An ambitious but controversial plan to clean up the Great Pacific Garbage Patch moves closer to reality this week, with the deployment of an ocean plastic cleanup boom off the coast of the Netherlands in the North Sea. Image: The Ocean Cleanup
The 100m floating boom is a scaled-down version of a 100km long system that Dutch nonprofit The Ocean Cleanup eventually hopes to deploy in the Pacific Ocean between California and Hawaii. The boom is meant to slurp up the millions of tonnes of unsightly plastic comprising the Great Pacific Garbage Patch. The prototype, aptly named "Boomy McBoomface", will sit roughly 20km off the Dutch coast for a year in a critical field test of the system's survivability.
The Ocean Cleanup's mission has garnered international media attention, thanks in no small part to the nonprofit's charismatic founder, 21-year-old Boyan Slat, who was just 18 when he started working on the idea. The basic concept is to use currents, wind and waves — the natural motion of the ocean — to push plastic garbage into screens that extend outward from floating booms. The booms, which are anchored to the sea floor through a system of cables, form a V-shaped structure that concentrates plastic at the centre, where it can be easily harvested by collection vessels.
Artist concept of The Ocean Cleanup boom system in the field. Image: The Ocean Cleanup
To bring that concept to life, the nonprofit has assembled a team of engineers, who've spent the last year testing a small-scale model at a maritime research institute in the Netherlands. That the team is already moving to field trials speaks to the strong public support for the project, which raised over $US2 million ($2.8 million) in a crowdfunding campaign in 2014, and secured an additional million dollars for its prototype test from the Dutch government and private supporters. The full-scale structure is expected to cost roughly $US350 million ($468.8 million).
But the plan is not without its critics — namely, members of oceanography and marine biology community, many of whom feel the design hasn't been properly vetted and are worried about the potential ecological impacts of what would become the largest offshore structure ever assembled.
After The Ocean Cleanup published a lengthy feasibility study in 2014, oceanographers Kim Martini and Miriam Goldstein responded with their own technical review, which found "major issues" with the plan. These included the use of average rather than extreme current speeds, which could cause engineers to significantly underestimate the loads and tensions the structure will be subjected to in the field. The feasibility study also failed to address biofouling — the accumulation of life forms that will add weight to the booms over time. What's more, it's unclear how the company will fix the system should a catastrophic failure occur in the middle of the ocean.
Others have raised concerns about the effects of the boom structure on marine life, either through direct by-catch or by impacting the behaviour of migratory species. As deep sea biologist and Southern Fried Science blogger Andrew Thaler pointed out in a blog post last year, The Ocean Cleanup boom system is, by definition, a Fish Aggregating Device, or FAD:
In it's crudest form, an FAD is any floating, semi-stationary structure in the open ocean. Prey species tend to aggregate under floating structures, and predators naturally follow. The Ocean Cleanup won't simply act as a barrier to migration, but will also attract pelagic species. Long term, this could create permanent or semi-permanent communities, resulting in changes to migratory patterns.
"Our engineers take all criticisms and concerns very seriously," said Ocean Cleanup spokesperson Jan van Ewijk, adding that the organisation was aware of the scientific community's response to its feasibility study. (Gizmodo was referred to the group's engineering team for response to technical questions about environmental impacts, but had not heard back by time of writing.)
Goldstein and Martini, meanwhile, received no feedback to their analysis outside of a video response from Slat, which downplayed their qualifications for commenting on engineering issues but acknowledged that they made many "valid points". How many of those valid points are being acted on is unclear.
"There are some changes to the version 2.0 of the feasibility study, but none that allows us to easily see what is different, as would be the case in normal peer review," Martini told Gizmodo in an email, adding that the limited response to her review and an earlier offer for review by the Scripps Institute of Oceanography "has discouraged engagement from other scientists."
It's possible that The Ocean Cleanup will address many of the concerns its critics have raised before deploying the full-scale array in 2020. The nonprofit is reportedly conducting an environmental impact analysis with Royal Haskoning DHV. And with its newly deployed prototype, the group stands to learn a lot more about how the system will fare and how it may fail under stormy conditions.
Kim Martini has posted some additional thoughts (and great questions, including why the heck is The Ocean Cleanup using RO-BOOMS, which have been around since the '90s?) on the blog Deep Sea News. Check out her post here.