Context of Blue planet II : take a deep breath, a BBC Studios Natural History Unit production ; a co-production with BBC America, Tencent, WDR, France Televisions and CCTV9 ; a BBC Open University partnership ; executive producer, James Honeyborne ; series producer, Mark Brownlow ; producers, Miles Barton, Orla Doherty, Kathryn Jeffs, Will Ridgeon, John Ruthven, Jonathan Smith