NUDREM – dynamics of eukaryotic diversity facing eutrophication in experimental ponds

We conducted a replicated pond mesocom experiment by manipulating two limiting nutrients, phosphorous and nitrogen, to shed light on the response of aquatic communities during nutrient enrichment. Overall, four different treatment combinations were applied in a full-factorial design to the ponds, namely two ecosystem engineers were added to the experimental setup (dreissenid mussels and macrophytes). The nutrients (K2HOPO4, KNO3) were added in pulses to all ponds (beside the control) in five sequential pulses over the course of several weeks. On a monthly basis over the course of a year, we sampled environmental DNA to observe community changes. Therefore, we collected 100 mL per pond that were filtered on a GF/F glass fiber filter (Whatman, 25 mm diameter, 0.7 µm pore size). We extracted the DNA from the filter with DNeasy Blood & Tissue kit (Qiagen) and performed an Illumina MiSeq dual-barcoded 2-step PCR amplicon sequencing protocol. We focused on the detection of eukaryotic diversity, therefore we used the Leray/Geller primers for COI (cytochrome c oxidase subunit 1).