How undersea cables may affect marine life


Beyond localised habitat damage or loss, submarine power and communication cables may temporarily or permanently impact the marine environment through heat, turbidity (during cable burial), risk of entanglement and the introduction of artificial substrates. Still, areas through which cables pass are often designated as protected, meaning anchors, bottom trawls and even fishing can be restricted. The Cook Strait Cable Protection Zone (CPZ) in New Zealand, for example, restricts fishing near cables, effectively creating a reserve and thus improving fish stocks.

And submarine cables do not pollute: they are stable, inert structures that can even be recovered and recycled after they’ve served their time (about 20-40 years, on average). “The carbon footprint is actually relatively low compared to most of the internet’s infrastructure,” says Nicole Starosielski,associate professor at NYU. Her book, The Undersea Network, examines the cultural and environmental dimensions of transoceanic cable systems, and she adds an important social science perspective to the discussion. “We’ve actually advocated for more cables, connecting large onshore data centers on renewable grids, in order to minimise fossil fuel consumption.”

Indeed, small developing island states are crucially tethered to these elaborate cable systems, without which they would struggle to obtain green energy, telecommunications, remote-work technology, e-medicine and other digital services. Ocean life – and its often-complex interaction with human activities – is riddled with unknowns; for ecologists worried about environmental conservation, these subsea cables remain a serpentine question mark.

But, as Clare explains: “There is value in the research, which will help industry leaders, policy-makers, cable companies and other parts of the wider Blue Economy strive to ensure any development of the seafloor is as sustainable as possible.”


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