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Entries in invertebrate (11)


There it is again!

That awesome feeling when you discover a species you never knew existed!  I just wrote about this in my last post, but it happened again today when I came across this video (cap tip to @support4oceans on Twitter) of Stygiomedusa, a giant jellyfish, seen for the first time in the Gulf of Mexico.  There’s not much to say because Mark Benfield from LSU says it all, but just consider that this thing has a bell the size of a beach umbrella and tentacles as long as a school bus!


Play Bit-o-Critter, round 28

In this weeks Bit-o-Critter, where the aim of the game is to guess the animal from the excerpt shown, we have two invertebrates, one of which was proposed by last weeks winner, David Gross.  I need the correct answer for both animals, in the same comment, for you to be declared the winner.  If you give away one, you just made it easier for someone else. OK, here we go:





12,081ft - The oceans, by the numbers

I was inspired by recent articles highlighting a revised calculation of the ocean’s average depth as 12,081ft, to consider the seas in a numerical light today. To that end, here’s a few random, sourced numbers and back-of-the-envelope calculations that might be food for thought:

0.87% = Amount we can see by diving from the surface (about 100ft) over the average depth
0.28% = Amount we can see by diving over the deepest part (Challenger Deep, Marianas Trench off the Philippines)
2.9 = Number of times deeper the deepest part is, compared to the average.
5,400 = Number of mammal species in the world
25,000 = Number of fish species in the world
Millions? = Number of marine invertebrates species in the world (no-one really knows)
2.3 Million = The number of US citizens directly dependent on ocean industries (source: NOAA)
$117 Billion = Value of ocean products and services to the US economy (yr 2000, source: NOAA)
50% = US population living in coastal zones
48% = The proportion of all human-produced CO2 absorbed by the oceans in the Industrial era (NatGeo)
0.1 = The pH drop in the surface oceans since 1900
0.35 = Expected pH drop by 2100 (source)
18 = The number of times more heat absorbed by the oceans than the atmosphere since 1950 (source - TAMU). Global warming is an ocean process far more than an atmospheric one.
3.5 Million = Estimated tons of plastic pollution circling in the Great Pacific Garbage Patch, and growing.

And yet:

30 = Number of times thicker the atmosphere is (out to the “edge of space” about 60 miles) than the average ocean. That would be the atmosphere that astronauts describe as a “thin veneer” on the planet…
0.06% = Thickness of the average ocean, compared to the radius of the earth. I think we can argue that the water is the veneer, not the air
$4.48 Billion = NOAA’s 2010 budget, including the National Ocean Service, Weather Service and Fisheries Services. (source NOAA)
$18.7 Billion = NASA’s 2010 budget, i.e. 4 times the size of the agency that looks after our own planet (source NASA)
$664 Billion = Department of Defense base budget 2010, not counting special allocations (source DoD)
0.6% = The amount you would need to cut Defense in order to double the NOAA budget

Some sources:  


Solutions to bit-o-critter 9, 10 and 11

Hi all,

I got a bit behind while I was in NY, but am back on deck today and will be back to posting a bit more regularly.  Here's the solutions to the recent bit-o-critters.

Round 9 - Six-gilled shark, Hexanchus griseus
A big ol' slug of a shark, most common in the colder waters of the world.   I picked it because it always seemed odd to me that six and seven gilled sharks manage to have one or two more than everyone else.  Five seems kind of a fundamental number for gills.

Round 10 - Bobbit worm, Eunice aphroditois.  This is a large (like, 5 feet long) and scary polychaete or bristle worm.  It mostly hangs out in the pose shown, waiting for some unfortunate fish to swim past the jaws or brush the antennae, then BAM!  The ant lions of the worm world.  Nicknamed after, you guessed it, Lorena Bobbit (remember her? snip! snip!)

Round 11 - Loriciferan.  OK, that was just mean.  A truly obscure group of microscopic invertebrates that live between sand grains on the bottom of the ocean.  A phylum unto themselves, they were only discovered in 1983Not much to them except the lorica or house (the clear baggy bit on the right), some somatic and reproductive cells (pink) and the ring of tentacles around the oral cone (on the left).


Field locations you have loved

In this thread I want to hear about field locations YOU have loved, and WHY.  Here's a couple of mine to get the ball rolling:

Kedron Brook, Brisbane, Australia.  A choked little stretch of suburban creek on the north east side of Brisbane Australia was a key field location for my PhD research, which was all about introduced (exotic) species and their parasites in rivers and streams in Australia.  At one point just above the tidal influence - stylishly named KB216 for its map reference - this creek is basically completely exotic: plants, invertebrates, fish, the whole shebang.  There aren't many parasites there, but those that were present were introduced hitchhikers.  Not sexy, but a veritable Shangri-La for a student on the hunt for ferals...
Heron Island, Queensland, Australia.  Where I met and fell in love with marine biology.  A patch of sand and guano-reeking Pisonia forest 800m long, on a reef 10 times that size, crawling with noddies, shearwaters, turtles, grad students and squinting daytrippers or more wealthy sunburned resort guests.  Too many firsts for me there to even list (but no, not that one - get your mind out of the gutter!).  Absolute heaven, hands-down.  How do I get back?

Throgs Neck, NY, USA.  You generally wouldn't think of the junction of Queens and the Bronx as a biologically interesting in any way (except maybe on the subway), but actually the western part of Long Island Sound was the epicenter of a lobster holocaust that started in (well, before, if you ask me) 1999.  When we were out on the RV Seawolf, the Throgs Neck bridge marked your entry into the East River and the start of one of the most unique and strangely beautiful urban research cruises around, right down the East side of Manhattan, past the Statue of Liberty and out into the Lower NY bays.  We would pass through on our way to do winter flounder spawning surveys off the beach at Coney Island (its that or go around Montauk).  Proof that not all interesting biology takes place in Peruvian rainforests...

In the comments, tell us about a field location YOU have loved and why.  Post links if you can find them.


I don't mean to say "I told you so"...
This morning I posted about how taxonomy underlies all else in biology, with respect to manta rays.  As if to make my point, an article is just out in Nature suggesting that the genus Drosophila - better known as fruit flies - may be revised such that one of science's best known model species - Drosophila melanogaster - gets kicked out of its genus!  The split hasn't taken place just yet, but the door is open, and if it were to happen, D. melanogaster might well become Sophophora melanogaster during the reorganisationOf the implications for the enormous literature and the many genetic databases that are heavily built on the current taxonomy, one Drosophila scientist is quoted in Nature as saying simply (but most unscientifically) "Oh my God".

What high drama!  And you thought taxonomy was only arcane monographs penned by bespectacled formalin-smelling old men in the basements of museums...

Dalton, R. (2009). A fly by any other name Nature DOI: 10.1038/457368a


Explosive radiation (in) rocks!

Much like internal waves, I always loved the idea of explosive radiation.  Not the nasty, pernicious Chernobyl kind; I mean the rapid evolution of a whole bunch of species from a common ancestor, over a relatively short period of time.   There's a few textbook examples of explosive radiations, but none so well-worn (possibly even hackneyed) as that of the cichlid fishes in the rift lakes of eastern Africa.  The startling diversity of these little fishes in lakes Tanganyika, Malawi and Victoria has kept evolutionary biologists busy (and Africans fed) for years.  See for example, the paper by Elmer and colleagues cited below, which points out that due to the drying-out of Lake Victoria 15-18,000 years ago, either all the cichlids there evolved since then based on stock that re-colonised from Lake Tanganyika, or they sought refuge elsewhere during the dry spell and returned when the lake refilled.

Cichlids are nice and all, but if you look around, you start to see radiations all over the place.  Turtles, bivalves and salamanders in the US south-east; tetras in the Amazon, eleotrid gudgeons in Australia, and gobies on coral reefs are just a handful of aquatic examples that are still with us, but there are many others in the fossil record too (hence my title) including trilobites and ammonoids and lots more.  Presumably these are the sorts of patterns that led Stephen Jay Gould and Niles Eldredge to develop the concept of punctuated equilibrium back in the 70's: theirs was the idea that evolution proceeds not gradually, but in fits and starts, in response to dramatic environmental changes and chance events.  The way I see this idea, most of the species we observe around us are the dregs of explosive radiations past, whittled away by extinctions to just the most successful few, either gradually or equally punctuated.  Cases like the rift-lake cichlids are just ones in which relatively few have gone extinct yet (but see the effects of the introduced Nile perch!)

All of this was just a preamble for what I really wanted to post about, which was about a radiation I only heard about recently.  Late last year I was at a scientific exchange  of US and Russian fish health researchers organised by the National Fish Health Research Laboratories and sponsored by the Living Oceans Foundation, at which one of the Russian speakers  Maxim Timofeev introduced us the radiation of several groups, including amphipods, in Russia.  Amphipods are (usually) tiny shrimp-like animals that live on the bottom or among dense plants or algae; read more about them in the Väinölä paper cited below.  Well, in Siberia's Lake Baikal, the worlds oldest, largest and deepest freshwater lake, they underwent a remarkable radiation, to produce over 300 species (a third of the worlds entire fauna), including spectacular beasts such as the fish predator (!) shown here. I mean, HOW AWESOME IS THAT THING?  Freaks me almost as much as giant wetas used to do, when I was younger (if you don't dig on bugs, I recommend not clicking that link...).  Anyway, I had no idea these things existed until Maxim gave his talk.  Don't you just love discovering new critters you never knew about before?  And not just one, but hundreds.

(Check out this link about Baikal fauna too; the language is just terrific.  Try this turn of phrase on for size: "When it comes to tenderness and gustatory qualities of meat, the omul knows no rivals")

Elmer, K., Reggio, C., Wirth, T., Verheyen, E., Salzburger, W., & Meyer, A. (2009). Pleistocene desiccation in East Africa bottlenecked but did not extirpate the adaptive radiation of Lake Victoria haplochromine cichlid fishes Proceedings of the National Academy of Sciences, 106 (32), 13404-13409 DOI: 10.1073/pnas.0902299106

Väinölä, R., Witt, J., Grabowski, M., Bradbury, J., Jazdzewski, K., & Sket, B. (2007). Global diversity of amphipods (Amphipoda; Crustacea) in freshwater Hydrobiologia, 595 (1), 241-255 DOI: 10.1007/s10750-007-9020-6


The ghost of fishers past

The folks you see out on their boats on the bay are not the only ones fishing; those who came before them still get a slice of the action, as this recent article about the retrieval of "ghost gear" from the Chesapeake Bay illustrates.  In many trap-based fishing industries, like lobsters and crabs, a significant number of traps are lost during the course of regular fishing efforts.  In addition, when a fishery turns bad, as happened in the Long Island Sound lobster fishery in 1999, some fishers cut their losses, and their marker floats, quit the fishery and just leave their gear where it is on the bottom of the bay.

The problem is, ghost gear like this keeps on fishing, long after the fisher has moved on to other endeavours.  The design of the trap continues to attract animals, even without bait, because the trap is basically a refuge or cave.  Those that enter are unable to leave and as they die they may act as bait to attract yet more animals to feed on their body.  In this way, the trap becomes a sort of "biomass black hole", sucking in animals from all around, for as long as the trap holds together.  Nets can ghost fish too, especially gillnets or any kind of trawl that can trap fish or strangle a reef

We used to trawl up ghost lobster gear all the time when I was working in Long Island Sound.  Indeed, few days on the water went by without snagging someone's old gear at some point, which speaks to the density of gear that's out there in some inshore waters.  I'm glad the fishers and the resource management agencies are working together to address the problem, because its one of those awful chronic out-of-sight, out-of-mind issues that can erode a fishery despite everyone's best efforts to manage things properly.  If you find ghost gear, call your local DEP or DEC, even the EPA, and let them know so they can come and retrieve it.

Picture of ghost gear on a coral reef from NOAA


Funny scientific names - Abra cadabra

I started my career in taxonomy.  Its a serious business, the naming of new species, and you're not supposed to make light or fun out of an animal (or plant) name.  After all, they are stuck with it for all time.  Nonetheless, people can't help themselves and from time to time, you get some real crackers!  A fella by the name of Arnold Menke at USDA put together a list of them, so did Doug Yanega.  Here's some of my favourites.  Which do you like best?

Agra vation (a beetle)
Colon rectum (another beetle)
Ba humbugi (a snail)
Aha ha ( a wasp)
Lalapa lusa (a wasp)
Leonardo davinci (a moth)
Abra cadabra (a clam)
Gelae baen, Gelae belae, Gelae donut, Gelae fish, and Gelae rol (all types of fungus beetles)
Villa manillae, Pieza kake and Reissa roni  (bee flies)
Ytu brutus (a beetle)

and my personal favourite (whenever possible):
La cerveza (a moth)

I'll drink to that - here's cheers to creative taxonomists!


Your calamari wants a flat screen

ResearchBlogging.orgOctopuses and their relatives are just incredible animals.  Not only do they manage to coordinate hundreds of suckers on 8 arms simultaneously without tripping over themselves (I can't even remember what I ate for breakfast) and have the most advanced eyes in the invertebrate world, but they can do other cool stuff like eat sharks,  fit through holes much smaller than themselves, use tools and learn from each other.  Now a new study has shown that they can tell the difference between regular TV and HD.  How did they determine this?  Simply, as it turns out.  The octopus show no reaction to footage of other octopus or crabs shown to them on regular TV screens.  When shown real crabs or crab footage in hi-def, however, the octopus lunged as if to attack the hapless decapod (video link).  In other words, octopus can tell the difference between real and imagery, if the image is not of high enough quality.
The explanation appears to lie not in the resolution of the screen (how small the pixels are) so much as how fast the picture can be draw and redrawn on the screen.  The picture on a TV screen is constantly being created line-by-line from the top of the screen in a process called rastering.  We don't perceive this rastering because it happens faster than we can see; faster than our "critical flicker frequency".  Well, not everyone has the same critical flicker frequency, and nor do all televisions have the same rastering rate.  Most hi-def TV's have a higher frequency (120 or even 240Hz, or times-per-second).  It may be that low-def TV is below the octopus critical flicker, but hi-def is above it.  In this way, they would see a sort of strobing effect in normal footage, but the hi-def stuff would look like, well, a crab.
The authors also noticed that the octopus showed "episodic personality", which is to say they were interested in the crab (or footage of another octopus) some times but not others.  I'm not sure I would class that as evidence of personality, just a less-than-100%-predictable response to a stimulus.  Having said that, ocotpus do have obvious personalities, which is one reason people are so drawn to them.  That, and sweet chilli sauce...

Pronk, R., Wilson, D., & Harcourt, R. (2010). Video playback demonstrates episodic personality in the gloomy octopus Journal of Experimental Biology, 213 (7), 1035-1041 DOI: 10.1242/jeb.040675


Octopus using tools

I couldn't let this go by.  My wife is something of a behavioural expert and a very good animal trainer, and we have often discussed how intelligent octopus are.  In that respect this isn't news, but the tool use is pretty cool and very exciting for behavioural scientists, what with them being invertebrates and all (the octopus that is, not the scientists...).