3.3. CBH for metazoans
The identification of taxa regarding their phyla in the NCBI taxonomy is presented in Fig. 4. As expected, generally higher diversity was detected by CBH-short (Kraken2), with 21 phyla, compared to 16 with metabarcoding. Some groups, Acanthocephala, Cycliophora, Entoprocta, Gnathostomulida, Micrognathozoa, and Nematomorpha, were only detected with CBH, while only one group was specifically detected by metabarcoding (Ctenophora). The greatest difference was in the number of detected nematodes, with 1074 (MTB) to 82 (CBH-short) taxa. Analyzing sample-specific results showed in more detail the differences but also similarities of the different methods (Figs. 5 and 6). As an example, CBH-short showed an outstanding number of detected sponges in sample 1A, with 20 taxa identified within all four lineages of Porifera, Calcarea, Demospongiae, Hexactinellida, and Homoscleromorpha. A total of 638602 (over 97% of all metazoan sequences in this sample) sequences belonging to Demospongiae were detected, representing 16 differe nt families. Within this sample, 29 different sequences of Demospongiae were reconstructed (CBH-long). Additionally, for the metabarcoding, over 87% of the metazoan sequences identified in this particular sample were Porifera, but only one large cluster (OTU) of Demospongiae and two small calcares were detected. At the species level, 12 demospongies were identified with CBH-long, where one overlap with the metabarcoding approach detected species at the genus level.