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“Mare Nostrum” has been the haven for a wide variety of marine species, the hub for perfect biodiversity conservation. Over the ages, however, it has emerged as one of the major global trading centres in the quickly evolving global economy, a distinct and delicate ecosystem that has been facing several environmental risks brought on by human activity. Among these, submarine cables.
Though both recyclable and necessary for worldwide energy supply, the installation and operation of these global communication infrastructures has sparked many concerns about the potential environmental impact, the economic issues arising from complex fisheries management, and the need for sustainable policies and regulatory changes to prevent a cyber-war on the seabed.
Cable industry vs. Science: game on!
The submarine cables framework appears to be a huge infrastructure that facilitates the flow of data and energy between continents from offshore energy stations to the mainland. In layman's terms, about 67,000 kilometres of new cables were installed worldwide between 2016 and 2020, with a current estimation of 113,000 kilometres to be installed annually by the end of 2023. A huge anthropological ecosystem through which $10 trillion worth of financial transactions are conducted every day on ever-more complicated supply chains, accounting for around 95% of all Internet traffic worldwide. A sizable industry that is projected to increase by 12.9% between 2022 and 2030, reaching a value of $48 billion, according to MarketResearch.com.
The cost of a single cable in the submarine cable sector can reach hundreds of millions of dollars, contingent upon the route's complexity and length. The “private owner” model, wherein a single IT corporation owns and operates the cable for its own purposes, has recently become more prevalent, despite the “consortia” one – between telecommunications, large technology businesses, and infrastructure specialised companies – has always been looked upon favourably. Collectively holding more than 66% of the submarine cable network's capacity, submarine cable routes are being redesigned by these “Over The Top” companies to connect their data centres in order to scale up digital production and storage, a recent industry report predicts.
High-voltage power cables are bigger and heavier: composed of insulating sheath-encased copper or aluminium conductors, they're usually buried beneath the seafloor for protection as they carry large currents of concentrated electricity. A recent construction concerning the Mediterranean lays with the new power line built by Italy’s Terna to connect the island of Elba and Piombino city: the 37-kilometre-long cable, according to the company’s press release, will “affect on its way out of the Piombino landing a Posidonia oceanic meadow for a stretch of about 3 km in length”.
Despite potential biodiversity effects, Terna assures that there is “maximum focus on the environmental impact with the transplantation of Posidonia oceanica from the affected area to a 1,650 m² site in the Gulf of Follonica”. In its official statements, the company speaks of “improvement for the quality of the local infrastructure, bringing significant benefits in terms of security, reliability, and sustainability". Yet it is important to acknowledge that a number of Posidonia - the most representative plant of the Mediterranean infralittoral zone - was removed and replanted during the project, somehow disturbing the marine ecosystem of the area.
“While burying the power cables lessens the intensity of the electromagnetic field at the seabed's surface, it does not completely eliminate it”, says Bastien Taormina, a marine ecology researcher at the Institute for Marine Research, in Norway. According to one of his papers, their placement can disturb the marine ecosystem by generating electromagnetic fields: “the higher the voltage and current, the stronger the electromagnetic field, the worse the environmental impact”. Taormina believes in the potential of renewable energy, “but its benefits” – he says – “must be weighted against the environmental impact of installing the vulnerable infrastructure to support it”, mainly if it affects the navigation of electrosensitive marine species, such as sharks and even eels, who use their internal magnetic north sense to prey and orientate.
High-voltage cables, also, can be connected to offshore wind farms too that float in the open sea. “If they are also placed on the water surface, the environmental risks will not only affect the benthic environment but also influence the pelagic one”, says Alessandro Cresci, Postdoctoral Research Scientist at the same Institute for Marine Research as Taormina, following the expansion of floating offshore wind farms in the Mediterranean. According to a research, the behaviour, ecology, and survival of species are among the aspects of life processes that are mostly impacted by EMFs associated with electricity production by offshore wind turbines that have both kinds of wires in marine habitats.
Telecommunication cables, instead, when ashore, end up in a concrete structure embedded in the beach, for later merging with a counterpart that travels to a landing station. Made of optical fibre, they are rather deposited on the seabed's top because the currents they carry are milder, conveying only simple data at low voltage. Much safer then? According to Michael Clare, leader of the Marine Geosystems department at the National Oceanography Centre (UK), they are. To safeguard cables from human activity in shallow waters, burying them may be necessary. In this scenario, "the seabed will be disturbed, but studies have shown that the benthos rapidly recolonise”, he says.
The greatest differentiation of Clare's vision on the impact of submarine cables on the marine environment from Taormina's lies in their degree of influence on the sea bottom, as well as the potential ecological repercussions: in his recent article, indeed, Clare presents a more “tentative” perspective on the tenuous relationship between environmental influences and marine organism behaviour. “Telecommunication cables do have an impact in terms of electromagnetic field disturbance for sea creatures”, he says, “but this is a minimal or even benign footprint on the marine environment”. And this applies to high-voltage power ones too: “Whether they are affected by the EMF intensities generated by power cables”, he says, “remains unclear and the subject of ongoing research".
So Giuseppe Valentino says too. Telecom Italia Sparkle’s Data Product Manager defends his company's strategy in implementing the construction of the BlueMed submarine cable by reiterating one message: “We want to consolidate Sparkle’s leadership in the Mediterranean basin through the extension and enhancement of our regional backbone". With a total system capacity of up to 400 terabits per second and a total length of about 1,000 kilometres, Sparkle's wholly owned BlueMed is an integral part of the Blue & Raman submarine cable system project, together with Google and other operators. This means that the entire project is based on a consortium model in which part of the shares belong to Google and a third partner. In addition, the cable itself shares fibre pairs with Blue.
