Microcystis abundance is predictable through ambient bacterial communities: A data-oriented approach.

The number of cyanobacterial harmful algal blooms (cyanoHABs) has increased, leading to the widespread development of prediction models for cyanoHABs. Although bacteria interact closely with cyanobacteria and directly affect cyanoHABs occurrence, related modeling studies have rarely utilized microbial community data compared to environmental data such as water quality. In this study, we built a machine learning model, the multilayer perceptron (MLP), for the prediction of Microcystis dynamics using both bacterial community and weekly water quality data from the Daechung Reservoir and Nakdong River, South Korea.

Response of particle-attached and free-living bacterial communities to Microcystis blooms.

The massive proliferation of Microcystis threatens freshwater ecosystems and degrades water quality globally. Understanding the mechanisms that contribute to Microcystis growth is crucial for managing Microcystis blooms. The lifestyles of bacteria can be classified generally into two groups: particle-attached (PA; > 3 µm) and free-living (FL; 0.

Dynamic response of bacterial communities to Microcystis blooms: A three-year study.

Although nutrient availability is widely recognized as the driving force behind Microcystis blooms, identifying the microorganisms that play a pivotal role in their formation is a challenging task. Our understanding of the contribution of bacterial communities to the development of Microcystis blooms remains incomplete, despite the fact that the relationship between Microcystis and bacterial communities has been extensively investigated. Most studies have focused on their interaction for a single year rather than for multiple years.

Network analysis reveals succession of Microcystis genotypes accompanying distinctive microbial modules with recurrent patterns.

Every member of the ecological community is connected via a network of vital and complex relationships, called the web of life. To elucidate the ecological network and interactions among producers, consumers, and decomposers in the Daechung Reservoir, Korea, during cyanobacterial harmful algal blooms (cyanoHAB), especially those involving Microcystis, we investigated the diversity and compositions of the cyanobacterial (16S rRNA gene), including the genotypes of Microcystis (cpcBA-IGS gene), non-cyanobacterial (16S), and eukaryotic (18S) communities through high-throughput sequencing. Microcystis blooms were divided into the Summer Major Bloom and Autumn Minor Bloom with different dominant genotypes of Microcystis.

Paucibacter oligotrophus sp. nov., isolated from fresh water, and emended description of the genus Paucibacter.

A Gram-stain-negative, rod-shaped, non-spore forming, motile and strictly oxidative bacterium, strain CHU3T, was isolated from fresh water in the Daecheong Reservoir, South Korea. A comparison of the 16S rRNA gene sequence showed that the novel bacterium is closely related to Paucibacter toxinivorans 2C20T (=KCTC 42569T) with a sequence similarity value of 97.8 %, Pelomonas saccharophila DSM 654T (=KCTC 52256T) with 97.

Caulobacter profunda sp. nov., isolated from deep freshwater sediment.

The Gram-stain-negative, aerobic, non-spore-forming, motile, with a single polar flagellum, or non-motile (stalked) and rod-shaped bacteria, DS48-5-2(T) and DS48-6-3, were isolated from a sediment sample collected from a depth of 48 m taken from Daechung Reservoir, Republic of Korea. Comparative 16S rRNA gene sequence studies showed that the two isolates had clear affiliation with Alphaproteobacteria and the closest relatedness to Caulobacter mirabilis FWC 38(T), Caulobacter fusiformis ATCC 15257(T) and Caulobacter daechungensis H-E3-2(T) showing 98.5%, 97.