Zooplankton mortality and distribution around a seismic survey
Emilie Hernes Vereide1, Anne Christine Utne-Palm2, Josefin Titelman3
1Ecosystem Acoustics Group, Institute of Marine Research, Nykirkekaien 1, Bergen, NO-5004, Norway. emilie.hernes.vereide@hi.no.
Scientific Reports
|October 1, 2025
Summary
Seismic airgun surveys in the North Sea showed limited immediate harm to zooplankton. However, delayed impacts on zooplankton populations from this underwater noise require further study.
Area of Science:
- Marine Biology
- Acoustic Ecology
- Oceanography
Background:
- Anthropogenic underwater noise from seismic airguns is a growing concern for marine ecosystems.
- Zooplankton are vital to marine food webs, yet seismic survey impacts remain poorly understood.
Purpose of the Study:
- To assess the effects of seismic airgun surveys on zooplankton in the North Sea.
- To investigate immediate and delayed mortality in zooplankton species exposed to seismic noise.
Main Methods:
- Field sampling of zooplankton biomass and distribution during an active seismic survey.
- Laboratory exposure of cultured zooplankton (Calanus finmarchicus) to simulated seismic noise.
- Measurement of sound exposure levels at various distances from the seismic source.
Main Results:
- Zooplankton biomass distribution was primarily influenced by hydrography and chlorophyll, unaffected by seismic activity.
- Immediate mortality of Calanus spp. in the field was low (<35.9%) and uniform across sound levels.
- Cultured Calanus finmarchicus showed low immediate mortality (<10%), but mortality increased up to 30% within 7 days post-exposure.
Conclusions:
- Immediate impacts of seismic surveys on zooplankton appear limited, with biomass distribution unaffected.
- Delayed mortality in zooplankton suggests potential for longer-term population effects.
- Further research is needed to understand the population-level consequences of seismic noise on zooplankton.
