Tag: Jellyfish

Posted on

New Research: A comparative molecular study of rhizostome jellyfishes from Japan reveals variability in Symbiodiniaceae taxon associations and cassiosome production.

Led by Kei Chloe Tan , this study dives deep into the complex world of Rhizostomeae that play massive roles in Asian ecology and industry.

What makes these jellies unique?

Rhizostome jellyfishes are unlike your average medusa. They don’t have long, trailing tentacles neither other structures at the eadg of theyr bell; they have eight highly branched oral arms, along which there are suctorial minimouth orifices.

Our study focused on three main goals:

  • Identity: Using DNA barcoding to accurately identify species in Japanese waters.
  • Partnership: Mapping which types of algae live inside which jellyfish.
  • The Sting: Identifying which species produce cassiosomes—the “mucus grenades” responsible for the mysterious “stinging water” syndrome.

Key Discoveries

  • A New Neighbor: We discovered that Cassiopea (Upside-down jellyfish) found in Kagoshima likely represents a new, undescribed species.
  • Symbiotic Flexibility: We found that these jellyfishes are “plastic” in their partnerships, meaning the same species of jellyfish can host different types of algae (Symbiodinium, Cladocopium, or Durusdinium) depending on the individual.
  • The “Grenade” Evolution: We confirmed that cassiosome production is a unique trait of the suborder Kolpophorae. Interestingly, we found that young jellies might not produce them until they reach a certain developmental stage.

“This research provides a baseline for understanding how jellyfish and algae co-evolve, helping us manage coastal ecosystems and the jellyfish fisheries that are so vital to the region.” — Chloe Tan, Lead Author

Lab Work in Action

This paper wasn’t just about sequences; it combined advanced molecular techniques with classic microscopy.

  • Tandem DNA Amplification: Chloe developed a new method to simultaneously sequence the DNA of both the jellyfish host and its tiny algal residents.
  • Microscopy: We captured high-resolution images of the cassiosomes—clusters of stinging cells (nematocysts) with algae at their core—proving exactly how these “contactless stings” work.

Read the Full Paper

Interested in the molecular data or the high-resolution phylogenetic trees? You can find the full study here:

Posted on

Dr. Ames’s research

As an experienced research scientist, teacher and mentor, Dr. Ames employs a combination of molecular and morphological tools to address major scientific questions in the fields of behavior, ecology, evolution and systematics. Her research focuses on venomous box jellyfish and seeks to further understanding of this cosmopolitan aquatic organism.

Cheryl has extensive field research experience having worked around the world including in the United States, Canada, Japan, and numerous tropical and subtropical regions. She has a demonstrated ability to collaborate with top-level government and academic researchers and obtain funding for multidisciplinary research projects. While designing experiments and conceiving ideas for publications, she strives to develop projects that strike an even balance between fundamental and applied marine biology.

A selected list of major research works appears below. For a full list of all of her work and more information about her research please visit her Research Gate profile.

Posted on

Raising Awareness of the Severity of “Contactless Stings” by Cassiopea Jellyfish and Kin

Current doctrine on jellyfish stings largely focuses on physical contact with a jellyfish. In rhizostome medusae capable of extruding agglomerations of nematocysts within mucus, physical contact is not necessary for skin irritation and pain. Here we highlight pain and symptoms reported by researchers and aquarists working with water around Cassiopea and several other jellyfish. We conclude that Cassiopea, long thought to be harmless, can lead to multi-day pain and rashes experienced largely as burning and itching sensations along entire limbs. We suggest that recommendations on sting avoidance expand to include consideration of these contactless stings so as to limit a previously under-publicized vector of envenomation.

Click here to access the full article.

Posted on

Live Jellyfish Make a Splash in Marine Education

The Smithsonian Magazine that takes you behind the scenes at the National Museum of Natural History! The piece shines a spotlight on the museum’s unique “AquaRoom” a dedicated facility where live jellyfish and other marine invertebrates are raised and studied.

The AquaRoom, co-founded by marine biologists Allen Collins and Dr. Cheryl Ames, had humble beginnings but a grand vision. As Allen Collins recounts,

“So, Cheryl and I started collecting freebie aquarium stuff that people were getting rid of in the department, including a 55-gallon tank.”

From these dedicated efforts, the facility grew to cultivate various jellyfish species and became instrumental in educational outreach, offering tours, bringing live jellyfish to the museum floor, and continuing its mission through virtual webinars and collaborations, even sending jellyfish polyps for student experiments.

Dive into the full story about this incredible educational program and the dedicated team behind it. Read the article on Smithsonian Magazine:

Posted on

Who’s in this Ocean? Tracking Down Species on the Go Using Environmental DNA

The article details the development of a novel method for tracking marine species: the portable eDNA sequencing kit (FeDS), spearheaded by Dr. Cheryl Lewis Ames’s team from Tohoku University. The article explains how the FeDS kit makes the complex process of environmental DNA identification — from water sample collection to species identification — entirely portable and capable of being conducted on-site without an internet connection, thanks to the Nanopore MinION device.

The effectiveness of the FeDS kit was successfully tested in the Florida Keys, where the team not only detected the upside-down jellyfish (Cassiopea) but also identified a remarkable 53 jellyfish species, including two venomous box jellyfish species previously unreported in the area. Dr. Ames envisions incredible practical applications for this technology, such as predicting jellyfish sting risks, much like a ‘weather forecast app’ for swimmers!

This innovative research was published in the esteemed Frontiers in Marine Science journal, underscoring its solid impact and global relevance.

To understand this groundbreaking innovation and how it’s shaping the future of marine life detection, read the full article on Asia Research News:

And to access the original scientific paper that underpins this research, click here:

Posted on

Cassiopea upside-down jellyfish in Key Largo mangrove forest waters (Florida Keys, USA)

Video showing footage of Cassiopea upside-down jellyfish in Key Largo mangrove forest waters (Florida Keys, USA). Water samples were taken from this collection site during a jellyfish environmental DNA (eDNA) metabarcoding study by Ames et al. 2021, published in Frontiers of Marine Science. Copyright A.C. Morandini (coauthor on the study) “Fieldable Environmental DNA Sequencing to Assess Jellyfish Biodiversity in Nearshore Waters of the Florida Keys, United States”

Posted on

Tracking Down Ocean Species On the Go Using eDNA

An image of the Smithsonian Museum logo

The article highlights the pioneering work of our own Dr. Cheryl Ames and her team in the Florida Keys. They led a crucial study demonstrating the potential of a portable Nanopore sequencer to detect the presence of upside-down jellyfish (Cassiopea xamachana) and other jellyfish species directly in the field! This represents an incredible leap forward, overcoming the challenges of bringing complex DNA analysis from labs into the marine environment.

This technology not only identified Cassiopea jellyfish but also revealed the presence of other species unseen at the time of sampling, such as moon jellyfish and venomous box jellyfish. The potential is vast: from predicting jellyfish sting risks to aiding fisheries management, supporting conservation efforts, and even integrating into autonomous underwater vehicles for comprehensive marine surveys.

This groundbreaking research stems from a foundational scientific paper published in Frontiers in Marine Science, underscoring its impact.

Read the full article on Smithsonian Ocean and dive into the future of species detection:

And for the original scientific paper that underpins this amazing work, access it here:

Posted on

Fieldable Environmental DNA Sequencing to Assess Jellyfish Biodiversity in Nearshore Waters of the Florida Keys, United States

Recent advances in molecular sequencing technology and the increased availability of fieldable laboratory equipment have provided researchers with the opportunity to conduct real-time or near real-time gene-based biodiversity assessments of aquatic ecosystems. In this study, we developed a workflow and portable kit for fieldable environmental DNA sequencing (FeDS) and tested its efficacy by characterizing the breadth of jellyfish (Medusozoa) taxa in the coastal waters of the Upper and Lower Florida Keys. Environmental DNA was isolated from seawater collection events at eight sites and samples were subjected to medusozoan 16S rRNA gene and metazoan mitochondrial cytochrome oxidase 1 gene profiling via metabarcoding onsite. In total, FeDS yielded 175,326 processed sequence reads providing evidence for 53 medusozoan taxa. Our most salient findings revealed eDNA from: (1) two venomous box jellyfish (Cubozoa) species, including taxa whose stings cause the notorious Irukandji envenomation syndrome; (2) two species of potentially introduced stalked jellyfish (Staurozoa); and (3) a likely cryptic species of upside-down jellyfish (Scyphozoa). Taken together, the results of this study highlight the merits of FeDS in conducting biodiversity surveys of endemic and introduced species, and as a potential tool for assessing envenomation and/or conservation-related threats.

Click here to access the full article