Man-made underwater sound may affect marine ecosystem

Underwater sound linked to human activity could alter the behaviour of seabed creatures that play a vital role in marine ecosystems, says a new research.

Exposure to increasing levels of sounds that resemble human activity such as shipping traffic and offshore construction activities results in behavioural changes in certain invertebrate species that live in coastal and shelf environments that support high levels of biodiversity, the study said.

Such sounds can cause certain species to reduce irrigation and marine sediment turnover, the findings revealed.

"Our study provides evidence that exposing coastal environments to anthropogenic sound (increased human-generated sound) fields is likely to have much wider ecosystem consequences than are presently understood," said Martin Solan, professor at University of Southampton in Britain.

These underwater species make a crucial contribution to the seabed ecosystem, as their burrowing and bioirrigation activities -- process of underwater organisms flushing sediment with overlying water -- are crucial in nutrient recycling and carbon storage, the researchers said.

Reductions in irrigation by these species can lead to the formation of compact marine sediments that suffer reduced oxygen, potentially becoming anoxic -- depleted of dissolved oxygen and a more severe condition of hypoxia --low oxygen -- which may impact the seabed productivity, sediment biodiversity and also the production of fisheries, the findings, published in the journal Scientific Reports, showed.

The Southampton researchers exposed three species - the langoustine (Nephrops norvegicus), a slim, orange-pink lobster which grows up to 25 cm long, the Manila clam (Ruditapes philippinarum) and the brittlestar (Amphiura filfiformis) to two different types of underwater sound fields: continuous broadband noise (CBN) that mimic shipping traffic and intermittent broadband noise (IBN) reflecting marine construction activity.

The results showed that the sounds could alter the way these species behaved when interacting with their environments.