To me, that is great news. I don't want the seas around the UK industrialised any more. Simples...
Good luck with that. Offshore wind is almost certain to increase.
My boss' cousin was a grass seed grower - they were expending huge efforts in 70's and 80's developing grass that produced less flatulence. Every bit of sugar converted into methane isn't being converted into cow, wasting ground, fertiliser, tractor fuel etc. It was done for purely commercial reasons but it would have had great environmental benefits. They never got it to yield enough vs other grasses (in his working life). I wonder if other dietary approaches like the seaweed you mention gave better results and made the research redundant?
It fascinating that such efforts were being made in the 70s and 80s. I have seen widely varying claims about methane reduction by using seaweed based additives: up to 99% which I take with a pinch of salt. Cattle and sheep will graze on seaweed so presumably they know it does them some good. The whole climate change issue is so much more complicated than we realise - the more I look into it, the more questions….. if cattle can stop burping methane using zero input seaweed aquaculture on grass land which sequesters carbon by both increasing soil carbon content and increasing the depth of soil, eating beef and drinking milk might be better for the planet than growing trees…
I'm talking about bacteria as the stuff decomposes, feeding it to things may well be different but irrelevant to my point. Too many people think that planting something, anything, will consume CO2 and the problem is solved. That's not the case and is more often than not harmful to the environment. Methane is well known to be worse than CO2 amonth scientists, unfortunately not so for those with commercial interests in CO2 or those purely consuming the marketing fluff.
That's been done for decades now on landfill (mostly burned on site as it isn't clean enough to pipe into homes) and at least a decade in (big, new) cow sheds
The issue isn't the direct methane from that stuff though, it's upstream. The cow feed is a crop and the vast majority of that crop is waste which stays in the field. The landfill is probably 1% of what was produced, so while it does reduce a tiny amount of the output it's a drop in the ocean compared to total output. Take a banana skin - you ate the banana and threw it away and we burn 100% of the methane at landfill. Then factor in the leaves on the banana tree, the tree itself, all of which will eventually rot, but add in any compost created and used, and you see it rapidly becomes impossible to manage.
Landfills that produce sufficient methane ( not all do) use the gas to produce on site electricity which is fed into the grid, it's not quite as rosey as it seems as the methane invariably has a significant amount of sulphur compounds ( mercaptans ) in it which are problematic for the generators and the release of sulphur oxides into the atmosphere is not good. I know of no landfills that use scrubbers but I am now out of date. Also the methane is of low CV and it's a marginal calculation as to if it's going to be cost effective, the methane comes during a specific period in the landfill cells development and life not over the entire life span of the landfill at least not in useable quantities, peoples noses might tell them different but noses especially for mercaptans are extremely sensitive.
From the reading I’ve done, plant decomposition results in CO2 being released in aerobic situations, where methane is only released in anaerobic conditions. Anaerobic conditions exists where water saturates the environment (eg bog, cows stomach etc) which is a relatively small part of the land based decomposition process. Regenerative farming in the US has yielded surprising increases in soil depths, from a proportion of carbon not being decomposed into gasses (after all this is how the prairies, savannahs and steppe got their soil in the first place). Reading about the decomposition of kelp, it seems kelp either decomposes into CO2 or solid carbon compounds - no mention of methane. It seems that aerobic decomposition is still possible under water so I guess the bacteria etc can live off O2 dissolved in water, presumably from photosynthesis within the kelp. Interestingly there seems to be scientific evidence that kelp might provide a significant long term carbon sink since a significant quantity of the carbon within kelp can be buried in the seabed.
All of the research I've seen about decomposition of seaweed basically says nobody knows. The general consensus seems to be based on the guess that it will decompose with oxygen and that for some reason the CO2 will magically sit in the seabed undisturbed. Just as likely that it will get covered and have no oxygen then bubble off to the surface, but nobody is trying to research that because it's hard to do given the environment, and nobody is funding it because the money is in CO2 right now.