ecology

Happy Fun Science Friday – Blinky, the 3-Eyed Crab

Posted on by Kersey Sturdivant

Blinky! The three-eyed crab from the Simpsons. Photo Credit: Matt Groening

Blinky! The three-eyed crab from the Simpsons.
Photo Credit: Matt Groening

Happy FSF everyone, this week we bring you Blinky! For the Simpsons aficionados amongst you, we are unfortunately not referring to the affable 3-Eyed fish, indicative of the radioactive influence of Springfield’s nuclear power plant.

No Blinky is a real-life, 3-eyed crab, discovered and documented by German researcher Gerhard Scholtz and colleagues while working in New Zealand’s Hoteo River. Scholtz and co stumbled upon this 3-eyed organism, and must have wonder during their cursory inspection if they had discovered a new species, one that was defying the principles of bilateral animals. However, upon closer anatomical inspection Scholtz realized that the mystery crab was not a 3-eyed wonder species, but conjoined twins of the already identified Amarinus lacustris crab species.

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Halloween Science: Fear Makes the Ocean Go Around

Posted on by Chuck Bangley

Halloween, in a lot of ways, is a celebration of fear.  We dress like ghosts, goblins, and movie serial killers to give ourselves a sense of control over the things we’re afraid of.  It’s also a good time of year to indulge in horror movies, where we can watch ghosts, goblins, and serial killers terrorize other people from the apparent safety of our own homes.

From an ecological standpoint, we have it pretty good.  We’ve more or less tamed most environments on land and only make short forays into the oceans under conditions where we still have quite a few advantages.  Most of the time we have more in common with Jason than his hapless victims.  Imagine being a member of a school of menhaden or a seal that has to make daily trips through Shark Alley.  It would be like spending your whole life as a camp counselor at Crystal Lake, constantly looking over your shoulder and getting picked off the second you let your guard down.  If mortal terror was a regular part of your life, you’d better believe it would affect your daily habits.  And if every member of your species lived with that same fear, there would be places no one in their right mind would go and choices between death by starvation and possible death by being eaten.  After all, fish are always eating other fish.  Let’s take a journey through the low end of the food web and see what horror can teach us about marine ecology.

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Climate Change is Moving Fish Around

Posted on by Chuck Bangley

Back in the day, I worked as an intern at Rhode Island Marine Fisheries, where my job was basically to provide general field work help with whatever survey needed an extra pair of hands (yes, it was an awesome job).  One of these was a beach seining survey looking at juvenile fishes using Rhode Island’s coastal salt ponds as nursery habitat.  Among the usual silversides, mummichogs, and juvenile flounder, two of the ponds were also home to entire schools of something that I was only familiar with due to having relatives in Virginia: spot.  These little Scianids, a member of the same family as Atlantic croaker and red drum, are caught in droves in the waters of Virginia and the Carolinas but traditionally have been rare north of the Chesapeake Bay.  They were one of the more common species we caught in these two Rhode Island salt ponds, and occurred so consistently that we could actually observe them growing over the course of the summer.  It isn’t unheard of for stray tropical fishes to get swept into Narragansett Bay on Gulf Stream eddies, where they’re either collected by aquarists or die during their first winter.  However, these were populations of spot that we were seeing.  I don’t know if these fish survived their first winter or have come back since I moved down to North Carolina, but even at the very beginning of my interest in fisheries ecology I knew this was odd.

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Eleven Marine Organisms that would make Amazing Aquaman Villains

Posted on by Andrew Thaler

Physalia_physalis1

Physalia physalis. Public domain.

Black Manta. Ocean Master. The Trench. Scavenger. King Shark. Toxin. The Fisherman. Aquaman has had some pretty memorable villains over the last 80 years. Also, the Fisherman. This is Southern Fried Science, a blog famous for two things – inspiring the world with our unique blend of marine science and conservation and doing horrible, horrible things to Aquaman.

Catch me flounder for I have finned. It has been 98 days since my last Aquaman is Awesome post.

Sure, Black Manta has some pretty sweet gear, a compelling back story that justifies his hatred of the Atlantean king, and he looks like he’s poised for some serious awesome during DC’s Villains Month. The Trench even appear to be able to utilize chemosynthesis, when they’re not trapping dogs in cocoons. You know where I’m going with this, don’t you?

That’s right. No matter how ridiculous Aquaman’s comic book foes become, you can bet all your clams I’ll find real marine organisms that would make equally amazing villains. Here’s eleven of them.

Meet Man-o-War, the colonial killer that understands the value of teamwork.

Imagine a super villain composed of thousand of individual organisms that form one giant super-organism. Rather than a body filled with vital organs, this villain can take massive damage without a loss of ‘self’, only to spawn new minions to replaced the damaged parts. Now give this deadly foe 60-foot long venom-filled tentacles whose sting brings excruciating pain. Such a villain would certainly assume the identity ‘Man-o-War’.

The Portuguese Man-o-War (Physalia physalis), arguably the best known of the siphonophores (it is a cnidarian, but it is not a jellyfish) possess tentacles that unleash an unbelievably painful sting, the weapon of choice for our newest menace. But the weapon does’t make the man (o-war), and our villain has a strategic secret. Man-o-Wars are not singular animals, they are a colony of highly specialized polyps — each one an individual animal that combines to form a deadly super-organism.

The pneumatophore is a polyp the creates a gas-filled bladder for flotation. This produces the distinctive ‘sail’ of the Man-o-War, a bilaterally symmetric air sac that allows the colonial to remain at the surface and provides some propulsion by catching the wind. The sail is not just a sac of air, it also has defensive capabilities. When attacked, the sail is able to deflate, allowing the colony to sink below the surface and avoid predators. The gonozooids, which occur in tight clusters, are responsible for reproduction. Man-o-Wars engage in both asexual and sexual reproduction. Young colonies can reproduce clonally by budding, but as the colony becomes more mature, that gonozooids become sexually differentiated and release eggs and sperm to form new colonies. The gastrozooid takes care of all the digestion-related needs and surround the dastardly dactylozooids. Finally, the dactylozooids produce 10-meter (or longer!) tentacles that capture prey and drag them towards the gastrozooids. This is some serious teamwork.

Man-o-War even has minions. The shepherd fish is immune t the stinging tentacles and hangs out within the tentacles. The fish gains the protection of its lethal ally while the Man-o-War gets to use the shepherd fish as bait to lure other fish into its deadly trap.

Imagine Aquaman facing off against a colony of polyps that combine to form a deadly super-organism with massive stinging tentacles. Siphonophores have no nervous system, so Aquaman’s fish-talking power are useless. No matter how many dactylozooids, gatrozooids, and pneumatophores he destroyed, the gonozooids are there, churning out more.

But Man-o-Wars are not without their own predators, the largest of which is the enormous, cnidarian nom nom-ing Leatherback Turtle. Despite their size, leatherbacks are the largest live sea turtle, they survive exclusively on large numbers of jelly-like organisms — to the tune of the equivalent of eating 16 cucumbers per day. Leatherbacks aren’t the only animals that prey on Man-o-War, the salacious siphonophore has many foes, two of which join this list as super-villains in their own right.

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Six sea monsters that make their horror movie counterparts look tame

Posted on by Andrew Thaler

Evolution is infinitely creative. Sometimes, amid the beauty and wonder, the awe that emanates from the shear power of natural selection, and the poetry of descent with modification, evolution produces something that terrifies. I am not talking about our natural predators, for whom fear is part of our evolutionary heritage, but rather creatures that appear as though they emerged from our darkest nightmares. But even our nightmares are limited by our finite minds.

Evolution has no such limits and the immense size and incomprehensible diversity of the oceans has produce animals that make us yearn for the comforting familiarity of the common Pumpkinhead. Submitted for the approval of the Midnight Society, I present six sea monsters that make their horror movie counterparts look tame:

1. These mind-bending tapeworms crawled straight out of Slither.

Here is a classic horror movie scenario for you: alien/parasite/mutant invaders enter your body, latch on to you brain, and take control, forcing you to do their bidding as they multiply and infect those around you. From Body Snatchers to Slither, mind-controlling parasites are a mainstay of the genre. But you’re a reader of Southern Fried Science. You already know all about barnacles that take over crab brains and induce sex-changes when necessary or fungi that invade ants and force them to climb to their doom. Mind control parasites aren’t really all that uncommon, but they mostly infect invertebrates. There aren’t any deadly mind-melting monsters that can take over us higher organisms, right? Right?!

Wrong.

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DiveTracks: because we can’t talk underwater

Posted on by Andrew Thaler

We’re happy to announce a new experiment in our ongoing effort with casual video adventures. We take short videos from one of our SCUBA diving adventures, watch them together, and do a running commentary about whatever issues, topics, and stories emerge during the video. There’s just two rules – neither of us can have watched the entire video more than once and the discussion must be completely unscripted. DiveTracks, because we can’t talk underwater.

Watch our very first episode, here:

httpv://youtu.be/v6XOj0SWRsQ

But we don’t want this to be the David and Andrew show. No, no, no. We want you, our loyal readers, to submit your own underwater videos for us to discuss. Feel free to e-mail me or David if you would like to contribute to DiveTracks.

Herring Wars: Quotas, Conflicts, and Climate Change in the North Atlantic

Posted on by Andrew Thaler

Herring and other fish hung out to dry on a trawler in Klaksvík. Photo by ADT.

Herring and other fish hung out to dry on a trawler in Klaksvík. Photo by ADT.

A small collection of islands in the North Sea, a few hundred miles south of the Arctic Circle, is preparing for war. The European Union, under the auspices of an international fisheries management agreement, is ready to levy heavy trade sanctions against the Faroe Islands, an independent protectorate of Denmark. The Faroes, with a population of less than 50,000, intends to fight these sanctions, defy EU authority, and defend their economic independence. The object of contention is the right to fish Atlanto-Scandian Herring; the driving force behind this dispute–dramatic shifts in fish distribution brought on by warming seas and altered currents. This may be the first international conflict directly attributable to climate change. It will not be the last. Regardless of the outcome, this confrontation will set a precedent for future climate conflicts. Welcome to the Herring War.

Despite their uninspiring name, herring are a rather handsome fish. Atlantic herring, Clupea harengus, are relatively small with a classically “fishy” (fusiform) body shape. They are among the most abundant fish in the ocean, forming schools that can number in the billions. Along with other planktivorous fishes, such as menhaden, that convert phyto- and zooplankton into higher trophic-level biomass, herring are critical to ocean food-webs. They are considered to be among the most important fish in the sea. Herring are the dominant prey species for many large, pelagic predators like tuna, sharks, marine mammals, salmon, and sea birds, among others. Their dominant predator, unsurprisingly, is us.

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Predation Matters

Posted on by Chuck Bangley

Today, Pew unleashed a mini-media blitz on the importance of predation in fisheries management.  This got my attention because the interaction between marine predators and fisheries is one of my major research interests.  They do a great (and slickly-designed) job explaining the basics of why paying attention to predation matters in fisheries management, and bonus points for using the most noble of sharks as one of their examples.  Check out the video here:

 

I particularly like that they go into enough detail to lay out options for incorporating predation into fisheries.  Personally, I’m a big fan of the “second fleet” option, in which predators are counted as another source of fishing mortality (and some of my favorite papers are cited in support of it).  It does require the most effort, but provides the most accurate estimations of predation mortality (and justifies funding for diet studies?  Please?).  Multi-species models are ideal, and really the only way to conclusively prove that trophic cascades are actually happening.  Precautionary buffers, in my opinion, should really follow thorough diet studies, but are certainly another important aspect of ecosystem-based management.

It’s neat to finally see this subject getting some attention.  Here’s hoping the word continues to get out about the importance of shark puke.

 

Five more marine organisms that put their superhero counterparts to shame

Posted on by Andrew 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.

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Watch these giant deep-sea isopods go about their day

Posted on by Andrew Thaler

headshot-thalerSMALLYou know the good stuff is going to keep rolling in from my research cruise to Mid-Cayman Spreading Center. At the end of JC82, we had the opportunity to join a bolt-on cruise to explore the seabed around Montserrat. During a biological survey of the surrounding abyssal plain, we twice stumbled on a giant deep-sea isopods hanging out on the sea floor, doing their isopod thing. This was my first opportunity to observe a giant deep-sea isopod (Bathynomus giganteus*) alive and in the wild. My previous experiences have been limited to well preserved specimens.

Giant isopod behavior is not something that falls within my expertise. Like Craig McClain at Deep Sea News, I’m fascinated by the evolution of their large body size and how a relatively abundant population of such giants can be supported in the food limited deep benthos. But giant isopods are not common in my study area and what little I know of their behavior comes from the very few videos available, mostly of them scavenging on baited camera traps. So I was pretty surprised when the ROV Isis came across this delightful giant maintaining its burrow.

httpv://youtu.be/5B2uT_Vp-UY

This isn’t the first time Bathynomus burrowing has been observed; the behavior is actually fairly well documented (at least, well-documented for deep-sea species). But as fascinating as watching a 20+ centimeter-long roly-poly digging it’s hole 800 meters deep on the seafloor near one of the most active volcanoes in the Caribbean is, what we found next was even more amazing:

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