Salinity drives meiofaunal community structure dynamics across the Baltic ecosystem

Area of Science:

• Marine Ecology
• Benthic Ecology
• Climate Change Science

Background:

• Coastal benthic ecosystems face increasing pressures from climate change, eutrophication, hypoxia, and altered salinity.
• The Baltic Sea, a brackish system with environmental gradients, serves as a model for studying climate change impacts on biodiversity.
• Meiofauna, crucial for organic matter degradation and nutrient cycling, remain underexplored in benthic systems.

Purpose of the Study:

• To analyze the impact of salinity gradients on benthic meiofaunal community structure in the Baltic Sea.
• To identify key drivers of meiofauna diversity and composition.
• To predict the consequences of climate change-induced salinity shifts on benthic ecosystems.

Main Methods:

• Benthic meiofaunal community structure was analyzed along a salinity gradient in the Baltic Sea proper.
• High-throughput sequencing was employed to assess community composition.
• Environmental data, including salinity, were correlated with biodiversity metrics.

Main Results:

• Biodiversity of benthic meiofauna was significantly higher in areas with increased salinity.
• Salinity was identified as the primary driver influencing meiofauna diversity and community composition.
• Predatory nematode genera and meiofauna-macrofauna associations were more prevalent in higher salinity, more diverse environments.

Conclusions:

• Decreasing salinity in the Baltic Sea, driven by climate change, is predicted to reduce benthic biodiversity.
• Profound changes in benthic communities are expected, potentially impacting ecosystem stability, functions, and services.
• Understanding meiofauna responses to salinity is critical for predicting future Baltic Sea ecosystem health.