Abundance of Common Aerobic Anoxygenic Phototrophic Bacteria in a Coastal Aquaculture Area

Abstract

Aerobic anoxygenic phototrophic bacteria (AAnPB) rely on not only heterotrophic but also phototrophic energy gain. AAnPB are known to have high abundance in oligotrophic waters and are the major portion of the bacterial carbon stock in the environment. In a yearlong study in an aquaculture area in the Uwa Sea, Japan, AAnPB, accounted for 4.7 to 24% of the total bacteria by count. Since the cell volume of AAnPB is 2.23 ± 0.674 times larger than the mean for total bacteria, AAnPB biomass is estimated to account for 10–53% of the total bacterial assemblage. By examining pufM gene sequence, a common phylogenetic AAnPB species was found in all sampling sites through the year. The common species and other season-specific species were phylogenetically close to unculturable clones recorded in the Sargasso Sea and Pacific Ocean. The present study suggests that the common species may be a cosmopolitan species with worldwide distribution that is abundant not only in the oligotrophic open ocean but also in eutrophic aquaculture areas.

High temperature accelerates growth of aerobic anoxygenic phototrophic bacteria in seawater

“…Sato‐Takabe et al. () reported seasonal dynamics of total and AAP bacterial abundances in aquaculture areas similar to the area sampled in the present study and found that higher AAP bacterial abundance tended to coincide with higher water temperature, whereas the abundance of total bacteria was not correlated with water temperature. Generally speaking, temperature is not always a primary factor in determining bacterial growth, but rather some other factors such as salinity, oxygen, organic, and inorganic nutrients can be alternative controlling factors.…”

“…Sato‐Takabe et al. () reported that the DO reaches a saturated level of around 150–200 mmol O 2 per m 3 in summer near aquaculture areas of the Uwa Sea where seawater was collected for the present microcosm and a calculated bacterial respiration rate of 5 mmol O 2 per m 3 /day in coastal mesocosms (Williams, ). This suggests that oxygen available at the start of the experimental period was not depleted and the probability of development of anaerobic anoxygenic species is negligible.…”

“…Bacterial cells were enumerated on images taken on a Zeiss Axioplan 2 epifluorescence microscope (Carl Zeiss, Germany) equipped with a mercury lamp (USH‐102D, Ushio, Japan) and a Photometrics CH‐250 cooled, slow scan, infrared (IR)‐sensitive CCD camera (iKon‐M, ANDOR, United Kingdom) and connected to a Windows PC, as described previously (Sato‐Takabe et al., , ). The following three epifluorescence filter sets were used: (a) BChl a (excitation 400–530 nm, emission >850 nm long pass, RG850, Edmund Optics, USA, >650 nm dichroic, XF‐2072, Omega Optical); (b) Chl a (excitation 546 ± 12 nm, emission >590 nm long pass, >580 nm dichroic, Zeiss Filter set 15, 488015–0000, Carl Zeiss); and (c) DAPI (excitation 365 ± 12 nm, emission >397 nm long pass, >395 nm dichroic, Zeiss Filter set 01, 488001–0000, Carl Zeiss).…”

“…Axioplan 2 epifluorescence microscope (Carl Zeiss, Germany) equipped with a mercury lamp (USH-102D, Ushio, Japan) and a Photometrics CH-250 cooled, slow scan, infrared (IR)-sensitive CCD camera (iKon-M, ANDOR, United Kingdom) and connected to a Windows PC, as described previously (Sato-Takabe et al, 2015, 2016. The following three epifluorescence filter sets were used:…”

Distribution of Aerobic Anoxygenic Phototrophs in Freshwater Plateau Lakes

“…The populations of anoxygenic phototrophic bacteria are morphologically and physiologically diverse, indicating an adaptation to the local stratified environments [16]. Indeed, common species of AAP bacteria might be a cosmopolitan species with worldwide distribution that were abundant not only in the oligotrophic open ocean but also in eutrophic aquaculture areas [17]. Some uncertainty remains regarding the the composition of AAP communities from various aquatic habitats.…”