone.0060223


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