Figure 2 - uploaded by Lindsay Martin
Content may be subject to copyright.
From Gower & King (2011) with permission, showing MERIS detected Sargassum distributions over the course of approximately one year shows large accumulations of the algae moving from the Gulf in the spring and early summer to the northern Sargasso Sea in the fall, moving towards the south in the late fall to winter. In 2008, an anomalously large quantity of Sargassum was detected off the coast of Florida.
Source publication
There are many species of the genus Sargassum distributed in tropical and subtropical waters but only two, S. natans and S. fluitans, have an entirely pelagic life cycle and offer ecologically-supportive structures of different forms in otherwise nutrient-poor environments. Sargassum represents a keystone species supporting relatively high levels o...
Context in source publication
Context 1
... they are difficult to track, the origins and drift patterns of pelagic Sargassum have always been uncertain. Remote satellite sensing techniques, which cannot distinguish Sargassum species, suggest that drifting Sargassum is moved through the oceans by surface currents and winds on an annual cycle that is thought to begin in the Gulf of Mexico during spring and ends in the southern Sargasso Sea during the following winter (Gower & King 2011) (Figure 2). fewer species per unit area than the same unit of area in a larger patch (i.e. a windrow) (Hansski & Simberloff 1997, MacArthur & Wilson 1967. ...
Similar publications
Citations
... They are both holopelagic, meaning they spend their entire life cycle floating on the surface, and aggregate under the effect of winds and currents to form mats (Langmuir, 1938;Ody et al., 2019). They have been observed in the north Atlantic Ocean for several centuries, with the first historical report dating back to the 15th century and Christopher Colombus' journey to the Americas during which the Sargasso Sea was described (Frazier, 2014;Martin, 2016;Wang et al., 2019). Their presence has also been reported in the Gulf of Mexico since the mid-19th century, through reports of strandings in the local press (Webster and Linton, 2013). ...
... Vibrio species) or microplastics, posing risks to local communities and ecosystems (Aldana Arana et al., 2024;Mendonça et al., 2024;Michotey et al., 2020;Tapia-Fuentes et al., 2023;Theirlynck et al., 2023;Van Tussenbroek et al., 2024). On beaches, Sargassum can affect turtle reproduction by limiting access to reproductive areas, preventing egg laying, or by modifying temperature, affecting sex ratio or leading to the death of embryos (Azanza Ricardo and Pérez Martin, 2016;Chávez et al., 2020;Gavio and Santos-Martinez, 2018;Maurer et al., 2015). Beach cleaning to remove Sargassum, often involving mechanical methods, is also harmful to the environment, compacting the sand, removing the sand along with the algae and accentuating erosion, in turn affecting the reproduction of sea turtles (Chávez et al., 2020). ...
Since 2011, massive strandings of holopelagic Sargassum have occurred on the coasts of the Caribbean and of West Africa. Although open ocean Sargassum mats are oases of biodiversity, their stranding has a number of negative ecological, economic and health consequences. To limit these impacts, Sargassum needs to be collected as quickly as possible to avoid its decomposition, which requires accurate predictions of the date, location and abundance of the strandings. Two complementary approaches have been developed for this purpose: satellite remote sensing technique, to detect Sargassum aggregations, and modeling, to forecast Sargassum displacement and growth. The objective of this review is to provide a synthesis of the current knowledge related to Sargassum monitoring in the tropical Atlantic Ocean. To better understand the issues surrounding Sargassum and its monitoring, the first two parts are devoted to an overview of the ecology of the two most prevailing holopelagic Sargassum species, to the current issues related to their strandings, to the causes of their occurrence in the tropical Atlantic Ocean and to their seasonal and interannual variabilities. The methods used to detect Sargassum from satellite images and their limitations are examined. The transport and biogeochemical models developed for seasonal forecast and stranding predictions are described along with their limitations. As both detection and modeling rely on validation data to assess their accuracy, previous works providing in situ characterization of Sargassum are also reviewed here. The last part provides recommendations to further increase knowledge on holopelagic Sargassum and improve the predictions of their strandings.
... Overall, our study aligns with the documented range of sargassumassociated epibionts observed in other regions across the Tropical Atlantic and Caribbean (see Taylor et al., 2017;Monroy-Velàzquez et al., 2019;Alleyne et al., 2023;Corbin et al., 2024;van Tussenbroek et al., 2024), and the western North Atlantic, including the Sargasso Sea and Gulf Stream (Weis, 1968;Fine, 1970;Stoner and Greening, 1984;Huffard et al., 2014;Martin, 2016;Martin et al., 2021) (see Table S1). Arthropoda and Mollusca are the most dominant Phyla among motile species associated with holopelagic sargassum, and Cnidaria (hydroids) the most dominant of sessile taxa. ...
... In terms of our study area, Valesco (2015) and Sargeant (2015) hypothesize that climate change might have caused the Sargasso Sea to migrate further south, carrying the seaweeds nearer to Caribbean islands. Additionally, Martin (2016) and Chavez et al. (2020) propose that the enormous Sargassum around Caribbean islands may be caused by sand dust blown from the Sahara Desert into the South Atlantic providing nutrients for its growth together with climate change impacts. In a more recent and comprehensive study, Wang et al. (2019) used remotely sensed imagery and models of ocean temperatures and currents and showed that changes in ocean temperatures and circulation patterns, seeds from previous high-volume episodes, and increased nutrient runoff from the Amazon River in Brazil have caused the recent seaweed surge in the Caribbean. ...
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.
... For over a decade now, Caribbean nations have been negatively affected by frequent and severe inundations of sargassum advected from the NERR and have suffered numerous associated ecological and socio-economic consequences. Dense accumulations of sargassum onshore have reduced nesting success of endangered sea turtle species (Azanza-Ricardo and Perez- Martin, 2016), and murky, eutrophic, hypoxic waters termed "sargassum brown tides" produced by decomposing sargassum in nearshore areas, have caused widespread mortality of seagrass meadows and reef-associated fauna such as corals and fish (van Tussenbroek et al., 2017;Rodríguez-Martínez et al., 2019;Chávez et al., 2020). This has reduced important ecosystem services and altered trophic dynamics in the affected coastal ecosystems (Cabanillas-Terán et al., 2019;Hendy et al., 2021). ...
... Clinging fauna (also referred to in the literature as 'cryptic fauna' or 'motile epifauna') include small invertebrates (e.g., shrimps, crabs, amphipods, molluscs, polychaetes and flatworms) and vertebrates (e.g., sargassum frogfish, larval fishes and turtle hatchlings) that cling to, climb around or hide within the floating sargassum thalli (Weis, 1968;Coston-Clements et al., 1991;Franks et al., 2017;Martin et al., 2021). Many are specially adapted to life in the floating sargassum habitat having evolved morphologies and coloration to maximize camouflage and movement within the confines of sargassum rafts (Butler et al., 1983;Bennice and Brooks, 2016;Martin, 2016); however, only 10 species are considered endemic to the sargassum community (Laffoley et al., 2011). Free-swimming fauna (also referred to as 'motile fauna') commonly associated with sargassum rafts include many pelagic fish species of commercial importance such as flyingfishes, jacks and dolphinfish (Dooley, 1972;Comyns et al., 2000;Hoffmayer et al., 2005;Laffoley et al., 2011) as well as endangered sea turtles, marine mammals and sea birds (Haney, 1986;de Boer and Saulino, 2020;Goodwin et al., 2022), all of which opportunistically utilize the floating habitat for shelter and/or foraging, and/or spawning (Dooley, 1972;Stoner and Greening, 1984;Casazza and Ross, 2008). ...
... Lowest AIC value indicates most parsimonious model. However, our study certainly falls within the range of sargassum-associated clinging macrofauna taxa recorded in open ocean areas from across the Tropical Atlantic and Caribbean (Taylor et al., 2017, 5 phyla, 20 taxa); the Eastern Caribbean (Martin, 2016, 3 phyla, 6 taxa) and the Western North Atlantic including the Sargasso Sea, Gulf of Mexico and Gulf Stream (Fine, 1970, 7 phyla, 58 taxa;Weis, 1968, 5 phyla, 16 taxa;Stoner and Greening, 1984, 5 phyla, 15 taxa;Muñoz, 2013, 6 phyla, 35 taxa;Huffard et al., 2014, 4 phyla, 23 taxa;Martin, 2016, 6 phyla, 21 taxa;Martin et al., 2021;5 phyla, 32 taxa). Overall, the phyla composition of the clinging macrofauna associated with sargassum rafts observed in this study generally agrees well with earlier reports. ...
Tropical Atlantic blooms of pelagic Sargassum species are associated with severe inundation events along the coasts of Caribbean and West African nations that cause extensive ecological and socioeconomic harm. The use of in-water harvesting as a management strategy avoids the plethora of challenges associated with shoreline in-undations. Moreover, with a growing interest in the valorisation of this raw material, in-water harvesting provides the best opportunity to collect substantial amounts of 'fresh' sargassum that can be used in a variety of applications. However, in-water harvesting of sargassum will remove organisms associated with the floating habitat, resulting in loss of biodiversity, thus creating a potential management dilemma. To address this management concern, we assessed the clinging fauna associated with sargassum rafts at various distances from shore. From a total of 119 dipnet samples of sargassum, we recorded 18 taxa, across 6 phyla (Arthropoda, Mollusca, Chordata, Platyhelminthes, Nemathelminthes, Annelida) with the phylum Arthropoda being the most speciose (n = 10). Our multivariate and model selection analyses support that distance from shore and season are the most important drivers of variability in community composition and that season is the most important driver of individual abundance and number of taxa across samples. Overall, rafts within 0-3000 m of the shoreline of Barbados harbored low biodiversity and were dominated by small invertebrates (mean size: 5.5 mm) of no commercial value. Results suggest that biodiversity trade-offs associated with in-water sargassum harvesting in coastal areas are likely to be negligible.
... The Sargassum could function as a floating nursery for the juvenile urchins, comparable to the assisted natural recovery method (Hylkema et al. 2022b). However, it is likely that the juveniles face high mortality rates from the multitude of predators living in Sargassum mats (Alleyne et al. 2023;Martin 2016) and the Sargassum could never reach suitable habitat or wash ashore (Cabanillas-Teran et al. 2019;Wang et al. 2019). ...
Tropical western Atlantic reefs have gradually shifted from being dominated by corals to being mainly covered by macroalgae. The mass-mortality of the sea urchin Diadema antillarum in the 80s and the slow to non-existent recovery exacerbated this shift. Chemical cues associated with these reefs are expected to have shifted too with potential negative effects on larval recruitment, possibly limiting recovery of important species like D. antillarum. In this study, we tested the effects of naturally derived biofilm and macroalgae species native to Caribbean coral reefs on the settlement rate of cultured D. antillarum larvae in two separate experiments. Crustose coralline algae (CCA) were included in both experiments, making it possible to compare settlement rates from both experiments. A biofilm of one week old yielded significantly lower settlement rates compared to two, four, and six weeks old biofilm and the highest settlement rate was found for CCA with over 62% of total larvae. All six tested macroalgae species resulted in settled larvae, with little significant difference between algal species, partly due to a high variation in settlement rates within treatments. Sargassum fluitans induced the highest settlement rate with 33%, which was not significantly different from CCA with 29%. We conclude that dominant macroalgae species likely to be encountered by D. antillarum on shifted reefs are no major constraint to settlement. Our findings increase the understanding of alternative stable state settlement dynamics for a keystone coral reef herbivore.
... In terms of our study area, Valesco (2015) and Sargeant (2015) hypothesize that climate change might have caused the Sargasso Sea to migrate further south, carrying the seaweeds nearer to Caribbean islands. Additionally, Martin (2016) and Chavez et al. (2020) propose that the enormous Sargassum around Caribbean islands may be caused by sand dust blown from the Sahara Desert into the South Atlantic providing nutrients for its growth together with climate change impacts. In a more recent and comprehensive study, Wang et al. (2019) used remotely sensed imagery and models of ocean temperatures and currents and showed that changes in ocean temperatures and circulation patterns, seeds from previous high-volume episodes, and increased nutrient runoff from the Amazon River in Brazil have caused the recent seaweed surge in the Caribbean. ...
... It is a perennial genus of about ten centimeters to several meters long (up to 8 m for S. muticum), fixed by a discoid-conical holdfast. Stipes of 1-20 cm long arise from this basal disc are stem-like with ramifications that are variable according to the species [188], and they are covered with small visible thorns (<1 mm) [189]. Air bladders (vesicles) are normally present in a swollen and berrylike form. ...
Seaweeds represent a promising and sustainable feedstock for biofuel production which raises increasing research interests. Their high availability, easy fermentable composition, and good degradation potential make them a suitable candidate for alternating fossil fuels as an advantageous energy resource. This comprehensive review aims to summarize and discuss data from the literature on the biochemical composition of seaweeds and its potential for biomethane and biohydrogen production, as well as to investigate the effect of the common pretreatment methods. Satisfactory yields comparable to terrestrial biomass could be obtained through anaerobic digestion; concerning dark fermentation, the challenge remains to better define the operating conditions allowing a stable production of biohydrogen. Finally, we propose a potential energy production scheme with the seaweed found by the Caribbean Islands of Guadeloupe and Martinique, as well as current techno-economic challenges and future prospects. An annual energy potential of 66 GWh could be attained via a two-stage biohythane production process, this tends to be promising in terms of energetic valorization and coastal management.
... Samples found in the Sargasso Sea were dominated by L. melanostoma (Stoner and Greening 1984). Other studies have investigated the Sargassum community structure in the Gulf Stream (e.g., Fine 1970;Casazza and Ross 2008;Huffard et al. 2014;Martin 2016), but no study has investigated the community from the locations in this study nor on a latitudinal gradient. ConClusion ...
... The diversity of species living in association with Sargassum remains high (see CBD, 2015a). There is new information on animal groups within the Sargasso Sea e.g., Squid (Lischka et al., 2017), Hydroids (Govindarajan et al., 2019) and fish (Ayala et al., 2016); molecular diversity within a speciesthe slender Sargassum shrimp (Sehein et al., 2014), and changes in time and scale in Sargassum communities (Huffard et al., 2014),.Compared to S.fluitans III, S. natans VIII hosts a reduced community of motile epifauna in terms of both species abundance and diversity (Martin, 2016;Martin et al., 2021). This may lead to it being less attractive to turtles, fish and seabirds which feed on or beneath Sargassum mats. ...
The Sargasso Sea is a high seas ecosystem located within the North Atlantic Subtropical Gyre. The floating Sargassum macroalgae for which it is named support a diverse and productive ocean ecosystem. The floating mats and windrows of Sargassum house distinct communities of animals including endemic species, and provide shelter, nursery areas and food for many others including juvenile turtles, fish, and birds. A decade ago, in 2012, the two million square mile core area of the Sargasso Sea was “described” by the parties to the Convention on Biological Diversity (CBD) as an Ecologically or Biologically Significant Marine Area (EBSA), having scored highly on six of the seven designated criteria. At the time it was the largest high seas EBSA to be so described. This paper reviews the scientific evidence supporting the finding that it meets the rigorous criteria for an EBSA and assesses whether there have been major changes in the decade since. It puts this in the context of the work of the Sargasso Sea Commission and the Hamilton Declaration Signatories to “conserve the Sargasso Sea for the benefit of present and future generations” and assesses the extent to which being an EBSA has assisted with these conservation efforts.
... Sargassum macroalgae exist either as fleshy brown benthic or pelagic species (S. fluitans and S. natans) that can form large floating mats that can be transported great distances in the ocean by prevailing currents and winds (Schell et al., 2015;Wang et al., 2019). These large mats create functional habitats for numerous marine species, such as invertebrates, fish, turtles, and birds (Martin, 2016). Pelagic Sargassum has been observed in the mid-Atlantic Ocean's Sargasso Sea dating back to the fifteenth century, but more recently its range has expanded geographically and spatially across the Atlantic Ocean from west Africa into the Caribbean Sea (Wang et al., 2019;Wang and Hu, 2021). ...
... Pelagic Sargassum has been observed in the mid-Atlantic Ocean's Sargasso Sea dating back to the fifteenth century, but more recently its range has expanded geographically and spatially across the Atlantic Ocean from west Africa into the Caribbean Sea (Wang et al., 2019;Wang and Hu, 2021). Pelagic Sargassum has an enormous biodiversity potential and serves as a vital nursery and shelter for commercially important juvenile fish (Martin, 2016), and is also a source of local nutrients and carbon . The presence of floating Sargassum can also dampen wave action and contribute to shoreline stability once beached. ...
... The concentration factor of trace elements and radionuclides in the Sargassum and potential leaching of those elements during decomposition could cause adverse effects to sensitive organisms and ecosystems. There is a risk not only from the decomposition process, but some marine organisms, including turtles, crabs, shrimp, mahi mahi, and amberjacks either eat, live or breed in the floating Sargassum mats (Martin, 2016) and could therefore bioaccumulate these trace elements and radionuclides in their tissues and organs. Additionally, as people increasingly harvest Sargassum for both research and commercial use, prolonged contact could also have negative impacts on human health. ...
In recent years, the North Atlantic and the Caribbean Sea have experienced unusual and unprecedented pelagic Sargassum blooms, which may adversely affect coastal ecosystems and productive ocean. Sargassum has the potential to scavenge trace elements and radionuclides from seawater, and when bioaccumulated and thus concentrated, can pose a potential threat to higher trophic organisms, including humans that consume impacted seafood. In this study, trace elements and naturally-occurring U/Th-series radionuclides were measured in Sargassum that were collected in the coastal waters of the Caribbean Sea (Antigua/Barbuda, Belize, and Barbados) to better define baseline concentrations and activities, and to assess the scavenging potential for these trace elements and radionuclides. The mean concentration of trace elements observed in Sargassum collected across these three Caribbean Sea are ranked accordingly to the following descending order: Sr > As>Fe > Mn > Zn > Ni > V > C > Cd > Se > Co > Cr > Pb > Ag > Hg. 210-Po and ²¹⁰Pb activities in Sargassum were observed to be more elevated than previously reported values.
