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Evaluation of the Effects of Extremely Low Frequency Electromagnetic Fields on Movement in the Marine Diatom Amphora coffeaeformis.

The Biological bulletin · 1998 · Mixed · Low evidence

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MixedLow evidencePaper 5392

Across five strains tested on agar plates over a broad range of field conditions, no effect on population motility was demonstrated, and exposure period, cell density, and cell-cycle position did not alter susceptibility. After at least a month of preincubati…

Study snapshot

PublicationThe Biological bulletin · 1998
Study typeanimal
Reported directionMixed
Evidence ratingLow

Abstract

Published work has shown that population motility in the marine diatom Amphora coffeaeformis can be influenced by externally applied electromagnetic fields (EMFs). Here we report attempts to repeat these experiments, which have been proposed as a model for assessing the effects of EMFs on biological systems. Susceptibility to EMFs was tested using five strains of diatoms on agar plates at a very broad range of field conditions, but no effect on population motility was demonstrated. Exposure period to the EMFs, cell density, and position in the cell cycle had no effect on EMF susceptibility, and the direction and distance moved by the diatoms were not affected by EMFs. When tested after at least a month of preincubation at 20 {mu}T, diatoms of strains #2038, IIIB, and IIIF did show an EMF-induced increase in population motility over control cells (up to ~20%) at conditions predicted by the "ion cyclotron resonance" model, but this effect was ephemeral. Later, IIIB showed a similar increase that was abolished when (1) non-pre-incubated cells were used, (2) the EMF-producing coils were not energized, and (3) even harmonics were used. On observing the response of diatoms to EMFs in real time, a significant increase (~2-fold) in diatom speed over control cells was evident at "ion cyclotron resonance" conditions, using strain #2038 (pre-incubated at 20 {mu}T). The effect was abolished at an even harmonic. We conclude that EMFs can modulate diatom motility, but that the system is, as yet, not consistently reproducible.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeanimal
Effect directionmixed
PopulationMarine diatom Amphora coffeaeformis (five strains; includes strains #2038, IIIB, IIIF)
Sample sizeNot supplied
ExposureELF
Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Across five strains tested on agar plates over a broad range of field conditions, no effect on population motility was demonstrated, and exposure period, cell density, and cell-cycle position did not alter susceptibility. After at least a month of preincubation at 20 µT, some strains showed increased motility (up to ~20%) at conditions predicted by an ion cyclotron resonance model, but the effect was described as ephemeral; real-time observations in strain #2038 showed an approximately 2-fold speed increase at ion cyclotron resonance conditions that was abolished at an even harmonic.

Outcomes measured

  • Population motility
  • Direction moved
  • Distance moved
  • Speed of movement

Limitations

  • Effects were not consistently reproducible across attempts/conditions
  • Observed increases were described as ephemeral
  • Positive effects depended on preincubation at 20 µT and specific resonance/harmonic conditions
  • Sample size and detailed exposure parameters (e.g., frequency) not reported in the abstract
View raw extracted JSON
{
  "study_type": "animal",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Marine diatom Amphora coffeaeformis (five strains; includes strains #2038, IIIB, IIIF)",
  "sample_size": null,
  "outcomes": [
    "Population motility",
    "Direction moved",
    "Distance moved",
    "Speed of movement"
  ],
  "main_findings": "Across five strains tested on agar plates over a broad range of field conditions, no effect on population motility was demonstrated, and exposure period, cell density, and cell-cycle position did not alter susceptibility. After at least a month of preincubation at 20 µT, some strains showed increased motility (up to ~20%) at conditions predicted by an ion cyclotron resonance model, but the effect was described as ephemeral; real-time observations in strain #2038 showed an approximately 2-fold speed increase at ion cyclotron resonance conditions that was abolished at an even harmonic.",
  "effect_direction": "mixed",
  "limitations": [
    "Effects were not consistently reproducible across attempts/conditions",
    "Observed increases were described as ephemeral",
    "Positive effects depended on preincubation at 20 µT and specific resonance/harmonic conditions",
    "Sample size and detailed exposure parameters (e.g., frequency) not reported in the abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low frequency",
    "ELF",
    "electromagnetic fields",
    "EMF",
    "diatom",
    "Amphora coffeaeformis",
    "motility",
    "movement speed",
    "ion cyclotron resonance",
    "preincubation",
    "20 µT"
  ],
  "suggested_hubs": []
}
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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.2307/1543050
PubMed: 28570846

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