Data from: Silent oceans: ocean acidification impoverishes natural soundscapes by altering sound production of the world’s noisiest marine invertebrate

Soundscapes are multidimensional spaces that carry meaningful information for many species about the location and quality of nearby and distant resources. Because soundscapes are the sum of the acoustic signals produced by individual organisms and their interactions, they can be used as a proxy for the condition of whole ecosystems and their occupants. Ocean acidification resulting from anthropogenic CO2 emissions is known to have profound effects on marine life. However, despite the increasingly recognised ecological importance of soundscapes, there is no empirical test of whether ocean acidification can affect biological sound production. Using field recordings obtained from three geographically separated natural CO2 vents, we show that forecasted end-of-century ocean acidification conditions can profoundly reduce biological sound quantity and quality. Snapping shrimps were among the noisiest marine organisms and the suppression of their sound production at vents was responsible for the vast majority of the soundscape alteration observed. To assess mechanisms that could account for these observations, we tested whether long-term exposure (2-3 months) to elevated CO2 induced a similar reduction in the snapping behaviour (loudness and frequency) of snapping shrimps. The results indicated that the soniferous behaviour of these animals was substantially reduced in both frequency and sound level of snaps produced. As coastal marine soundscapes are dominated by biological sounds produced by snapping shrimps, the observed suppression of this component of soundscapes could have important and possibly pervasive ecological consequences for organisms that use soundscapes as a source of information. This trend towards silence could be of particular importance for those species whose larval stages use sound for orientation towards settlement habitats.

声景（soundscapes）是多维空间，可为众多物种传递关于远近各类资源的位置与质量的关键信息。由于声景是单个生物体发出的声学信号及其相互作用的总和，因此可作为整体生态系统及其栖息生物状态的替代指标。由人为CO₂排放引发的海洋酸化（ocean acidification），已知会对海洋生物造成深远影响。然而，尽管学界日益认识到声景的生态重要性，但目前尚无实证研究检验海洋酸化是否会影响生物发声行为。本研究通过采集三处地理分隔的天然CO₂喷口的野外录音，证明预估的世纪末海洋酸化水平可大幅降低生物发声的数量与质量。鼓虾（snapping shrimps）是海洋中最喧闹的生物类群之一，喷口处鼓虾发声行为受到抑制，是观测到的声景发生显著改变的主要原因。为探究造成上述观测结果的潜在机制，本研究检验了长期暴露（2至3个月）于高浓度CO₂环境中，是否会同样降低鼓虾的螯夹合行为（包括发声响度与频率）。结果显示，鼓虾的发声行为在螯夹合的频率与声压级两方面均出现显著下降。由于近岸海洋声景主要由鼓虾产生的生物声学信号主导，观测到的该类声景组分受到抑制的现象，可能会对依赖声景获取信息的生物造成重要且广泛的生态影响。这种声景逐渐沉寂的趋势，对于幼体阶段依赖声音定向寻找定居生境的物种而言尤为关键。