Background
DúlaBio is a social and environmental start-up working on lowering the carbon footprint of food, using nature-based solutions - beginning with seaweed. We have designed and tested an Irish seaweed blend for anti-methanogenic activity in livestock agriculture, to reduce emissions and resource intensity, while remediating nutrient build-up and acidification in aquaculture systems during the cultivation stage.
Several research projects have been investigating the inclusion of certain red seaweed species for methane reduction in cattle feed for a number of years, with a recent publication reporting a reduction of up to 98% when included at 0.2% of the total diet fed. This latest study, along with a growing number of academics and companies working on the feasibility of using seaweed as a tool for agricultural greenhouse gas reduction, stemmed initially from a farmer's own observation on the benefits of feeding his herd the seaweed washed up from nearby beaches. Feeding seaweed to livestock as a complimentary source of minerals, vitamins and fibre is a well-known, traditional practice in livestock rearing in Ireland, as well as other Island or coastal agricultural nations across the world. We started our work with the aim of developing and integrating this traditional knowledge into modern practices that work in balance with nature, to mitigate climate change and feed people, while supporting farming livelihoods.
We have recently completed the first trial study of our seaweed blend for livestock methane reduction in Ireland, which examined the effects on methane eruptions in an organic beef cattle herd, as well as any impacts the supplement had on overall animal health and productivity.
These are the first publicly available data examining seaweed for livestock methane reduction in the Irish agricultural context, and which looks at the effects on a pasture-fed diet. We are sharing the details of our first trial study in this report, but any further questions can be directed to info@dulabio.com where we would be happy to share and discuss further.
Trial results
The trial took place over the course of 11 weeks on a high nature value, organic beef farm in Co. Sligo, where cows (a mixture of Hereford, Angus and Shorthorn) were fed their pasture diet supplemented with 0.5% seaweed blend for methane reduction. They were individually monitored for methane gas emissions using a hand-held gas detector, similar to those used in other enteric methane reduction studies. We approached this trial not as an exhaustive study to quantify absolute methane emissions, but as a collaborative exploration on how this could work in practice on a farm. Could we administer a seaweed supplement to a herd, avoiding painstaking individual dosing regimens and simply mixing the supplement with hay, given to the herd at large? Could we detect changes in eruptions across the herd, even with a minimal sampling approach? And what would seaweed supplementation accomplish in a pasture-fed herd, where most other studies focused on feedlot systems? We were enthusiastic to explore these questions further on the farm.
Trial cows sampling the seaweed supplement - passing the first taste test!
Methane emissions from cattle are typically detected as short-lived eruptions (usually lasting 1 - 10 seconds, see Figure 1) that can be periodically detected when sampling methane within 1m of a target cow’s nostrils, either during feeding or rumination. We sampled methane between 11:00 and 13:00 while the herd was feeding through a feeding barrier, for consistency and ease of sampling. By the end of the trial, we had observed a large reduction in the typical methane eruption profile for the herd, suggesting that the cumulative effect for seaweed supplementation may be as high as 79% reduction in total methane emissions. Here’s a rundown of the details:
Figure 1: Periodic methane eruptions from cattle were measured using flame ionization detection (FID). We used a GasTec Mk5 FID, with a methane sensitivity of 1ppm, to detect periodic methane eruptions from cattle within the trial herd. Individual eruption events were logged and attributed to individual cows, and aligned at the peak detected concentration of methane (grey traces). We used this to compute an average profile for the herd at various stages of the trial (seen here for the baseline recordings before seaweed supplementation, dark red trace). We also logged the peak values of individual eruption events (orange scatter).
The methane data we collected involved 21 cows within the herd. We recorded in 4 intervals; 2 days of baseline recording, followed by 2 further sampling days at 4 and 11 weeks from the onset of seaweed supplementation. Throughout the trial, we recorded 186 individual methane eruptions. We also tracked 6 cows individually across the 3 timepoints of the trial, taking multiple replicates (an average of 17 eruptions were recorded per cow within this subgroup).
Some examples of typical methane eruptions can be seen in Figure 1, where we have plotted the individual methane eruptions recorded prior to seaweed supplementation and aligned them at the peak of the eruption. Using these data, we derived two key metrics to assess the impact of seaweed supplementation. First, we computed the mean methane eruption profile for the herd, based on each individual eruption logged, to allow us to make a straightforward comparison for the herd before and after seaweed supplementation. Second, we took the peak values for the methane eruptions, in order to better assess individual animal responses.
In Figure 2A, we plotted the mean eruption profile for the herd at the three stages of the trial; at baseline, at 4 weeks after beginning seaweed supplementation and at 11 weeks. The trend was clear - the mean methane eruption profile for the herd decreased dramatically, with a 79.5% decrease in the profile integral at 11 weeks compared to baseline. Comparing the individual methane eruption peaks at the various timepoints revealed a similar pattern (Figure 2B), where the median peak methane value decreased from 251ppm, to 225ppm (at 4 weeks), to 47ppm (at 11 weeks).
Figure 2: Seaweed supplementation reduced the peak of methane eruptions within the trial herd. Following generation of the typical eruption profile for the herd (A, baseline, black trace), seaweed supplementation was begun and the herd was subsequently profiled at 4 and 11 weeks after supplementation began (red and pink traces, respectively). Both the (A) mean methane eruption profile and the (B) peak methane eruption values were reduced in a time-dependent fashion. The integral of the eruption profiles was computed from (A), revealing that the cumulative methane released during a typical eruption was reduced by 79.5% after 11 weeks of seaweed supplementation, compared to baseline.
As grouping all of the individual eruption data might introduce a sampling bias, where differences in sampling rates may apply, we took 6 cows that were sampled at least 3 times across all timepoints and looked at their individual responses too (Figure 3). The data are illuminating - we can see high variance in methane eruptions from individual cows, as well as differences in their response times. Some animals seem to respond to seaweed supplementation more quickly than others. However, despite the variance, the trend is again very clear. The methane eruption peaks are drastically reduced by 11 weeks for all these individuals (see the summary data in the inset figure). We performed Friedman test, a common statistical test to appraise response to treatments when sampling a population over time, and found that seaweed supplementation was highly significant (p<0.01) in reducing the amount of methane released during an animal’s eruption.
We are being particularly careful with our language here - our sampling approach was not exhaustive, as stated above, so we cannot account for any large changes in eruption frequency that may involve changes in eruption events that do not alter overall emissions. However, many previous studies, much more exhaustive than ours, report similar decreases. We also failed to observe any major differences in the frequency of observed methane eruptions during our sampling periods, recording between 0.64 and 0.76 eruptions per minute during active sampling.
Figure 3: Seaweed supplementation significantly reduces the peak methane eruption values in individual cows. We tracked 6 individual cows across all three stages of the trial. Although individual eruption events are highly variable, all 6 cows showed a consistent and marked decrease in the peak methane values recorded during eruptions throughout the trial. This decrease was significant at 11 weeks (inset). **Ρ<0.01, Friedman Test, with Dunn’s post-hoc test for multiple comparisons.
What we can demonstrate, however, is that this is a tangible solution to our rising emissions that equips livestock farmers with further biological tools available to them, away from chemical and artificial inputs and costs that not only add to their ever-increasing financial risks, but the immediate and growing exposure to the impacts of climate change, which should be everybody’s concern as consumers of food.
Of the biological tools, we are not just referring to the use of seaweed - there is a growing body of evidence-based research on the viability of other methods that may be more suited to specific climates and ecosystems, such as the use of willow for methane reduction in sheep. There is no one-size fits all model to address something as complex as reducing emissions in our food systems, but we believe this is a start in contributing something beneficial for farmers and citizens, that will work in favour of a food system that is about balance, dignity and respect.
Social and Environmental impact
As a start-up, we are based in Donegal and aligned ourselves with the ecosystems and communities here. We aim to be part of a socially progressive circular economy model, that positively collaborates for ecosystem improvements and justice in our food system. As a region highly connected to the marine environment, rural economy and the bioeconomy, Donegal has the longest coastline in Ireland yet supports the least infrastructure to maximize on coastal development and enterprise for social and environmental benefit. This development will create employment as it scales and replicates in other suitable coastal locations in Ireland, which have been disproportionately hit by the effects of the last recession and are now facing unprecedented hardship in the post COVID-19 economic landscape. DúlaBio will offer opportunities for an ecologically regenerative economy that invests in a just transition away from fossil fuel-dependence for jobs and power - towards climate resilience and restoration.
Seaweed cultivation offers a unique means of aquaculture diversification which goes well beyond the economic value that would come from the products created downstream of a biorefinery concept - the potential to create sustainable employment from regenerative seaweed farming and localised processing activities create valuable social and environmental opportunities. The number of seaweed farming licenses in Ireland have increased considerably in the last 3 years alone, yet arguably it remains a nascent industry here, with technical and commercial challenges to be met if it is to be developed to its full potential. In saying this, we understand the need to also incorporate an ‘ecology of values’ when talking about creating value for society from an important bioresource as seaweed. We are at the beginning of shaping a new bioeconomy for Ireland and should look to further examples of regenerative principles for ocean farming to do so responsibly, and incorporating circularity principles when designing and creating further products from seaweed, for a sustainable society.
The benefits in seaweed cultivation are far-reaching: if supplies can be sourced from controlled, polyculture farming systems (to be implemented alongside fisheries as an IMTA configuration), carbon and nutrient bioremediation can also improve profitability of fish farms, while nature inclusive solutions to multi-use sea farming in offshore wind are further promising developments for a sustainable future. We are actively seeking partnerships with aquaculture operations, as well as livestock farmers to build on this work, which requires further rigorous testing procedures and collaboration to address the questions it raises on impact and replication as a solution to reduce methane in the immediate future, of which several of our own concerns were highlighted in a recent Greenhouse Gas webinar hosted by Teagasc.
Besides these obstacles, it’s without doubt that we report on the significance of using seaweed in Ireland as part of the effort that’s needed to produce a food system that’s rooted in regeneration and climate resilience, rather than commodities, extraction and export markets. We support farmers who are working with nature to feed society, and organisations who represent farmers’ interests as well as our rights as citizens to define our own food and agri systems as a nation.
We need to address an imbalance in the current carbon cycle of our livestock systems. Although it is true to say that methane is part of the natural cycle of cattle, there are some significant issues with the accumulation of methane in the atmosphere. As both our national herd and the international herd are projected to increase in size, so too will the amount of biogenic methane in the atmosphere at any given time. Methane has a far higher warming potential than CO2 (as high as 86 times that of CO2 over a 20 year span) and is increasing at an alarming rate in the last few years alone.
Although there are many sources of methane, including natural sources, many of them are difficult or impossible to curtail. Of those that can be curtailed, there are two major sources in Ireland that require close attention, including methane release from ruminant livestock (the other being release arising throughout the expansion of natural gas and other fossil fuel exploitation). Regardless of the source of methane, biogenic or artificially released, immediate action on methane accumulation in the atmosphere will be instrumental to reaching our national climate goals and helping meet the temperature targets set out in the Paris Climate Agreements.
As a thought experiment, if we could imagine a simple switch of all atmospheric methane to carbon dioxide, it would buy an enormous amount of time in which to engineer a zero-carbon transition. A simple, if inelegant, solution is to reduce the national herd size. DúlaBio recognises that the Irish climate and landscape is uniquely suited to livestock production and that Irish farmers are embattled and under duress in today's economy. However, we are also aware that continued intensification is not sustainable and that conventional practices in agriculture in Ireland will be increasingly scrutinised for their damaging effects on biodiversity, soil health and soil carbon. If the scale of the methane reductions suggested here can be replicated, direct action on ruminant methane sources is achievable almost immediately, and without drastic cuts to the national herd size - but it must be done in cooperation with farming practices that pursue absolute reductions in GHG emissions rather than efficiency gains.
As we know, methane accounts for 65% of our agricultural emissions in Ireland, 90% of which is driven by enteric fermentation. Of the 33% of total GHG emissions agriculture contributes to in Ireland, 19% of our national emissions arise from enteric methane emissions alone. A 79% reduction from the application of this seaweed supplement would result in 15% total emissions reduction in Ireland p.a., or 7.5% reduction if half the national herd were supplemented.
Co-operation for a sustainable future
We are advocating this as an effective and direct contribution to address climate change, with an immediate impact in curtailing rising emissions. It would buy us the much needed time to facilitate the multiple transitions we are facing that will impact on every single aspect of our lives. But this application, along with the other major adjustments ahead, requires a massive collective effort if it is to carry the responsibility we share in moving towards ecological sustainability and social justice. Our global goals outline the need for cooperation and partnership to reinforce the common thread of humanity, a sustainable future can only be achieved if we are empowered to take action and work on this together.
We want to take this opportunity to reach out to potential collaborations or partners who want to effect real change in our food systems now. There are many others like us working towards similar goals - we propose combining our efforts and focusing on making this available in each of our specific, bioregional contexts that we are uniquely placed in to help, rather than wasting energy trying to out run each other.
We also want to reach out to seaweed farmers who are developing their processes and markets now, so that we can support and collaborate on regenerative ecological principles in sea and on land. In cultivating a productive and sustainable supply of seaweed as a bioresource for climate change mitigation, these developments have the potential to bring a traditional practice to the forefront as a nature-based climate solution for agriculture, our food systems, as well as a tool for building a bio-based economy towards carbon neutrality.
But most importantly, we want citizens and farmers to be a part of this as one of the many ways we can produce food that is in balance with nature and in line with our shared values for climate justice. We are therefore looking towards co-operative business models and alternative funding structures in how we grow this solution further, as we believe in building democratic climate strategies that emphasise the local economies they serve, are grounded in providing climate resilient livelihoods, and that reinvests back into community and ecological needs. We believe this will create an inclusive structure to achieve our goals by aligning incentives, decentralising and democratising decision-making as we address one of the biggest existential threats humanity are faced with, collectively.
