Have you ever wondered what happens to the tiny, unseen microbes that work tirelessly to clean our wastewater when the seasons change, or when the climate itself starts to shift? As climate change continues to reshape the world around us, its impacts extend far beyond melting ice caps and rising sea levels. The changing climate is also transforming the biological processes that sustain life on Earth, including those quietly taking place in our wastewater treatment systems.
Climate and Seasonal Change: A Shifting Rhythm
Climate change is no longer a distant warning; it’s here. Global temperatures are climbing, rainfall patterns are shifting, and extreme weather events like droughts, floods, and heat domes are becoming more frequent and intense (du Plessis and du Plessis, 2019; Loucks, 2021). These shifts are altering the natural cycles that many organisms rely on for survival.
Traditionally, seasonal changes created regular variations in temperature, rainfall, and daylight that helped regulate biological processes (Kwiecien et al., 2022). Now, winters are warmer, summers are longer, and transitions between seasons are less predictable. This growing uncertainty affects not only plants and animals, but also microorganisms that drive critical ecosystem functions.
The Role of Constructed Wetlands
Constructed wetlands have become a sustainable and cost-effective solution for domestic wastewater treatment, especially in rural and decentralized regions (Li et al., 2021). These engineered systems mimic natural wetlands, using a combination of plants, soil, and microbial activity to remove pollutants from wastewater (Sgroi et al., 2018). Among the most important actors in this process are microbes, the microscopic bacteria and fungi that break down organic matter, nutrients, and even emerging contaminants. They operate under both aerobic and anaerobic conditions, working invisibly to improve water quality (Meng et al., 2014; Wang et al., 2022b). Globally, wetlands cover about 6% of the Earth’s surface, around 800 million hectares, and are found almost everywhere except Antarctica (Conlisk et al., 2023; Reddy et al., 2010). Their contributions to water purification, carbon storage, and biodiversity are immense, but their stability is now being tested by a changing climate.
When the Climate Challenges the Microbial Workforce
The performance of constructed wetlands depends heavily on microbial activity, which is sensitive to environmental conditions such as temperature, moisture, and nutrient availability. As climate change progresses, rising temperatures and extreme weather events pose significant challenges to these microbial communities (Salimi et al., 2021). For instance, higher temperatures can accelerate microbial metabolism, potentially enhancing pollutant removal efficiency (Alkorta et al., 2017). However, if temperatures rise too much, they may favor heat-tolerant, but less effective species, or even inhibit sensitive microbes, reducing the system’s overall treatment performance (Moon et al., 2023).
Changes in rainfall patterns also play a role. Prolonged droughts can limit water flow and oxygen exchange, stressing microbial populations, while heavy rainfall or flooding can dilute pollutants or wash away essential microbial biomass (Corman et al., 2018). This constant fluctuation makes it challenging for microbial communities to maintain the balance necessary for efficient wastewater treatment.
Adapting for Resilience
Understanding how microbial communities respond to seasonal and climatic variations is key to designing more resilient constructed wetlands. By studying microbial diversity and enzyme activity under different conditions, we can identify which microbes thrive in warmer or colder environments, and optimize wetland performance throughout the year.
As climate extremes become more common, integrating adaptive design strategies such as flexible water flow management, improved aeration, or temperature regulation will be essential to maintain treatment efficiency and protect these systems from failure.
A Microscopic Lesson on Climate Resilience
As a researcher studying microbial community dynamics in constructed wetlands, I find it fascinating how these microscopic organisms respond to large-scale environmental shifts. They remind us that climate resilience begins at the smallest level. Even the tiniest organisms play an outsized role in protecting our water resources and maintaining the balance of our ecosystems. In the face of a changing climate, empowering these natural processes through science and innovation offers a hopeful path toward a more sustainable water future.
References
Alkorta, I., Epelde, L. and Garbisu, C. 2017. Environmental parameters altered by climate change affect the activity of soil microorganisms involved in bioremediation. FEMS microbiology letters 364(19), fnx200.
Corman, J.R., Bertolet, B.L., Casson, N.J., Sebestyen, S.D., Kolka, R.K. and Stanley, E.H. 2018. Nitrogen and phosphorus loads to temperate seepage lakes associated with allochthonous dissolved organic carbon loads. Geophysical Research Letters 45(11), 5481-5490.
Conlisk, E., Chamberlin, L., Vernon, M. and Dybala, K.E. 2023. Evidence for the Multiple Benefits of Wetland Conservation in North America: Carbon, Biodiversity, and Beyond. Point Blue, March 32.
du Plessis, A. and du Plessis, A. 2019. Climate change: Current drivers, observations and impacts on the Globe’s natural and human systems. Water as an Inescapable Risk: Current Global Water Availability, Quality and Risks with a Specific Focus on South Africa, 27-53.
Kwiecien, O., Braun, T., Brunello, C.F., Faulkner, P., Hausmann, N., Helle, G., Hoggarth, J.A., Ionita, M., Jazwa, C.S. and Kelmelis, S. 2022. What we talk about when we talk about seasonality–A transdisciplinary review. Earth-Science Reviews 225, 103843.
Li, D., Chu, Z., Zeng, Z., Sima, M., Huang, M. and Zheng, B. 2021. Effects of design parameters, microbial community and nitrogen removal on the field-scale multi-pond constructed wetlands. Science of the Total Environment 797, 148989.
Loucks, D.P. (2021) The impacts of climate change, pp. 19-50, Elsevier.
Moon, S., Ham, S., Jeong, J., Ku, H., Kim, H. and Lee, C. 2023. Temperature Matters: Bacterial Response to Temperature Change. Journal of Microbiology 61(3), 343-357.
Salimi, S., Almuktar, S.A.A.A.N. and Scholz, M. 2021. Impact of climate change on wetland ecosystems: A critical review of experimental wetlands. Journal of Environmental Management 286, 112160.
Sgroi, M., Pelissari, C., Roccaro, P., Sezerino, P.H., García, J., Vagliasindi, F.G.A. and Ávila, C. 2018. Removal of organic carbon, nitrogen, emerging contaminants and fluorescing organic matter in different constructed wetland configurations. Chemical Engineering Journal 332, 619-627.
Wang, J., Long, Y., Yu, G., Wang, G., Zhou, Z., Li, P., Zhang, Y., Yang, K. and Wang, S. 2022b. A review on microorganisms in constructed wetlands for typical pollutant removal: species, function, and diversity. Frontiers in Microbiology 13, 845725.
Written by: Bridget Ataa Fosua
Bridget Ataa Fosua is a graduate student and researcher at the University of Northern British Columbia, pursuing a Master of Natural Resources and Environmental Studies under the supervision of Dr. Deborah Roberts and Dr. June Garcia-Becerra. She holds a master’s degree in environmental engineering from Central South University, China, and a Bachelor’s degree in Agricultural Science Education from the University of Education, Winneba, Ghana. Her research focuses on microbial community dynamics in constructed wetlands, examining how microbial enzymes contribute to wastewater treatment under varying climatic and seasonal conditions. Bridget is passionate about sustainable water management, environmental conservation, and developing innovative, nature-based solutions for wastewater treatment.
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