Shallow epifaunal sea cucumber densities and their relationship with the benthic community in the Okinawa Islands

Hamamoto, Kohei; Poliseno, Angelo; Soliman, Taha; Reimer, James Davis

doi:10.7717/peerj.14181

Cited by 3 publications

(1 citation statement)

References 42 publications

(63 reference statements)

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“…The sea cucumber, Apostichopus japonicus (Selenka), is a temperate marine invertebrate and an economically important aquatic echinodermic species in China [ 1 , 2 ]. As benthic organisms, sea cucumbers feed on small benthic particulate matter and are easily affected by pollutants [ 3 ]. Thus, it is important to investigate the effects of pollutants on sea cucumbers to conserve wild sea cucumber species.…”

Section: Introductionmentioning

confidence: 99%

Bisphenol A (BPA) Directly Activates the G Protein-Coupled Estrogen Receptor 1 and Triggers the Metabolic Disruption in the Gonadal Tissue of Apostichopus japonicus

Yuan

Yang

et al. 2023

Biology

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The sea cucumber, Apostichopus japonicus, is a marine benthic organism that feeds on small benthic particulate matter and is easily affected by pollutants. Bisphenol A (BPA, 4,4′-isopropylidenediphenol) has been identified as an endocrine disruptor. It is ubiquitously detectable in oceans and affects a variety of marine animals. It functions as an estrogen analog and typically causes reproductive toxicity by interfering with the endocrine system. To comparatively analyze the reproductive effects of estradiol (E2) and BPA on sea cucumbers, we identified a G protein-coupled estrogen receptor 1 (GPER1) in A. japonicus and investigated its effects on reproduction. The results showed that BPA and E2 exposure activated A. japonicus AjGPER1, thereby mediating the mitogen-activated protein kinase signaling pathways. High-level expression of AjGPER1 in the ovarian tissue was confirmed by qPCR. Furthermore, metabolic changes were induced by 100 nM (22.83 μg/L) BPA exposure in the ovarian tissue, leading to a notable increase in the activities of trehalase and phosphofructokinase. Overall, our findings suggest that AjGPER1 is directly activated by BPA and affects sea cucumber reproduction by disrupting ovarian tissue metabolism, suggesting that marine pollutants pose a threat to the conservation of sea cucumber resources.

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Section: Introductionmentioning

confidence: 99%

Bisphenol A (BPA) Directly Activates the G Protein-Coupled Estrogen Receptor 1 and Triggers the Metabolic Disruption in the Gonadal Tissue of Apostichopus japonicus

Yuan

Yang

et al. 2023

Biology

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Searching for drivers of the patchy distribution of sympatric deposit‐feeding sea cucumbers: A multi‐scale monitoring study

Pierrat,

Urbistondoy,

Modi

et al. 2024

Limnology & Oceanography

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Three sea cucumber species, Holothuria atra, Holothuria leucospilota, and Stichopus chloronotus, are patchily distributed within the coral reefs of Reunion Island, exhibiting locally high densities (> 1 ind m−2). Previous studies stated that these sympatric species have thrived for almost four decades; however, factors involved in their distribution and spatiotemporal dynamics are not well understood yet. The aims of this study are to analyze the fine‐scale spatiotemporal dynamics of these sympatric species and identify the key sedimentary factors (substrate composition and cover) involved in their distribution. Sea cucumber populations and sedimentary factors were monitored along back‐reef and shore‐to‐ocean gradients during four consecutive seasons. Meanwhile, feeding behavior was assessed by measuring motility and excretion rates. Each species presents its own dynamic between the beginning and the end of the monitoring: increase of density for H. leucospilota, stability for H. atra, and decrease for S. chloronotus. Distribution of H. atra was closely related to substrate organic features (high organic matter, chlorophyll a, and ∂13C), H. leucospilota with the occurrence of seagrass and S. chloronotus with none. Results on feeding behavior showed that S. chloronotus emerges as a specialist while the two others appear to be generalists. Conspecific attraction or recruitment pattern may drive the high‐density patchy distribution of both Holothuria species, while the drastic decrease of S. chloronotus could be linked to unstudied factors related to predation or climate change. Water flow regime could also have a significant effect on the patchy distribution of these species, therefore, further studies should pay particular attention to this factor.

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Diversity, composition and potential roles of sedimentary microbial communities in different coastal substrates around subtropical Okinawa Island, Japan

Hamamoto,

Mizuyama,

Nishijima

et al. 2024

Environmental Microbiome

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Background Marine benthic prokaryotic communities play crucial roles in material recycling within coastal environments, including coral reefs. Coastal sedimentary microbiomes are particularly important as potential reservoirs of symbiotic, beneficial, and pathogenic bacteria in coral reef environments, and therefore presumably play a core role in local ecosystem functioning. However, there is a lack of studies comparing different environments with multiple sites on the island scale, particularly studies focusing on prokaryotic communities, as previous investigations have focused mainly on a single site or on specific environmental conditions. In our study, we collected coastal sediments from seven sites around Okinawa Island, Japan, including three different benthic types; sandy bottoms, seagrass meadows, and hard substratum with living scleractinian corals. We then used metabarcoding to identify prokaryotic compositions and estimate enzymes encoded by genes to infer their functions. Results The results showed that the three substrata had significantly different prokaryotic compositions. Seagrass meadow sites exhibited significantly higher prokaryotic alpha-diversity compared to sandy bottom sites. ANCOM analysis revealed that multiple bacterial orders were differentially abundant within each substratum. At coral reef sites, putative disease- and thermal stress-related opportunistic bacteria such as Rhodobacterales, Verrucomicrobiales, and Cytophagales were comparatively abundant, while seagrass meadow sites abundantly harbored Desulfobacterales, Steroidobacterales and Chromatiales, which are common bacterial orders in seagrass meadows. According to our gene-coded enzyme analyses the numbers of differentially abundant enzymes were highest in coral reef sites. Notably, superoxide dismutase, an important enzyme for anti-oxidative stress in coral tissue, was abundant at coral sites. Our results provide a list of prokaryotes to look into in each substrate, and further emphasize the importance of considering the microbiome, especially when focusing on environmental conservation. Conclusion Our findings prove that prokaryotic metabarcoding is capable of capturing compositional differences and the diversity of microbial communities in three different environments. Furthermore, several taxa were suggested to be differentially more abundant in specific environments, and gene-coded enzymic compositions also showed possible differences in ecological functions. Further study, in combination with field observations and temporal sampling, is key to achieving a better understanding of the interactions between the local microbiome and the surrounding benthic community.

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Shallow epifaunal sea cucumber densities and their relationship with the benthic community in the Okinawa Islands

Cited by 3 publications

References 42 publications

Bisphenol A (BPA) Directly Activates the G Protein-Coupled Estrogen Receptor 1 and Triggers the Metabolic Disruption in the Gonadal Tissue of Apostichopus japonicus

Bisphenol A (BPA) Directly Activates the G Protein-Coupled Estrogen Receptor 1 and Triggers the Metabolic Disruption in the Gonadal Tissue of Apostichopus japonicus

Searching for drivers of the patchy distribution of sympatric deposit‐feeding sea cucumbers: A multi‐scale monitoring study

Diversity, composition and potential roles of sedimentary microbial communities in different coastal substrates around subtropical Okinawa Island, Japan

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