The reason I asked the question is that there is a huge undersea...

The reason I asked the question is that there is a huge undersea impact if they are fixed .
Both pose a significant impact due to the ongoing vibration and electromagnetic (cabling) disturbance to marine life .in particular pelagic spieces and marine life using natural magnetic navigation. But the fixed version footprint also requires (depending on the bedrock,depth..drilling pile-driving concreting and sedimentary disturbance ) significantly more and multitudes greater by quantity,than a single "dining room table" sized hole to hit gas ...(see previous wind farm installs)

as well as the above water visual and navigational .and environmental hazards they pose

Therefore it's pertinent to the argument ,in relation to the two potential arguments.

some will counter negate the benifits of installing and may attract equal opposition .. however will also highlight the deluded coastal saviours mis- informed opinion.