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Insights into the Microbial and Viral Dynamics of a Coastal Downwelling-Upwelling Transition.

Gregoracci GB, Soares AC, Miranda MD, Coutinho R, Thompson FL - PLoS ONE (2015)

Bottom Line: This integrated approach allowed for a better understanding of the dynamics of the downwelling upwelling transition, suggesting that a wealth of metabolic processes and ecological interactions are occurring in the minute fractions of the plankton (femto, pico, nano).These processes and interactions included evidence of microbial predominance during downwelling (with nitrogen recycling and aerobic anoxygenic photosynthesis), different viral predation pressures over primary production in different states (cyanobacteria vs eukaryotes), and a predominance of diatoms and selected bacterial and archaeal groups during upwelling (with the occurrence of a wealth of nitrogen metabolism involving ammonia).Thus, the results provided insights into which microbes, viruses and microbial-mediated processes are probably important in the functioning of upwelling systems.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Ciências do Mar, UNIFESP Baixada Santista. Santos, SP, Brazil; Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil.

ABSTRACT
Although previous studies have described opposing states in upwelling regions, i.e., the rise of cold nutrient-rich waters and prevalence of surface warm nutrient-poor waters, few have addressed the transition from one state to the other. This study aimed to describe the microbial and viral structure during this transition and was able to obtain the taxonomic and metabolic compositions as well as physical-chemical data. This integrated approach allowed for a better understanding of the dynamics of the downwelling upwelling transition, suggesting that a wealth of metabolic processes and ecological interactions are occurring in the minute fractions of the plankton (femto, pico, nano). These processes and interactions included evidence of microbial predominance during downwelling (with nitrogen recycling and aerobic anoxygenic photosynthesis), different viral predation pressures over primary production in different states (cyanobacteria vs eukaryotes), and a predominance of diatoms and selected bacterial and archaeal groups during upwelling (with the occurrence of a wealth of nitrogen metabolism involving ammonia). Thus, the results provided insights into which microbes, viruses and microbial-mediated processes are probably important in the functioning of upwelling systems.

No MeSH data available.


Related in: MedlinePlus

Significantly different most abundant viral functions and auxiliary metabolic genes (Subsystems lvl2)–over 1% average abundance (relative percentage).The remaining functions are grouped as”Other lvl2 functions”. The total number of reads included in this analysis is 47,833. Different letters (a > b > c) represent statistically significant differences (corrected p <0.05), while ab are intermediate values.
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pone.0137090.g002: Significantly different most abundant viral functions and auxiliary metabolic genes (Subsystems lvl2)–over 1% average abundance (relative percentage).The remaining functions are grouped as”Other lvl2 functions”. The total number of reads included in this analysis is 47,833. Different letters (a > b > c) represent statistically significant differences (corrected p <0.05), while ab are intermediate values.

Mentions: Most recognizable viruses were cyanobacterial phages, algal viruses or similar from deep chlorophyll maximum phages from other studies (Fig 1). Among the most abundant phages, it was also possible to locate a Roseobacter infecting species. As the upwelling progressed, the abundance of most cyanobacterial phages decreased, as did the overall richness of phage species (Fig 1). By contrast, most of the phages similar to those found on a deep chlorophyll maximum (DCM, see Discussion) increased in abundance with the upwelling, as did the Roseobacter phages and Acanthocystis chlorella viruses. Among the most abundant viruses, only a few strains responded directly to the transition stage, either positively or negatively, and most belong to cyanophages, DCM phages or heterotrophic Gammaproteobacteria, such as T4, P22 and nt-1. S2 Table presents the detailed taxonomical annotation and statistical analysis, but all aspects highlighted in the text refer to statistically significant observations. Most recognizable functions were related to viral functions, such as phages, prophages (structural components), nucleotides synthesis, nucleic acids processing and replication (Fig 2, S3 Table). Some abundant functions, however, seemed to be auxiliary metabolic genes, being annotated as, e.g., respiration (dehydrogenases), phosphorus metabolism and uptake, and nitrogen metabolism (ammonia assimilation and nitrogen fixation). Interestingly, over a third of viral functions presented a reduced abundance during the transition (19th) relative to the downwelling (18th) or upwelling (20th) conditions. Notably, basic viral functions (phages, prophages, capsid proteins, nucleosides and nucleotides metabolism) were increased during the transition, while most remainder accessory functions were reduced, including tRNA and ribosome modification proteins. S3 Table presents the detailed functional annotation and statistical analysis, but all aspects highlighted in the text refer to statistically significant observations.


Insights into the Microbial and Viral Dynamics of a Coastal Downwelling-Upwelling Transition.

Gregoracci GB, Soares AC, Miranda MD, Coutinho R, Thompson FL - PLoS ONE (2015)

Significantly different most abundant viral functions and auxiliary metabolic genes (Subsystems lvl2)–over 1% average abundance (relative percentage).The remaining functions are grouped as”Other lvl2 functions”. The total number of reads included in this analysis is 47,833. Different letters (a > b > c) represent statistically significant differences (corrected p <0.05), while ab are intermediate values.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4556663&req=5

pone.0137090.g002: Significantly different most abundant viral functions and auxiliary metabolic genes (Subsystems lvl2)–over 1% average abundance (relative percentage).The remaining functions are grouped as”Other lvl2 functions”. The total number of reads included in this analysis is 47,833. Different letters (a > b > c) represent statistically significant differences (corrected p <0.05), while ab are intermediate values.
Mentions: Most recognizable viruses were cyanobacterial phages, algal viruses or similar from deep chlorophyll maximum phages from other studies (Fig 1). Among the most abundant phages, it was also possible to locate a Roseobacter infecting species. As the upwelling progressed, the abundance of most cyanobacterial phages decreased, as did the overall richness of phage species (Fig 1). By contrast, most of the phages similar to those found on a deep chlorophyll maximum (DCM, see Discussion) increased in abundance with the upwelling, as did the Roseobacter phages and Acanthocystis chlorella viruses. Among the most abundant viruses, only a few strains responded directly to the transition stage, either positively or negatively, and most belong to cyanophages, DCM phages or heterotrophic Gammaproteobacteria, such as T4, P22 and nt-1. S2 Table presents the detailed taxonomical annotation and statistical analysis, but all aspects highlighted in the text refer to statistically significant observations. Most recognizable functions were related to viral functions, such as phages, prophages (structural components), nucleotides synthesis, nucleic acids processing and replication (Fig 2, S3 Table). Some abundant functions, however, seemed to be auxiliary metabolic genes, being annotated as, e.g., respiration (dehydrogenases), phosphorus metabolism and uptake, and nitrogen metabolism (ammonia assimilation and nitrogen fixation). Interestingly, over a third of viral functions presented a reduced abundance during the transition (19th) relative to the downwelling (18th) or upwelling (20th) conditions. Notably, basic viral functions (phages, prophages, capsid proteins, nucleosides and nucleotides metabolism) were increased during the transition, while most remainder accessory functions were reduced, including tRNA and ribosome modification proteins. S3 Table presents the detailed functional annotation and statistical analysis, but all aspects highlighted in the text refer to statistically significant observations.

Bottom Line: This integrated approach allowed for a better understanding of the dynamics of the downwelling upwelling transition, suggesting that a wealth of metabolic processes and ecological interactions are occurring in the minute fractions of the plankton (femto, pico, nano).These processes and interactions included evidence of microbial predominance during downwelling (with nitrogen recycling and aerobic anoxygenic photosynthesis), different viral predation pressures over primary production in different states (cyanobacteria vs eukaryotes), and a predominance of diatoms and selected bacterial and archaeal groups during upwelling (with the occurrence of a wealth of nitrogen metabolism involving ammonia).Thus, the results provided insights into which microbes, viruses and microbial-mediated processes are probably important in the functioning of upwelling systems.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Ciências do Mar, UNIFESP Baixada Santista. Santos, SP, Brazil; Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil.

ABSTRACT
Although previous studies have described opposing states in upwelling regions, i.e., the rise of cold nutrient-rich waters and prevalence of surface warm nutrient-poor waters, few have addressed the transition from one state to the other. This study aimed to describe the microbial and viral structure during this transition and was able to obtain the taxonomic and metabolic compositions as well as physical-chemical data. This integrated approach allowed for a better understanding of the dynamics of the downwelling upwelling transition, suggesting that a wealth of metabolic processes and ecological interactions are occurring in the minute fractions of the plankton (femto, pico, nano). These processes and interactions included evidence of microbial predominance during downwelling (with nitrogen recycling and aerobic anoxygenic photosynthesis), different viral predation pressures over primary production in different states (cyanobacteria vs eukaryotes), and a predominance of diatoms and selected bacterial and archaeal groups during upwelling (with the occurrence of a wealth of nitrogen metabolism involving ammonia). Thus, the results provided insights into which microbes, viruses and microbial-mediated processes are probably important in the functioning of upwelling systems.

No MeSH data available.


Related in: MedlinePlus