Vibrio vulnificus

Five more marine organisms that put their superhero counterparts to shame

Posted on by Andrew David Thaler

Evolution is the most creative force on the planet. Everywhere we look, we find species with novel and phenomenal adaptations that put their comic book brethren to shame. In no ecosystem is this more apparent than in the vast and unfathomable ocean. Marine species, especially those in the deep sea, have evolved to survive in a environment that is completely alien to us. Several months ago, I unveiled “Five organisms with real super powers that rival their comic book counterparts“, but that was just the beginning. Without further adieu, I give you 5 more marine organisms that put their superhero counterparts to shame (and one bonus critter).

The blind shrimp with super senses

Rimicaris exoculata – http://eol.org/data_objects/13231836

In the deep sea, eyes are not among the most useful sense organs. While many deep-sea species have extremely reduced eyes, some have abandoned these organs entirely. Rimicaris exoculata is a shrimp endemic to deep-sea hydrothermal vents in the mid-Atlantic that is completely eyeless. Its carapace is smooth, without even a hint of reduced, vestigial eyes. This, unfortunately, is a problem because Rimicaris exoculata is a farmer. The blind shrimp grows bacteria in its gill chamber, bacteria that can convert the chemical-rich hydrothermal vent fluid into food for the shrimp.

For lack of a more descriptive adjective, hydrothermal vents are hot. Some can exceed 400°C. Rimicaris exoculata needs to get close to this hot vent fluid to feed its crop of bacteria, but not so close as to become a hydrothermal hors d’oeuvre. And so, the blind shrimp evolved a completely new light-sensitive organ mounted on the top of its carapace–the rhodopsin-rich dorsal eyespot.

The dorsal eyespot of Rimicaris exoculata doesn’t “see” in the normal sense, there is still almost no light in the deep sea. Rather, this shrimp is adapted to detect the black body radiation emitted by the hydrothermal vent. For Rimicaris exoculata, the deep sea glows with the light of super-heated hydrothermal fluid, allowing it to both find food for its bacterial crop and avoid getting cooked itself.

It should be no surprise that Rimicaris exoculata is undoubtedly the favorite deep sea organism of another blind champion with super senses–Daredevil.

Read More

Flesh-eaters of the Crystal Coast: why I prefer my oysters roasted

Posted on by Andrew David Thaler

Title screen for "Escape from the Manatee II", a thing that happened (at least twice) in the eighties.

Title screen for “Escape from the Manatee II”, a thing that happened (at least twice) in the eighties.

Imagine swimming out from the beach on a warm, summer day. You feel a tingle in your spine and the ba-dumping chords of the Jaws theme inexplicably rise from your subconscious. There is something in the water and it is going to kill you. The deadliest creature in the ocean has chosen you, and there is no escape. You panic. You scan the waves, searching for a sign, something that reveals the threat. Where is it? What is it?!

You could be forgiven if you think, perhaps due to that ominous tune, a shark is stalking you. Despite their killer reputation, sharks rarely attack people and shark attacks, when they do occur, are rarely fatal. Perhaps you are fresh from a Marine Invertebrate Zoology course and your nightmares are now filled with images of cubozoans, the deadly box jellyfish. Box jellies may be extremely venomous, but they are responsible for less than 50 deaths a year and envenomation results in approximately a 20% mortality rate. Ah, but you’re clever, and you watch Discovery channel specials about the “Ten Most Deadly X in Y”, so you know that the deadliest creature is the ocean is the lethal sea snake, relative of the cobra. Clearly one must be stalking you through the shallows. Wrong. While sea snake venom is quite potent, only 1 in every 10 bites results in envenomation, and even then, the mortality rate is a comforting 10%.

No matter how hard you look, you won’t see the monster slowly gliding up behind you. The deadliest marine organism is not a shark, a jellyfish, or a snake. It is not the beautiful blue ring octopus or the unassuming cone snail. It is not the giant squid, the killer whale, or the murderous, man-eating, manatee. The undisputed king of maritime mortality is the lowly bacteria, Vibrio vulnificus.

Read More