Does a Decrease in Chlorophyll &lt;I&gt;a&lt;/I&gt; Concentration in Lake Biwa Mean a Decrease in Primary Productivity by Phytoplankton?

Kishimoto, Naoyuki; Yamamoto, Chihiro; Suzuki, Kei; Ichise, Satoshi

doi:10.2965/jwet.2015.1

Cited by 5 publications

(5 citation statements)

References 16 publications

(24 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This suggests that in the deeper layer, labile DOC, which can be estimated as the subtraction of refractory and semi-labile DOC concentrations from bulk DOC concentration, is consumed almost entirely and depleted. This is probably because in the deeper layer, net primary production is ≤0 g C m −3 y −1 , suggesting that new organic matter production is limited and the deeper layer is a decomposition layer ( Kishimoto et al, 2015 ). In this case, lysed DOM could be an important source of organic substrates for heterotrophic prokaryotes in the deeper layer.…”

Section: Discussionmentioning

confidence: 99%

Seasonal Variation in Viral Infection Rates and Cell Sizes of Infected Prokaryotes in a Large and Deep Freshwater Lake (Lake Biwa, Japan)

Shen

Shimizu

2021

Front. Microbiol.

View full text Add to dashboard Cite

As viruses regulate prokaryotic abundance and the carbon cycle by infecting and lysing their prokaryotic hosts, the volume of infected prokaryotes is an important parameter for understanding the impact of viruses on aquatic environments. However, literature regarding the seasonal and spatial variations in the cell volume of infected prokaryotes is limited, despite the volume of the prokaryotic community varying dynamically with season and water column depth. Here, we conducted a field survey for two annual cycles in a large and deep freshwater lake (Lake Biwa, Japan), where large prokaryotes inhabit the deeper layer during the stratified period. We used transmission electron microscopy to reveal the seasonal and spatial variation in the frequency of viral infection and cell volume of infected prokaryotes. We found that the viral infection rate in the surface layer increased when estimated contact rates increased during the middle of the stratified period, whereas the infection rate in the deeper layer increased despite low estimated contact rates during the end of the stratified period. In addition, in the deeper layer, the fraction of large prokaryotes in the total and infected prokaryotic communities increased progressively while the number of intracellular viral particles increased. We suggest different ways in which the viral abundance is maintained in the two water layers. In the surface layer, it is speculated that viral abundance is supported by the high viral infection rate because of the high activity of prokaryotes, whereas in the deeper layer, it might be supported by the larger number of intracellular viral particles released from large prokaryotes. Moreover, large prokaryotes could contribute as important sources of organic substrates via viral lysis in the deeper layer, where labile dissolved organic matter is depleted.

show abstract

Section: Discussionmentioning

confidence: 99%

Seasonal Variation in Viral Infection Rates and Cell Sizes of Infected Prokaryotes in a Large and Deep Freshwater Lake (Lake Biwa, Japan)

Shen

Shimizu

2021

Front. Microbiol.

View full text Add to dashboard Cite

show abstract

“…Fourth, this study only focused on dsDNA viruses. Recently, there has been a growing recognition of the importance of RNA and ssDNA viruses, which were removed during the purification step (CsCl density centrifugation, see Materials and Methods) in the oceans ( 40 – 43 ). As most of the described prokaryote-infecting viruses are dsDNA viruses ( 8 ), ssDNA and RNA viruses were excluded from the purview of the current study, which may limit the comprehensive understanding of viral diversity.…”

Section: Discussionmentioning

confidence: 99%

“…1A and C ). Moreover, new organic production is limited ( 41 ) and usable (labile) organic matter is depleted ( 21 ), leading to the slow growth of prokaryotes. Notably, 23 ASVs in the deep layer showed a short pattern ( Fig.…”

Section: Discussionmentioning

confidence: 99%

Virus–prokaryote infection pairs associated with prokaryotic production in a freshwater lake

Shen,

Tominaga,

Tsuchiya

et al. 2024

mSystems

View full text Add to dashboard Cite

Viruses infect and kill prokaryotic populations in a density- or frequency-dependent manner and affect carbon cycling. However, the effects of the stratification transition, including the stratified and de-stratified periods, on the changes in prokaryotic and viral communities and their interactions remain unclear. We conducted a monthly survey of the surface and deep layers of a large and deep freshwater lake (Lake Biwa, Japan) for a year and analyzed the prokaryotic production and prokaryotic and viral community composition. Our analysis revealed that, in the surface layer, 19 prokaryotic species, accounting for approximately 40% of the total prokaryotic abundance, could potentially contribute to the majority of prokaryotic production, which is the highest during the summer and is suppressed by viruses. This suggests that a small fraction of prokaryotes and phages were the key infection pairs during the peak period of prokaryotic activity in the freshwater lake. We also found that approximately 50% of the dominant prokaryotic and viral species in the deep layer were present throughout the study period. This suggests that the “kill the winner” model could explain the viral impact on prokaryotes in the surface layer, but other dynamics may be at play in the deep layer. Furthermore, we found that annual vertical mixing could result in a similar rate of community change between the surface and deep layers. These findings may be valuable in understanding how communities and the interaction among them change when freshwater lake stratification is affected by global warming in the future. IMPORTANCE Viral infection associated with prokaryotic production occurs in a density- or frequency-dependent manner and regulates the prokaryotic community. Stratification transition and annual vertical mixing in freshwater lakes are known to affect the prokaryotic community and the interaction between prokaryotes and viruses. By pairing measurements of virome analysis and prokaryotic production of a 1-year survey of the depths of surface and deep layers, we revealed (i) the prokaryotic infection pairs associated with prokaryotic production and (ii) the reset in prokaryotic and viral communities through annual vertical mixing in a freshwater lake. Our results provide a basis for future work into changes in stratification that may impact the biogeochemical cycling in freshwater lakes.

show abstract

“…1A, C). Moreover, new organic production is limited [63] and usable (labile) organic matter is depleted [20], leading to the slow growth of prokaryotes. Notably, 23 ASVs in the deep layer showed a short pattern (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…1A, C). Moreover, new organic production is limited [63] and usable (labile) organic matter is depleted [20],…”

Section: Most Prokaryotes and Viruses In The Deep Layer Persist Durin...mentioning

confidence: 99%

Identification of key virus–prokaryote infection pairs that contribute to viral shunt in a freshwater lake

Shen

Tominaga

Tsuchiya

et al. 2023

Preprint

View full text Add to dashboard Cite

Viruses infect and kill productive prokaryotes in a density- or frequency-dependent manner and affect carbon cycling. However, the effects of the stratification transition, including the stratified and de-stratified periods, on the changes in prokaryotic/viral communities and the interactions among them remain unclear. We conducted a monthly survey of the surface and deep layers of a large and deep freshwater lake (Lake Biwa, Japan) for a year and analyzed the prokaryotic production and prokaryotic/viral metagenome. Our analysis (including 1 608 prokaryotes and 13 761 viruses) revealed that 19 prokaryotic species, accounting for ~40% of total abundance, might be suppressed by viruses when prokaryotic production is higher. This suggests that a small proportion of prokaryotes contribute to a large amount of prokaryotic abundance, and these prokaryotes are infected and lysed by viruses, driving the viral shunt in the freshwater lake. Furthermore, we found that annual vertical mixing might yield a similar rate of community change between the surface and deep layers. This finding might be valuable in understanding how the communities change when the stratification of freshwater lakes is affected by global warming in the future.

show abstract

Does a Decrease in Chlorophyll <I>a</I> Concentration in Lake Biwa Mean a Decrease in Primary Productivity by Phytoplankton?

Cited by 5 publications

References 16 publications

Seasonal Variation in Viral Infection Rates and Cell Sizes of Infected Prokaryotes in a Large and Deep Freshwater Lake (Lake Biwa, Japan)

Seasonal Variation in Viral Infection Rates and Cell Sizes of Infected Prokaryotes in a Large and Deep Freshwater Lake (Lake Biwa, Japan)

Virus–prokaryote infection pairs associated with prokaryotic production in a freshwater lake

Identification of key virus–prokaryote infection pairs that contribute to viral shunt in a freshwater lake

Contact Info

Product

Resources

About