The sounds of silence: regime shifts impoverish marine soundscapes
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Regime shifts are well known for driving penetrating ecological change, yet we do not recognise the consequences of these shifts much beyond species diversity and productivity. Sound represents a multidimensional space that carries decision-making information needed for some dispersing species to locate resources and evaluate their quantity and quality.
Here we assessed the effect of regime shifts on marine soundscapes, which we propose has the potential function of strengthening the positive or negative feedbacks that mediate ecosystem shifts.
We tested whether biologically relevant cues are altered by regime shifts in kelp forests and seagrass systems and how specific such shifted soundscapes are to the type of driver; i.e. local pollution (eutrophication) vs. global change (ocean acidification).
Here, we not only provide the first evidence for regime-shifted soundscapes, but also reveal that the modified cues of shifted ecosystems are similar regardless of spatial scale and type of environmental driver. Importantly, biological sounds can act as functional cues for orientation by dispersing larvae, and observed shifts in soundscape loudness may alter this function.
These results open the question as to whether shifted soundscapes provide a functional role in mediating the positive or negative feedbacks that govern the arrival of species associated with driving change or stasis in ecosystem state.
KeywordsRegime shift Kelp Seagrass Soundscape Snapping shrimps Orientation Population replenishment Ocean acidification Climate change
This study was supported by Australian Research Council (ARC) Future Fellowship to I.N. (Grant No. FT120100183) and a grant from the Environment Institute (The University of Adelaide). S.D.C. was supported by an ARC Future Fellowship (Grant No. FT0991953).
All authors contributed to the design of the study, collection of the data, and writing of the article. T.R. analysed the data.
Compliance with ethical standards
Conflict of Interest
The authors declare that they have no conflict of interest.
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