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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 cellular functions 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 802,136. Different letters (a > b > c) represent statistically significant differences (corrected p <0.05), while “ab” are intermediate values.
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pone.0137090.g004: Significantly different most abundant cellular functions 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 802,136. Different letters (a > b > c) represent statistically significant differences (corrected p <0.05), while “ab” are intermediate values.

Mentions: The majority of cellular species identified were recognized as bacteria that are common members of the marine community, such as Pelagibacter, Alteromonas and several members of the Flavobacteriales and Rhodobacteriales orders (Fig 3). Except for Pelagibacter and Alteromonas, which increased with the upwelling, most bacteria seem more abundant in the downwelling period (Fig 3). Three exceptions to the bacterial dominance are noteworthy, having increased with the upwelling: Nitrosopumilus maritimus, a thaumarchaea; Thalassiosira pseudonana, a centric diatom; and Ostreococcus lucimarinus, a picoeukaryote (Fig 3, S2 Table). Ostreococcus and uncultivated Gammaproteobacterium HTCC 2207, in fact, peaked over the transition, suggesting that the transition benefited at least a few microbial species. S2 Table presents the detailed taxonomic annotation and statistical analysis, but all aspects highlighted in the text refer to statistically significant observations. The cellular functions annotated are more diverse than the viral functions, with protein biosynthesis, transcription, electron-accepting and electron-donating reactions (respiration), membrane transport (Ton/Tol, Zn, Mn), nitrogen metabolism (ammonia assimilation, denitrification, nitrogen fixation), phosphorus metabolism (phosphate), sulfate reduction, inorganic sulfur assimilation and protein folding responding positively to the upwelling (Fig 4, S3 Table for details). By contrast, most carbohydrate metabolism, DNA metabolism, cell division, membrane and cell wall synthesis and sulfur oxidation are more prevalent in downwelling conditions (Fig 4). Only branched chain amino acid metabolism (isoleucine degradation) was affected by the transition, and it was affected negatively. 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 cellular functions 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 802,136. 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.g004: Significantly different most abundant cellular functions 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 802,136. Different letters (a > b > c) represent statistically significant differences (corrected p <0.05), while “ab” are intermediate values.
Mentions: The majority of cellular species identified were recognized as bacteria that are common members of the marine community, such as Pelagibacter, Alteromonas and several members of the Flavobacteriales and Rhodobacteriales orders (Fig 3). Except for Pelagibacter and Alteromonas, which increased with the upwelling, most bacteria seem more abundant in the downwelling period (Fig 3). Three exceptions to the bacterial dominance are noteworthy, having increased with the upwelling: Nitrosopumilus maritimus, a thaumarchaea; Thalassiosira pseudonana, a centric diatom; and Ostreococcus lucimarinus, a picoeukaryote (Fig 3, S2 Table). Ostreococcus and uncultivated Gammaproteobacterium HTCC 2207, in fact, peaked over the transition, suggesting that the transition benefited at least a few microbial species. S2 Table presents the detailed taxonomic annotation and statistical analysis, but all aspects highlighted in the text refer to statistically significant observations. The cellular functions annotated are more diverse than the viral functions, with protein biosynthesis, transcription, electron-accepting and electron-donating reactions (respiration), membrane transport (Ton/Tol, Zn, Mn), nitrogen metabolism (ammonia assimilation, denitrification, nitrogen fixation), phosphorus metabolism (phosphate), sulfate reduction, inorganic sulfur assimilation and protein folding responding positively to the upwelling (Fig 4, S3 Table for details). By contrast, most carbohydrate metabolism, DNA metabolism, cell division, membrane and cell wall synthesis and sulfur oxidation are more prevalent in downwelling conditions (Fig 4). Only branched chain amino acid metabolism (isoleucine degradation) was affected by the transition, and it was affected negatively. 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