Responses of bacterioplankton, particle- and colony-attached bacterial communities to Phaeocystis globosa blooms in Mirs Bay, China

Abstract

Microalgae blooms are a frequent occurrence in coastal waters worldwide. It is reasonable to assume that these blooms have various influences on bacterial communities, which in turn may affect the development and dissipation of the bloom. However, the bacterial community characteristics, particularly of attached bacteria, associated with microalgae blooms remain unclear. In this study, we investigated the community profiles of bacteria using high-throughput sequencing during a Phaeocystis globosa bloom in Mirs Bay, southern China, in January 2021. Bacteria living in three habitats, i.e., bacterioplankton, particle-attached bacteria, and colony-attached bacteria, were studied from the exponential growth phase to the decline growth phase of the bloom. Distinct variations in bacterial community composition existed among the three habitats. Bacteroidota, Proteobacteria, and Cyanobacteria were the dominant phyla of bacterioplankton, particle–attached bacteria, and colony-attached bacteria, respectively. Richness and diversity were significantly highest (p < 0.01) in particle-attached bacteria, followed by bacterioplankton, and lowest in colony-attached bacteria. The community diversities of bacterioplankton and particle-attached bacteria decreased significantly (p < 0.05) as the bloom shifted from the exponential to the decline phase. During the decline growth phase of the bloom, Bacteroidota and Verrucomicrobiota were the dominant remarkably abundant bacteria in the bacterioplankton community, whereas Verrucomicrobiota was dominant in the particle-attached bacteria community. No significant difference was observed in the colony-attached bacterial community between the exponential and decline phases of the P. globosa bloom owing to their complex network. The results of this study suggest that P. globose bloom has a profound impact on marine bacteria, particularly species that can decompose organic matter, which could play a crucial role in the dissipation of algal blooms.

Responses of attached bacterial communities to blooms of the swimming shelled pteropod Creseis acicula in Daya Bay, southern China

“…For bacterial DNA extraction, 2.5 L of seawater was passed through 3-µm polycarbonate membranes (EMD Millipore Corporation, Billerica, MA, USA), and 1.5 L of the filtrate was passed through 0.2-µm polycarbonate membranes (EMD Millipore Corporation). The particle-attached bacteria (attached to particles with a diameter of 3–20 µm) and free-living bacteria (with a size of 0.2–3 µm) that were captured with the 3- and 0.2-µm membranes, respectively, were frozen in liquid nitrogen and stored at –80°C until DNA extraction (Ortega-Retuerta et al 2013 , Shi et al 2023 ).…”

“…The V4–V5 hypervariable regions of the bacterial 16S rRNA gene were amplified using the universal bacterial primers 515F (5′-GTG YCA GCM GCC GCG GTA A-3′) and 926R (5′-CCG YCA ATT YMT TTR AGT TT-3′) with a GeneAmp™ PCR System 9700 (Applied Biosystems, Carlsbad, CA, USA) (Parada et al 2015 ). The reaction system and reaction conditions were according to Shi et al ( 2023 ). PCR products were extracted from 2% agarose gel and purified using the AxyPrep DNA Gel Extraction Kit (Axygen Biosciences, Union City, CA, USA) according to the manufacturer's instructions, and were quantified using a Quantus™ Fluorometer (Promega Co., Madison, WI, USA).…”

“…The raw 16S rRNA gene sequencing reads were demultiplexed, quality filtered and merged using fastp version 0.20.0 (Chen et al 2018 ) and FLASH version 1.2.7 (Magoč and Salzberg 2011 ), and the applied criteria were according to Shi et al ( 2023 ). Operational taxonomic units (OTUs) were clustered at a 97% similarity cutoff using UPARSE version 7.1 (Edgar 2013 ) and rarefied based on the smallest number of sequences (16 405) to standardize uneven sequence depth, and the taxonomy of each OTU representative sequence was analyzed with RDP Classifier version 2.2 against the 16S rRNA gene database (Silva v138.1) with a confidence threshold of 0.7 (Wang et al 2007 ).…”

“…Rapid and vigorous proliferation of any marine organisms, culminating in predominance within the local population, exerts profound impacts upon both the environment and the other species, thus a comprehensive understanding of these impacts is essential (Blauw et al 2010 , Zohdi and Abbaspour 2019 ). Extensive attention and research have been focused on blooms of algae and jellyfish to clarify direct and indirect impacts on bacterial communities (Sun et al 2020 , Xia et al 2020 , Peng et al 2021 , Shi et al 2023 ). However, our current understanding of these impacts remains insufficient.…”

“…Bacterial communities, either floating in seawater or attached to the surfaces of particulate matter, play crucial roles in the biogeochemical cycles of almost all elements in the ocean ecosystem (Ruiz-Gonzalez et al 2013 , Shi et al 2023 ). Additionally, active bacterial exchange occurs with changes to the environmental conditions of two or more habitats, where each habitat favors the proliferation of specific taxa that are typically unrepresentative in the other (De Corte et al 2014 , 2018 , Liu et al 2023 ).…”