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Sargassum provides a valuable habitat for many species including flying fish, which build bubble nests in its fronds. Long filaments on the eggs keep these attached to the weed. Photo credit: JP Rouja.
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The Sargasso Sea is a fundamentally important part of the world’s ocean, located within the North Atlantic sub-tropical gyre with its boundaries defined by the surrounding currents. It is the only sea without land boundaries with water depths ranging from the surface coral reefs of Bermuda to abyssal plains at 4500 m. The Sargasso Sea’s importance...
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... The Atlantic's floating "golden rainforest," comprise primarily of three Sargassum genotypes, S. natans I, S. natans VIII, and S. fulitans III and they serve as a crucial habitat fostering biodiversity (Alleyne et al. 2023). Its golden mats are home to many fishes and invertebrates (Coston-Clements et al. 1991;Niermann 1986), a nursey for even sea turtles (Wells and Rooker 2004;Laffoley et al. 2011), a home for endemic species (Hemphill Disclaimer/Publisher's Note: The statements, opinions, and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions, or products referred to in the content. ...
Several environmental and economic issues have been brought about by mass accumulations of Sargassum along the coastlines in Trinidad and Tobago, and the wider Caribbean region. Though there are massive environmental issues associated with this seaweed biomass, there is also a chance to make innovations, thereby making this problem into a solution. The holopelagic species such as S. natans and S. fulitans have considerably high amounts of beneficial compounds which can be leveraged for agriculture. The value chain transformation of Sargassum from a nuisance to a resource for agricultural production is narrated in the following report. Details of the application of products from Sargassum including composts, soil amendments, and liquid biostimulants are given. A case study is presented for OJA1 biostimulant, which was developed from Sargassum biomass at the University of the West Indies, St. Augustine, Trinidad. This biostimulant has shown increased productivity and resistance to diseases of several cash crops. The valorization of Sargassum contributes to sustainable agriculture and propels economic development in coastal communities. The Caribbean could lead with the adoption of the circular economy, turning environmental adversity into a lever for sustainable development.
... The holopelagic species of the brown alga Sargassum (S. fluitans and S. natans; sargassum from hereon) play a vital role in ocean scale processes and provision of biodiversity of the Atlantic Ocean, and their drifting masses (rafts) are also known as the "golden rainforest" (Laffoley et al. 2011). Historically, sargassum rafts have been concentrated by a subtropical Atlantic gyre in the Sargasso Sea, with periodical releases of drifting masses into the northern Caribbean Sea and the Gulf of Mexico (Acton et al. 2019;Frazier 2014). ...
... Consequently, the rafts play a crucial role in redistributing organisms within the pelagic environment, and may impact the survivorship of species dependent on it for both shelter and food. In the Gulf of Mexico and Sargasso Sea, 145 species of invertebrates and 80 species of fish have been reported in offshore (high-sea) rafts (Coston-Clements et al. 1991;Laffoley et al. 2011;Niermann 1986), including endemic and iconic species (Fine 1970;Hemphill 2005;Mansfield et al. 2021). The rafts are important recreational fishing areas for wahoo and jacks, and serve as a nursery and spawning area for a wide array of species, including commercially important ones (Laffoley et al. 2011;Wells and Rooker 2004). ...
... In the Gulf of Mexico and Sargasso Sea, 145 species of invertebrates and 80 species of fish have been reported in offshore (high-sea) rafts (Coston-Clements et al. 1991;Laffoley et al. 2011;Niermann 1986), including endemic and iconic species (Fine 1970;Hemphill 2005;Mansfield et al. 2021). The rafts are important recreational fishing areas for wahoo and jacks, and serve as a nursery and spawning area for a wide array of species, including commercially important ones (Laffoley et al. 2011;Wells and Rooker 2004). ...
Holopelagic Sargassum spp. (sargassum) are the founding species of diverse communities in the Sargasso Sea. Since 2011, a new area of concentration of these algae was formed in the equatorial North Atlantic and Caribbean Sea. We analyzed elemental composition, and the small mobile fauna associated with sargassum collected at 41 stations, during two expeditions in the Caribbean Sea in 2018 and 2019, that covered open-sea stations in two marine ecoregions, and coastal stations (< 20 km from the shore) in one of them. Metal(loid) concentrations generally followed the order As > Zn > Cu > Cd > Se > Pb > Hg, and contents of As (195.5 ± 13.7 µg g⁻¹), Cd (0.59 ± 0.02 µg g⁻¹), and Hg (0.22 ± 0.09 µg g⁻¹) were highest in S. fluitans III in the South-Western-Caribbean ecoregion. Mean [Ctot] per ecoregion varied between 26.1 and 30.1 mg g⁻¹, and variation was mainly accounted for by higher [Cinorg] (likely produced by calcifying epibionts) in the South-Western Caribbean (10.12) compared to the Western Caribbean (8.92 and 7.19); this tendency that was also found for [Ntot] (between 1.06 and 1.27), and these contents were positively correlated with seawater chlorophyll concentrations. Sixty-six taxa of mobile fauna were identified, with the phylum Arthropoda being most abundant and diverse. The faunal community composition was similar in both open-sea regions, but differed in the coastal stations, which was mostly explained by differential relative abundance of Latreutes fucorum, Carpias minutus, Litiopa melanostoma, and some fish species. The Caribbean open-sea rafts harbor a diverse fauna comparable to that found in the Sargasso Sea, and likely provide similar ecosystem services, and thus merit similar protective efforts as those directed towards sargassum in the Sargasso Sea.
... Thus, whole ecosystem components can float and flow with the marine currents as seen in rivers. Take, for instance, the Sargasso Sea, a rich and diverse ecosystem providing essential habitat for many endangered species, hailed as the 'golden floating rainforest of the Atlantic Ocean' as it is based upon the floating Sargassum macroalgae (Laffoley et al., 2011). ...
Area-based management tools (ABMTs), including marine protected areas (MPAs) are often static and fail to reflect the dynamic realities of marine ecosystems. Marine ecosystems are characterized by their embodiment of constant change, which is further amplified by anthropogenic stressors, particularly climate change. ABMTs and MPAs are, however, premised on an implicit assumption of environmental equilibrium as their boundaries and management framework are often fixed and difficult to adjust. This article seeks to lay bare the tension between static conservation strategies and the deeply and inherently dynamic nature of marine ecosystems. It further seeks to advance the notion of dynamic ABMTs, proposing an integrated conceptualization of ABMT governance, one that is more apt to respond to the type of challenges that the dynamism of complex marine ecosystems presents. Dynamism, in this context, is broadly construed as encompassing three dimensions: spatial, with fluid and adjustable conservation measures; normative, denoting a volatile and adaptive management framework that utilizes ecological and management thresholds as an initiator for adaptive, timely, and prospective approaches to enhance management outcomes; and institutional, i.e., sufficiently flexible and dynamic institutional machinery overseeing ABMT implementation. Following a comprehensive conceptualization of dynamic ABMTs, the article addresses the question whether the legal frameworks governing the ocean can sustain such a dynamic mode of ocean governance.
... While small amounts of Sargassum is not new to the Caribbean, since 2011 the region has been experiencing large inundations of the seaweed on its coastlines and beaches (Schell et al., 2015;Smetacek and Zingone, 2013). Historically large masses of the seaweed are found concentrated in the Sargasso Sea in the North Atlantic Ocean (Smetacek and Zingone, 2013;Laffoley 2011;Lapointe 1995). Floating Sargassum serves many benefits by providing a pelagic habitat out at sea. ...
Since 2011 the Caribbean has been experiencing large amounts of Sargassum on its beaches causing disruptions to tourism. There are nonetheless no large-scale empirical studies across the regizon on the impact of Sargassum on tourism and local economies. In addressing this knowledge gap this study investigates the impact of Sargassum on sandy beaches on tourism and sandy beach economic activity across 30 Caribbean Small Island Developing States. Spectral reflectance data from the MODIS satellite mission and a Floating Algae Index were used to detect the presence of Sargassum on sandy beaches. Tourism activity was measured using monthly tourist arrivals data from the Caribbean Tourism Organization and near sandy beaches nightlights data from the United States Air Force Defense Meteorological Satellite Program-Operational Linescan System. A Fixed effects panel regression model which controls for island specific time invariant effects, monthly and yearly time effects, and island specific time trends and allow for cross-sectional dependence and serial correlation was adopted. The results demonstrate that the average incidence of Sargassum reduces tourist arrivals growth by 1.1 percentage points up to 8 months after an outbreak with the highest incidence event having a 9 percentage points reduction. The results from nightlight intensity show a fall in sandy beach economic activity up to 6 months after an outbreak. An average Sargassum event of 0.25 and 0.15 constitute a reduction in sandy beach nightlight intensity of about 1.6 and 0.9 percent respectively.
... To remedy this issue, the CTRL simulation is restarted from 31 December 2001 and run until 31 December 2006 with the surface wind forcing replaced by the ERA-Interim. The W I in the CTRL simulation is stronger and shows better agreement with the observations (Figure S4bin Supporting Information S1;Laffoley et al., 2011). ...
Plain Language Summary
Turbulent mixing contributes to the vertical transport of heat, carbon and nutrients in the ocean, exerting significant effects on the ocean circulations and climate. It is thus important to know how turbulent mixing in the ocean will change under anthropogenic forcing. There is a prevailing thought that turbulent mixing should be weakened under anthropogenic forcing, as the enhanced stratification due to the faster warming in the upper than deeper ocean would hinder the processes generating turbulence. Here, using observation data sampled during the Bermuda Atlantic Time‐Series Study (BATS), we find that the turbulent mixing in the permanent thermocline there has increased by 42% over the past three decades. This positive trend is due to stronger wind energy input on internal waves that are gravity waves propagating within the ocean interior rather than on its surface. As these waves radiate downward and equatorward, they transfer their energy into smaller‐scale internal waves and eventually break, leading to enhanced turbulent mixing in the northern Sargasso Sea.
... Green turtles making developmental migrations from Bermuda encounter additional threats during their southward transits across the Sargasso Sea in the North Atlantic Ocean, e. g., pelagic longline fisheries, recreational and commercial vessel traffic, pollution and marine debris. These long-distance and international transits illustrate the need for broad, multinational marine conservation programs such as the Sargasso Sea Alliance [85,86]. ...
To characterize the movements and habitat use of juvenile green turtles (Chelonia mydas) in benthic developmental habitat, we deployed Fastloc-GPS-enabled satellite transmitters on 16 individuals captured as part of a multi-decade study of green turtles on the Bermuda Platform. We characterized residence areas, distinct use areas within them, and seasonal movements based on an average of 562 Fastloc-GPS positions and 284 tracking days per turtle. We estimated residence area sizes using traditional home range methods, e.g., 90% utilization distribution (UD) (mean 2.29 ±2.71 km²) and 50% UD (mean 0.54 ±0.69 km²). Total residence area size increased significantly over the 8-year study, from <1 km² before 2013 to ≥3 km² in 2018 (R² = 0.51, F1,14 = 14.55, p = 0.0019), corresponding to a period of decline in seagrass habitat and suggesting increased foraging effort. We identified three types of distinct use areas within residence areas where tracked turtles typically exhibited behavioral fidelity: foraging, resting, and cool weather refugia. These distinct use areas were smaller than high-use areas from previous studies; e.g., seagrass meadow foraging areas averaged 0.05 km². Most turtles made daily transits between foraging and resting sites; for some individuals, these involved crossing frequently used vessel navigation channels. Seasonal variation in behavior suggested that the overwintering strategy for green turtles on the Bermuda Platform involves “optional dormancy,” during which turtles spent less time on seagrass meadows and made brief excursions to distinct deeper habitats. Four individuals made directed (mean path straightness = 0.93 ±0.02 SD) developmental migrations away from Bermuda toward known adult foraging range. Results of our study further knowledge of the green turtle life cycle at a high-latitude site; they demonstrate that green turtles show fidelity to distinct use areas within developmental habitats over many years and exhibit seasonal movements.
... Although the Sargassum in the Sargasso Sea is not typically considered to be a bloom due to its longevity, it is characterized by the same qualities of having drifting, large quantities of biomass similar to those found in macroalgal blooms. The Sargassum species in the Sargasso Sea are well recognized for their importance as a habitat for numerous fish and invertebrate species as well as food sources [95]. As a genus, Sargassum can reproduce sexually or asexually; pelagic S. fluitans and S. natans reproduce via the latter mechanism, with vegetative growth and division [66], which enhances their potential rate of biomass increase. ...
Marine macroalgae (seaweeds) are important primary global producers, with a wide distribution in oceans around the world from polar to tropical regions. Most of these species are exposed to variable environmental conditions, such as abiotic (e.g., light irradiance, temperature variations, nutrient availability, salinity levels) and biotic factors (e.g., grazing and pathogen exposure). As a result, macroalgae developed numerous important strategies to increase their adaptability, including synthesizing secondary metabolites, which have promising biotechnological applications, such as UV-absorbing Mycosporine-Like Amino Acid (MAAs). MAAs are small, water-soluble, UV-absorbing compounds that are commonly found in many marine organisms and are characterized by promising antioxidative, anti-inflammatory and photoprotective properties. However, the widespread use of MAAs by humans is often restricted by their limited bioavailability, limited success in heterologous expression systems, and low quantities recovered from the natural environment. In contrast, bloom-forming macroalgal species from all three major macroalgal clades (Chlorophyta, Phaeophyceae, and Rhodophyta) occasionally form algal blooms, resulting in a rapid increase in algal abundance and high biomass production. This review focuses on the bloom-forming species capable of producing pharmacologically important compounds, including MAAs, and the application of proteomics in facilitating macroalgal use in overcoming current environmental and biotechnological challenges.
... Sargasso has not been contained absolutely in the Sargasso Sea, as evidenced by the Sargasso Loop System [5], which has usually caused minor landings on the coasts of NW Caribbean islands and mainland and the Gulf of Mexico (Figure 1). Pelagic masses of these species support a biodiverse community by providing sustenance, refuge, and protection to many organisms, such as fish, sea turtles, and invertebrates [6]. ...
Since 2011, the distribution, abundance, and composition of holopelagic Sargassum spp. (sargasso) have changed by the emergence of the Great Atlantic Sargasso Belt (GASB) in the northern tropical Atlantic. We expected that the north of the Cuban coast would receive sargasso from both the original Sargasso Sea and the GASB. We systematically monitored six beaches on the NW coast of Cuba to assess changes in sargasso composition from June 2019 to June 2021. During landing months, mean Sargasso wet biomass was at 1.54 kg/m 2 (SE: 0.7), which was considerably lower than the sargasso on the Atlantic coasts directly impacted by GASB. Eleven out of 13 landings occurred in the autumn-winter seasons 2019-2020 and 2020-2021, with a dominance of S. natans I (accounting for 41-63% of total biomass), followed by S. fluitans III (25-36%) and S. natans VIII (12-31%). This composition is similar to those observed on the Sargasso Sea. During this season, dominant winds (≥14 km/h) came from northern (N), eastern (E), and east-northeastern (ENE) directions. In May and August 2020 (spring-summer season), S. fluitans III dominated (52-56%), followed by S. natans VIII (33-43%) and S. natans I (5-12%). This composition is similar to those observed on GASB-impacted Atlantic coasts in the spring-summer seasons (April to September). During this season, dominant winds (≥20 km/h) came from eastern (E) and east-northeastern (ENE) directions. Thus, the NW Cuba's morphotype composition suggests that landings have different origin sources depending on season and specific meteorological and oceanographic conditions.
... The Sargassum genus includes more than 350 species, constituting one of the most diverse genera of brown macroalgae (Guiry and Guiry 2022). Among this genus, only two species are holopelagic as they drift during their entire life cycle (Dawes and Mathieson 2008) constituting floating rafts called "the golden floating rainforest of the Atantic Ocean" (Laffoley et al. 2011). Morphological and molecular studies differentiated three genotypes: S. fluitans III and S. natans I and VIII (Amaral-Zettler et al. 2017). ...
Since 2011, the Caribbean Islands have experienced unprecedented stranding of a pelagic brown macroalgae Sargassum inducing damages for coastal ecosystems and economy. This study measures the kinetics of metal trace elements (MTE) in Sargassum reaching different coastal environments. In July 2021, over a period of 25 days, fixed experimental floating cages containing the three Sargassum morphotypes (S. fluitans III and S. natans I and VIII) were placed in three different coastal habitats (coral reef, seagrass, and mangrove) in Guadeloupe (French West Indies). Evolution of biomasses and their total phenolic content of Sargassum reveals that environmental conditions of caging were stressful and end up to the death of algae. Concentrations of 19 metal(loid) trace elements were analyzed and three shapes of kinetics were identified with the MTE that either concentrate, depurate, or remains stable. In the mangrove, evolution of MTE was more rapid than the two other habitats a decrease of the As between 70 and 50 μg g−1 in the mangrove. Sargassum natans I presented a different metal composition than the two other morphotypes, with higher contents of As and Zn. All Sargassum morphotype are rapidly releasing the metal(oid)s arsenic (As) when they arrive in studied coastal habitats. In order to avoid the transfer of As from Sargassum to coastal environments, Sargassum stranding should be avoided and their valorization must take into account their As contents.
... Knowledge and evidence By 2010, there was a well-developed understanding of the ecology of sargassum, i.e. assemblages and structure of associated ecological communities. Knowledge about sargassum came from the widely researched Sargasso Sea, where sargassum is known as the 'golden rainforest of the sea' [38]. After the first tropical Atlantic influx in 2011, fear and misinformation about sargassum spread among coastal residents. ...
Climatic and anthropogenic changes appear to be driving the emergence of new ecosystem and human health risks. As new risks emerge, and the severity or frequency of known risks change, we ask: what evidence is there of past adaptations to emergent risks? What scientific and policy processes lead to adaptive solutions that minimise the impacts of these events, and draw out opportunities? We identify science and policy lessons learned from coping with, and responding to, the sudden arrival of brown macroalgae (pelagic sargassum) that has proliferated across the tropical Atlantic since 2011. Drawing on an evidence base developed from a systematic search of literature relating to sargassum seaweed, and using event timelines and word clouds, we provide an analysis of lessons learned from a case study of adaptive responses across three continents to an emergent risk over the course of a decade. We reflect on successes and failures as well as opportunities taken in building adaptive capacity to address the risk in four key domains: policy, knowledge and evidence, monitoring and early warning, and technology and valorisation. Failures include: lack of environmental risk registries; missed opportunities to share monitoring data; and lack of a shared approach to manage the risk. Successes include: development of national management strategies; open-access knowledge hubs, networks and webinars sharing information and best practice; semi-operational early advisory systems using open access remote sensing data; numerous innovations customising clean-up and harvesting equipment, and research and development of new uses and value-added products.
