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2011-07-27

Nyuni - Batch #4 - boat round the island.

Various of us took one of the boats for a trip round the island. Nothing particularly spectacular to be seen form the boat, but once we were back into the lagoon, I went over the side to a patch reef that the boat-master indicated.
First thing to draw my attention was a patch of "Needle Sea Urchins" amongst corals (a species probably in Acropora, but I won't hang for that). Just pretty.
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While photographing that, I noticed that, for reasons still unclear, the sea urchins were congregating in particular patches. I don't know why ; I guess that there was something about the substrate that they liked there, but not elsewhere.













A brilliant blue+yellow fish was shoaling in the area.


















They particularly liked gathering around a large lobster pot on the reef, but they would also follow each other around over the reef edge too (where I wasn't going to go on ALP, Available Lung Power).
















After much hunting around on the net, I identified these as Yellowtail Fusiliers ; they shoaled with Twinstripe Fusiliers, which are only marginally less colourful. (Though this picture doesn't do the colour of the two yellow stripes justice ; I'm going to have to start using the colour balance tool for these duck dives to 3 or 5m.


















On my next dive, I spotted this "different" branching coral - which I can't identify.



















I've spent more time than I care to think about staring at this sort of assemblage of fossils and sediments ("wackestone to packstone", anyone?), but even so it was very nice to see these environments "in the flesh" as it were.

Nyuni - batch #3









Attempted to swim out from east end of the island to the eastern barrier/ fringing reef. Didn't get there. Partly through meeting this "cleaner station" (?) on the reef top. Organisms : "brain coral" (fewer zombie jokes, please) ; sea urchins (one of 3 genera seen on this swim ; others have more robust spines in two different colours (which may or may not be important) ; the yellow-black striped fish is, I think, a "Sergeant Major" (distinguished from the Convict Surgeonfish by relatively thicker black bars, and the body being yellow above and silver-white below) ; and the blobby B+W fish looks like it should be a Clown Fish (stars of "Nemo: Found", or some film like that) ... and indeed, visually it looks like a
"Saddleback clownfish". But that's a Western Indian Ocean species (not a problem itself ; coelacanths went one way, why couldn't something go the other way?, AND it should have a yellow mouth. Looking on the web ... there seem to be several closely similar species. And considerable intra-specific variation. So I'm not going to worry too much more about it.

Next! Well , after leaving the "cleaning station, I carried on out toward the reef front. But things were getting gradually more interesting as the water very slowly got deeper. After 50mins of travel, I got to this area where - hard to see in static photos - there were in the order of 30 more "LBJ" shoaling around in the seaweed. Obviously, the brownness works for camouflage.
Then ... horror of horrors ... the battery went flat!
Well there's a lesson : if swimming OUT to somewhere, try to do it on your back to avoid being distracted.


And that's me caught up to today!

2011-07-25

Nyuni, Tz, Batch #02 : Today, I swims with zee fishes

Title to be spoken in a menacing gangster-esque voice. "Sung Soprano", or something like that.


Went for a bit of a swim yesterday, but there is quite a current around high tide on the headland of the island, so I moved round to the south. Between wind and current there was quite a chop going - 30cm or more, which made snorkelling a less than comfortable occupation.
Fair amount of sea life, but I made no attempt at getting out to the reef margin - I'm really regretting not bringing my fins to Nyuni, but may have a Cunning Plan (TM, Pat.Pending).


Snorkelling in very shallow water, I was being constantly buffeted by the swell. So when I tried videoing things, the steadiness wasn't. No point in even thinking about shrinking them to something postable.
Firstly, these lobate or fan-shaped organisms (a major component of the biota :


I've named the file as if they're seaweed, but the more I think about it, the less I'm convinced. The colour isn't wrong for some algae (red photosynthetic organisms are nothing new), but the paleness of the colour ... doesn't make sense. They're thick enough to be more-or-less opaque, so why not absorb all the light you can in your waveband? Besides, I'm pretty sure that I've seen something similar common in UK waters, but can't find it in online compendia of algae ... therefore, it's probably not an alga. Could they be Bryozoa? But my memory tells me that Bryozoa have stiff meshes as a water filtering device. Rather like a stalk-less crinoid. Which doesn't really fit for these. [SHRUGs ; moves on]

I can't find these yellow-bar-fish in any online references either, but that's probably just the crudity of my search techniques. These wriggly things that go under the name of "alive fossils" don't really attract my attention until they've got fossilized. But this couple of "yellow-bar-fish" seemed to be defending the seabed hole against big ugly me. So once I'd taken a few photos, I moved on. (Without fins, holding station in chest-deep water against around a 1m/s current was a noisy affair.) There's a flashy fish in shot as well - brilliant reflections of "structural colour". I don't recognise either species.


THIS is what happens to people who look (too closely) at the small stuff. (American Scientist, v99#4 p311)
"Wow. A tube worm actually emerging from it's tube! Isn't this the most exciting thing you've ever seen?"
--
Aidan Karley

2011-07-24

Fun with Fysiks

A review of this book ("How the Hippies Saved Physics : Science, Counterculture, and the Quantum Revival" by David Kaiser, 2011) in this bi-month's American Scientist by David Woit starts with a personal (Woit's) anecdote about the problems of getting a physics job in the mid-1980s :
[a sizeable group of physicists] appeared to have managed to pursue scientific research by dropping out of academia and adopting a countercultural lifestyle that included soaking in hot tubs at Big Sur, engaging in Tantric sex, hanging out at North Beach cafes and taking psychedelic drugs. Some of them had gotten rich writing books that mixed physics with various kinds of mysticism. I wasn't very interested in the mysticism part, but I figured that I could handle the rest.
[Edit : link to article]
Needless to say, I was reading this while towelling myself off after a nice 3/4 hour swim in the Indian Ocean, collecting a nice specimen that got me thinking all sorts of interesting palaeontological thoughts on the topic of ecdysis, enjoying a cup of coffee, and thinking about ambling back up to the drilling rig to engage in my paid work for the day.

I think I can handle the tribulations of this job too!

--
Aidan Karley

Batch #01 from Tanzania

I've arrived on the sunny island of Nyuni, but am stuck behind various firewalls, so have to post indirectly to get my pictures to the outside world.
To quote my earlier email :
"Bloody Internet here is as wobbly as whatever. And lots of stuff is blocked too.
Attached is a batch of photos ... Needless to say, these are drastically-shrunken versions of the original photos, as the "-small" suffix in the file names might give away.
First image :
2011-07-21 11-28 Tanzania, flight over Rufiji delta, This is Kiechuru inlet, rivermouth bars forming with breakers DSCF1496-small

I've made a horrible mess of crossing the links and the photo names, but I'll know better in future posts. I'm sure one can figure out what it's meant to do, but it is now lunch time and my belly is growling.