Freshwater Ecoacoustics
The field of freshwater ecoacoustics is a new and rapidly growing area of research in which the sounds in a pond, lake or river are recorded and analysed to answer ecological questions. A hydrophone (pictured below on the right) is used to capture underwater sounds. Listening to the underwater sounds in freshwaters has huge potential to reveal novel insights into freshwater ecosystem function and condition. In addition, to showcase the impressive biodiversity of freshwater ecosystems and raise awareness of conservation efforts through scientific and artistic sound recordings.
Ponds are bursting with life and full of mysterious sounds! Aquatic insects rub hard body parts together to attract mates and submerged plants release oxygen bubbles as they respire in the hot sun.
As pond weeds photosynthesize in the hot sun they release tiny oxygen bubbles through small pores in the leaf surface called stomata into the water producing strange buzzing, whirring, and popping sounds.
Water boatmen (below) dominate most pond soundscapes with eerie rattling sounds. These sounds are produced by rubbing hard body parts together in a process called stridulation. The pygmy water boatman (Micronecta scholtzi) is capable of making the loudest sound in the animal kingdom relative to body size!
We suspect that different species of aquatic insects produce different sounds because identification books focus on sound producing anatomy to distinguish between species. If different species use different instruments, then surely the sounds they produce will be species-specific!
Some species are indicators of specific environmental conditions because they are fussy about where they live. By cataloguing species-specific sounds in ponds we will be able to assess the condition of ponds based on the presence or absence of certain fussy species simply by listening.
Click HERE to read about the first detailed description of daily acoustic activity cycles in temperate ponds. In addition, we outline the use of six common acoustic indices for describing temperate pond soundscapes and provide guidelines for survey design.
Click HERE to read about my use of freshwater ecoacoustics to evaluate the success of pond restoration in Norfolk and describe the species-specific sounds produced by three species of water beetle.
Click HERE to read my systematic review of the freshwater bioacoustics literature. I describe taxonomic and habitat type representations within the literature and identify promising areas for future research.
Click HERE to read the first ever standardised ecoacoustic survey protocol for small waterbodies. I provide an overview of recording equipment, provide a workflow for surveying small water bodies, and establish an open-access Zenodo community for sharing soundscape data.