Faunal mortality associated with massive beaching and decomposition of pelagic Sargassum

Rodríguez-Martínez, Rosa E.; Medina-Valmaseda, Alexis Enrique; Blanchon, Paul; Monroy-Velázquez, Luz Verónica; Almazán-Becerril, Antonio; Delgado-Pech, Benjamín; Vásquez–Yeomans, Lourdes; Francisco, Vanessa; García-Rivas, M.C.

doi:10.1016/j.marpolbul.2019.06.015

Cited by 157 publications

(84 citation statements)

References 17 publications

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“…In this study, values of DO (1.51 mg L −1 ) and pH (7.5) in the 25% leachate concentration were similar to those reported in two Mexican Caribbean reefs 10,11 at similar distances to where A. palmata gametes were collected (from 60 m away from the coast; Fig. 1 and Suppl.…”

Section: Discussionsupporting

confidence: 87%

Leachate effects of pelagic Sargassum spp. on larval swimming behavior of the coral Acropora palmata

Antonio-Martínez

Hénaut

Vega‐Zepeda

et al. 2020

Sci Rep

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An emerging disturbance for Caribbean reefs is the massive arrival of pelagic Sargassum, which deteriorates water quality due to the production of leachates. The highest arrivals of Sargassum took place when broadcasting corals spawned. We experimentally determined the effect of Sargassum leachates on swimming behavior of Acropora palmata larvae through five treatments (control, stain (simulating 100% leachate color), and 25%, 50% and 100% Sargassum leachate concentrations) during 30 min (10 min of videos and 20 min of post-observations). In the videos, larvae with leachates reduced swimming speed, were positively geotactic, the percentage of individuals that swam in a spiral pattern increased, and most behavioral displacements occurred at lower frequencies than larvae without leachates. Moreover, symptomatic spiral behavior was higher in the presence of leachates, suggesting that this behavior may be an effect of pollution. During post-observations, most larvae with leachates were motionless. This is the first time that Sargassum leachates have been documented modifying larval swimming behavior, which may reduce larval dispersion and genetic diversity. We suggest that a future evaluation of the effects of leachates at lower concentrations and over longer periods of exposure is needed. The resilience of corals may be compromised if Sargassum arrivals become frequent events. Globally, coral reefs are being degraded by several stressors (e.g., climate change, bleaching, overfishing and emergent diseases 1-5), especially those in the Caribbean 6. An emerging stressor for Caribbean reefs is the massive arrival of two pelagic macroalgal species: Sargassum fluitans and S. natans. Pelagic Sargassum drifts on the surface of the sea, providing an important habitat for a great diversity of organisms 7,8. The presence of a high biomass of pelagic Sargassum spp. began in 2011 in the central Atlantic Ocean and the Caribbean Sea 9. However, Sargassum influx in the Mexican Caribbean has only occurred since 2014, with the highest peaks reported in September 2015 (~2360 m 3 algae km −1) and May 2018 (8793 m 3 algae km −1) 10. Unfortunately, the massive arrival of pelagic Sargassum is predicted to become a recurring disturbance 9. Decomposition of the accumulated biomass of pelagic Sargassum in the coastline produces leachates that reduce dissolved oxygen (DO) and pH, and increase turbidity and temperature, deteriorating water quality 10,11. These leachates create conditions similar to eutrophication and may contain heavy metals such as mercury (Hg) and methylmercury (MeHg) 12 , methane 13 , lactic acid 14 , and high concentrations of ammonium and phosphorus 10. In the Mexican Caribbean, many coral species inhabit lagoon reefs (i.e., near to the coastline) where leachates of pelagic Sargassum have been observed and dispersed from the coastline toward the reef crest. In this context, some coral species became stressed and presented partial or total mortality due to the presence and decomposition of Sargassum 11 (Fig. 1). Brooding a...

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Section: Discussionsupporting

confidence: 87%

Leachate effects of pelagic Sargassum spp. on larval swimming behavior of the coral Acropora palmata

Antonio-Martínez

Hénaut

Vega‐Zepeda

et al. 2020

Sci Rep

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“…Beaching of sargasso has caused havoc to the Caribbean coastal ecosystems. Leachates and particulate organic matter from stranded decaying algal masses depleted the oxygen in near shore waters and reduced visibility of the water column, causing mortality of near-shore seagrasses and fauna (van Tussenbroek et al, 2017;Rodríguez-Martínez et al, 2019). Onshore and near shore masses of sargasso interfered with the seaward journeys of the juvenile turtles (Maurer, De Neef & Stapleton, 2015), affected sea turtle nestings (Maurer, Stapleton & Layman, 2018) and altered the trophic structure of the sea urchin Diadema antillarum in coastal marine systems (Cabanillas-Terán et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…The Mexican Caribbean coast began receiving massive amounts of sargasso during the late 2014 and it reached a peak in September 2015, when in the northern section of the coast between Cancun and Puerto Morelos an average of ∼2,360 m 3 of algae (mixed with sand, seagrasses and other algae) arrived per km of coastline (Rodríguez-Martínez, van Tussenbroek & Jordán-Dahlgren, 2016). During 2016, and 2017, the influxes decreased, increasing again in 2018, when in the peak month May ∼8,793 m 3 km −1 of algae (mixed with sand, seagrasses and other algae) were removed from the same shore section (Rodríguez-Martínez et al, 2019). In the tourist beaches, the algae removed from the beach and sea have been disposed in areas that are not properly prepared to avoid leakage of the leachates into the aquifer.…”

Section: Introductionmentioning

confidence: 99%

Element concentrations in pelagicSargassumalong the Mexican Caribbean coast in 2018-2019

Rodríguez-Martínez

Roy

Torrescano-Valle

et al. 2020

PeerJ

115

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The massive influx of pelagic Sargassum spp. (sargasso) into the Mexican Caribbean Sea has caused major deterioration of the coastal environment and has affected the tourism industry as well as livelihoods since 2015. Species of Sargassum have high capacity to absorb metals; thus, leachates of sargasso may contribute to contamination by potentially toxic metals when they drain into the sea and into the groundwater when dumped in inadequate land deposits. Valorization of sargasso would contribute to sustainable management; therefore, knowledge on potentially toxic metal content is necessary to define possible uses of the algae. We present concentrations of 28 elements measured using a non-destructive X-ray fluorescence analyzer (XRF) in 63 samples of sargasso collected between August 2018 and June 2019 from eight localities along ∼370 km long coastline of the Mexican Caribbean Sea. The sargasso tissues contained detectable concentrations of Al, As, Ca, Cl, Cu, Fe, K, Mg, Mn, Mo, P, Pb, Rb, S, Si, Sr, Th, U, V, and Zn. The element concentration in sargasso varied on spatial and temporal scales, which likely depended on the previous trajectory of the pelagic masses, and whether these had (or had not) passed through contaminated areas. Total arsenic concentration varied between 24–172 ppm DW, exceeding the maximum limit for seaweed intended as animal fooder (40 ppm DW) in 86% of the samples. For valorization, we recommend analyses of metal contents as a mandatory practice or avoiding uses for nutritional purposes. The high arsenic content is also of concern for environmental contamination of the sea and aquifer.

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“…The decomposition of Sargassum masses produces a "brown tide" that severely depletes oxygen levels and reduces light penetration, killing the seagrass and changing the environmental conditions of the shallow habitats [72]. This is of concern for the biological communities of the reef lagoon, including the populations of juvenile P. argus, as the altered environmental conditions can cause mass mortalities of local fauna [73] and can also affect immunity either directly, by changing components of the immune responses, or indirectly, by inducing general stress responses [74]. According to recent studies, recurrent blooms of pelagic Sargassum in the tropical Atlantic and Caribbean Sea arrivals reflect a regime shift and may become the new norm [75].…”

Section: Discussionmentioning

confidence: 99%

Do ecological characteristics drive the prevalence of Panulirus argus virus 1 (PaV1) in juvenile Caribbean spiny lobsters in a tropical reef lagoon?

et al. 2020

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PaV1 is a pathogenic virus found only to infect Caribbean spiny lobsters Panulirus argus, a major fishing resource. P. argus is a benthic mesopredator and has a complex life history, with several ontogenetic habitat changes. Habitat characteristics and species diversity of surrounding communities may have implications for disease dynamics. This is of more concern for juvenile lobsters, which are more susceptible to PaV1 and are far less mobile than adult lobsters. We targeted a population of juvenile P. argus in a reef lagoon in Mexico, where PaV1 was first observed in 2001. Prevalence has been since irregularly assessed, but in 2016 we began a more systematic assessment, with two sampling periods per year (June and November) in three different zones of the reef lagoon. To examine the relationship between PaV1 prevalence and potential ecological determinants, we assessed habitat complexity, cover of different substrates, and invertebrate community composition in all zones during the first four sampling periods (June and November 2016 and 2017). Habitat complexity and percent cover of some substrates varied with zone and sampling period. This was the case for seagrass and macroalgae, which nevertheless were the dominant substrates. The invertebrate community composition varied with sampling period, but not with zone. Probability of infection decreased with increasing lobster size, consistent with previous studies, but was not affected by zone (i.e., variations in ecological characteristics did not appear to be sufficiently large so as to influence prevalence of PaV1). This result possibly reflects the dominance of marine vegetation and suggests that lobsters can be sampled throughout the reef lagoon to assess PaV1 prevalence. Prevalence was higher in only one of seven sampling periods (November 2017), suggesting that the pathogen has leveled off to an enzootic level.

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Faunal mortality associated with massive beaching and decomposition of pelagic Sargassum

Cited by 157 publications

References 17 publications

Leachate effects of pelagic Sargassum spp. on larval swimming behavior of the coral Acropora palmata

Leachate effects of pelagic Sargassum spp. on larval swimming behavior of the coral Acropora palmata

Element concentrations in pelagicSargassumalong the Mexican Caribbean coast in 2018-2019

Do ecological characteristics drive the prevalence of Panulirus argus virus 1 (PaV1) in juvenile Caribbean spiny lobsters in a tropical reef lagoon?

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