Morphology and taxonomy of the Aphanizomenon spp. (Cyanophyceae) and related species in the Nakdong River, South Korea

Abstract

Background: The purpose of this study is to describe the morphological characteristics of the Aphanizomenon spp. and related species from the natural samples collected in the Nakdong River of South Korea. Aph. flos-aquae was similar to Aph. klebahnii, whereas these species differed from each other by the size and shape of fascicles, which was macroscopic in Aph. flos-aquae and microscopic in the Aph. klebahnii. One of their characteristics was that trichomes are easily disintegrating during microscopic examination. C. issatschenkoi could be clearly distinguished from other species by hair-shaped terminal cell. Its terminal cell was almost hyaline and markedly pointed. Young populations of the species without heterocytes run a risk of a misidentification. Aph. skujae was characterized by akinete. Morphological variability of akinetes from natural samples collected in the Nakdong River was rather smaller than those reported by previous study. Conclusions: C. issatschenkoi are described for the first time in the Nakdong River. In addition, Aph. klebahnii and Aph. skujae are new to South Korea.

Influence of Abiotic Factors on the Growth of Cyanobacteria Isolated from Nakdong River, South Korea1

“…The diversity of cyanobacteria in the Nakdong River was observed during the summer season (Hur et al 2013, Lee et al 2018b. Also recently, bloomforming cyanobacterial species such as Aphanizomenon klebahnii, Aphanizomenon skujae, and Cuspidothrix issatschenkoi are first recorded from the Nakdong River, South Korea (Ryu et al 2017). However, the studies on cyanobacterial growth under abiotic factors such as pH, temperature, and nutrients in the Nakdong River have been scarce.…”

Harmful Cyanobacterial Blooms: Going beyond the “Green” to Monitor and Predict HCBs

“…Other examples can be Raphidiopsis raciborskii and Cuspidothrix issatschenkoi, which were formerly known as Cylindrospermopsis raciborskii (Woloszynska) Seenayya and Subba Raju and Aphanizomenon issatschenkoi (Usačev) Proshkina-Lavrenko, respectively [107,108]. Therefore, many concerns have been raised related to the probability of misidentifications only relying on morphological characters under a light microscope, particularly when heterocysts and akinetes are not visible for nostocacean cyanobacteria [88,[109][110][111][112][113]. In fact, although necessary, the controversy over the past decades on cyanobacterial taxonomy regarding Nostocales order, in particular, has also increased the confusion for a proper identification [65,[95][96][97]99,101,103,114,115].…”

Prediction of Cyanobacteria Using Decision Tree Algorithm and Sensor Monitoring Data

“…Most studies on algal communities in the Nakdong River after completion of the Four Major Rivers Restoration Project focused on the downstream parts of the river, while few such studies have been carried out in the middle and upper reaches [8]. investigated the succession of blue-green algae in the mainstream section of the Nakdong River after weir installation and identified the morphological characteristics of the genus Dolichospermum that is commonly found in natural freshwater populations [9]. investigated the phytoplankton community in the middle and lower reaches of the river from January to December 2012 and estimated the indices of species diversity and dominance.…”