Use of Kohonen Self Organizing Maps (SOM) for the characterization of benthic diatom associations of the River Danube and its tributaries
Várbíró, Gábor; Borics, Gábor; Kiss, Keve T.; Szabó, Katalin E.; Plenković-Moraj, Andelka; Ács, Éva
Benthic diatom flora of the River Danube was investigated along the river from the source streams to the end of the Hungarian stretch during a four-year period. Characteristic diatom community assemblages were established using Kohonen Self-Organizing Map (SOM) algorithm. We found five sample clusters, arranged according to the location. The first three groups are located in the German-Austrian stretch, while the fourth and fifth groups are located in the Slovakian-Hungarian stretch. Characteristic species of the clusters 1 and 2 are Achnanthidium minutisimum (Kütz.) Czarnecki, Denticula tenuis Kütz., Nitzschia fonticola Grun., Psammothidium bioretii (Germain) BukhtT. & Round, Melosira varians Ag., Planothidium subatomoides (Hust.) Bukht. & Round, character species of cluster 3 is Amphora pediculus (Kütz.) Grun., while character species of the clusters 4 and 5 are Nitzschia dissipata (Kütz.) Grun., Navicula cryptotenella Lange-Bert., Cocconeis placentula var. euglypta (Ehr.) Grun., Rhoicosphenia abbreviata (Ag.) Lange-Bert., Nitzschia inconspicua Grun. This arrangement is also well in agreement with the poorer water quality of the lower, and the better water quality of the upper stretch.