Question 1

How do you calculate projected CO2 uptake?

Accepted Answer

We use a very conservative method to estimate CO2 uptake of our Blusinkies, to ensure that we don’t overpromise/account for CO2 storage that won’t occur.

As our solution is unit based, we know the uptake per Blusinkie, and thus can calculate the potential uptake of different sizes of deployment based on simple unit economics (accounting for a peaking/saturation effect).
We have low, medium and high estimates of CO2 uptake based on our lab and live incubations - we apply the lowest rate to account for the varying productivity of different ocean regions. In the most productive regions we estimate that Blusinkies will capture twice as much carbon as what we account for.
We assume a loss rate of 10% of the size of the deployment per year (which could be caused by Blusinkies relocating from the project site, being damaged by large storm events or similar), allowing for up to 50% loss by the end of a project period. This is likely an overestimation of the loss rate.
We only calculate for five years worth of carbon uptake, despite many studies showing that Rhodoliths productively capture carbon for at least 10-15 years.

Question 2

How do you ensure you don’t create a new habitat which competes with existing habitats?

Accepted Answer

We don’t introduce new species into a local habitat; we only provide a foundation for native species to settle on. This means that if something wasn’t there before, it won’t be present when our substrates are colonised. Our technology works by mimicking and accelerating nature, where Rhodolith/Maerl beds provide vital shelter to many and varied marine creatures, and it has been proven to enhance existing local biodiversity and species only.

Additionally, many studies (including Costa et al., 2020, Moura et al., 2021 and Carneiro et al., 2022) have found that Rhodolith/Maerl beds are important for ecological and genetic connectivity with other habitats (e.g., seagrass beds, mangroves, coral reefs), by ensuring the survival of juvenile fish, providing corridors for reef fish migration towards spawning grounds and increasing the abundance of reef species. Introducing Rhodolith beds actively supports the health and biodiversity of surrounding ecosystems by providing these ecological connectively corridors.

Question 3

Doesn’t the calcification process typically release CO2?

Accepted Answer

As in any process occurring in marine waters, there are ecosystems where the net effect of both chemical and biological processes is more complex than indicated by looking at each of these elements individually. These ecosystems require us to look at the overall carbon budget (including photosynthesis and respiration). CO2 is actually just a small fraction of seawater carbon and the focus of marine carbon solutions should be on total inorganic carbon removal (as well as ensuring beneficial pH changes).

Ocean alkalinity reflects the system’s ability to absorb or buffer acidic changes without significant shifts in pH. pH is directly influenced by CO₂ levels because dissolved CO₂ forms carbonic acid, lowering pH. When CaCO3 forms, despite the fact that carbon is removed from seawater to make the mineral, the calcification process can result in a change to the seawater chemistry (reducing the alkalinity) which in turn results in an increase in dissolved CO2 (forming carbonic acid). This excess or supersaturation of CO2 can lead to a release of CO2 to the atmosphere.

Our lab and deployed studies show that Blusinkies primarily remove bicarbonate (HCO3-), the most abundant form of inorganic carbon in seawater. This process shifts carbonate equilibrium, increasing carbonate and pH (showing that the system has buffering capacity) while decreasing total dissolved inorganic carbon (DIC). This indicates that instead of reducing the systems ability to buffer acidic changes, the presence of Blusinkies actually enhances it, resulting in a net effect of CO2 drawdown (decreased total DIC + increased buffer capacity).

Our most recent lab incubations, monitoring both new and 6-month live deployed Blusink units (from Madeira) show:

Control (new) units remove 0.4-1.3 mg carbon/hour
Deployed units (rock/sand) maintain similar removal rates
pH increase from ~8.1 to up to 8.7 during incubations - demonstrating that Blusinkies can actually counteract the effects of ocean acidification and improve the buffer capacity of the ocean. This may support the recovery of coral reefs and improve the survival rates of young marine organisms sensitive to pH changes.
Significant carbon removal and calcification occur in both light and dark conditions

In summary, whilst calcification alone does add a small volume of CO2 to the ocean which has potential to be released back to the atmosphere, this is more than counteracted by the volume of DIC reduction enabled by our Blusinkies and the increase in pH (buffer capacity). In addition, there are ocean health benefits with regards to increased pH and availability of carbonate ions, improving ocean biodiversity.

Question 4

Isn’t it risky to introduce foreign material into delicate marine environments?

Accepted Answer

The materials our Blusinkies are composed of are found naturally in marine environments and are widely present anywhere Rhodoliths/Maerl beds occur. Again, we are essentially mimicking existing calcite seafloor composition, but offering an improvement where seafloor composition has been degraded. We have conducted a wide range of materials tests to ensure that there are no heavy or trace metals in our Blusinkies, using an independent laboratory to conduct Graphite Furnace Atomic Absorption Spectrometry (GFAAS).

Question 5

How do you select locations for deployment?

Accepted Answer

Rhodoliths/Maerl beds occur around the world - so we target areas where there is already a good indication of these beds. As with kelp forests, water clarity determines the depth to which Rhodolith/Maerl beds are found. Rhodoliths remain a relatively under-studied marine habitat, and many believe that their abundance might be even greater than is currently documented (Tuya et al, 2023).

In addition, we look to find areas that have:

Low sedimentation levels and good visibility (for light availability).
Sandy bottom seafloors that are relatively flat, and ideally which have reef ecosystems present in the vicinity.

Sometimes client may have a specific deployment site in mind (e.g. somewhere they already have access to). This is great for us, however as the ocean varies massively we always conduct a site feasibility assessment at target deployment sites to understand how suitable and productive a region might be.

The areas in yellow below are major Rhodolith/Maerl occurrence fields. The areas in blue are areas where there is potential for successful deployment. The pink geomarkers are locations where Blusinkies have already been deployed.

Question 6

How do you monitor project success?

Accepted Answer

For every deployment, regardless of whether the primary aim is restoration or carbon capture, we develop a bespoke monitoring plan. We monitor our sites on an annual basis, and sample a representative proportion of the total population. The methods applied will depend on the size, scale and primary objective of the project - we use a combination of specially designed incubation chambers and ROVs for monitoring.

Question 7

What happens to Blusinkies after a project monitoring period ends?

Accepted Answer

The beauty of Blusinkies is that they transform over time into fully organic, living organisms. These organisms (Rhodoliths) are self sustaining - they continue to assimilate calcium carbonate in to their structures and to shelter resident biota - meaning that there is no need to remove or decommission them from the water after the end of a project/monitoring period.

Question 8

What advantages does Blusink have over other nature-based solutions approaches? Why should customers be keen to choose this solution?

Accepted Answer

Blusink offers a number of benefits over equivalent Nature Based Solutions (NbS):

The modularity of deployment, adaptability to different deployment styles, and buyer’s marine spatial needs. At scale, marine permitting is easier for us since Blusink’s deployability doesn’t entail mega structures like the ones found in other solutions. Most importantly our technology seamlessly integrates with the seafloor meaning no maritime transit or engineering operation of our clients would be interfered with.
Nature vs Engineered: Social science has strongly emphasised society’s preference for natural solutions over engineered ones, however many NbS solutions aren’t able to offer high durability removals due to the risk of biological decomposition. Further, solutions that only offer removals without nature benefits face the limitations of CO2e as a simplistic metric for the wide range of ecosystem benefits from natural systems. Blusink is the first of its kind to be able to address both elements.
Accurate Quantification and Measurement: Our client interviews have revealed the challenges in assessing NbS or more specifically restoration services come from the uncertainty of the outcomes and the absence of clear measurement and verification steps especially over long-term maintenance periods. Our quantification methods are rooted in years of research and peer-reviewed methodologies. Furthermore, we utilise robust biostatistics methods to standardise sites, improve predictability, and model their behaviour.
Standardised Technology: We’ve successfully tested our technology in different geographies - allowing us to forecast and extrapolate for similar geographies and standardise procedures to yield quantifiable restoration per unit of deployable tech (our blusinkies).
Non-generic material: While we see many companies using “Nature Positive” approaches and even materials to make biodiversity claims, the materials used are generic and so are the species growing on them. NbS that allege biodiversity improvement from “turf” and other forms of biofouling on structures are not improving biodiversity in the long term due to this single species reliance.

Question 9

What are the positive climate impact(s) that can be achieved through your solution?

Accepted Answer

Our technology accelerates the growth of carbon capture and storage (CCS) species, particularly Rhodoliths/Maerls, which are widely recognised for their carbon sequestration capabilities. Through scalable production and operations, we have the potential to sequester millions of tons of carbon globally, tapping into the vast presence of rhodoliths across coastlines worldwide.

There are also a number of environmental co-benefits:

Our solution establishes a sustainable feedback cycle, as deployed areas remain productive for years, attracting additional carbon-capturing species and fostering marine ecosystem growth. By serving as a foundation for diverse ecosystems, including coral reefs, our technology enhances biodiversity and promotes the replenishment of local fish stocks in coastal deployment sites.
Our solution increases the pH levels, in turn increasing the availability of carbonate ions, which are essential for organisms that build calcium carbonate structures. A more alkaline (higher pH) environment supports coral reef growth and shell formation in species like oysters, clams, and certain plankton. Many photosynthetic organisms, like seagrass and certain types of algae, thrive in conditions with higher pH. These organisms also play a role in sequestering CO₂ and further contribute to ocean de-acidification.
Our solution uses waste materials from other industries, enhancing circularity and mitigating the need to rely on or extract virgin resources. Manufacturing with repurposed materials also uses less energy than starting with raw materials, and avoids accumulation of materials in landfill, minimising associated issues like leachate contamination and land use pressures.

Question 10

What supports your claim that your solution offers permanent ocean CDR (i.e. over 1000 years storage)?

Accepted Answer

The carbon used to create the calcium carbonate structure in Blusinkies which will eventually transform into rhodoliths is expected to be stored for hundreds of years. Rhodoliths are long-lived organisms, with records showing some individuals have survived for over a century. Fossil records have even revealed 8000-year-old rhodoliths in Scotland (Costa et al., 2023).  Rhodoliths also have slow growth rates meaning that the carbon is gradually incorporated into their structure over long periods, contributing to long term storage. Additionally, geological records shows that Rhodolith deposits have been stable over thousands of years, further supporting the idea that they can sequester carbon over similar timescales (Aguirre et al., 2017).

Question 11

Which of the UN SDG's does your service/solution address?

Accepted Answer

We believe our solution meets a number of the UN SDGs, including:

SDG 9: Industry, Innovation & Infrastructure
SDG 11: Sustainable Cities & Communities
SDG 12: Responsible Consumption and Production
SDG 13: Climate Action
SDG 14: Life Below Water

Your questions answered: Carbon capture, ecosystem impact, and avoiding unintended consequences