Since I was three years old, I have been captivated by reptiles and amphibians. This early fascination guided me through my studies in biology and ecology, culminating in a unique opportunity to conduct research in the Evo region of Finland in 2023. With the support of the Lammi Biological Station (LBS) and the Lammin biologisen aseman Ympäristötutkimuksen Säätiö foundation, I explored how water browning – a phenomenon driven by increased dissolved organic matter – might influence the larval development of the common frog (Rana temporaria).
Amphibians, especially during their larval stages, are integral to aquatic ecosystems. Tadpoles play an important role as primary consumers and nutrient recyclers, while also serving as prey for a variety of predators. These roles position them as a key link in aquatic food webs and make them highly sensitive indicators of environmental changes. Water browning, which alters light penetration and nutrient dynamics, is a growing concern in freshwater systems, particularly as it relates to climate change. My research sought to understand how this phenomenon could affect tadpole development, with implications for broader ecosystem health.
The study was conducted in six lakes in the Evo region, selected for their varying levels of water coloration, which ranged from relatively clear to heavily brown-tinted. Frog eggs were collected from these lakes and reared under standardized laboratory conditions at LBS to ensure comparable developmental stages. Once the tadpoles reached the free-swimming stage, they were placed in experimental cages submerged in their respective lakes. This approach allowed us to track their development in a controlled yet natural setting while monitoring environmental variables, such as temperature, dissolved oxygen, and the biomass of chlorophyll in biofilms – a key food source for tadpoles.
The findings, although still under analysis, suggest complex interactions between water browning and tadpole development. While we observed variations in size and growth patterns across the browning gradient, other aspects, such as survival, appeared less affected. These preliminary results highlight the potential adaptability of Rana temporaria to diverse environmental conditions, possibly linked to its ability to exploit different food sources. However, more detailed analyses are required to confirm and understand the underlying mechanisms driving these observations.
Spending several months in the Evo region was an unforgettable experience. The boreal lakes, with their unique biodiversity and ecological dynamics, offered an incredible setting for research and a chance to deepen my understanding of freshwater ecosystems. I am profoundly grateful to the team at Lammi Biological Station for their warm welcome, invaluable guidance, and unwavering support throughout the project. Their expertise and assistance were instrumental in overcoming the logistical and scientific challenges of this work.
This project allowed me to connect my passion for amphibians with applied research addressing critical ecological questions. Investigating how tadpoles respond to environmental changes like water browning has reinforced my commitment to understanding the resilience of freshwater ecosystems in the face of climate change. I sincerely thank the foundation for its financial support, which made this project possible. The opportunity to work in such a remarkable environment and contribute to this important field of study is an experience I will always treasure.