After the first working telegraph was invented by William Cooke and Charles Wheatstone in 1839, the idea to connect North America and Europe with a transatlantic submarine cable was born. The desire to connect continents was always present, and after a decade of experiments and testings, the idea became reality.
The first successful attempt in the early 1850s connected Great Britain to the mainland Europe and laid the foundation for the first transatlantic telegraph cable in 1858 that connected Valentia Island in western Ireland to Heart’s Content in eastern Newfoundland, successfully reducing the communication time from 10 days to a matter of minutes. The first cable didn’t last very long but it was the first successful attempt of a long-distance communication cable. Until the 1870s a couple more cables were laid. The mentioned cables were much more durable and they allowed much quicker transmission than the first one. 
(Fig. 1: Laying the cables in the early 20th century)
Even though the first cables were laid in the middle of the 19th century, the environmental concern of the potential impact of cables on the marine environment is a much more recent question. During installation, maintenance and decommissioning phases many potential environmental effects can occur. Habitat disturbances, sediment resuspension, chemical pollution and underwater noise emission, while during the operation phase the changes in electromagnetic fields, heat emission, risk of entanglement, chemical pollution, and creation of artificial reef and reserve effects can all harm the environment.
(Fig 2: Corals growing on one of the old cables)
In my opinion, we must acknowledge the potential environmental effects and try to avoid interfering with nature. I believe that we should try and leave the marine environment intact as much as we possibly can. Even though some of the old submarine cables are still working and could be used, they were abandoned because of their small capacity that wouldn’t be enough for heavy commercial use. The abandonment of said cables and the decision to just leave them at the bottom of the ocean possesses a threat to the environment and present irreversible damage to our environment.
 Cookson, Gillian. (2006). Submarine Cables: Novelty and Innovation, 1850–1870. Transactions of the Newcomen Society. 76. 207-219.
 Wikipedia, 2020, Submarine Communications Cable, Last modified November 8, 2020, https://en.wikipedia.org/wiki/Submarine_communications_cable
 & [Fig. 2] Bastien Taormina, Juan Bald, Andrew Want, Gérard Thouzeau, Morgane Lejart, Nicolas Desroy, Antoine Carlier (2018), A review of potential impacts of submarine power cables on the marine environment: Knowledge gaps, recommendations and future directions
[Fig. 1] LTE Magazine, 2018, Submarine cables from 1850 to present days, Last modified November 5, 2018, https://ltemagazine.com/submarine-cables-from-1850-to-present-days