Assessment of the Chemical Diversity and Potential Toxicity of Benthic Cyanobacterial Blooms in the Lagoon of Moorea Island (French Polynesia)

In the last decades, an apparent increase in the frequency of benthic cyanobacterial blooms has occurred in coral reefs and tropical lagoons, possibly in part because of global change and anthropogenic activities. In the frame of the survey of marine benthic cyanobacteria proliferating in the lagoon of Moorea Island (French Polynesia), 15 blooms were collected, mainly involving three species—Anabaena sp.1, Lyngbya majuscula and Hydrocoleum majus-B. Their chemical fingerprints, obtained through high performance liquid chromatography combined with UV detection and mass spectrometry (HPLC-UV-MS) analyses, revealed a high extent of species-specificity. The chemical profile of Anabaena sp.1 was characterized by three major cyclic lipopeptides of the laxaphycin family, whereas the one of L. majuscula was characterized by a complex mixture including tiahuramides, trungapeptins and serinol-derived malyngamides. Toxicity screening analyses conducted on these cyanobacterial samples using Artemia salina and mouse neuroblastoma cell-based (CBA-N2a) cytotoxic assays failed to show any toxicity to a degree that would merit risk assessment with regard to public health. However, the apparently increasing presence of blooms of Lyngbya, Hydrocoleum, Anabaena or other benthic cyanobacteria on coral reefs in French Polynesia encourages the implementation of ad hoc monitoring programs for the surveillance of their proliferation and potential assessment of associated hazards.

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Benthic cyanobacteria on coral reefs of Moorea Island (French Polynesia): diversity response to habitat quality

Hydrobiologia ◽

10.1007/s10750-019-04029-8 ◽

2019 ◽

Vol 843 (1) ◽

pp. 61-78 ◽

Cited By ~ 3

Author(s):

Mayalen Zubia ◽

Christophe Vieira ◽

Katarzyna A. Palinska ◽

Mélanie Roué ◽

Jean-Claude Gaertner ◽

...

Keyword(s):

Coral Reefs ◽

Habitat Quality ◽

French Polynesia ◽

Benthic Cyanobacteria ◽

Moorea Island

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Long term relationship between farming damselfish, predators, competitors and benthic habitat on coral reefs of Moorea Island

Scientific Reports ◽

10.1038/s41598-021-94010-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

William E. Feeney ◽

Frédéric Bertucci ◽

Emma Gairin ◽

Gilles Siu ◽

Viliame Waqalevu ◽

...

Keyword(s):

Coral Reefs ◽

Marine Protected Area ◽

Keystone Species ◽

French Polynesia ◽

Benthic Habitat ◽

Long Term Monitoring ◽

Moorea Island ◽

Term Monitoring ◽

Dusky Damselfish

AbstractUnderstanding the processes that shape biodiversity is essential for effective environmental management. Across the world’s coral reefs, algal farming damselfish (Stegastes sp.) modify the surrounding benthic community through their creation of algae “farms”. Using a long-term monitoring dataset (2005–2019) from Moorea Island, French Polynesia, we investigated whether the density of dusky damselfish (Stegastes nigricans) is associated with benthic habitat composition, the density of predators and/or competitors, and whether the survey area was inside or outside of a Marine Protected Area (MPA). We found no evidence that benthic cover or number of competitors were associated with dusky damselfish densities, both inside and outside MPAs. In contrast, fluctuations in dusky damselfish densities were negatively associated with the density of predators (e.g. Serranidae, Muraenidae and Scorpaenidae) in the preceding year in non-MPA areas, and both within and outside of MPAs when predator densities were high (2005–2010). These results suggest that healthy predator populations may be important for regulating the abundances of keystone species, such as algal farming damselfish, especially when predator densities are high.

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Nitrogen enrichment in macroalgae following mass coral mortality

Coral Reefs ◽

10.1007/s00338-021-02079-w ◽

2021 ◽

Author(s):

Eleanor J. Vaughan ◽

Shaun K. Wilson ◽

Samantha J. Howlett ◽

Valeriano Parravicini ◽

Gareth J. Williams ◽

...

Keyword(s):

Coral Reefs ◽

Coral Cover ◽

Strong Association ◽

French Polynesia ◽

Mass Mortality ◽

Transplant Experiment ◽

Bleaching Event ◽

Coral Mortality ◽

Absolute Increase ◽

Inorganic Matter

AbstractScleractinian corals are engineers on coral reefs that provide both structural complexity as habitat and sustenance for other reef-associated organisms via the release of organic and inorganic matter. However, coral reefs are facing multiple pressures from climate change and other stressors, which can result in mass coral bleaching and mortality events. Mass mortality of corals results in enhanced release of organic matter, which can cause significant alterations to reef biochemical and recycling processes. There is little known about how long these nutrients are retained within the system, for instance, within the tissues of other benthic organisms. We investigated changes in nitrogen isotopic signatures (δ15N) of macroalgal tissues (a) ~ 1 year after a bleaching event in the Seychelles and (b) ~ 3 months after the peak of a bleaching event in Mo’orea, French Polynesia. In the Seychelles, there was a strong association between absolute loss in both total coral cover and branching coral cover and absolute increase in macroalgal δ15N between 2014 and 2017 (adjusted r2 = 0.79, p = 0.004 and adjusted r2 = 0.86, p = 0.002, respectively). In Mo’orea, a short-term transplant experiment found a significant increase in δ15N in Sargassum mangarevense after specimens were deployed on a reef with high coral mortality for ~ 3 weeks (p < 0.05). We suggest that coral-derived nutrients can be retained within reef nutrient cycles, and that this can affect other reef-associated organisms over both short- and long-term periods, especially opportunistic species such as macroalgae. These species could therefore proliferate on reefs that have experienced mass mortality events, because they have been provided with both space and nutrient subsidies by the death and decay of corals.

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Multi-domain probiotic consortium as an alternative to chemical remediation of oil spills at coral reefs and adjacent sites

Microbiome ◽

10.1186/s40168-021-01041-w ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Denise P. Silva ◽

Helena D. M. Villela ◽

Henrique F. Santos ◽

Gustavo A. S. Duarte ◽

José Roberto Ribeiro ◽

...

Keyword(s):

Microbial Community ◽

Coral Reefs ◽

Environmental Changes ◽

Oil Spills ◽

Anthropogenic Activities ◽

Oil Contamination ◽

Negative Effects ◽

Corexit 9500 ◽

Coral Health ◽

The Impact

Abstract Background Beginning in the last century, coral reefs have suffered the consequences of anthropogenic activities, including oil contamination. Chemical remediation methods, such as dispersants, can cause substantial harm to corals and reduce their resilience to stressors. To evaluate the impacts of oil contamination and find potential alternative solutions to chemical dispersants, we conducted a mesocosm experiment with the fire coral Millepora alcicornis, which is sensitive to environmental changes. We exposed M. alcicornis to a realistic oil-spill scenario in which we applied an innovative multi-domain bioremediator consortium (bacteria, filamentous fungi, and yeast) and a chemical dispersant (Corexit® 9500, one of the most widely used dispersants), to assess the effects on host health and host-associated microbial communities. Results The selected multi-domain microbial consortium helped to mitigate the impacts of the oil, substantially degrading the polycyclic aromatic and n-alkane fractions and maintaining the physiological integrity of the corals. Exposure to Corexit 9500 negatively impacted the host physiology and altered the coral-associated microbial community. After exposure, the abundances of certain bacterial genera such as Rugeria and Roseovarius increased, as previously reported in stressed or diseased corals. We also identified several bioindicators of Corexit 9500 in the microbiome. The impact of Corexit 9500 on the coral health and microbial community was far greater than oil alone, killing corals after only 4 days of exposure in the flow-through system. In the treatments with Corexit 9500, the action of the bioremediator consortium could not be observed directly because of the extreme toxicity of the dispersant to M. alcicornis and its associated microbiome. Conclusions Our results emphasize the importance of investigating the host-associated microbiome in order to detect and mitigate the effects of oil contamination on corals and the potential role of microbial mitigation and bioindicators as conservation tools. Chemical dispersants were far more damaging to corals and their associated microbiome than oil, and should not be used close to coral reefs. This study can aid in decision-making to minimize the negative effects of oil and dispersants on coral reefs.

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Spatiotemporal distribution of nocturnal coral reef fish juveniles in Moorea Island, French Polynesia

Ichthyological Research ◽

10.1007/s10228-006-0368-9 ◽

2007 ◽

Vol 54 (1) ◽

pp. 18-23 ◽

Cited By ~ 3

Author(s):

David Lecchini ◽

Yohei Nakamura ◽

Makoto Tsuchiya ◽

René Galzin

Keyword(s):

Coral Reef ◽

Reef Fish ◽

Coral Reef Fish ◽

French Polynesia ◽

Spatiotemporal Distribution ◽

Fish Juveniles ◽

Moorea Island

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Consistency in the supply of larval fishes among coral reefs in French Polynesia

PLoS ONE ◽

10.1371/journal.pone.0178795 ◽

2017 ◽

Vol 12 (6) ◽

pp. e0178795 ◽

Cited By ~ 5

Author(s):

Marc Besson ◽

Camille Gache ◽

Rohan M. Brooker ◽

Rakamaly Madi Moussa ◽

Viliame Pita Waqalevu ◽

...

Keyword(s):

Coral Reefs ◽

French Polynesia ◽

Larval Fishes

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Seasonal variations of downward particle fluxes in front of a reef pass (Moorea Island, French Polynesia)

Oceanologica Acta ◽

10.1016/s0399-1784(02)01182-9 ◽

2002 ◽

Vol 25 (2) ◽

pp. 61-70 ◽

Cited By ~ 6

Author(s):

Muriel Schrimm ◽

Serge Heussner ◽

Roselyne Buscail

Keyword(s):

Seasonal Variations ◽

French Polynesia ◽

Particle Fluxes ◽

Moorea Island

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Intraspecific Variability in the Toxin Production and Toxin Profiles of In Vitro Cultures of Gambierdiscus polynesiensis (Dinophyceae) from French Polynesia

Toxins ◽

10.3390/toxins11120735 ◽

2019 ◽

Vol 11 (12) ◽

pp. 735 ◽

Cited By ~ 11

Author(s):

Sébastien Longo ◽

Manoella Sibat ◽

Jérôme Viallon ◽

Hélène Darius ◽

Philipp Hess ◽

...

Keyword(s):

Neuroblastoma Cell ◽

Intraspecific Variability ◽

Toxin Production ◽

French Polynesia ◽

Stationary Growth ◽

Noticeable Increase ◽

Intraspecific Variations ◽

Geographic Origins ◽

Liquid Chromatography Tandem Mass

Ciguatera poisoning (CP) is a foodborne disease caused by the consumption of seafood contaminated with ciguatoxins (CTXs) produced by dinoflagellates in the genera Gambierdiscus and Fukuyoa. The toxin production and toxin profiles were explored in four clones of G. polynesiensis originating from different islands in French Polynesia with contrasted CP risk: RIK7 (Mangareva, Gambier), NHA4 (Nuku Hiva, Marquesas), RAI-1 (Raivavae, Australes), and RG92 (Rangiroa, Tuamotu). Productions of CTXs, maitotoxins (MTXs), and gambierone group analogs were examined at exponential and stationary growth phases using the neuroblastoma cell-based assay and liquid chromatography–tandem mass spectrometry. While none of the strains was found to produce known MTX compounds, all strains showed high overall P-CTX production ranging from 1.1 ± 0.1 to 4.6 ± 0.7 pg cell−1. In total, nine P-CTX analogs were detected, depending on strain and growth phase. The production of gambierone, as well as 44-methylgamberione, was also confirmed in G. polynesiensis. This study highlighted: (i) intraspecific variations in toxin production and profiles between clones from distinct geographic origins and (ii) the noticeable increase in toxin production of both CTXs, in particular CTX4A/B, and gambierone group analogs from the exponential to the stationary phase.

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