Caribbean-Wide, Negative Emissions Solution to Sargassum spp. Low-Cost Collection Device and Sustainable Disposal Method

Folkers E Rojas,Luke A Gray,Alexander H Slocum,Andres G Bisonó León,Samuel S Veroneau

doi:10.3390/phycology1010004

Folkers E Rojas, Luke A Gray + Show 3 more

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https://doi.org/10.3390/phycology1010004

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Abstract

Sargassum spp. blooms exacerbated by climate change and agricultural runoff are inundating Caribbean beaches, emitting toxic fumes and greenhouse gases through decomposition. This hurts tourism, artisanal fishing, shore-based industry, human health, standards-of-living, coastal ecology, and the global climate. Barriers, collection machinery, and Sargassum valorization have been unable to provide sufficient, sustainable, or widespread relief. This article presents a total Sargassum management system that is effective, low-impact, and economically scalable across the Caribbean. Littoral Collection Modules (LCMs), attached to artisanal fishing boats, collect Sargassum in nets which are brought to a barge. When full, the barge is towed to the deep ocean where Sargassum is pumped to ~150–200 m depth, whereafter it continues sinking (Sargassum Ocean Sequestration of Carbon; “SOS Carbon”). Costing and negative emissions calculations for this system show cleanup costs <$1/m3 and emissions reduction potential up to 1.356 → 3.029 tCO2e/dmt Sargassum. COVID-19 decimated Caribbean tourism, adding to the pressures of indebtedness and natural disasters facing the region. The “SOS Carbon strategy” could help the Caribbean “build back better” by establishing a negative emissions industry that builds resilience against Sargassum and flight shame (“flygskam”). Employing fishermen to operate LCMs achieves socioeconomic goals while increasing Sargassum cleanup and avoiding landfilling achieves sustainable development goals.

Highlights

Caribbean coastal zones have experienced increasing and overwhelming inundations of pelagic Sargassum spp
Prior work has documented the beginnings of the recent, unprecedented Sargassum inundations in the Caribbean in 2011 [1], identified its source in the Northern Equatorial Recirculation Region (NERR) [2,3,4,5], and identified samples of this pelagic Sargassum as Sargassum natans, making it likely that this new source originated from the Sargasso Sea [6]
Sink zones should be chosen such that there is no sensitive area nearby that could be affected by moderate migration of Sargassum and 3D benthic current modeling should be applied to the selection of sink zones to reduce the risk of coastal upwelling of sunken Sargassum. It has been a decade since the beginning of the Sargassum inundations in the Caribbean

Summary

Introduction

Caribbean coastal zones have experienced increasing and overwhelming inundations of pelagic Sargassum spp. (hereinafter, “Sargassum”). Prior work has documented the beginnings of the recent, unprecedented Sargassum inundations in the Caribbean in 2011 [1], identified its source in the Northern Equatorial Recirculation Region (NERR) [2,3,4,5], and identified samples of this pelagic Sargassum as Sargassum natans, making it likely that this new source originated from the Sargasso Sea [6]. Scientists have dubbed this reoccurring archipelago of Sargassum, stretching all the way from West Africa to the Gulf of Mexico, the “great Atlantic Sargassum belt.”. While Sargassum usually blooms once a year, giving rise to a “Sargassum season” lasting from April through August, the 2018 and 2019 seasons extended almost until each year’s end [9]

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