Thanks for the link, the thing I wanted to know and this paper answered was how they measured the current and this was the cool part! They used voltage inductio

Thanks for the link, the thing I wanted to know and this paper answered was how they measured the current and this was the cool part! They used voltage induction caused by salt water flowing past abandoned submarine telephone cables. [1] [1]https://journals.ametsoc.org/jtech/article/31/5/1169/262 https://journals.ametsoc.org/jtech/article/31/5/1169/262