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The evaluation of biogenic silica in brackish and freshwater strains reveals links between phylogeny and silica accumulation in picocyanobacteria

Aguilera, Anabella LU ; Lundin, Daniel ; Charalampous, Evangelia ; Churakova, Yelena ; Tellgren-Roth, Christian ; Śliwińska-Wilczewska, Sylwia ; Conley, Daniel J. LU orcid ; Farnelid, Hanna and Pinhassi, Jarone (2025) In Applied and Environmental Microbiology 91(4).
Abstract

Through biosilicification, organisms incorporate dissolved silica (dSi) and deposit it as biogenic silica (bSi), driving the silicon (Si) cycle in aquatic systems. While Si accumulation in marine picocyanobacteria has been recently observed, its mechanisms and ecological implications remain unclear. This study investigates biosilicification in marine and brackish picocyanobacteria of the Synechococcus clade and two model freshwater coccoid cyanobacteria. Brackish strains showed significantly higher Si quotas when supplemented with external dSi (100 µM) compared to controls (up to 60.0 ± 7.3 amol Si.cell-1 versus 9.2 to 16.3 ± 2.9 amol Si.cell-1). Conversely, freshwater strains displayed no significant differences in Si quotas between... (More)

Through biosilicification, organisms incorporate dissolved silica (dSi) and deposit it as biogenic silica (bSi), driving the silicon (Si) cycle in aquatic systems. While Si accumulation in marine picocyanobacteria has been recently observed, its mechanisms and ecological implications remain unclear. This study investigates biosilicification in marine and brackish picocyanobacteria of the Synechococcus clade and two model freshwater coccoid cyanobacteria. Brackish strains showed significantly higher Si quotas when supplemented with external dSi (100 µM) compared to controls (up to 60.0 ± 7.3 amol Si.cell-1 versus 9.2 to 16.3 ± 2.9 amol Si.cell-1). Conversely, freshwater strains displayed no significant differences in Si quotas between dSi-enriched treatments and controls, emphasizing that not all phytoplanktons without an obligate Si requirement accumulate this element. The Si-accumulating marine and brackish picocyanobacteria clustered within the Synechococcus clade, whereas their freshwater counterparts formed a distinct sister group, suggesting a link between phylogeny and silicification. Rapid culture growth caused increased pH and led to dSi precipitation, influencing apparent dSi uptake; this was mitigated by pH control through bubbling. This phenomenon has significant implications for natural systems affected by phytoplankton blooms. In such environments, pH-induced silicon precipitation may reduce dSi availability impacting Si-dependent populations like diatoms. Our findings suggest brackish picocyanobacteria could significantly influence the Si cycle through at least two mechanisms: cellular Si accumulation and biologically induced changes in dSi concentrations.

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; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
biosilicification, brackish picocyanobacteria, silicon accumulation, Synechococcus
in
Applied and Environmental Microbiology
volume
91
issue
4
publisher
American Society for Microbiology
external identifiers
  • pmid:40145754
  • scopus:105003322594
ISSN
0099-2240
DOI
10.1128/aem.02527-24
language
English
LU publication?
yes
id
dc9d6fe8-060c-4fc0-b7c0-634a5fee9349
date added to LUP
2025-08-12 12:19:54
date last changed
2025-08-13 03:00:03
@article{dc9d6fe8-060c-4fc0-b7c0-634a5fee9349,
  abstract     = {{<p>Through biosilicification, organisms incorporate dissolved silica (dSi) and deposit it as biogenic silica (bSi), driving the silicon (Si) cycle in aquatic systems. While Si accumulation in marine picocyanobacteria has been recently observed, its mechanisms and ecological implications remain unclear. This study investigates biosilicification in marine and brackish picocyanobacteria of the Synechococcus clade and two model freshwater coccoid cyanobacteria. Brackish strains showed significantly higher Si quotas when supplemented with external dSi (100 µM) compared to controls (up to 60.0 ± 7.3 amol Si.cell-1 versus 9.2 to 16.3 ± 2.9 amol Si.cell-1). Conversely, freshwater strains displayed no significant differences in Si quotas between dSi-enriched treatments and controls, emphasizing that not all phytoplanktons without an obligate Si requirement accumulate this element. The Si-accumulating marine and brackish picocyanobacteria clustered within the Synechococcus clade, whereas their freshwater counterparts formed a distinct sister group, suggesting a link between phylogeny and silicification. Rapid culture growth caused increased pH and led to dSi precipitation, influencing apparent dSi uptake; this was mitigated by pH control through bubbling. This phenomenon has significant implications for natural systems affected by phytoplankton blooms. In such environments, pH-induced silicon precipitation may reduce dSi availability impacting Si-dependent populations like diatoms. Our findings suggest brackish picocyanobacteria could significantly influence the Si cycle through at least two mechanisms: cellular Si accumulation and biologically induced changes in dSi concentrations.</p>}},
  author       = {{Aguilera, Anabella and Lundin, Daniel and Charalampous, Evangelia and Churakova, Yelena and Tellgren-Roth, Christian and Śliwińska-Wilczewska, Sylwia and Conley, Daniel J. and Farnelid, Hanna and Pinhassi, Jarone}},
  issn         = {{0099-2240}},
  keywords     = {{biosilicification; brackish picocyanobacteria; silicon accumulation; Synechococcus}},
  language     = {{eng}},
  number       = {{4}},
  publisher    = {{American Society for Microbiology}},
  series       = {{Applied and Environmental Microbiology}},
  title        = {{The evaluation of biogenic silica in brackish and freshwater strains reveals links between phylogeny and silica accumulation in picocyanobacteria}},
  url          = {{http://dx.doi.org/10.1128/aem.02527-24}},
  doi          = {{10.1128/aem.02527-24}},
  volume       = {{91}},
  year         = {{2025}},
}