Creature subacquee

BIOACUSTIC STUDIES IN ARCTIC NATURE

Basan

Climate change caused by the accumulation of greenhouse gases of anthropo­genic origin in the atmosphere has a growing impact on the environment. The anthropogenic influence on the Earth's climate is extended along latitudinal and altitudinal gradients from habitats to biomes and the speed at which climate change occurs impede the majority of species to adapt.

The retreat of sea ice, especially in the warm winter months, has decreased the available platforms that seals, walruses, and polar bears use to rest on and hunt from. All of Svalbard's resident marine mammals (i.e., the narwhal Monodon monoceros, bowhead whale Balaena mysticetus, the white whale Delphinapterus leucas) have evolved within the Arctic sea ice environment, over the millions of years of its existence, and their adaption to rapid climate change is not obvious.

Sounds play an important role in detecting the first signs of stress in animals from individual species, populations, communities, and landscapes. From the analysis of the literature, it emerges an unexpected influence of climate change in the ecoacoustic processes because vocal communication of animals is related to many environmental constraints of which climate change is a primary actor. Environmental conditions (e.g., temperature, humidity, noise, social organization, ice presence in polar seas) have direct effects on the presence of species and on their acoustic performances that are the result of complex interactions between the energetic environment, the animal biomass, and the structure of the social interactions.

For instance, the sound from ice melting and ice calving and the presence of free floating ice mass have an impact on geophones and on the transmission of bio­phonic sounds that at the moment are not well investigated. Due to the extreme plasticity of the acoustic characters, several change in the environment is imme­diately reflected in the acoustic behaviour of organisms where different ecoacoustic processes are involved (e.g., acoustic adaptation (hypothesis), acoustic niche  (hypothesis), acoustic active space, acoustic community, and acoustic phenology postulates. Here, we proposed a marine bioacoustics survey along the coast of Svalbard (see the red line in the Figure) through a towed acoustic array. The array can monitor sound from 0.1 to 60 kHz and it is useful to reveal the presence and acoustic behaviour of marine mammals. This information will allow us to assess the distribution and abundance of species along the latitudinal gradient and study their ecology.

Pod of Whales