Effect of anthropogenic electromagnetic fields used for subsurface oil and gas exploration (controlled-source electromagnetics, CSEM) on the fertilization success and embryonic development of Atlantic cod (Gadus morhua).

Abstract

Surveys that rely on Controlled Source Electromagnetics (CSEM) explore the seabed for hydrocarbon deposits. These surveys can overlap temporally and spatially with spawning areas for Atlantic cod (Gadus morhua). Cod eggs are planktonic and develop in the water column and therefore may be exposed to the electromagnetic fields (EMFs) generated by CSEM. We replicated equivalent EMFs in the laboratory and tested their potential effects on cod reproduction. Two experiments were conducted: 1) 15-min. single EMF exposure of male cod, followed by assessment of sperm motility and subsequent monitoring of offspring development; 2) 15-min, single EMF exposure of fertilized eggs, followed by monitoring of embryonic development. Three EMF intensities, corresponding to 30 [50.3 μT], 100 [12.6 μT] and 1000 m [0.126 μT] between the organism and the source, were applied in each experiment. Exposure to EMFs had no effect on size, morphology or cardiac function in any of the experiments. Sperm velocities increased slightly, by 0.5 % in curvilinear path and 0.6 % in average path length post-exposure. However, the functional significance of this effect is likely negligible.

AI evidence extraction

Main findings

In laboratory-replicated CSEM-equivalent EMFs, 15-min single exposures of male cod or fertilized eggs showed no effects on size, morphology, or cardiac function during development. Sperm velocities increased slightly post-exposure (0.5% curvilinear path; 0.6% average path length), described as likely functionally negligible.

Outcomes measured

• fertilization success
• sperm motility (sperm velocities)
• offspring development
• embryonic development
• size
• morphology
• cardiac function

Limitations

• Frequency characteristics of the EMF exposure are not reported in the abstract.
• Sample size and statistical details are not provided in the abstract.
• Only acute (single 15-min) exposures were tested.
• Laboratory replication may not capture full field conditions of CSEM surveys.

Suggested hubs

• occupational-exposure (0.2)
  Study concerns anthropogenic EMFs from industrial geophysical surveys (CSEM), though not human occupational exposure.

{
    "study_type": "animal",
    "exposure": {
        "band": null,
        "source": "controlled-source electromagnetics (CSEM) for subsurface oil and gas exploration",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "15-min single exposure"
    },
    "population": "Atlantic cod (Gadus morhua) males (sperm) and fertilized eggs/embryos",
    "sample_size": null,
    "outcomes": [
        "fertilization success",
        "sperm motility (sperm velocities)",
        "offspring development",
        "embryonic development",
        "size",
        "morphology",
        "cardiac function"
    ],
    "main_findings": "In laboratory-replicated CSEM-equivalent EMFs, 15-min single exposures of male cod or fertilized eggs showed no effects on size, morphology, or cardiac function during development. Sperm velocities increased slightly post-exposure (0.5% curvilinear path; 0.6% average path length), described as likely functionally negligible.",
    "effect_direction": "mixed",
    "limitations": [
        "Frequency characteristics of the EMF exposure are not reported in the abstract.",
        "Sample size and statistical details are not provided in the abstract.",
        "Only acute (single 15-min) exposures were tested.",
        "Laboratory replication may not capture full field conditions of CSEM surveys."
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "controlled-source electromagnetics",
        "CSEM",
        "anthropogenic electromagnetic fields",
        "oil and gas exploration",
        "Atlantic cod",
        "Gadus morhua",
        "sperm motility",
        "embryonic development",
        "fertilization success",
        "cardiac function"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.200000000000000011102230246251565404236316680908203125,
            "reason": "Study concerns anthropogenic EMFs from industrial geophysical surveys (CSEM), though not human occupational exposure."
        }
    ]
}

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