Influences of pesticides, nutrients, and local environmental variables on phytoplankton communities in lentic small water bodies in a German lowland agricultural area | JoVE Visualize

Influences of pesticides, nutrients, and local environmental variables on phytoplankton communities in lentic small water bodies in a German lowland agricultural area

Lishani Wijewardene¹, Naicheng Wu², Yueming Qu³

¹Department of Hydrology and Water Resources Management, Institute for Natural Resource Conservation, Kiel University, 24118 Kiel, Germany; Department of Biology, Aarhus University, Ole Worms Allé 1, 8000 Aarhus C, Denmark.

The Science of the Total Environment|March 28, 2021

View abstract on PubMed

Summary

Agricultural runoff, including pesticides and nutrients, significantly alters freshwater phytoplankton communities. Local environmental factors play a larger role than chemical stressors in shaping species composition.

Area of Science:

Environmental Science
Ecology
Aquatic Biology

Background:

Freshwater ecosystems near agricultural areas face concurrent chemical stressors from pesticides and nutrients.
Lentic small water bodies (LSWB) are vital for biodiversity but remain understudied.
Phytoplankton serve as sensitive indicators of stress and reveal community structure dynamics.

Purpose of the Study:

To investigate the impact of pesticide toxicity, nutrient levels, and local environmental variables on phytoplankton species composition and functional traits in LSWB.
To determine the relative contributions of these factors in shaping phytoplankton communities.
To identify key environmental drivers of phytoplankton functional features.

Main Methods:

Studied 94 pesticides, 3 nutrients (NH4-N, NO3-N, PO4-P), and local variables (precipitation, water level, temperature, DO, conductivity, pH) in 5 LSWB over 12 weeks.
Applied redundancy analysis and variance partitioning to link community composition with stressors.
Utilized multiple linear regression to identify drivers of functional traits.

Main Results:

Pesticide toxicity, nutrients, and local environmental variables significantly influenced phytoplankton community composition (p < 0.001).
Local variables had the highest pure contribution (12%), followed by nutrients (8%) and pesticide toxicity (2%).
Pesticide toxicity and nutrient concentrations significantly affected functional diversity and redundancy; PO4-P negatively impacted functional richness and evenness.

Conclusions:

Concurrent multiple stressors, particularly pesticides and nutrients, are crucial in shaping phytoplankton community structure.
These findings highlight potential impacts on aquatic metacommunity structures due to agricultural runoff.
Understanding these dynamics is essential for managing freshwater ecosystem health.