我有以下数据：
df1 <- structure(list(Wastewater_Treatment_Plant = c("D_S1_L001_R1_001",
"D_S1_L001_R1_001", "D_S1_L001_R1_001", "D_S1_L001_R1_001", "D_S1_L001_R1_001",
"D_S1_L001_R1_001", "D_S1_L001_R1_001", "D_S1_L001_R1_001", "D_S1_L001_R1_001",
"D_S1_L001_R1_001", "D_S1_L001_R1_001", "D_S1_L001_R1_001", "D_S1_L001_R1_001",
"D_S1_L001_R1_001", "D_S1_L001_R1_001", "D_S1_L001_R1_001", "D_S1_L001_R1_001",
"D_S1_L001_R1_001"), Domain = c("Archaea", "Archaea", "Archaea",
"Archaea", "Archaea", "Bacteria", "Bacteria", "Bacteria", "Bacteria",
"Bacteria", "Bacteria", "Bacteria", "Eukaryota", "Eukaryota",
"Eukaryota", "Eukaryota", "Other Sequences", "Viruses"), Phylum = c("Crenarchaeota",
"Euryarchaeota", "Korarchaeota", "Nanoarchaeota", "Thaumarchaeota",
"Acidobacteria", "Actinobacteria", "Aquificae", "Bacteroidetes",
"Candidatus Poribacteria", "Chlamydiae", "Chlorobi", "Streptophyta",
"Xanthophyceae", "unclassified (derived from Eukaryota)", "unclassified (derived from Fungi)",
"unclassified (derived from other sequences)", "unclassified (derived from Viruses)"
), Alignment_Length …