Terschek, A., Tremblay, N., Wang, S.V. et al. Anthropogenic low-frequency sound effects on resting metabolism and energy pathways in two marine benthic crustaceans. Mar Biol 172, 67 (2025). https://doi.org/10.1007/s00227-025-04634-3
Noise Pollution
Anthropogenic noise, or human made noise, in the ocean has been constantly growing over the last few decades. From cargo ships to drilling and offshore wind turbine operation, our noise is everywhere. This doesn’t just disturb marine organisms, it has widespread negative impacts on their behavior. Exposure disrupts marine mammal feeding, reproduction behavior in gobies, and resting in whales to name a few.
Research in the last 15 years also indicates anthropogenic noise exposure can damage cells in invertebrates as well. Cephalopods exposed to 48 hours of low frequency noise experienced damage to their mitochondria. This resulted in reduced sensory perception, reflexes, and balance. Not that anyone needs a reminder that the mitochondria is the powerhouse of the cell, but it quite literally is the heart of our cells, giving them the power to function. If it’s damaged, it can have major impacts on how an organism can function.
Terschek et al. 2025 studied how short term and long term exposure to anthropogenic noise impacted the isopod Idotea balthica and amphipod Gammarus locusta. Both are widespread, bottom-dwelling invertebrates that are key grazers on aquatic plants. A decline in either group would upset the balance of these communities, leading to unchecked growth of the plants they feed on.
Invertebrate Trials
Both invertebrates were exposed to an additional 25 decibels of noise above ambient background noise for 4 hours (short term exposure) and 72 hours (long term exposure). Idotea balthica showed no significant change in behavior when being exposed to the additional noise in either exposure trial. However, Gammarus locusta had significantly lower oxygen consumption rates when exposed to the additional noise. There was a 39% reduction during the short term exposure and a 35% reduction in the long term exposure compared to controlled conditions.
Stressful Noise
As anthropogenic noise in the ocean increases, it’s important to understand how it affects marine animals. Idotea balthica demonstrated no behavioral changes being exposed to additional noise beyond the ambient background that exists in the environment. This seems to indicate I. balthica has a high tolerance to noise stressors and may be able to adapt easily to future increases. On the other hand, Gammarus locusta had a significant adverse reaction to the additional noise. Even though its oxygen consumption decreased, there was no detectable change in mitochondrial enzymes. This means that the behavior change was more than likely not because of mitochondrial damage, but rather as a predator avoidance reaction. Reducing oxygen consumption makes prey like G. locusta less detectable to predators. Either G. locusta interpreted the noise as a potential predator, or it became stressed by the noise and instinctually enacted this behavior.
Anti-predator behavior can be costly for animals. Not only does it cost energy to do this behavior, but it disrupts other behaviors like feeding or mating. In a world with increasing noise, this means G. locusta may be constantly stressed, reducing its fitness. However, more research is needed to understand these long term effects. In the meantime, identifying the significant impact noise has on Gammarus locusta helps set up future research targeted at understanding its fitness moving forward.
I am a recent MSc graduate in marine biology from Bangor University, where I studied population dynamics of elasmobranchs off the coast of Wales. My interests lie in ecological data analysis to understand environmental processes and identify natural patterns. However, nothing beats being in the field and interacting directly with the marine life.
