Reef Cubes®

1 Review
8 Deploys

Low carbon concrete-like building blocks for marine habitat enhancement

Page last modified
April 10 2024

ARC Marine's flagship product is the patented reef cube®, these are robust cuboid units with five or six ports and a spherical hollow chamber proven to enhance marine biodiversity and abundance.  They are manufactured from Marinecrete, our own Portland cement replacement mix that offers a 91% carbon footprint saving compared to Portland cement.  They are made from 98% recycled materials, contain no plastic and are certified as non-toxic to the marine environment.

Reef cubes® can be supplied in a variety of sizes from 150mm to 1500mm sided and weight upto 5.5Tonnes in air to suit a variety of intertidal and subsea applications.  Larger sizes are planned and units can be combined to form multi-tied structures for additional height in the water column.  We have supplied smaller reef cubes in side larger ones for added weight and habitat complexity.  We can supply with a scallop or oyster shell veneer to encourage bivalve settlement.  We have successfully trialled units with juvenile oysters and kelp paste to help seed new biodiverse reefs that deliver enhanced ecosystem services. 

Colonisation by fauna and flora is very rapid and the units often become unrecognisable as man made structures within 12 months.

Smaller reef cubes can be employed at scale using fall-pipe vessels for scour protection (see RESP entry) whilst larger units can act as eco-friendly gravity moorings  or protect subsea infrastructure or aquaculture sites by acting as a deterrent to bottom trawling and dredging.  They can shield subsea wellheads from ghost nets and reduce the risk of bottom trawling related production or environmental losses.  The 5-port 1.5m Krib Karn intertidal reef cubes are used for coastal defence with a large internal shade rockpool.

This innovative award-winning technology is designed using nature inclusive design (NID) principles to deliberately encourage marine life to create a positive reef effect.  There is a strong decommissioning case for units to be left in situ as they do no harm and are deliberately designed to accelerate reef creation (the ARC in ARC marine) to leave a positive hard substrate legacy and consequent thriving ecosystem for future generations.  This is the subject of cautious ongoing stakeholder consultations and requires developer support to put through license applications to allow regulator consideration on a case by case basis until full confidence in their use and impact is obtained and shared.    A number of peer reviewed scientific papers on their impact are already published and available upon request.

Pros & Limitations
Low carbon footprint, support net zero ambitions
Deliberate marine habitat enhancement at scale increasing biodiversity and abundance of key target species
Multiple applications e.g. OSV eco-friendly moorings or subsea wellhead protection
Can act as a deterrent to bottom trawling and dredging close to critical infrastructure and increases sonar image/detectability
Causes some seabed benthic smothering (but 20% less than a solid structure) due to footprint but 6x more habitat created in water column due to surface area
Smaller units not stable under all metocean conditions so only larger units recommended in shallow or high energy applications.
Specification Title Specification Description
Concrete Strength
Compressive strengths from 15MPa to 60MPa+ depending on mix used
Plastic Content
Zero plastics used
Leachate Testing
Passed stringent independent EU leachate testing
Carbon Footprint
91% saving compared to Portland cement, we can make units carbon neutral or even carbon negative.
Recycled Material Content
Typically made from 98% repurposed raw materials supporting the circular economy
1.5m sided units weigh 5.5 tonnes in air - larger units and combinations possible. Can be made heavier with magnadense.
100mm to 1500mm sided ref cube units made as standard. 2m units planned.
Can be supplied with scallop shell veneer, mooring inserts and/or pre-seeded with kelp.

Reviews (1)

Get access to reviews

to your explorer or platform subscription to get access to the reviews written about this technology.

Technology Readiness Level

The Technology Readiness Level (TRL) indicates the maturity level of novel technologies. Learn more about the TRL scale used by us.


Development Technology demonstration Mature / Proven
Ask the supplier
 to contact this technology supplier.

ARC Marine is an award winning (2022 SPE Offshore Achievement Award for Emerging Technology, 2022 RWE Ecology Award) eco-engineering company specialising in low carbon footprint high impact marine materials for subsea cable/pipeline protection, scour protection, coastal defence, eco-friendly moorings and deliberate marine habitat enhancement.  Our patented product Reef Cubes® is made from Marinecrete® and creates sustainable eco-friendly marine habitats intended to benefit both people and the planet. Our expertise is in the design, manufacturing and deployment of Marinecrete, Marine Matts and Reef Cubes® and the monitoring and long-term custodianship of new ecosystems these help create. Further marine habitat enhancing products are under development.

Applications include coastal defence, offshore energy, eco-tourism, aquaculture, moorings, habitat enhancement and anti-bottom trawling deterrents in areas closed to such practises e.g. marine protected areas or around critical subsea infrastructure. Our products are non-toxic, contain no plastics and can be made locally using sustainably sourced aggregates and recycled materials, creating jobs in the communities impacted and minimising transportation carbon footprint.

Relative Business Impact

Solution Deployed By
Company Name

to your explorer or higher plan to get access to all the 8 deployment references.

Last Deployment YearTotal DeploymentsComment