July 2010 Archives

Lobster molt

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Meanwhile, back at the lab...

As Cameron heads back out to sea with the full suite of instrumentation, Rebecca, Pete and I work tirelessly to pull together the data we've collected over the past fortnight.  Today I was sorting through our optical data for vertical migration patterns--which I will chronicle later--when Meredyth (from the education team) burst in exclaiming, "What do you know about lobsters molting!?"

Alas, my meager knowledge of decapod molting comes from the accounts of the late Stubb, an eloquent blogging crayfish.  Nevertheless, we gathered the crew together, along with a loose assortment of equipment, and cobbled together a video system for documenting this fascinating phenomenon.

These images diagram our video system, composed of sticks, tape, and bungee cords.  The 95 second video below shows a time-lapse of this mesmerizing event, from almost the beginning of ecdysis until the teneral lobster emerges from its exoskeleton.

Ples My apologies for the choppy footage.  Filming continues even as I compose this, and we will post the full video later.  Fascinated readers may also enjoy this nice animation of a molting cicada.

Nick Record, signing off.

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I think these videos speak for themselves.

the presentation:

fancy snack from peter stetson on Vimeo.


the naming:

copepod sur la petite four from peter stetson on Vimeo.

just how good is it?

One for me, one for the birds from peter stetson on Vimeo.

mola mola mola mola mola

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Described as "stray visitors to the gulf" by Bigelow and Schroeder, the Mola mola, or ocean sunfish, is a large fish readily noticed by it's floppy dorsal fin when at the surface. They generally move pretty slowly, although I'm told (Bigelow and Schroeder, and personal communication with others) that they can really move when they want to. We came across one on day 5 of the cruise, in the vicinity of Jordan's basin. They like to eat Ctenophores and other jellies.

Top view of the mola as it approached the boat:
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You can see in the pictures below, how it moves it's dorsal and anal fins to swim:

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(in photo above: dorsal fin extended, anal fin pointing towards the camera)

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(in this picture, the dorsal fin is at the surface bent toward us, and the anal fin is extended downward)



basking with a basking shark

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On day 3 of the cruise, between stations 5 and 6 (between the offshore most x's on the second transect from the right in Nick's map - see post below) we spotted a basking shark. Basking sharks can be quite large and scary looking, but, like whale sharks, they eat plankton. Which means you don't have to worry about one eating you. I had an underwater housing onboard, and the day was calm, so I asked the captain if I could jump in and try to get an underwater shot. I was in luck, the captain gave a green light to "operation swim with a shark" and I rushed to set-up the gear and don my wetsuit.
 I jumped in the water off the diving platform on the transom, fired off a test shot (the greater shearwater from below - also included is a greater shearwater shot from above. shots taken on separate days) and started swimming as fast as I could toward the shark.
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     You can see from the shearwater "from below" shot, the water is beautiful. It's was ~400 feet deep, too. When you're looking down or in any direction other than up, it's all blue... unless you're within 20 or so feet of something.  This meant as I swam toward the ~25' shark, I was surrounded by immense blue and I wouldn't see anything in the water until I was right there next to it. My heartrate was flying.
     I was pretty far from the shark when I got in the water and was working hard to catch up. My thoughts were split between, "I hope I can get a shot" and "I hope I don't stumble upon this massive creature in the middle of the Gulf of Maine... to realize I mis-identified the species..."
     The folks on deck were kind enough to sing the JAWS theme when the basking shark went below the surface for a bit. Thanks guys.

     After a serious effort in the water, everyone on deck informed me that after I reached a certain point, the shark was swimming away from me just as quickly as I was approaching, and we had stations to finish. So, no underwater shot of a basking shark, this time. But Cameron got a nice shot from the deck of me swimming toward the shark, camera in tow, with a nice sized fin in the background.

Too add some size perspective, I've also included two shots of the shark shot from the deck before I jumped in. It was too big to fit in the frame of just one shot. In the first, you can make out the pectoral fin: the white markings below the surface. The nose and body of the shark are detectable by the subtle change in color from the water.
The second shot is easier to make out: The dorsal fin on the left, and the caudal fin just below the surface, stirring  the water on the right.

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Swimming with the basking shark (above).

Dorsal and caudal fins seen from the boat (below).
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Enjoy. I'll put up more pictures of other cruise adventures over the next week.

Hasty update

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Each night, as we dock further and further downeast, wireless resources dwindle.  One might find oneself quailed down against a warehouse, between a flickering coke machine and a trash bin, dodging raccoons, just to get a link to the grid.

So, I'll be brief. 

We continue to pound out our transects, as the attached cartography indicates.  We have only a handful of stations left.  Depending on how we prioritize our remaining time, we may or may not hit all of them.  In either case, we've had our most successful cruise of this project, covering a much broader area than in previous years.  Wildlife has been modest, though we have had cameos from fin, sei, and humpback whales, basking sharks and mola molas, and our old chum, the Atlantic puffin.  Expect Pete to follow up with photos, when we reach ample wireless.

Nick Record, signing off.

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Dockside monstrosities

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We arrived in Stonington on Monday evening, after four straight days of good weather.  We'd knocked off four of our six transects already, and were feeling refreshed after a five-minute shower at the marina and some ice cream in town.  Not ready to call it a night, still with the thirst for scientific endeavor unsated, Pete and I poked our heads over the side of the dock to explore the ecosystem there.

A dockside ecosystem is a fascinating universe.  Small crabs were picking barnacles off the pilings, slinking away as we peered into the foggy black pool.  A headlamp illuminated a column of water that reached only a few inches in, before running into a wall of dense suspended sediment.  At first, we saw only specks.  We quickly noticed that some of the specks were moving--copepods.  Soon our patch of light was teeming and skittering with the little bugs, too numerous to count.

As Pete snapped photos, larger figures began to emerge from the shadowy border around our copepod city.  Mysid shrimp, zipping through the cloud of copepods, and disappearing into the dark.  Then other, larger crustaceans, eyes glowing in our light, each one dwarfing the last, until they were the size of fish.  Pete tried to catch one in a sieve, but it leapt from the water, and skipped ten feet along the surface to its escape.  And below those, just beyond the reach of the lamp's beam, still larger, ominous outlines glided silently by in a hazy blur.

Before the larger, man-eating crustaceans could creep in to catch us unawares, we were able to collect some interesting specimens to view on board in the lab.  Shown below are a couple of images of a caprellid amphipod--the skeleton shrimp.    This otherworldly creature latches on to other organisms with its rear legs, and snatches at passing prey with its (relatively speaking) massive claws.  We captured some eerie video of our skeleton shrimp squirming around the dish, gobbling up copepods one by one.  I'll post that later.  Meanwhile, here are a couple of stills.  

After a thrilling night of exploring the dockside ecosystem, we released all of the creatures back into the ocean.  To their freedom.  Except of course for the hoards of copepods that were mercilessly slaughtered by the skeleton shrimp.

Nick Record, signing off.
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Day 1: well-oiled machine

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This is the third year for Ecosystem Modeling and Biological Oceanography labs' zooplankton sampling cruise, and this is the first time that I've managed to get on the boat.  I was there to practice whale surveys and to test the hydrophone.  Since there were no whales (well, one whale) the most interesting part of the trip was watching the team do its thing.  After three years, Becky, Nick, Pete, and Cameron have developed into an oceanographic sampling force.

As Nick documented, the cruises is divided into a series of transects that run perpendicular to shore.  Along each transect, we've specified several stations where the actual samples are taken.  The first step at any station is to lower the CTD instrument to near the bottom.  The instrument has three sensors.  The "C" stands for conductivity and this sensor measures how easily an electrical current can travel through the water. The more dissolved in the water, the easier the current can flow, so the conductivity sensor measures the salinity of the water. The "T" stands for temperature, and you all know what that measures.  Together, salinity and temperature determine the density of the water.  "D" stands for depth, and by measuring all three together, we can learn how the temperature and salinity change from the surface to the bottom.  This year, the Bio-Oce lab has added a PAR sensor to the CTD.  This sensor measures that amount of Photosynthetically-Active Radiation at each depth--basically, how far light reaches into the ocean.  In addition to being important for photosynthesis, visual predators like fish need light to see their prey,

After the CTD comes the main event, the ring net tows.  The ring net is actually two nets bolted together.  These are also lowered to the bottom and then pulled back up.  Water and plankton enter the mouth of the net.  The water goes out, but the plankton are collected.  We (meaning Becky and Cameron) will then identify and count the plankton. In order to determine the density of plankton (number per cubic meter of water), we need to know how much water passes through the net. Each net is equipped with a flow meter.  The tow begins with two people--usually Pete and Cameron, calling out the numbers on each flow meter.  
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The net is then lowered into the water.  The crew member running the winch monitors the depth of the net by the amount of wire payed out.  When the net comes up, two people guide the nets on to the deck.  They read out the numbers on the flow meters and then hose them down to make sure all the plankton are washed down to the cod-end.  Then, the cod ends are unclipped and the contents are dumped onto a sieve.  
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The cod ends are rinsed and dumped a few more times.  Then the stuff on each sieve is dumped into a jar containing formalin (a preservative).  

The last activity at the station is the Laser Optical Plankton Counter (LOPC) that Nick's been writing about.  This uses lasers to detect plankton and estimate their size and shape.  The LOPC allows us to get an idea of whether the plankton collected in the nets were packed into a few dense layers or spread out over a large range of depths.


The krill handoff

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Day two. 

A request came in from Steve Shema at Bigelow Labs for live krill.  Being the only sampling boat in krill waters, we were quick to respond in affirmative.

Krill are difficult to capture with ring nets.  It requires modifying the cod end of the net so as not to damage the critters.  They're also evasive to begin with, and can swim fast enough to avoid nets.  After an intense and thrilling pursuit, we pulled in our nets with excitement.  We were lucky enough to haul in a cooler full, and so we headed into Boothbay with our catch.

Transferring a scientific payload--whether it be nuclear fuel rods, top-secret digital codes, or krill--is always the stuff of action movies.  We packed each individual krill into its own glass jar with ambient seawater to keep the payload safe.  We rendezvoused with Dr. Shema on the open water, and passed off each jar, as you can see in the photo below.

The transaction was a success, and now the krill are headed to the lab for experimentation.  Dr. Shema will determine exactly what makes these krill tick.  What stimulates them?  What motivates them?  When they encounter something, how do they decide whether to flee from it, eat it, or mate with it?  We look forward to his results.

Nick Record, signing off.

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night at the dock

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A quick update before we leave land and the wireless at the UNH marine station dock.
Here's a picture of nick relaxing on one of the bunks. My bunk is right next to him, where the blue sleeping bag is. There are also 4 other bunks that appear, at least partially, in this photo. Spacious! Despite the close quarters, the gentle rocking of the boat makes for a good sleep.

I think Andy is going to post about yesterday, so I'll keep this short and hope it uploads before we leave the dock.

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DMR cruise 2010

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It's time again for our July cruise.  We head out on Friday for a full tour of coastal Maine, unveiling the secrets of the planktonic community.  The image below shows our proposed cruise track.  Last year we called it the "VOLT" cruise, because the cruise track spelled the word volt.  This year, I'm not sure what it spells.  Something like OWAUG.

Last year's cruise was a great one, with lots of interesting fauna and some bioluminescence.  You can read up on it here.  We'll do our best to blog this year's cruise as well, when we're on the grid.  It promises to be good, with a new boat, hopefully some deep stations and downeast stations, and appearances by the PIs listening for whales.  Stay tuned.

Nick Record, signing off.

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Celebration at sea

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This weekend, just in case you missed it, was the fourth of July. It's all very well and good celebrating it at home, with a barbeque and a fireworks display, but how do you celebrate when you are on a ship in the middle of the Bering Sea, miles from anything?

Simple! You have a barbeque and some fireworks! Only this way, the fireworks were expired flares that had to be "disposed of". It's pretty cool to see how parachute flares launch themsleves in to the sky and then light up, or to watch people parading round with signal flares doing terrible impressions of the Statue of Liberty.

Anyway, just because we're scientists at sea, doesn't mean that we don't allow some time for fun...

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The back deck BBQ

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A demonstration of signal and parachute flares - AKA shipboard fireworks!

About this Archive

This page is an archive of entries from July 2010 listed from newest to oldest.

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