Evaluation of the Effects of Various Chemicals on Discharge of and Pain Caused by Jellyfish Nematocysts

Portuguese Man-of-War (Physalia physalis).

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This study evaluated the effect of well-known remedies on the discharge of nematocysts in three species of Cnidarians: the sea nettle (Chrysaora quinquecirrha), sea wasp (Chiropsalmus quadrumanus) and the Portuguese man-of-war (Physalia physalis).  The remedies tested include acetic acid, ammonia, meat tenderizer, baking soda, and urea.  These remedies were evaluated to determine whether they stimulated or inhibited nematocyst discharge and if they brought relief to testers who were exposed to jellyfish tentacles.  It was found that many of the remedies did not relieve the pain and it actually stimulated nematocyst discharge.  However, immediate relief was experienced with lidocaine, a common anesthetic.  Exposure of the tentacle to lidocaine prevented nematocyst discharge when preceding exposure to acetic acid, ethanol, ammonia or bromelain.  Based on these observations, it is possible that lidocaine blocks the sodium and/or calcium channels of the nematocysts, preventing discharge.  The nematocysts of organisms in Phylum Cnidaria are hollow tubules in a saline solution containing neurotoxins.  Typical symptoms of jellyfish stings include pain, localized areas of swelling, redness and bleeding.  Used for defense, both mechanical and chemical stimuli cause nematocysts to be discharged.  With an increase in the number of envenomations in coastal beaches around the world, this study aimed to answer the question if traditionally used methods have effect on nematocyst discharge or if they dampened the pain associated with being stung.

Specimens were collected in coastal waters and tentacles were clipped and transferred to seawater.  These tentacle pieces were added to wells containing 1mL of seawater and examined under a light microscope.  To determine whether the chemical remedies had an effect on the nematocysts, 100µL of each chemical was added and observations were noted.  In a separate experiment, lidocaine was first added to the wells and then after one minute, each chemical was added in separate well plates.  A camera was attached to the light microscope to capture nematocyst discharging, and discharged nematocysts were counted.

During the human skin exposures, sea nettle and sea wasp tentacles were used.  Two of the authors exposed their inner arm to the tentacles over a period of 20 days with only one treatment per day.  Observations of skin redness before and after the addition of chemicals were made by outside observers.  Notes were taken of the stinging sensation as well. 

It was determined that chemicals traditionally used to treat jellyfish stings were found to stimulate nematocyst discharge and provided little or no relief from the pain and stinging sensation.  Lidocaine appears to provide relief by acting as an anesthetic and by preventing further nematocyst discharge.  Although blocking the pain, it did not prevent redness on the skin.  Also, when first applying lidocaine, then acetic acid or ammonia, the nematocyst discharge was prevented.  Overall, the best treatment option for jellyfish stings appear to be with the anesthetic lidocaine, as it blocks sodium ion channels in nerves that sense pain.            

Reference:

Birsa, L. M., Verity, P. G., & Lee, R. F. (2010). Evaluation of the effects of various chemicals on discharge of and pain caused by jellyfish nematocysts. Comparative Biochemistry and Physiology:Toxicology and Pharmacology, 151, 426-430.

 

 

 

Invasive Sea Anemones Threaten the Health of Coral Reefs Due to Sunken Ships

Healthy coral reef- Picture by Kydd Pollock

 

Iron leached out from sunken ship with surrounding invasive sea anemone- Picture by Jim Maragos, USFWS 

 

In 2008, scientists began to notice the declining health of the Palmyra Atoll coral reef in the central Pacific due to several shipwrecks in the surrounding area.  Warming seas and ocean acidification were already affecting the health of the reef, but excessive growth of Rhodactis howesii due to leached iron from sunken ships further reduced the quality of the coral reef.  Iron is an essential element for many marine organisms, but in excess, invasive species like R. howesii can thrive.

R. howesii is a type of sea anemone that is very aggressive.  When excess nutrients like iron are available with no predators to keep populations in check, the anemones thrive.  R. howesii also preys upon coral, which further degrades the health of the coral reef. 

In September 2007, USGS researcher Dr. Thierry Work, Dr. Greta Aeby from the Hawaii Institute of Marine Biology, and Dr. James Maragos from U.S. Fish and Wildlife Service studied a shipwreck from 1991 on Palmyra Atoll in the Pacific Ocean.  The researchers discovered that R. howesii was growing in high densities surrounding the ship, and densities steadily decreased with distance from the wreck.  Since the atoll is isolated, runoff from agricultural or industrial activities is unlikely, so the shipwrecks are the only logical source of excess nutrients. 

With the sea anemone growing rapidly, it causes a change in the dominant life form of the reef and is referred to as ‘phase shift’.  Even though phase shifts can have long-term negative effects, eliminating organisms like R. howesii are an impossible feat, especially over a large area.  Rapid removal of shipwrecks to prevent reefs from being overgrown by invasive species like R. howesii is crucial to reef health. 

Remediation projects are currently being implemented to evaluate the resiliency of coral reefs after shipwrecks removal. On January 29^th 2014, the Fish and Wildlife Service completed a $5.5 million conservation project to remove three wrecked ships, weighing a total of one million pounds, from protected wildlife areas in the Pacific Remote Islands National Wildlife Refuge. The shipwrecks caused miles of damage to the Palmyra Atoll and Kingman Reef.  With the reefs being home to 176 species of coral and 418 types of reef fish, protecting the damaged reef from further destruction was vital.  A team of 16 people cut and removed the wreckage from the coral reefs without causing further damage, bringing the salvage to California to be recycled. 

A representative of the remediation project stated, "We know Palmyra Atoll is resilient; it's one of the last remaining healthy coral reefs.  We've done some experiments with removal, and within three weeks we saw new species coming back to the area—mainly microscopic coral recruits.  These resilient areas can heal themselves when they get back on track."

Using Palmyra Atoll and Kingman Reef as controls, scientists can begin to understand how coral reefs heal.  It is possible that these examples can teach scientists in other parts of the world how to restore coral reef health.

What's a ctenophore?

Last week we examined cnidarians in lab.  Another animal phylum traditionally thought to be closely related to corals, anemones and sea jellies are the comb jellies, or ctenophores.  What is a ctenophore?  Check out the video from the CreatureCast:


CreatureCast - Comb Jellies from Casey Dunn on Vimeo.

While many textbooks state that combjellies and sea jellies are sister taxa (each other's closest relative), current work suggests that they are more distantly related.

You might also enjoy some additional information on barnacle sex from the same site.