Bird-eating fish and bone-eating worms
“Pufferfish can sculpt, what’s your excuse?” This was the caption for a video I watched a few weeks ago. Maybe I wasn’t in a hurry to have my artistic abilities put to shame by a fish, but I was skeptical – silently, I heckled him: “Yeah? Really? You build symmetrical sand patterns huh? Show me. Don’t just hover there looking cute, get to work.” Forty seconds into this video, however, I was leaning forward in my chair, eyes fixated on the computer, mouth agape. I mean, just WATCH this little guy:
This is just one example of the many things we are only now discovering about the creatures who live in the ocean. And the deep sea is the ultimate unknown. Most of the huge discoveries (e.g. hot vents, chemosynthetic communities) have occurred within the last 50 years. So here’s my short list of awesome things I’ve stumbled across in the past year….
DEEPLY AWESOME DEEP THINGS
1) Orange Roughy can live over one hundred years. Well, 149 years to be exact. Considering that your average gold fish lives up to 10 years, the orange roughy is freakin’ ancient! Just like rings in a tree’s trunk, fish have growth rings in their bones. Certain bones (e.g. ear bones called otoliths) are particularly useful and can even tell scientists information about a fish’s growth rate during certain years. Unfortunately, all of this information was discovered after the Orange Roughy became a prime fish market meat. In countries such as New Zealand, supply was actually exceeding demand, so the fishing industry dumped several tons of Orange Roughy into New Zealand landfills (for a short clip on overfishing roughy go to 27:00 in this video). Maximum Sustainable Yield (MSY) estimations had been based on much shallower species with much shorter life spans. After 1990, the Orange Roughy populations abruptly dropped off and it wasn’t long before Australia declared the fish as endangered.
2) Whale falls provide food for up to a century in deep sea communities. The Monterrey Bay Aquarium Research Institute has done a few studies on this, including studying how wood and kelp falls also provide food. Basically, any organic matter that reaches the deep sea floor is considered food – most of it falls to the sea floor in the form of marine snow (organic matter from dead animals + poop). The patch of sediment where a whale falls receives an influx of organic carbon equivalent to 2000 years of marine snow drifting down. It’s like getting all of your Christmas presents for the next fifty years when you’re eight years old.
The first to arrive on the scene is scavengers – animals such as hagfish (snot eels), sharks, and rat-tail fish. Once there’s enough bone exposed, the worms start to move in, and strangely – some of them eat bones by secreting an acid in order to find their way to the tasty lipids (i.e. fat) within the bone matrix. If you think that’s awesome, then read some other whacked out facts about bone-eating worms from this Deep Sea News post.
Finally, different groups of bacteria, including those who thrive on the sulphide build-up from the bone breakdown, make the whale skeleton their permanent home. In total, there can be more than 400 species of creatures devouring a whale skeleton – that’s the most species rich habitat in the ocean! Additionally, it’s believed that some deep sea species are only found on whale falls. Which begs the question…how much did the whaling industry fundamentally (and permanently) alter the deep sea landscape?
3) Some deep sea coral reefs are 40,000 years old. First off, did you know the deep sea even had REEFS?! Well, it does. And they’re everywhere. In fact, they could possibly cover more area than shallow reefs! But unlike shallow reefs, deep coral doesn’t rely on sunlight or zooxanthellae (tiny symbiotic algae that live in shallow coral). Instead, they just pick up tiny organisms from the water and positions themselves in opportune areas (e.g. seamounts). Unfortunately, these havens for deep sea life are devastated by human activity – namely trawling. So, if you felt bad about eating a 100 year old fish…just think about 40,000 year old coral being swept away by metal contraptions of death. Thanks humans!
4) Evidence of a 2.2 million year-old Supernova can be found in ancient bacteria from the seafloor. Yes, you read that correctly. These were the findings from a study published just a few months ago. A little astronomy primer here (for those as ignorant of astronomy as me!): a supernova is an exploding star. And when a star explodes, lots and lots of nuclear fusion occurs, forming awkward and unstable radioactive isotopes (as in volatile versions of the same element). One element formed through this fusion bonanza is iron-60 (for reference, iron-56 is the most common naturally occurring stable isotope). So when a star explodes, it releases a CRAP TON of materials that float through space, some of which find their way to Earth – like iron-60 – and many of which are essential elements for life.
Soooooo…where does the bacteria come in? Well, certain types of bacteria are suckers for good iron, including some ancient bacteria that existed well over 2 million years ago. When the iron-60 from the supernova entered the Earth’s atmosphere, it eventually made its way down to the ocean, and like most materials, drifted all the way down to the seafloor. At this point, these iron-loving bacteria snatched it up, and like any element, iron-60 left a chemical signature in the bacteria.
So when some brilliant scientist had the idea to examine sediment cores drilled from the Pacific Ocean, they found fossilized bacteria! And iron-60! Since iron-60 has a half-life of 2.6 million years, they were able to calculate the approximate date of the supernova – 2.2 million years ago. Now tell me that’s not awesome!!
5) Bird-eating Goosefish. Goosefish do not eat geese. No – they eat other cute delectable little birdies like dovekies, loons, gulls, cormorants and more. We saw a small goosefish on our last dive in July – ugly little thing – but gotta give him props for figuring out the secret to good eatin’ when you live in the deep. Goosefish come up thousands of feet, all the way to the surface to snatch unsuspecting birds. Scientists believe they use their lure (goosefish are a type of angler fish) to attract birds that dive below the surface to eat crustaceans and other delectables. If successful, goosefish will swallow the birds whole in one fell swoop (pun definitely intended):
There are, of course, MANY other fantastically amazing things about the deep sea that I couldn’t possibly fit into one blog post. If you want more – check out Deep Sea News.
Fenton GE, Short SA, Ritz DA (1991) Age determination of orange roughy, Hoplostethus atlanticus (Pisces: Trachichthyidae) using 210Pb:226Ra disequilibria. Marine Biology 109: 197-202
Smith CR, Baco AR (2003) Ecology of Whale Falls at the Deep-Sea Floor. Oceanography and Marine Biology: an Annual Review 411: 311-354