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.