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.
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).
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.
You 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.
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:
There is no force more creative than the painstakingly slow process of evolution. Ever wanted to walk through walls? Naked mole rats can physically bore through concrete. How about fly? There are a couple dozen different ways to accomplish that goal, even if you’re a squid. Incredible power of regeneration? Flatworms, roundworms, and echinoderms have us beat. Among the vertebrates, species like the axolotl can regrow limbs, organs, and parts of their brain. For practically every super power we can imagine, something on the tree of life has come up with a real-world analog.
Some real super power are more super than others:
1. The immortal rotifer that absorbs the abilities of anything it touches.
Bdelloid Rotifers. photo by Diego Fontaneto
Around 80 million years ago, a small, unassuming group of metazoa decided that sex just wasn’t for them. Instead of going through the effort of recombining their genetic material with a mate every generation to produce a viable offspring with a roughly 50% contribution from each parent, Bdelloid Rotifers started reproducing asexually. Males completely disappeared from class bdelloidea, leaving females to generate genetic duplicates through parthenogenesis. This is not their super power.
Bdelloid rotifers are incredibly tough. When environmental conditions are less than favorable, they can enter a dormant state. In this dormant state,they can survive the worst unscathed. Dehydrated, they can endure extreme temperatures, drought, even ionizing radiation. A bdelloid rotifer in its dormant state can even survive in space. If that isn’t enough, while dormant, these rotifers continue to produce offspring, which also remain dormant. This is not their super power.
Bdelloid rotifers’ super power appears when they recover from their dormant state. As they rehydrate and repair whatever damage their cells incurred, they incorporate DNA fragments from their environment. This includes partially digested food and any DNA in close proximity to them, even bacterial and archael DNA. It is this ability that allows bdelloid rotifers to overcome the limitations of asexual reproduction and survive for 80 million years without mates. They can literally absorb the attributes of those around them.
Their incredible toughness, celibate lifestyle, and ability to absorb the powers of anything they touch, put Bdelloid Rotifers firmly on par with X-Men perennial favorite: Rogue.
Technology in water? That seems a bit counter-intuitive doesn’t it? Well, Dr. Kersey Sturdivant, during his undergraduate and graduate years, denied the golden rule of electronics and submerged a video camera under water. But this is not your typical Canon Powershot D10.
As much as I love thumbing through magazines and flipping page after page of vibrant underwater pictures of colorful flora and fauna, WormCam skips the excess and gets right to the bottom. Literally.
The video camera, modified from your average security camera, is set at certain time intervals and takes still pictures, as opposed to recording a video, for technical reasons. WormCam unveils the under-sediment realm. The images are not of mystical jellyfish and elegant fish nor the teeming micro and macro-zooplankton; rather the camera captures worms, crabs, snails and all things benthic.
WormCam, a dense yet delicate technology, is encased within a waterproof, blade-shaped prism, which is attached to the side of a larger platform. The lead battery, also in a waterproof case, sits on top of the rectangular prism. Linking the two components together with a waterproof wire, WormCam is complete and ready to be deployed.
Back view of deployed WormCam. Photo by Lucy Ma
Depending on the depth of the water, WormCam can either be deployed by hand in shallow waters or by rope in deeper waters. When held horizontally, the prism, where the camera is housed, protrudes below the bottom of the platform. Strategically designed, WormCam inserts itself within the sediment like a spoon sinking into yogurt. The camera is then peeking halfway beneath and halfway above the sediment. Through the clear, plexi-glass window, the camera snaps images of the water-sediment interface.
Now, Dr. Sturdivant, other scientists and aspiring undergraduates can observe the happenings at the sediment-water interface for extended periods of time. You can too! Watch a movie from a WormCam deployed in the York River (if you look closely, the grooves in the sediments are worms wiggling around!).
But the seafloor is stereotypically dark and unattractive. Why is this important and why should we care?
Having the ability to observe sediment changes and sediment-organism interactions over time offers marine scientists an enormous advantage. For example, during eutrophication, the phytoplankton bloom is incredibly obvious, thanks to the single-celled organisms’ conspicuous chlorophyll. Studies have confirmed that fish and other organisms die because of the lack of oxygen, but what about the worms and other sea-dwelling creatures that live beneath our scope of vision? WormCam widens this limited scope. With WormCam, scientists can then begin to understand these silent creatures and their roles in the aquatic ecosystem. Bioturbation in a Declining Oxygen Environment, in situ Observations from WormCam offers more technical information on the application of WormCam.
Thus far, WormCam has been deployed off of the Chesapeake Bay, Gulf of Mexico and Pivers Island. Each location has offered a benthic perspective on what is happening on and beneath the seafloor in the least intrusive way as possible. For example, the deployed WormCam off of the Gulf of Mexico has facilitated scientists’ understanding of the effects of Deepwater Horizon oil spill on sediment and benthic organisms.
Currently, Dr. Sturdivant and I, one of the aspiring undergraduates, have deployed a WormCam off of Pivers Island. We want to understand how chemical cues from gastropods affect crustacean behavior as well as how the attracted crustaceans impact other species residing in the sediment. Some very interesting observations have been made, but there is more to come. It’s a good thing that WormCam has its very own twitter page. Follow @wormcam.
Lucy Ma is an undergraduate who participated in a blog writing workshop led by Andrew Thaler. She works with Dr. Sturdivant on WormCam.
Your next post should be “What would aquaman look like at different depths?”
This question is more complex than it first appears, and needs a little unpacking. Water is denser than air. When light passes through, the water acts as a filter, absorbing visible light in a predictable pattern from longest wavelengths (infrareds and reds) to shortest wavelengths (purples and ultraviolets). As Aquaman dives deeper, the brilliant colors of his orange and green costume will begin to fade.
The American Elasmobranch Society is a non-profit professional society focusing on the scientific study and conservation of sharks, skates, and rays. AES members meet each year in a different North American city, and this meeting is the world’s largest annual gathering of shark scientists. AES recently met in Vancouver, British Columbia for the 2012 meeting, and for the first time the event was live-tweeted by meeting attendees, including myself. I’ve organized the best conference tweets by session using Storify. If anyone has any questions or comments about the research presented below, please feel free to share it in the comments section of this blog post.
Here are selected tweets from the Elasmobranch Ecology sessions.
Deep-sea mining is once again in the news. As Kevin Zelnio frustratingly points out on twitter, news articles often fail to mention the primary research that has been conducted at these sites or make more than a cursory statement concerning their ecology. This has the effect of marginalizing an entire ecosystem and makes it difficult for the public to grasp the richness and diversity of deep-sea hydrothermal vent communities, some of which may face commercial exploitation. Here is a selection of recent primary literature, with abstracts, on the ecology of deep-sea hydrothermal vents at the center of the mining debate, Manus Basin (you may recognize some of the authors).
Since that post made its way across the internet, several people have asked me to discuss what adaptations Aquaman would need to survive in this, science-based, ocean. So I went back to my comic books and my textbooks to assemble an Aquaman with a suite of evolutionary adaptations that would allow a largely humanoid organism to rule the waves, trident triumphantly raised.
Unfortunately, these “eating different stuff” articles rarely reflect the deep and nuance ecologic reality of trophic interactions and instead capitalize on the narrative of “even animals are going veggie to save the planet!” Allow me to revel in my cultural roots with a hearty “Oy vey!”