The relationship between seaweed and the reduction of Methane emissions
An paper that I wrote on a fascinating topic for the aquatic permaculture module of the Ecosystem Restoration Design Certification course in 2020.
Ruminant animals are mammals that are able to acquire nutrients from plant-based foods by fermenting their foods in a specialized stomach called the rumen. Since most vertebrates do not contain the adequate digestive enzymes to break down cellulose (the main polysaccharide in the cell walls of plants), ruminant animals have evolved a complex digestive processes that allows them to break down these plant polymers and, well, ultimately, eat lots and lots of grass. In ruminants, the fermentation or pre-digestion of plant compounds occurs prior to digestion in the front part of the digestive system and is attributed to a unique consortia of microbial communities that live in the rumen. These microbial communities look very different than ours, and are specialized to break down and metabolize huge qualities of plant material. This process is called rumination.
There are roughly 200 species of ruminants alive today; wild ruminants (giraffes, antelope, bovines, deer, gazelles) numbering at 75 million, and domestic ruminants numbering at a whopping 3.5 billion, with cattle, sheep and goats accounting for 95% of the total population.
That’s almost 1 domestic ruminant for every 2 humans.
As each individual animal goes about its day to day life, eating enormous amounts of plants, mostly in the form of grasses (an average sized adult cow will consume 2.0% of body weight or an average of 24 pounds of grass per day) a specific class of Archea present in the rumen called methanogens produce methane as their main gaseous metabolic byproduct. This methane is excreted out of the animal through mostly burps (95%), but also some farts.
Methane CH4
Methane is a strong greenhouse gas and a huge contributor to the well known ‘greenhouse gas effect’ that’s contributing to global climate change and climactic warming feedback loops. In 2010, it was found that the methane production from rumen fermentation accounted for 43% of the total greenhouse gas emissions from all agricultural activity in the world and 36% of the total US methane emissions. Methane production by meat animals, principally ruminants, is estimated at 20% of the global production of methane.
“Each year, livestock production pumps out greenhouse gases with the equivalent warming effect of more than 7 gigatons of carbon dioxide, roughly the same global impact as the transportation industry. Nearly 40% of that is produced during digestion: cattle, goats, and sheep belch and pass methane, a highly potent, albeit relatively short-lived, greenhouse gas.
If the reductions achieved in the UC Davis study could be applied across the worldwide livestock industry, it would eliminate nearly 2 gigatons of those emissions annually — about a quarter of United States’ total climate pollution each year.” -James Temple, 2018
Ultimately when you break it all down, there is no way of denying that the sheer mass of livestock is feeding climate alteration in a big way (not to mention the other ways our insatiable appetite for industrialized, factory farmed meat is proving to be ecologically destructive ie mass deforestation for the production of livestock feed), and still, no one is really talking about it enough tp actually move towards solutions.
However, in the past decade there has been some incredible discoveries showing that adding certain types of seaweed or kelp to ruminant livestock feed can drastically reduce the amount of methane they produce. A completely natural solution which also improves the health of the animal and improves immune function, reducing the need for antibiotics, hormones, and other synthetic medications.
When it comes to seaweed, a little goes a long way. A study from University of California Davis states that a small amount of seaweed added to the animals feed cut the cows methane production by nearly 60%! Also, its been found that blocking methane production (‘spared methane energy’) leads to more of the consumed carbohydrates from grasses get directed to the task of building tissue, leading to higher body weights and more meat and milk from livestock.
“In 2014, Australian researchers found that low doses of a red algae known as Asparagopsis taxiformis virtually eliminated methane production in lab experiments. Field trials with live sheep cut emissions as much as 80%, while the UC Davis experiment, the first on live cattle, showed a 58% reduction on average when a related seaweed made up 1% of their diet.”
Without a doubt, from many resources I have read on the issue, it seems to be that seaweed is a fool-proof way to reduce methane emissions from domestic ruminant animals. I hold curiosity about the biochemical mechanisms happening in the digestion process of these animals that seaweed so drastically effects. I wonder if it’s the salt, minerals, or microbial communities living on/in seaweed that are interfering or competing with the methanogens in the rumen. Whatever it may be, seaweed seems like a promising solution for this systemic issue.
Gathering Kombu (Laminaria setchellii) and Chainbladder (Cystoseira osmundacea) kelp on the Pacific coast (Coast Miwok territory)
If this approach is being claimed as a regenerative solution, why aren’t we seeing this being applied on a large scale then?
Well, from my research I found that the largest limiting variable is that there just isn’t enough seaweed to meet the needs of all of the hungry animal bodies. Given the enormous population of domestic livestock (the whole 3.5 billion of them) there isn’t even close to enough seaweed of which we could harvest sustainably to meet the needs of including even 1% of seaweed addition into regular feed, which based on the studies thus far, would be all they need.
This is where seaweed farming on a large scale comes into play. If more cattle ranchers step into this movement, there will be an enormous demand for seaweed; a huge economic incentive for scaling up seaweed farming around the globe. And, there’s signs that this knowledge is catching on (well, being enforced) in the ranching communities. In 2016 California lawmakers passed a law that aims to reduce the states methane emissions by 40% below 2013 levels by 2030. The California Air Resources Board subsequently ordered a majority of the reductions in the new law to come from the dairy industry.
So, it looks like there is a very promising demand that has the potential to catalyze the need for large scale seaweed farming operations in the near future.
Time to go back to where it all started, the oceans.
